List of abbreviations

Introduction

1. General part

1.3 Tectonic structure

1.4 Oil and gas content

2.Special part

3.Design part

3.3 Apparatus and equipment

3.4 Methodology for processing and interpreting field data

4.Special task

4.1 AVO analysis

4.1.1 Theoretical aspects of AVO analysis

4.1.2 AVO classification of gas sands

4.1.3 AVO crossplotting

4.1.4 Elastic inversion in AVO analysis

4.1.5 AVO analysis in an anisotropic environment

4.1.6 Examples of practical application of AVO analysis

Conclusion

List of sources used

stratigraphic seismic field anisotropic

List of abbreviations

GIS-geophysical surveys of wells

MOB-method of the reflected wave

CDP method total point depth

Oil and gas complex

Oil and Gas Region

NGR-gas-bearing region

OG-reflecting horizon

CDP-common depth point

PV item explosion

PP-point of reception

s/n-seismic party

hydrocarbons

Introduction

This bachelor's thesis provides for the substantiation of CDP-3D seismic surveys in the Vostochno-Michayuskaya area and consideration of AVO-analysis as a special issue.

Seismic surveys and drilling data carried out in recent years have established the complex geological structure of the work area. Further systematic study of the East Michayu structure is necessary.

The work provides for the study of the area in order to clarify the geological structure of the CDP-3D seismic survey.

Bachelor's thesis consists of four chapters, introduction, conclusion, set out on pages of text, contains 22 figures, 4 tables. The bibliographic list contains 10 titles.

1. General part

1.1 Physical and geographical outline

The Vostochno-Michayuskaya area (Figure 1.1) is administratively located in the Vuktyl region.

Figure 1.1 - Map of the area of ​​the East Michayu area

Not far from the study area is the city of Vuktyl and the village of Dutovo. The area of ​​work is located in the Pechora River basin. The area is a hilly, gently undulating plain, with pronounced valleys of rivers and streams. The work area is swampy. The climate of the region is sharply continental. Summers are short and cool, winters are harsh with strong winds. Snow cover is established in October and disappears at the end of May. In terms of seismic work, this area belongs to the 4th category of difficulty.

1.2 Lithological and stratigraphic characteristics

The lithological and stratigraphic characteristics of the section (Figure 1.2) of the sedimentary cover and foundation are given based on the results of drilling and seismic logging of wells 2-, 4-, 8-, 14-, 22-, 24-, 28-Michayu, 1 - S. Savinobor, 1 - Dinyu-Savinobor.

Figure 1.2 - Lithological and stratigraphic section of the Vostochno-Michayuskaya area

Paleozoic erathema - PZ

Devonian - D

Middle Devonian - D 2

Terrigenous formations of the Middle Devonian, Givetian Stage unconformably overlie the carbonate rocks of the Silurian sequence.

Deposits of the Givetian stage with a thickness of wells 1-Dinyu-Savinobor 233 m is represented by clays and sandstones in the volume of the Stary Oskol superhorizon (I - in the reservoir).

Upper Devonian - D 3

The Upper Devonian is distinguished in the volume of the Frasnian and Famennian stages. Fran is represented by three sub-tiers.

The deposits of the Lower Frasnian are formed by the Yaran, Dzhier, and Timan horizons.

Frasnian - D 3 f

Upper Franzian Substage - D 3 f 1

Yaransky horizon - D 3 jr

The section of the Yaran horizon (88 m thick in Q. 28-Mich.) is composed of sandy layers (from bottom to top) V-1, V-2, V-3 and interstratal clays. All layers are not consistent in composition, thickness and number of sand interlayers.

Jyers skyline - D 3 dzr

Clayey rocks occur at the base of the Dzhyer horizon, and sandy beds Ib and Ia are distinguished higher along the section, separated by a clay unit. The thickness of the jier varies from 15 m (KV. 60 - Yu.M.) to 31 m (KV. 28 - M.).

Timan horizon - D 3 tm

Deposits of the Timan horizon, 24 m thick, are composed of clayey-siltstone rocks.

Middle Fransian Substage - D 3 f 2

The Middle Fransian substage is represented in the volume of the Sargaev and Domanik horizons, which are composed of dense, silicified, bituminous limestones with black shale interbeds. The thickness of the sargay is 13 m (borehole 22-M) - 25 m (borehole 1-Tr.), domanik - 6 m in the well. 28-M. and 38 m in well 4-M.

Upper Frasnian - D 3 f 3

The undivided Vetlasyan and Sirachoi (23 m), Evlanovsk and Liven (30 m) deposits form the section of the Upper Frasnian substage. They are formed by brown and black limestones interbedded with shale.

Famennian - D 3 fm

The Famennian stage is represented by the Volgograd, Zadonsk, Yelets, and Ust-Pechora horizons.

Volgograd horizon - D 3 vlg

Zadonsky horizon - D 3 zd

The Volgograd and Zadonsk horizons are composed of clay-carbonate rocks 22 m thick.

Yelets horizon - D 3 el

The deposits of the Yelets horizon are formed by organogenic-detrital limestone areas, in the lower part by strongly clayey dolomites, at the base of the horizon there are marls and calcareous, dense clays. The thickness of the deposits varies from 740 m (wells 14-, 22-M) to 918 m (well 1-Tr.).

Ust-Pechora horizon - D 3 up

The Ust-Pechora horizon is represented by dense dolomites, black argillite-like clays, and limestones. Its thickness is 190m.

Carboniferous system - C

Above unconformity deposits of the Carboniferous system occur in the volume of the lower and middle sections.

Lower Carboniferous - C 1

Visean - C 1 v

Serpukhovian - C 1 s

The lower section is composed of the Visean and Serpukhovian stages, formed by limestones with clay interbeds, with a total thickness of 76 m.

Upper Carboniferous Division - C 2

Bashkirian - C 2 b

Moscow Stage - C 2 m

The Bashkirian and Moscow stages are represented by clay-carbonate rocks. The thickness of the Bashkir deposits is 8 m (borehole 22-M.) - 14 m (borehole 8-M.), and in the well. 4-, 14-M. they are missing.

The thickness of the Moscow stage varies from 24 m (borehole 1-Tr) to 82 m (borehole 14-M).

Permian system - R

Moscow deposits are unconformably overlain by Permian deposits in the volume of the lower and upper sections.

Nizhnepermsky department - R 1

The lower section is presented in full and is composed of limestones and clayey marls, and in the upper part - clays. Its thickness is 112m.

Upper Permian department - R 2

The upper section is formed by the Ufa, Kazan and Tatar stages.

Ufimian - P 2 u

The Ufim deposits with a thickness of 275 m are represented by intercalation of clays and sandstones, limestones and marls.

Kazanian - P 2 kz

The Kazanian stage is composed of dense and viscous clays and quartz sandstones; there are also rare interlayers of limestones and marls. The layer thickness is 325 m.

Tatarian - P 2 t

The Tatarian stage is formed by terrigenous rocks 40 m thick.

Mesozoic erathema - MZ

Triassic system - T

The Triassic deposits in the volume of the lower section are composed of alternating clays and sandstones with a thickness of 118 m (well 107) - 175 m (well 28-M.).

Jurassic - J

The Jurassic system is represented by terrigenous formations with a thickness of 55 m.

Cenozoic erathema - KZ

Quaternary - Q

The section is completed by loams, sandy loams and sands of Quaternary age 65 m thick in well 22-M. and 100 m in well 4-M.

1.3 Tectonic structure

In tectonic terms (Figure 1.3), the area of ​​work is located in the central part of the Michayu-Pashninsky swell, which corresponds to the Ilych-Chiksha fault system along the foundation. The fault system is also reflected in the sedimentary cover. Tectonic disturbances in the work area are one of the main structural-forming factors.

Figure 1.3 - Copy from the tectonic map of the Timano-Pechora province

Three zones of tectonic faults were identified on the work area: western and eastern submeridional strike, and, in the southeast, the area of ​​northeast strike.

Tectonic disturbances observed in the west of this area can be traced along all reflectors, and disturbances in the east and southeast fade, respectively, in the Famennian and Frasnian times.

The tectonic faults in the western part are a graben-like trough. The sagging of horizons is most clearly seen on profiles 40990-02, 40992-02, -03, -04, -05.

The amplitude of the vertical displacement along the horizons ranges from 12 to 85 m. In plan view, the faults are oriented northwest. They stretch in the southeast direction from the reporting area, limiting the Dinya-Savinobor structure from the west.

Faults probably separate the axial part of the Michayu-Pashninskii swell from its eastern slope, which is characterized by continuous eastward subsidence of sediments.

In geophysical fields g, disturbances correspond to intense zones of gradients, the interpretation of which made it possible to single out a deep fault here, separating the Michayu-Pashninskaya zone of uplifts along the basement from the relatively lowered Lemyu step and being, probably, the main structure-forming fault (Krivtsov K.A., 1967 , Repin E.M., 1986).

The western zone of tectonic faults is complicated by northeast-trending feathering faults, due to which separate uplifted blocks are formed, as on profiles 40992-03, -10, -21.

The amplitude of the vertical displacement along the horizons of the eastern fault zone is 9-45 m (project 40990-05, station 120-130).

The southeastern fault zone is represented by a graben-like trough, the amplitude of which is 17-55 m (project 40992-12, site 50-60).

The western tectonic zone forms an elevated near-fault structural zone, consisting of several tectonically limited folds - Srednemichayuskaya, East Michayuskaya, Ivan-Shorskaya, Dinyu-Savinoborskaya structures.

The deepest horizon OG III 2-3 (D 2-3), on which structural constructions were made, is confined to the boundary between the Upper Devonian and Middle Devonian deposits.

Based on structural constructions, analysis of time sections and drilling data, the sedimentary cover has a rather complex geological structure. Against the background of the submonocline subsidence of the layers in the east direction, the East Michayu structure is distinguished. It was first identified as an open complication of the "structural nose" type with materials s\n 8213 (Shmelevskaya I.I., 1983). Based on the work of the 1989-90 season. (S\n 40990) the structure is presented as a fault fold, contoured along a sparse network of profiles.

Reporting data established the complex structure of the East Michayu structure. According to OG III 2-3, it is represented by a three-dome, linearly elongated, northwest-trending anticlinal fold, the dimensions of which are 9.75 × 1.5 km. The northern dome has an amplitude of 55 m, the central one - 95 m, and the southern one - 65 m. From the west, the East Michayu structure is limited by a graben-like trough of northwestern strike, from the south - by a tectonic fault with an amplitude of 40 m. In the north, the East Michayu anticline fold is complicated by an uplifted block (project nos. 40992-03), and in the south - a subsided block (projects 40990-07, 40992-11), due to feathering disturbances of the northeast strike.

To the north of the East Michayu uplift, the Middle Michayu near-fault structure was revealed. We assume that it closes to the north of the reporting area, where earlier work was carried out with / p 40991 and structural constructions were made along reflecting horizons in Permian deposits. The Middle Michayu structure was considered within the East Michayu uplift. According to the work with \ n 40992, the presence of a deflection between the East Michayu and Srednemichayu structures on the project 40990-03, 40992-02 was revealed, which is also confirmed by the reporting works.

In the same structural zone with the uplifts discussed above, there is the Ivan-Shorskaya anticline structure, identified by works s\n 40992 (Misyukevich N.V., 1993). From the west and south it is framed by tectonic faults. The dimensions of the structure according to OG III 2-3 are 1.75×1 km.

To the west of the Srednemichayuskaya, Vostochno-Michayuskaya and Ivan-Shorskaya structures are the South-Lemyuskaya and Yuzhno-Michayuskaya structures, which are affected only by the western ends of the reported profiles.

Southeast of the South-Michayu structure, a low-amplitude East-Tripanyel structure was revealed. It is represented by an anticline fold, the dimensions of which according to OG III 2-3 are 1.5×1 km.

In the western marginal part of the submeridional-trending graben in the north of the reporting area, small near-fault structures are isolated. To the south, similar structural forms are formed due to small tectonic faults of various strikes, which complicate the graben zone. All these small structures in the blocks lowered relative to the East Michayu uplift are united by us under the general name of the Central Michayu structure and require further seismic exploration.

Reference point 6 is associated with OG IIIf 1 at the top of the Yaran horizon. Structural plan of reflecting horizon IIIf 1, inherited from OG III 2-3. The dimensions of the East Michayu near-fault structure are 9.1 × 1.2 km, in the contour of the isohypse - 2260 m, the northern and southern domes are distinguished with an amplitude of 35 and 60 m, respectively.

The dimensions of the Ivan-Shorskaya near-fault fold are 1.7 × 0.9 km.

The structural map of OG IIId reflects the behavior of the base of the Domanik horizon of the Middle Frasnian substage. In general, there is an uplift of the structural plan to the north. To the north of the reporting area, the base of the domanik was exposed by well No. 2-Sev.Michayu, 1-Sev.Michayu at absolute elevations - 2140 and - 2109 m, respectively, to the south - in the borehole. 1-Dinyu-Savinobor at the mark - 2257 m. The East Michayu and Ivan-Shor structures occupy an intermediate hypsometric position between the North-Michayu and Dinyu-Savinobor structures.

At the level of the Domanik horizon, the feathering disturbance at Project 40992-03 fades out; instead of the uplifted block, a dome has formed, covering the adjacent profiles 40990-03, -04, 40992-02. Its dimensions are 1.9 × 0.4 km, the amplitude is 15 m. To the south of the main structure, to another feathering fault on project 40992-10, a small dome closes with an isohypse of -2180 m. Its dimensions are 0.5 × 0.9, the amplitude is 35 m. The Ivan-Shor structure is located 60 m below the East Michayu structure.

The structural plan of the OG Ik confined to the top of the carbonates of the Kungurian stage differs significantly from the structural plan of the underlying horizons.

The graben-like trough of the western fault zone on the time sections has a cup-like shape; in connection with this, the structural plan of the OG Ik was restructured. The shielding tectonic faults and the arch of the East Michayu structure are shifting to the east. The size of the East Michayu structure is much smaller than in the underlying deposits.

The tectonic disturbance of the northeast strike breaks the East Michayu structure into two parts. Two domes stand out in the contour of the structure, and the amplitude of the southern one is greater than that of the northern one and is 35 m.

To the south is the Ivan-Shorsky fault uplift, which is now a structural nose, in the north of which a small dome stands out. The fault is fading, screening the Ivan-Shor anticline in the south along the lower horizons.

The eastern flank of the South Lemew structure is complicated by a slight tectonic disturbance of the submeridional strike.

Throughout the area there are small rootless tectonic disturbances, with an amplitude of 10-15 m, which do not fit into any system.

Productive at the Severo-Savinoborsky, Dinyu-Savinoborsky, Michayusky deposits, the sandy reservoir V-3 is located below the benchmark 6, which is identified with OG IIIf1, by 18-22 m, and in the well. 4-Mich. at 30 m.

On the structural plan of the top of the V-3 formation, the highest hypsometric position is occupied by the Michayuskoye field, the northeastern part of which is confined to the South Lemyu structure. The WOC of the Michayuskoye field runs at a level of - 2160 m (Kolosov V.I., 1990). The East Michayu structure closes with an isohypse - 2280 m, an uplifted block at a level of - 2270 m, a lowered block at the southern end at a level of - 2300 m.

At the level of the Vostochno-Michayu structure, to the south there is the Severo-Savinoborskoye field with OWC at a level of - 2270 m. 1-Dinyu-Savinobor is defined at the level of - 2373 m.

Thus, the East Michayu structure, which is located in the same structural zone as the Dinya-Savinobor one, is much higher than it and may well be a good trap for hydrocarbons. The screen is a graben-shaped trough of northwestern strike of an asymmetric shape.

The western side of the graben runs along low-amplitude normal faults, except for some profiles (projects 40992-01, -05, 40990-02). Violations of the eastern side of the graben, the most subsided part of which is located at pr. 40990-02, 40992-03, are high-amplitude. According to them, the alleged permeable formations are in contact with the Sargaev or Timan formations.

To the south, the disturbance amplitude decreases and, at the level of profile 40992-08, the graben closes in the south. Thus, the southern periclinal of the Vostochno-Michayuskaya structure is in the lowered block. In this case, the V-3 formation can contact, by disturbance, with interstratal clays of the Yaran horizon.

To the south in this zone is the Ivan-Shorskaya near-fault structure, which is crossed by two meridional profiles 13291-09, 40992-21. The absence of seismic profiles across the strike of the structure does not allow us to judge the reliability of the object identified by s\n 40992.

The graben-like trough, in turn, is broken by tectonic faults, due to which isolated uplifted blocks are formed within it. They are named by us as the Central Michayu structure. On profiles 40992-04, -05, fragments of the East Michayu structure were reflected in the lowered block. There is a small low-amplitude structure at the intersection of profiles 40992-20 and 40992-12, which we named East Trypanyelskaya.

1.4 Oil and gas content

The area of ​​work is located in the Izhma-Pechora oil and gas region within the Michayu-Pashninsky oil and gas region.

At the fields of the Michayu-Pashninsky region, a wide complex of terrigenous-carbonate deposits from the Middle Devonian to the Upper Permian, inclusive, is oil-bearing.

Near the area under consideration are the Michayuskoye and Yuzhno-Michayuskoye deposits.

Deep prospecting and exploratory drilling, carried out in 1961 - 1968. at the Michayuskoye field, wells No. 1-Yu. tiers. The deposit is layered, arched, partially waterfowl. The height of the deposit is about 25 m, the dimensions are 14 × 3.2 km.

At the Michayuskoye field, commercial oil-bearing capacity is associated with sandy formations at the base of the Kazanian stage. For the first time, oil from the Upper Permian deposits at this field was obtained in 1982 from well 582. The oil-bearing capacity of the R 2 -23 and R 2 -26 formations was established by testing in it. Oil deposits in the P 2 -23 formation are confined to sandstones, presumably of channel genesis, stretching in the form of several strips of submeridional strike through the entire Michayuskoye field. Oil-bearing capacity is established in the well. 582, 30, 106. Light oil, with a high content of asphaltenes and paraffin. The deposits are confined to a trap of a structural-lithological type.

Oil deposits in the layers P 2 -24, P 2 -25, P 2 -26 are confined to sandstones, presumably of channel genesis, stretching in the form of strips through the Michayuskoye field. The width of the strips varies from 200 m to 480 m, the maximum thickness of the seam is from 8 to 11 m.

Reservoir permeability is 43 mD and 58 mD, porosity is 23% and 13.8%. Starting stocks cat. A + B + C 1 (geol. / izv.) are equal to 12176/5923 thousand tons, category C 2 (geol. / izv.) 1311/244 thousand tons. Remaining reserves as of 01.01.2000 in categories А+В+С 1 are 7048/795 thousand tons, in category С 2 1311/244 thousand tons, cumulative production is 5128 thousand tons.

The Yuzhno-Michayuskoye oil field is located 68 km northwest of the city of Vuktyl, 7 km from the Michayuskoye field. It was discovered in 1997 by well 60 - Yu.M., in which an oil inflow of 5 m 3 /day was obtained from the interval 602 - 614 m according to PU.

The reservoir oil deposit, lithologically shielded, confined to the sandstones of the P 2 -23 formation of the Kazanian stage of the Upper Permian.

The depth of the formation roof in the crest is 602 m, the reservoir permeability is 25.4 mD, and the porosity is 23%. The oil density is 0.843 g/cm 3 , the viscosity in reservoir conditions is 13.9 MPa. s, the content of resins and asphaltenes 12.3%, paraffins 2.97%, sulfur 0.72%.

Initial stocks are equal to residual stocks on 01.01.2000. and amount to 1,742/112 thousand tons for categories A+B+C, and 2,254/338 thousand tons for category C.

At the Dinyu-Savinoborskoye field, an oil deposit in terrigenous deposits of the V-3 formation of the Yaran horizon of the Frasnian stage of the Upper Devonian was discovered in 2001. well 1-Dinyu-Savinobor. In the well section, 4 objects were tested (Table 1.2).

When testing the interval 2510-2529 m (formation V-3), an inflow (solution, filtrate, oil, gas) was obtained in the amount of 7.5 m 3 (of which oil - 2.5 m 3).

When testing the interval 2501-2523 m, oil was obtained with a flow rate of 36 m 3 / day through a choke with a diameter of 5 mm.

When testing the overlying reservoirs of the Yaran and Dzhyer horizons (layers Ia, Ib, B-4) (test interval 2410-2490 m), no oil shows were observed. A solution was obtained in a volume of 0.1 m 3.

To determine the productivity of the V-2 formation, a test was carried out in the interval of 2522-2549.3 m. As a result, a solution, filtrate, oil, gas and formation water in the amount of 3.38 m 3 were obtained, of which 1.41 m3 were due to leaks in the tool 3, inflow from the reservoir - 1.97 m 3.

When studying the Lower Permian deposits (test interval 1050 - 1083.5 m), a solution in the volume of 0.16 m 3 was also obtained. However, in the process of drilling, according to the core data, signs of oil saturation were noted in the indicated interval. In the interval 1066.3-1073.3 sandstones are inequigranular, lenticular. Oil effusions were observed in the middle of the interval, 1.5 cm - a layer of oil-saturated sandstone. In the intervals of 1073.3-1080.3 m and 1080.3-1085 m, interlayers of sandstones with oil effusions and thin (in the interval of 1080.3-1085 m, core removal 2.7 m) interlayers of polymictic oil-saturated sandstone are also noted.

Signs of oil saturation according to the core data in the well 1-Dinyu-Savinobor were also noted in the top of the member of the Zelenetsky horizon of the Famennian stage (core sampling interval 1244.6-1253.8 m) and in layer Ib of the Dzhiersky horizon of the Frasnian stage (core sampling interval 2464.8-2470 m).

In reservoir V-2 (D3 jr) there are sandstones with hydrocarbon odor (core sampling interval 2528.7-2536 m).

Information about the results of testing and oil shows in the wells is given in tables 1.1 and 1.2.

Table 1.1 - Well testing results

			formation.	Test results.
				1 object. Mineralized water inflow Q=38 m 3 /day according to PU.
				2 object. Min. water Q \u003d 0.75 m 3 / day according to PU.
				3 object. No inflow received.
				1 object. Min. water Q \u003d 19.6 m 3 / day.
				2 object. Minor inflow min. water Q \u003d 0.5 m 3 / day.
				1 object. IP reservoir min. water with an admixture of the filtrate solution Q=296 m 3 /day.
				2 object. IP reservoir min. water with the smell of hydrogen sulfide, dark green.
				3 object. Min. water Q \u003d 21.5 m 3 / day.
				4 object. Min. water Q \u003d 13.5 m 3 / day.
				In the column, the free flow of oil is 10 m 3 /day.
				Oil Q=21 t/day at 4 mm choke.
				1 object. Industrial oil inflow Q=26 m 3 /day on a 4 mm choke.
				1 object. Oil gusher Q \u003d 36.8 m 3 / day on a 4 mm fitting.
				Oil inflow 5 m 3 /day according to PU.
				3, 4, 5 objects. Weak oil inflow Q \u003d 0.1 m 3 / day.
				IP oil 25 m 3 in 45 min.
				The initial oil flow rate is 81.5 tons/day.
				5.6 m 3 of oil in 50 minutes.
				The initial oil flow rate is 71.2 tons/day.
				Oil Q beg. =66.6 t/day.
				Oil inflow Q=6.5 m 3 /hour, P pl. =205 atm.
				The initial oil flow rate is 10.3 t/day.
				Oil Q \u003d 0.5 m 3 / hour, R pl. =160 atm.
				Mineral water with films of oil.
				Solution, filtrate, oil, gas. Inflow volume 7.5 m 3 (of which oil 2.5 m 3). R sq. =27.65 MPa.
				Solution, filtrate, oil, gas, produced water. V pr. \u003d 3.38 m 3, R pl. =27.71 MPa.
				Oil flow rate 36 m 3 /day, diam. PCS. 5 mm.
				No inflow received.

Table 1.2 - Information about oil shows

		Interval		The nature of manifestations.
				Limestones with oil smears in caverns and pores.
				Films of oil during drilling.
				According to GIS, oil-saturated sandstone.
				Limestone with suture joints filled with bituminous clay.
				Oil-saturated core.
				Alternation of oil-saturated sandstones, siltstones, thin layers of clays.
				Oil-saturated core.
				Oil-saturated polymictic sandstones.
				Water-saturated sandstones.
				Oil-saturated limestones.
				The limestone is cryptocrystalline, with rare cracks containing bituminous material.
				Argillite, limestone. Mid-interval oil effusion; 1.5 cm - layer of oil-saturated sandstone.
				The sandstone is inequigranular and fine-grained with oil exudates.
				Limestone and individual layers of oil-saturated sandstone.
				Alternation of dolomite and dolomitic limestone with oil exudates.
				Argillite with effusions and films of oil along cracks; siltstone with the smell of oil.
				Alternation of sandstones with effusions and oil stains.
				Alternation of sandstones with HC odor and mudstones with bitumen interspersed.
				Fine-grained sandstones with hydrocarbon odor, bituminous along fissures.
				Limestone with oil exudates and hydrocarbon smell; sandstone and mudstone with oil exudates.
				Dense and strong sandstone with a hydrocarbon smell.
				Alternation of quartz sandstone with hydrocarbon smell, siltstone and mudstone.
				Quartz sandstones with low hydrocarbon odor.

2. Special part

2.1 Geophysical work carried out in this area

The report was compiled based on the results of reprocessing and reinterpretation of seismic data obtained in the northern block of the Dinyu-Savinobor field in different years by seismic crews 8213 (1982), 8313 (1984), 41189 (1990), 40990 (1992), 40992 (1993) according to the agreement between Kogel LLC and Dinyu LLC. The methodology and technique of work is shown in Table 2.1.

Table 2.1 - Information about the methodology of field work

			" Progress"	"Progress - 2"	"Progress - 2"
Observation system	Central	Central naya	flank	flank	flank
Source Options
	Explosive	Explosive	non-explosive"falling weight" - SIM	Non-explosive "drop weight" - SIM	Non-explosive "Yenisei - SAM"
Number of wells in a group
Charge amount
Distance between shots
Placement Options
multiplicity
Geophone grouping	26 joint ventures based on 78 m	26 joint ventures based on 78 m	12 joint ventures on a base of 25 m	11 joint ventures on the base of 25 m	11 joint ventures on the base of 25 m
Distance between PP
Minimum explosion-device distance
Maximum distance explosion-device

The Vostochno-Michayu tectonic-limited structure identified by the works s / p 40991 was transferred to drilling on the Lower Frasnian, Lower Famennian and Lower Permian deposits in 1993 s / p 40992. Seismic surveys were generally focused on the study of the Permian part of the section, structural constructions in the lower part of the section performed only on the reflecting horizon III f 1 .

To the west of the work area are the Michayuskoye and Yuzhno-Michayuskoye oil fields. The commercial oil and gas potential of the Michayuskoye field is associated with the Upper Permian deposits, the oil deposit is contained in the sandstones of the V-3 formation at the top of the Yaran horizon.

South-east of the Vostochno-Michayu structure in 2001, the 1-Dinyu-Savinobor well discovered an oil deposit in the Lower Frasnian deposits. The Dinyu-Savinobor and East Michayu structures are located in the same structural zone.

In connection with these circumstances, it became necessary to revise all available geological and geophysical materials.

The reprocessing of seismic data was carried out in 2001 by Tabrina V.A. in the ProMAX system, the volume of reprocessing was 415.28 km.

Pre-processing consisted of converting the data to the internal ProMAX format, assigning the geometry, and restoring the amplitudes.

Interpretation of the seismic material was carried out by the leading geophysicist I.Kh. Mingaleeva, geologist E.V. Matyusheva, category I geophysicist N.S. The interpretation was carried out in the Geoframe exploration system on the SUN 61 workstation. The interpretation included the correlation of reflective horizons, the construction of isochron, isohyps, and isopach maps. The workstation was loaded with digitized logs for wells 14-Michayu, 24-Michayu. To recalculate the logging curves to the time scale, the velocities obtained from the seismic logging of the corresponding wells were used.

The construction of isochron, isohyps, and isopach maps was carried out automatically. If necessary, they were corrected manually.

Velocity models needed to transform isochrone maps into structural ones were determined from drilling and seismic data.

The isohypse cross section was determined by the construction error. In order to preserve the features of the structural plans and for better visualization, the isohypse section was taken to be 10 m along all reflective horizons. Map scale 1:25000. Stratigraphic confinement of reflecting horizons was carried out according to seismic logging of wells 14-,24-Michayu.

6 reflecting horizons were traced on the area. Structural constructions were presented for 4 reflecting horizons.

OG Ik is confined to benchmark 1, identified by analogy with the Dinyu-Savinobor well in the upper Kungurian, 20-30 m below the Ufim deposits (Figure 2.1). The horizon is well correlated in the positive phase, the reflection intensity is low, but the dynamic features are consistent over the area. The next reflecting horizon II-III is identified with the boundary of the Carboniferous and Devonian deposits. GO is quite easily recognized on the profiles, although in places there is interference of two phases. At the eastern ends of the latitudinal profiles, an additional reflection appears above OG II-III, which wedges out to the west in the form of a plantar overlap.

OG IIIfm 1 is confined to benchmark 5, identified in the lower part of the Yeletsk Horizon of the Lower Famennian. In wells 5-M., 14-M, benchmark 5 coincides with the bottom of the Yelets horizon identified by the TP NIC, in other wells (2,4,8,22,24,28-M) 3-10 m above the official breakdown of the bottom D 3 el. The reflecting horizon is a reference horizon, has pronounced dynamic features and high intensity. Structural constructions for OG IIIfm 1 are not provided by the program.

OG IIId is identified with the base of the Domanik deposits and is confidently correlated in time sections in the negative phase.

Reference point 6 at the top of the Lower Franian Yaran horizon is associated with OG IIIf 1 . Benchmark 6 stands out quite confidently in all wells 10-15m below the base of the Dzher deposits. Reflecting horizon IIIf 1 is tracked well, despite the fact that it has a low intensity.

Productive at the Michayuskoye, Dinyu-Savinoborskoye fields, the V-3 sandy reservoir is located 18-22 m below the IIIf 1 OG, only in the 4-M well. the thickness of the deposits enclosed between the OG IIIf 1 and the V-3 formation is increased to 30 m.

Figure 2.1 - Comparison of sections of wells 1-C. Michayu, 24-Michayu, 14-Michayu and snap reflective horizons

The next reflecting horizon III 2-3 is weakly expressed in the wave field, traced near the top of the Middle Devonian terrigenous deposits. OG III 2-3 is correlated in negative phase as an erosion surface. In the south-west of the reporting area, there is a decrease in the temporal thickness between OG IIIf 1 and III 2-3, which is especially clearly seen on profile 8213-02 (Figure 2.2).

Structural constructions (Figures 2.3 and 2.4) were made along the reflectors Ik, IIId, IIIf 1 , III 2-3 , an isopach map was built between OG IIId and III 2-3 , a structural map is presented along the top of the B-3 sand bed, for the entire Dinho - Savinoborskoye deposit.

Figure 2.2 - Fragment of the time section along the profile 8213-02

2.2 Results of geophysical surveys

As a result of reprocessing and reinterpretation of seismic data on the northern block of the Dinyu-Savinobor field.

We studied the geological structure of the northern block of the Dinyu-Savinoborskoye field based on the Permian and Devonian deposits,

Figure 2.3 - Structural map along the reflecting horizon III2-3 (D2-3)

Figure 2.4 - Structural map along the reflecting horizon III d (D 3 dm)

- traced and linked across the area 6 reflectors: Ik, II-III, IIIfm1 , IIId, IIIf1 , III2-3 ;

Performed structural constructions on a scale of 1:25000 for 4 OG: Ik, IIId, IIIf1, III2-3;

A general structural map was built along the top of the V-3 formation for the Dinyu-Savinobor structure and the northern block of the Dinyu-Savinobor field, and an isopach map between OG IIId and III2-3;

We built deep seismic sections (horizon scales 1:12500, ver. 1:10000) and seismo-geological sections (horizon scales 1:25000, ver. 1:2000);

We built a comparison scheme for the Lower Frasnian deposits by wells in the Michayuskaya area, well No. 1-Dinyu-Savinobor and 1-Tripanyel on a scale of 1:500;

Clarified the geological structure of the East Michayu and Ivan-Shor structures;

Revealed the Middle Michayu, Central Michayu, East Trypanyol structures;

A NE-trending graben-like trough was traced, which is a screen for the northern block of the Dinyu-Savinobor structure.

In order to study the oil potential of the Lower Frasnian deposits within the central block of the East Michayu structure, drill a prospecting well No. 3 on the profile 40992-04 pk 29.00 with a depth of 2500 m until the opening of the Middle Devonian deposits;

On the southern block - exploratory well No. 7 at the cross of profiles 40990-07 and 40992 -21 with a depth of 2550 m;

On the northern block - exploratory well No. 8 profile 40992-03 pk 28.50 with a depth of 2450 m;

Carrying out detailed seismic surveys within the Ivan-Shor structure;

To carry out reprocessing and reinterpretation of seismic surveys on the South-Michayuskaya and Srednemichayuskaya structures.

2.3 Rationale for choosing 3D seismic

The main reason that justifies the need to use a rather complex and rather expensive 3D areal seismic technology at the exploration and detailing stages is the transition in most regions to the study of structures and deposits with more and more complex reservoirs, which leads to the risk of drilling empty wells. It has been proven that with an increase in spatial resolution by more than an order of magnitude, the cost of 3D works in comparison with detailed 2D survey (~ 2 km/km 2) increases only 1.5-2 times. At the same time, the detail and total amount of 3D shooting information is higher. A practically continuous seismic field will provide:

· Higher detail description of structural surfaces and mapping accuracy compared to 2D (errors are reduced by 2-3 times and do not exceed 3-5 m);

· Unambiguity and reliability of tracing by area and volume of tectonic faults;

· Seismic facies analysis will provide identification and tracking of seismic facies in volume;

· Possibility of interpolation into the interwell space of reservoir parameters (layer thickness, porosity, boundaries of reservoir development);

· Refinement of oil and gas reserves by detailing the structural and estimated characteristics.

This indicates the possible economic and geological feasibility of using a three-dimensional survey on the East Michayu structure. When choosing economic feasibility, it must be borne in mind that the economic effect of applying 3D to the entire complex of exploration and development of deposits also takes into account:

· growth of reserves in categories C1 and C2;

· savings by reducing the number of uninformative exploration and low-rate production wells;

· optimization of the development mode by refining the reservoir model;

· growth of C3 resources due to the identification of new objects;

· cost of 3D survey, data processing and interpretation.

3. Design part

3.1 Substantiation of the work methodology CDP - 3D

The choice of an observation system is based on the following factors: tasks to be solved, features of seismogeological conditions, technical capabilities, and economic benefits. The optimal combination of these factors determines the observation system.

In the Vostochno-Michayuskaya area, CDP-3D seismic surveys will be carried out in order to study in detail the structural-tectonic and lithofacies features of the structure of the sedimentary cover in sediments from Upper Permian to Silurian; mapping of zones of development of lithofacies heterogeneities and improved reservoir properties, discontinuous tectonic disturbances; study of the geological history of development based on paleostructural analysis; identification and preparation of oil-promising objects.

To solve the tasks, taking into account the geological structure of the region, the factor of minimal impact on the natural environment and the economic factor, an orthogonal observation system is proposed with excitation points located between the reception lines (i.e., with overlapping reception lines). Explosions in wells will be used as excitation sources.

3.2 Example of calculation of a "cross" observing system

The observation system of the "cross" type is formed by successive overlapping of mutually orthogonal arrangements, sources and receivers. Let us illustrate the principle of areal system formation on the following idealized example. Let us assume that the geophones (a group of geophones) are evenly distributed along the line of observation coinciding with the X axis.

Along the axis intersecting the arrangement of seismic receivers in the center, m is placed uniformly and symmetrically at the sources. The step of the sources of do and the seismic receivers of dx is the same. The signals generated by each source are received by all geophones of the array. As a result of such testing, a field of m 2 midpoints of reflection is formed. If we sequentially shift the arrangement of seismic receivers and the line of sources orthogonal to it along the X axis by a step dx and repeat the registration, then the result will be a multiple overlap of the band, the width of which is equal to half the excitation base. Sequential displacement of the excitation and reception base along the Y-axis by a step du leads to an additional - multiple overlap, and the total overlap will be. Naturally, in practice, more technologically advanced and economically sound variants of a system with mutually orthogonal lines of sources and receivers should be used. It is also obvious that the overlap ratio must be chosen in accordance with the requirements determined by the nature of the wave field and processing algorithms. As an example, Figure 3.1 shows an eighteen-fold areal system, for the implementation of which one 192-channel seismic station is used, which sequentially receives signals from 18 excitation pickets. Consider the parameters of this system. All 192 geophones (groups of geophones) are distributed on four parallel profiles (48 on each). The step dx between the reception points is 0.05 km, the distance d between the reception lines is 0.05 km. The step of Sy sources along the Y axis is 0.05 km. A fixed distribution of sources and receivers will be called a block. After receiving vibrations from all 18 sources, the block is shifted by a step This is how a strip is worked out along the X axis from the beginning to the end of the study area. The next lane of four reception lines is placed parallel to the previous one so that the distance between adjacent (nearest) reception lines of the first and second lanes is equal to the distance between the reception lines in the block (?y = 0.2 km). In this case, the source lines of the first and second bands overlap by half the excitation base. When working out the third band, the source lines of the second and third bands overlap by half, etc. Consequently, in this version of the system, the receiving lines are not duplicated, and at each source point (excluding the extreme ones) the signals are excited twice.

Let us write down the main relations that determine the parameters of the system and its multiplicity. To do this, following Figure 8, we introduce additional notation:

W - number of receiving lines,

m x - number of receiving points on each receiving line of the given block;

m y - the number of sources on each excitation line of the given block,

P is the width of the interval in the center of the excitation line, within which the sources are not placed,

L - offset (displacement) along the X axis of the source line from the nearest reception points.

In all cases, the intervals ?x, ?y, and L are multiples of the step dx. This ensures the uniformity of the network of midpoints corresponding to each source-receiver pair, i.e. do it! requirement of the condition necessary for the formation of seismograms of common midpoints (CMP). Wherein:

Ax=Ndx N=1, 2, 3…

tSy-MdyM=1, 2, 3…

L=q qxq=1, 2, 3…

Let us explain the meaning of the parameter P. The shift between the lines of the midpoints is equal to half the step? If the sources are uniformly distributed (there is no discontinuity), then for similar systems the overlap ratio along the Y axis is equal to W (the number of reception lines). To reduce the multiplicity of overlaps along the Y axis and to reduce costs due to a smaller number of sources, a gap is made in the center of the excitation line by a value P equal to:

Where, k = 1,2,3...

When k=1,2, 3, respectively, the overlap ratio decreases by 1, 2, 3, i.e. becomes equal to W-K.

The general formula relating the multiplicity of overlaps n y with the parameters of the system

hence the expression for the number of sources m y on one excitation line can be written as follows:

For the observation system (Figure 3.1), the number of sources on the excitation line is 18.

Figure 3.1 - Observation system of the "cross" type

It follows from expression (3.3) that since the step of the profiles?y is always a multiple of the step of the sources dy, the number of sources my for this type of system is an even number. Distributed on a straight line parallel to the Y axis symmetrically to the reception profiles included in this block, the excitation points either coincide with the reception points, or are shifted relative to the reception points by 1/2·dy. If the overlap multiplicity n y in a given block is an odd number, the sources always do not coincide with the receiving points. If n y is an even number, two situations are possible: ?y/du is an odd number, the sources coincide with the reception points, ?y/du is an even number, the sources are shifted relative to the reception points by dy/2. This fact should be taken into account when synthesizing the system (choosing the number of reception profiles W and the step? y between them), since it depends on whether the vertical times necessary to determine the static corrections will be recorded at the reception points.

The formula that determines the multiplicity of overlaps n x along the X axis can be written similarly to formula (3.2)

thus, the total multiplicity of overlaps n xy by area is equal to the product of n x and n y

In accordance with the accepted values ​​of m x, dx and? x, the multiplicity of overlaps n x along the X axis calculated by formula (3.4) is 6, and the total multiplicity n xy = 13 (Figure 3.2).

Figure 3.2 - Multiplicity of overlaps nx = 6

Along with the observation system, which provides for overlapping sources without overlapping reception lines, systems are used in practice in which the excitation lines do not overlap, but part of the reception lines is duplicated. Let us consider six receiving lines, on each of which seismic receivers receiving signals sequentially excited by sources are evenly distributed. When working out the second band, three reception lines are duplicated by the next block, and the source lines go as a continuation of the orthogonal profiles of the first band. Thus, the applied work technology does not provide for duplication of excitation points. With double overlapping of the receiving lines, the multiplicity n y is equal to the number of overlapping receiving lines. The full equivalent of a system of six profiles followed by an overlap of three receive lines is a system with overlapping sources, the number of which is doubled to achieve the same fold. Therefore, systems with overlapping sources are economically unprofitable, because. this technique requires a large amount of drilling and blasting.

Transition to 3D seismic.

The design of a 3D survey is based on the knowledge of a number of characteristics of the seismological section of the work site.

Information about the geoseismic section includes:

Multiplicity of shooting 2D

maximum depths of target geological boundaries

minimal geological boundaries

the minimum horizontal size of local geological objects

maximum frequencies of reflected waves from target horizons

average speed in the layer lying on the target horizon

time of registration of reflections from the target horizon

the size of the study area

To register the time field in MOGT-3D, it is rational to use telemetry stations. The number of profiles is selected depending on the multiplicity n y =u.

The distance between the common midpoints on the reflective surface along the X and Y axes determines the bin size:

The maximum permissible minimum offset of the source line is selected based on the minimum depth of the reflecting boundaries:

Minimum offset.

Maximum offset.

To ensure the multiplicity n x, the distance between the excitation lines?x is determined:

For the recording unit, the distance between the receiving lines? y:

Taking into account the technology of work with double overlapping of the receiving line, the number of sources m y in one block to ensure the multiplicity n y:

Figure 3.3 - Multiplicity ny =2

Based on the results of planning a 3D survey, the following data set is obtained:

distance between channels dx

the number of active channels on one receiving line m x

total number of active channels m x u

minimum offset Lmin

bin size

total multiplicity n xy

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It is obvious that the main tasks of seismic exploration with the existing level of equipment are:
1. Increasing the resolution of the method;
2. Possibility of predicting the lithological composition of the medium.
In the last 3 decades, the most powerful industry of seismic exploration of oil and gas fields has been created in the world, the basis of which is the common depth point method (CDP). However, with the improvement and development of CDP technology, the unacceptability of this method for solving detailed structural problems and predicting the composition of the medium becomes more and more clearly manifested. The reasons for this situation are the high integrity of the obtained (resulting) data (sections), incorrect and, as a result, incorrect in most cases determination of effective and average velocities.
The introduction of seismic exploration in complex environments of ore and oil regions requires a fundamentally new approach, especially at the stage of machine processing and interpretation. Among the new developing areas, one of the most promising is the idea of ​​a controlled local analysis of the kinematic and dynamic characteristics of a seismic wave field. On its basis, the development of a method for differential processing of materials in complex media is being developed. The basis of the method of differential seismic survey (DMS) is local transformations of the initial seismic data on small bases - differential in relation to the integral transformations in the CDP. The use of small bases, leading to a more accurate description of the hodograph curve, on the one hand, the selection of waves in the direction of arrival, which allows processing complexly interfering wave fields, on the other hand, creates the prerequisites for using the differential method in complex seismogeological conditions, increases its resolution and accuracy of structural constructions ( Fig. 1, 3). An important advantage of the MDS is its high parametric equipment, which makes it possible to obtain the petrophysical characteristics of the section - the basis for determining the material composition of the medium.
Wide testing in various regions of Russia has shown that MDS significantly exceeds the capabilities of CMP and is an alternative to the latter in the study of complex environments.
The first result of differential processing of seismic data is a deep structural section of the MDS (S is a section), which reflects the nature of the distribution of reflective elements (areas, boundaries, points) in the studied medium.
In addition to structural constructions, MDS has the ability to analyze the kinematic and dynamic characteristics of seismic waves (parameters), which in turn allows you to proceed to the assessment of the petrophysical properties of the geological section.
To construct a section of quasi-acoustic stiffness (A - section), the values ​​of the amplitudes of the signals reflected on the seismic elements are used. The obtained A-sections are used in the process of geological interpretation to identify contrasting geological objects (“bright spot”), zones of tectonic faults, boundaries of large geological blocks and other geological factors.
The quasi-attenuation parameter (F) is a function of the frequency of the received seismic signal and is used to identify areas of high and low consolidation rocks, zones of high absorption ("dark spot").
The sections of average and interval velocities (V, I - sections), which characterize the petro-density and lithological differences of large regional blocks, carry their own petrophysical load.

DIFFERENTIAL PROCESSING SCHEME:

INITIAL DATA (MULTIPLE OVERLAPS)

PRELIMINARY PROCESSING

DIFFERENTIAL PARAMETERIZATION OF SEISMOGRAMS

EDITING PARAMETERS (A, F, V, D)

DEEP SEISMIC SECTIONS

PETROPHYSICAL PARAMETER MAP (S, A, F, V, I, P, L)

TRANSFORMATION AND SYNTHESIS OF PARAMETER MAP (IMAGE FORMATION OF GEOLOGICAL OBJECTS)

PHYSICAL AND GEOLOGICAL MODEL OF THE ENVIRONMENT

Petrophysical parameters
S - structural, A - quasi-rigidity, F - quasi-absorption, V - average velocity,
I - interval velocity, P - quasi-density, L - local parameters

Time section of CDP after migration

Deep section of MDS

Rice. 1 COMPARISON OF THE EFFICIENCY OF MOGT AND MDS
Western Siberia, 1999

Time section of CDP after migration

Deep section of MDS

Rice. 3 COMPARISON OF THE EFFICIENCY OF MOGT AND MDS
North Karelia, 1998

Figures 4-10 show typical examples of MDS processing in various geological conditions.

Time section of CDP

Quasi-absorption section Deep section of MDS

Section of average speeds

Rice. 4 Differential processing of seismic data under conditions
complex dislocations of rocks. Profile 10. Western Siberia

Differential processing made it possible to decipher the complex wave field in the western part of the seismic section. According to the MDS data, an overthrust was found, in the area of ​​which there is a “collapse” of the productive complex (PK PK 2400-5500). As a result of a complex interpretation of the sections of petrophysical characteristics (S, A, F, V), zones of increased permeability were identified.

Deep section of MDS Time section of CDP

Quasi-acoustic stiffness section Quasi-absorption section

Section of average speeds Section of interval velocities

Rice. 5 Special processing of seismic data in searches
hydrocarbons. Kaliningrad region

Special computer processing makes it possible to obtain a series of parametric sections (maps of parameters). Each parametric map characterizes certain physical properties environment. The synthesis of parameters serves as the basis for the formation of the "image" of an oil (gas) facility. The result of a comprehensive interpretation is a Physical-Geological Model of the environment with a forecast for hydrocarbon deposits.

Rice. 6 Differential processing of seismic data
in search of copper-nickel ores. Kola Peninsula

As a result of special processing, areas of anomalous values ​​of various seismic parameters were revealed. A comprehensive interpretation of the data made it possible to determine the most probable location of the ore object (R) at pickets 3600-4800 m, where the following pertophysical features are observed: high acoustic rigidity above the object, strong absorption below the object, and a decrease in interval velocities in the area of ​​the object. This "image" corresponds to the previously obtained R-etalons in the areas of deep drilling in the area of ​​the Kola super-deep well.

Rice. 7 Differential processing of seismic data
when looking for hydrocarbon deposits. Western Siberia

Special computer processing makes it possible to obtain a series of parametric sections (maps of parameters). Each parametric map characterizes certain physical properties of the medium. The synthesis of parameters serves as the basis for the formation of the "image" of an oil (gas) facility. The result of a comprehensive interpretation is a physical-geological model of the environment with a forecast for hydrocarbon deposits.

Rice. 8 Geoseismic model of the Pechenga structure
Kola Peninsula.

Rice. 9 Geoseismic model of the northwestern part of the Baltic Shield
Kola Peninsula.

Rice. 10 Quasi-density section along profile 031190 (37)
Western Siberia.

The oil-bearing sedimentary basins of Western Siberia should be attributed to a favorable type of section for the introduction of new technology. The figure shows an example of a quasi-density section constructed using the MDS programs on a R-5 PC. The resulting interpretation model is in good agreement with the drilling data. The lithotype marked in dark green at depths of 1900 m corresponds to mudstones of the Bazhenov Formation; The densest lithotypes of the section. Yellow and red varieties are quartz and mudstone sandstones, light green lithotypes correspond to siltstones. In the bottomhole part of the well, under the water-oil contact, a lens of quartz sandstones with high reservoir properties was opened.

PREDICTION OF THE GEOLOGICAL SECTION BASED ON MDS DATA

At the stage of prospecting and exploration, MDS is an integral part of the exploration process, both in structural mapping and at the stage of real forecasting.
On fig. 8 shows a fragment of the Geoseismic model of the Pechenga structure. The basis of the fuel and lubricants are the seismic data of the international experiments KOLA-SD and 1-EB in the area of ​​the Kola superdeep well SG-3 and the data of prospecting and exploration works.
The stereometric combination of the geological surface and deep structural (S) sections of the MDS on real geological scales allows one to get a correct idea of ​​the spatial structure of the Pechenga synclinorium. The main ore-bearing complexes are represented by terrigenous and tuffaceous rocks; their boundaries with surrounding mafic rocks are strong seismic boundaries, which provides reliable mapping of ore-bearing horizons in the deep part of the Pechenga structure.
The resulting seismic framework is used as a structural basis for the Physical Geological Model of the Pechenga ore region.
On fig. Figure 9 shows elements of the geoseismic model for the northwestern part of the Baltic Shield. Fragment of geotraverse 1-EV along the line SG-3 - Liinakha-mari. In addition to the traditional structural section (S), parametric sections were obtained:
A - quasi-stiffness section characterizes the contrast of various geological blocks. The Pechenga block and the Liinakhamari block are distinguished by high acoustic rigidity; the zone of the Pitkjarvin syncline is the least contrasting.
F - the section of quasi-absorption reflects the degree of consolidation of rock
breeds. The Liinakhamari block is characterized by the least absorption, and the largest is noted in the inner part of the Pechenga structure.
V, I are sections of average and interval velocities. The kinematic characteristics are noticeably heterogeneous in the upper part of the section and stabilize below the level of 4-5 km. The Pechenga block and the Liinakhamari block are characterized by increased velocities. In the northern part of the Pitkyayarvin syncline, in section I, a “trough-like” structure is observed with consistent values ​​of interval velocities Vi = 5000-5200 m/s, corresponding in terms of the distribution area of ​​Late Archean granitoids.
A comprehensive interpretation of the parametric sections of the MDS and materials of other geological and geophysical methods is the basis for creating a Physical and Geological model of the West Kola region of the Baltic Shield.

PREDICTION OF LITHOLOGY OF THE ENVIRONMENT

The identification of new parametric capabilities of the MDS is associated with the study of the relationship of various seismic parameters with the geological characteristics of the environment. One of the new (mastered) MDS parameters is the quasi-density. This parameter can be identified on the basis of studying the sign of the seismic signal reflection coefficient at the boundary of two lithophysical complexes. With insignificant changes in the velocities of seismic waves, the sign characteristic of the wave is determined mainly by the change in the density of rocks, which makes it possible to study the material composition of the medium in some types of sections using a new parameter.
The oil-bearing sedimentary basins of Western Siberia should be attributed to a favorable type of section for the introduction of new technology. Below in fig. Figure 10 shows an example of a quasi-density section constructed using the MDS programs on a R-5 PC. The resulting interpretation model is in good agreement with the drilling data. The lithotype marked in dark green at depths of 1900 m corresponds to mudstones of the Bazhenov Formation; the densest lithotypes of the section. Yellow and red varieties are quartz and mudstone sandstones, light green lithotypes correspond to siltstones. A lens of quartz sandstones was opened in the bottomhole part of the well under the water-oil contact
with high collection properties.

COMPLEXING THE DATA OF THE CDP AND THE SHP

When conducting regional and CDP prospecting and exploration works, it is not always possible to obtain data on the structure of the near-surface part of the section, which makes it difficult to link geological mapping materials to deep seismic data (Fig. 11). In such a situation, it is advisable to use the profiling of refraction in the variant of the GCP, or the processing of the available CDP materials using the special technology of the PMA-OGP. The bottom drawing shows an example of combining refraction and CDP data for one of the CDP seismic profiles worked out in Central Karelia. The obtained materials made it possible to link the deep structure with the geological map and clarify the location of the Early Proterozoic Paleodepressions, which are promising for ore deposits of various minerals.

The experience of conducting field seismic surveys using the classical method and the high-performance Slip-Sweep method by the forces of Samaraneftegeofizika is considered.

The experience of conducting field seismic surveys using the classical method and the high-performance Slip-Sweep method by Samaraneftegeofizika is considered.

The advantages and disadvantages of the new technique are revealed. The economic indicators of each of the methods are calculated.

At present, the productivity of field seismic surveys depends on many factors:

Land use intensity;

Movement of cars and rail Vehicle, through the area under study;

Activity on the territory of settlements located on the study area; influence of meteorological factors;

Rough terrain (ravines, forests, rivers).

All of the above factors significantly reduce the speed of seismic surveys.

In fact, during the day there are 5-6 hours of night time for seismic observations. This is critical and insufficient to fulfill the volumes within the stipulated time, and also significantly increase the cost of work.

The time of work, in the 1st stage, depends on the following stages:

Topogeodetic preparation of the observation system - installation of pickets of profiles on the ground;

Installation, adjustment of seismic equipment;

Excitation of elastic vibrations, registration of seismic data.

One way to reduce the time spent is to use the Slip-Sweep technique.

This technique allows to significantly speed up the production of the excitation stage - registration of seismic data.

Slip-sweep is a high-performance seismic system based on the overlapping sweep method, in which the vibrators work simultaneously.

In addition to increasing the speed of field work, this technique allows you to compact the points of the explosion, thus increasing the density of observations.

This improves the quality of work and increases productivity.

The Slip-Sweep technique is relatively new.

The first experience of CDP-3D seismic exploration using the Slip-Sweep method was obtained in the amount of only 40 km 2 in Oman (1996).

As you can see, the Slip-Sweep technique was used mainly in the desert area, with the exception of work in Alaska.

In Russia, in experimental mode (16 km2), the Slip-Sweep technology was tested in 2010 by Bashneftegeofizika.

The article presents the experience of conducting field work using the Slip-Sweep method and comparing the indicators with the standard method.

The physical foundations of the method and the possibility of compacting the observation system simultaneously with the use of the Slip-Sweep technology are shown.

The primary results of the work are given, the shortcomings of the method are indicated.

In 2012, using the Slip-Sweep method, Samaraneftegeofizika performed 3D work at the Zimarny and Mozharovsky license blocks of Samaraneftegaz in the amount of 455 km2.

The increase in productivity due to the Slip-Sweep technique at the stage of excitation-registration in the conditions of the Samara region occurs due to the use of short-term periods of time allotted for the registration of seismic data during the daily work cycle.

That is, the task of performing the largest number of physical observations in a short time is performed by the Slip-Sweep technique most efficiently by increasing the performance of recording physical observations by 3-4 times.

The Slip-Sweep technique is a high-performance seismic survey system based on the method of overlapping vibratory sweep signals, in which vibrators at different SPs operate simultaneously, recording is continuous. ranges (Fig. 1).

The emitted sweep signal is one of the operators of the cross-correlation function in the process of obtaining a corelogram from a vibrogram.

At the same time, in the process of correlation, it is also a filter operator that suppresses the influence of frequencies other than the frequency emitted at a given time, which can be applied to suppress radiation from simultaneously operating vibrators.

With sufficient response time of vibration units, their emitted frequencies will be different, thus it is possible to completely eliminate the influence of neighboring vibration radiation (Fig. 2).

Therefore, with a correctly selected slip-time, the influence of simultaneously operating vibration units is eliminated in the process of converting the vibrogram into a corelogram.

Rice. 1. Slip-time delay. Simultaneous emission of different frequencies.

Rice. 2. Evaluation of the use of an additional filter for the influence of neighboring vibrations: A) correlogram without filtering; B) corelogram with filtering by vibrogram; C) frequency-amplitude spectrum of filtered (green light) and unfiltered (red) corelograms.

The use of one vibrator instead of a group of 4 vibrators is based on the sufficiency of the vibration radiation energy of one vibrator for the formation of reflected waves from the target horizons (Fig. 3).

Rice. 3. Sufficiency of vibration energy of one vibration unit. A) 1 vibration unit; B) 4 vibration units.

The Slip-Sweep technique is more efficient when applying surveillance system compaction.

For the conditions of the Samara region, a 4-fold compaction of the observation system was applied. 4-fold division of one physical observation (f.n.) into 4 separate f.n. is based on the equality of the distance between the vibrator plates (12.5 m) with a group of 4 vibrators, a 50 m PV step and the use of one vibrator with a 12.5 m PV step (Fig. 4).

Rice. 4. Sealing the surveillance system with 4-fold separation of physicalobservations.

In order to combine the results of observation by the standard technique and the sleep-sweep technique with 4-fold compaction, the principle of parity of the total vibro-radiation energies is considered.

The parity of the energy of vibration action can be estimated by the total time of vibration action.

Total vibration exposure time:

St = Nv *Nn * Tsw * dSP,

where Nv is the number of vibration units in the group, Nn is the number of accumulations, Tsw is the duration of the sweep signal, dSP is the number of f.n. within the basic step PV=50m.

For the traditional technique (ST step = 50m, a group of 4 sources):

St = 4 * 4 * 10 * 1 = 160 sec.

For the slip-sweep method:

St = 1 * 1 * 40 * 4 = 160 sec.

The result of the parity of energies by the equality of the total time shows the same result in the total Bin 12.5m x 25m.

To compare the methods, Samara geophysicists received two sets of seismograms: 1st set - 4 seismograms processed by one vibrator (Slip-Sweep method), 2nd set - 1 seismogram processed by 4 vibrators (standard method). Each of the 4 seismograms of the first set is about 2-3 times weaker than the seismogram of the second set (Fig. 3). Accordingly, the signal-to-microseism ratio is 2-3 times lower. However, a more qualitative result is the use of compacted 4 relatively weak in energy individual seismograms (Fig. 5).

In the case of junction of areas worked out by different methods, the application of processing procedures oriented to the wave field of the standard method, the result turned out to be practically equivalent (Fig. 6, Fig. 7). However, if you apply processing parameters adapted to the Slip-Sweep technique, the result will be time sections with increased time resolution.

Rice. Fig. 5. A fragment of the primary total time section by INLINE (without filtering procedures) at the junction of two areas worked out using the slip-sweep method (left) and standard technique (right).

Comparison of time sections and spectral characteristics of the standard method and the Slip-Sweep method shows a high comparability of the resulting data (Fig. 8). The difference lies in the presence of higher energies of the high-frequency component of the Slip-Sweep seismic data signal (Fig. 7).

This difference is explained by the high noise immunity of the compacted observation system, the high multiplicity of seismic data (Fig. 6).

Also important point is the point effect of one vibrator instead of a group of vibrators and its single effect instead of the sum of vibration effects (accumulation).

The use of a point source of excitation of elastic vibrations instead of a group of sources expands the spectrum of recorded signals in the region high frequencies, reduces the energy of near-surface interference waves, which affects the increase in the quality of the recorded data, the reliability of geological constructions.

Rice. Fig. 6. Amplitude-frequency spectra from seismograms processed according to differentmethods (according to the results of processing): A) Slip-sweep technique; B) Standard method.

Rice. 7. Comparison of time sections worked out by different methods(according to the results of processing): A) Slip-sweep technique; B) Standard method.

Benefits of the Slip-Sweep technique:

1. High productivity of work, expressed in an increase in the productivity of registration of f.n. 3-4 times, an increase in overall productivity by 60%.

2. Improved quality of field seismic data due to the compression of shots:

High noise immunity of the surveillance system;

High frequency of observations;

Possibility of increasing the space;

Increase in the share of the high-frequency component of the seismic signal by 30% due to point excitation (vibration impact).

Disadvantages of using the technique.

Operation in the Slip-Sweep technique mode is operation in a "conveyor" mode in a streaming information environment with non-stop registration of seismic data. With non-stop recording, the visual control of the seismic complex operator over the quality of seismic data is significantly limited. Any failure can lead to a mass marriage or stop work. Also, at the stage of subsequent control of seismic data at the field computer center, the use of more powerful computer systems for field support of data preparation and preliminary field processing is required. However, the costs of acquiring computer equipment, as well as equipment for retrofitting the recording complex, are paid off within the framework of the profit of the work contractor by reducing the time for their implementation. Among other things, more efficient logistical procedures are required for preparing profiles for the development of physical observations.

During the work of Samaraneftegeofizika using the Slip-Sweep method in 2012, the following economic indicators were obtained (table 1).

Table 1.

Economic indicators of comparison of methods of work.

These data allow us to draw the following conclusions:

1. With the same amount of work, the overall productivity of Slip-Sweep is 63.6% higher than when conducting work with the "standard" method.

2. Growth in productivity directly affects the duration of work (decrease by 38.9%).

3. When using the Slip-Sweep technique, the cost of field seismic surveys is 4.5% lower.

Literature

1. Patsev V.P., 2012. Report on the performance of work on the object of field seismic surveys MOGT-3D within the Zimarny licensed area of ​​OJSC Samaraneftegaz. 102 p.

2. Patsev V.P., Shkokov O.E., 2012. Report on the performance of work on the object of field seismic surveys MOGT-3D within the Mozharovsky licensed area of ​​JSC Samaraneftegaz. 112 p.

3. Gilaev G.G., Manasyan A.E., Ismagilov A.F., Khamitov I.G., Zhuzhel V.S., Kozhin V.N., Efimov V.I., 2013. Experience in conducting seismic surveys MOGT-3D according to the Slip-Sweep method. 15 s.

(fundamentals of the theory of elasticity, geometric seismic, seismoelectric phenomena; seismic properties of rocks (energy, attenuation, wave velocities)

Applied seismic exploration originates from seismology, i.e. science dealing with the registration and interpretation of waves arising from earthquakes. She is also called explosive seismology- seismic waves are excited in separate places by artificial explosions in order to obtain information about the regional and local geological structure.

That. seismic exploration- this is a geophysical method for studying the earth's crust and upper mantle, as well as for the exploration of mineral deposits, based on the study of the propagation of elastic waves excited artificially, using explosions or impacts.

Rocks, due to the different nature of formation, have different propagation velocities of elastic waves. This leads to the fact that at the boundaries of the layers of different geological media, reflected and refracted waves with different speeds are formed, the registration of which is carried out on the surface of the earth. After interpreting and processing the obtained data, we can obtain information about the geological structure of the area.

Huge successes in seismic exploration, especially in the field of observation methods, began to be seen after the 20s of the outgoing century. About 90% of the funds spent on geophysical exploration in the world falls on seismic exploration.

Seismic exploration technique is based on the study of the kinematics of waves, i.e. on study travel times of various waves from the point of excitation to seismic receivers, which amplify oscillations at a number of points in the observation profile. Then the vibrations are converted into electrical signals, amplified and automatically recorded on magnetograms.

As a result of the processing of magnetograms, it is possible to determine the wave velocities, the depth of seismogeological boundaries, their dip, strike. Using geological data, it is possible to establish the nature of these boundaries.

There are three main methods in seismic exploration:

method of reflected waves (MOW);

refracted wave method (MPV or CMPV - correlation) (this word is omitted for abbreviation).

transmitted wave method.

In these three methods, a number of modifications can be distinguished, which, in view of the special methods of conducting work and interpreting materials, are sometimes considered independent methods.

These are the following methods: MRNP - a method of controlled directed reception;

Variable Directional Reception Method

It is based on the idea that in conditions where the boundaries between the layers are rough or formed by heterogeneities distributed over the area, interference waves are reflected from them. On short receiving bases, such oscillations can be split into elementary plane waves, the parameters of which more accurately determine the location of inhomogeneities, the sources of their occurrence, than interference waves. In addition, the MIS is used to resolve regular waves that simultaneously arrive at the profile in different directions. The means of resolving and splitting waves in the MRS are adjustable multi-temporal rectilinear summation and variable frequency filtering with emphasis on high frequencies.

The method was intended for reconnaissance of areas with complex structures. Its use for reconnaissance of gently sloping platform structures required the development of a special technique.

The areas of application of the method in oil and gas geology, where it was most widely used, are areas with the most complex geological structure, the development of complex folds of foredeeps, salt tectonics, and reef structures.

RTM - method of refracted waves;

CDP - common depth point method;

MPOV - method of transverse reflected waves;

MOBV - method of converted waves;

MOG - the method of inverted hodographs, etc.

Inverted hodograph method. The peculiarity of this method lies in the immersion of the seismic receiver into specially drilled (up to 200 m) or existing (up to 2000 m) wells. below the zone (ZMS) and multiple boundaries. Oscillations are excited near the daylight surface along profiles that are located longitudinally (with respect to wells), non-longitudinally or along the area. Linear and inverted surface hodographs of waves are distinguished from the general wave pattern.

AT CDP apply linear and areal observations. Areal systems are used in separate wells to determine the spatial position of reflecting horizons. The length of the inverted hodographs for each observation well is determined empirically. Usually the length of the hodograph is 1.2 - 2.0 km.

For a complete picture, it is necessary that the hodographs overlap, and this overlap would depend on the depth of the registration level (usually 300 - 400 m). The distance between the shotguns is 100 - 200 m, under unfavorable conditions - up to 50 m.

Borehole methods are also used in the search for oil and gas fields. Borehole methods are very effective in studying deep boundaries, when, due to intense multiple waves, surface noise and the complex deep structure of the geological section, land seismic results are not reliable enough.

Vertical seismic profiling - this is an integrated seismic logging performed by a multi-channel sonde with special clamping devices that fix the position of geophones near the borehole wall; they allow you to get rid of interference and correlate waves. VSP is an effective method for studying wave fields and the process of seismic wave propagation at internal points of real media.

The quality of the studied data depends on the correct choice of excitation conditions and their constancy in the process of conducting research. VSP observations (vertical profile) are determined by the depth and technical condition of the well. VSP data is used to evaluate the reflective properties of seismic boundaries. From the ratio of the amplitude-frequency spectra of the direct and reflected waves, the dependence of the reflection coefficient of the seismic boundary is obtained.

Piezoelectric exploration method is based on the use of electromagnetic fields arising from the electrification of rocks by elastic waves excited by explosions, impacts and other impulse sources.

Volarovich and Parkhomenko (1953) established the piezoelectric effect of rocks containing piezoelectric minerals with oriented electric axes in a certain way. The piezoelectric effect of rocks depends on piezoelectric minerals, patterns of spatial distribution and orientation of these electrical axes in textures; sizes, shapes and structure of these rocks.

The method is used in ground, borehole and mine variants in the search and exploration of ore-quartz deposits (gold, tungsten, molybdenum, tin, rock crystal, mica).

One of the main tasks in the study of this method is the choice of an observation system, i.e. the relative position of the points of explosions and receivers. Under ground conditions, a rational observation system consists of three profiles, in which the central profile is the profile of explosions, and the two extreme profiles are the profiles of the arrangement of receivers.

According to the tasks to be solved seismic exploration subdivided into:

deep seismic exploration;

structural;

oil and gas;

ore; coal;

engineering hydrogeological seismic survey.

According to the method of work, there are:

ground,

well types of seismic exploration.