Enhancement of geological exploration efficiency and its risk mitigation during on the territory of Siberia and Arctic shelf

UDK: 553.982.2
DOI: 10.24887/0028-2448-2018-3-8-12
Key words: Siberia, the Arctic shelf, pressure, abnormally high pressure
Authors: B.L. Aleksandrov (Kuban State Agrarian University, RF, Krasnodar), Z.H. Mollaev (RN-Krasnodarneftegas LLC, RF, Krasnodar), G.I. Shilov (Gubkin Russian State University of Oil and Gas (National Research University), RF, Moscow)

The authors consider several questions of geological exploration efficiency and its geological and ecological risk mitigation on the territory of Siberia and the Arctic shelf under conditions of abnormally high pore (AHPP) and formation (AHFP) pressures. In these cases, especially within the Arctic shelf, holding trouble-free drilling and optimization of t productive horizons opening is impossible without an operational definition of geotagging in sections of wells and the study of patterns of development.

The opportunity to meet with the strata of rocks with abnormally high pore and reservoir pressures is illustrated on the examples of the well logging results of pressures assessment in wells of Messoyakha group of fields in the North of Western Siberia, and wells of Leningradskoye, Rusanovskoye, Kharasaveyskoye fields. The article presents examples of processing materials and evaluation of pressures for specific wells. So in well No. 2 of Sredne-Messoyakhskoye field we identified five zones of AHPP. The maximum gradient of the pore pressures in these zones is 0.15-0,16 MPa/m. In wells of Rusanovskoye and Leningradskoye deposits located on the Arctic shelf of the Kara Sea, we revealed three zones AHPP with maximum gradients of pressures up to 0,155-0.172 MPa/m. The data obtained allowed to recommend the optimal design of wells and density of drilling fluids.

It is shown that the cause of AHPP is lithogenetic factor when compaction of clay rocks occurs at the complicated outflow of pore fluid. The genesis of AHFP in sand and siltstone reservoirs of these deposits may be associated with a combined mechanism of formation of anomalously high geofluid pressures. Here along with lithogenetic factor, there are also processes of vertical migration of fluids from sources of gas in the sedimentary cover. On the basis of the analysis the conclusion is made that it is necessary to create a permanent center for the promotion of well drilling with continuous assessments of geofluid pressures, areas of AHPP and AHFP logging and technological parameters of drilling.

References

1. Aleksandrov B.L., Anomal'no vysokie plastovye davleniya v neftegazonosnykh basseynakh (Abnormally high reservoir pressures in oil and gas basins), Moscow: Nedra Publ., 1987, 216 p.

2. Aleksandrov B.L., Golland R.V., Abnormally high reservoir pressure zonation and quantitative evaluation of pressure on the sludge (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1973, no. 8, pp. 7-9.

3. Aleksandrov B.L., Sinel'nikova V.N., Isaev M.E., Possibility of preliminary forecast of zones of abnormally high reservoir pressure on  seismic data (In Russ.), Razvedochnaya geofizika, 1974, V. 62, рр. 45–51.

4. Shilov G.Ya., Comparative analysis of the distribution of pore and reservoir pressures in the oil and gas deposits in the Yamal region (In Russ.), Gazovaya promyshlennost', 2010, no. 9, pp. 24 – 27.

5. Certificate of authorship no. 1298359, Sposob prognozirovaniya ustoychivosti stvola skvazhiny vo vremeni (A method for predicting the stability of a wellbore in time), Author: Aleksandrov B.L.

6. Aleksandrov B.L., Akent'ev E.P., Panchenko G.G. et al., Prognozirovanie anomal'no-vysokikh plastovykh davleniy pri poiskakh nefti i gaza v yugo-zapadnoy Turkmenii (Forecasting abnormally high reservoir pressures in the search for oil and gas in southwestern Turkmenistan), Moscow: Publ. of VNIIOENG, 1978, 63 p.

7. Aleksandrov B.L., Orkina T.G., Nekotorye osobennosti razvitiya tolshch s AVPD v razrezakh Zapadno-Sibirskoy neftegazonosnoy provintsii (Some features of strata with abnormally high reservoir pressures in the sections of the West Siberian oil and gas province), Collected papers “Razvitie geofizicheskikh issledovaniy na neft' i gaz v Zapadnoy Sibiri” (Development of geophysical studies for oil and gas in Western Siberia), Tyumen', 1980, 261 р.

8. Shilov G.Ya., Aleksandrov B.L., Bondarev A.V., Belyaev S.V., Features of distribution Ahpp according to Grc in cuts of Bolshekhetsk depression and Average Messoyakhsk of a shaft (In Russ.), Neft', gaz i biznes, 2012, no. 8, pp. 37-40.

9. Aleksandrov B.L., Afanas'ev V.S., Katsman F.I., Kas'yanov G.E., Improvement of drilling technology on the basis of forecasting abnormally high reservoir pressures by geophysical methods (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1980, no. 2, pp. 9-11.

10. Shilov G.Ya., On the role of breeds-of tires in education and the preservation of the hydrocarbon deposits and their importance in the process of geological survey (In Russ.), Nedropol'zovanie XXI vek, 2013, no. 1, pp. 74 – 76.

11. Aleksandrov B.L., Khasanov M.A., Sedieva I.B., Radiogenic nature of hydrocarbons generation (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2013, no. 7, pp. 37-41.

12. Patent no. 2520067 RF, Method predicting development zones of secondary fracture-type reservoirs in sedimentary section, Inventors: Aleksandrov B.L., Kerimov I.A., Khasanov M.A., El'zhaev A.S..

13. Mollaev Z.Kh., Prognozirovanie kollektorov v karbonatnykh porodakh Tersko-Kaspiyskogo progiba (Forecasting of reservoirs in carbonate rocks of the Tersko-Caspian trough): thesis of candidate of geological and mineralogical science, Moscow, 19856 15 p.

The authors consider several questions of geological exploration efficiency and its geological and ecological risk mitigation on the territory of Siberia and the Arctic shelf under conditions of abnormally high pore (AHPP) and formation (AHFP) pressures. In these cases, especially within the Arctic shelf, holding trouble-free drilling and optimization of t productive horizons opening is impossible without an operational definition of geotagging in sections of wells and the study of patterns of development.

The opportunity to meet with the strata of rocks with abnormally high pore and reservoir pressures is illustrated on the examples of the well logging results of pressures assessment in wells of Messoyakha group of fields in the North of Western Siberia, and wells of Leningradskoye, Rusanovskoye, Kharasaveyskoye fields. The article presents examples of processing materials and evaluation of pressures for specific wells. So in well No. 2 of Sredne-Messoyakhskoye field we identified five zones of AHPP. The maximum gradient of the pore pressures in these zones is 0.15-0,16 MPa/m. In wells of Rusanovskoye and Leningradskoye deposits located on the Arctic shelf of the Kara Sea, we revealed three zones AHPP with maximum gradients of pressures up to 0,155-0.172 MPa/m. The data obtained allowed to recommend the optimal design of wells and density of drilling fluids.

It is shown that the cause of AHPP is lithogenetic factor when compaction of clay rocks occurs at the complicated outflow of pore fluid. The genesis of AHFP in sand and siltstone reservoirs of these deposits may be associated with a combined mechanism of formation of anomalously high geofluid pressures. Here along with lithogenetic factor, there are also processes of vertical migration of fluids from sources of gas in the sedimentary cover. On the basis of the analysis the conclusion is made that it is necessary to create a permanent center for the promotion of well drilling with continuous assessments of geofluid pressures, areas of AHPP and AHFP logging and technological parameters of drilling.

References

1. Aleksandrov B.L., Anomal'no vysokie plastovye davleniya v neftegazonosnykh basseynakh (Abnormally high reservoir pressures in oil and gas basins), Moscow: Nedra Publ., 1987, 216 p.

2. Aleksandrov B.L., Golland R.V., Abnormally high reservoir pressure zonation and quantitative evaluation of pressure on the sludge (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1973, no. 8, pp. 7-9.

3. Aleksandrov B.L., Sinel'nikova V.N., Isaev M.E., Possibility of preliminary forecast of zones of abnormally high reservoir pressure on  seismic data (In Russ.), Razvedochnaya geofizika, 1974, V. 62, рр. 45–51.

4. Shilov G.Ya., Comparative analysis of the distribution of pore and reservoir pressures in the oil and gas deposits in the Yamal region (In Russ.), Gazovaya promyshlennost', 2010, no. 9, pp. 24 – 27.

5. Certificate of authorship no. 1298359, Sposob prognozirovaniya ustoychivosti stvola skvazhiny vo vremeni (A method for predicting the stability of a wellbore in time), Author: Aleksandrov B.L.

6. Aleksandrov B.L., Akent'ev E.P., Panchenko G.G. et al., Prognozirovanie anomal'no-vysokikh plastovykh davleniy pri poiskakh nefti i gaza v yugo-zapadnoy Turkmenii (Forecasting abnormally high reservoir pressures in the search for oil and gas in southwestern Turkmenistan), Moscow: Publ. of VNIIOENG, 1978, 63 p.

7. Aleksandrov B.L., Orkina T.G., Nekotorye osobennosti razvitiya tolshch s AVPD v razrezakh Zapadno-Sibirskoy neftegazonosnoy provintsii (Some features of strata with abnormally high reservoir pressures in the sections of the West Siberian oil and gas province), Collected papers “Razvitie geofizicheskikh issledovaniy na neft' i gaz v Zapadnoy Sibiri” (Development of geophysical studies for oil and gas in Western Siberia), Tyumen', 1980, 261 р.

8. Shilov G.Ya., Aleksandrov B.L., Bondarev A.V., Belyaev S.V., Features of distribution Ahpp according to Grc in cuts of Bolshekhetsk depression and Average Messoyakhsk of a shaft (In Russ.), Neft', gaz i biznes, 2012, no. 8, pp. 37-40.

9. Aleksandrov B.L., Afanas'ev V.S., Katsman F.I., Kas'yanov G.E., Improvement of drilling technology on the basis of forecasting abnormally high reservoir pressures by geophysical methods (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1980, no. 2, pp. 9-11.

10. Shilov G.Ya., On the role of breeds-of tires in education and the preservation of the hydrocarbon deposits and their importance in the process of geological survey (In Russ.), Nedropol'zovanie XXI vek, 2013, no. 1, pp. 74 – 76.

11. Aleksandrov B.L., Khasanov M.A., Sedieva I.B., Radiogenic nature of hydrocarbons generation (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2013, no. 7, pp. 37-41.

12. Patent no. 2520067 RF, Method predicting development zones of secondary fracture-type reservoirs in sedimentary section, Inventors: Aleksandrov B.L., Kerimov I.A., Khasanov M.A., El'zhaev A.S..

13. Mollaev Z.Kh., Prognozirovanie kollektorov v karbonatnykh porodakh Tersko-Kaspiyskogo progiba (Forecasting of reservoirs in carbonate rocks of the Tersko-Caspian trough): thesis of candidate of geological and mineralogical science, Moscow, 19856 15 p.



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