DOI: https://doi.org/10.24028/gzh.0203-3100.v41i1.2019.158865

Simultaneous seismic inversion to identify prospective areas in carbonate rocks of the southeastern part of the West Siberian Platform

O. M. Tiapkina, Yu. K. Tyapkin

Abstract


This paper focuses on the description of a technology and results of identifying and mapping areas in Devonian carbonate rocks prospective for hydrocarbons and associated with increased fracture-cavern porosity in the southeastern part of the West Siberian Platform. The lack of wide-azimuthal seismic data and recording of only the vertical component in the study area did not allow the use of the direct indicators of fracture systems based either on azimuthal anisotropy of the amplitudes of pressure waves or on splitting converted waves into fast and slow. Instead, abnormally low values of the ratio of pressure-wave and shear-wave velocities derived by deterministic simultaneous pre-stack seismic inversion were used as an indirect indicator of increased fracturing. The choice of this seismic signature of fractures is substantiated by a brief review of publications on its successful use in the identification and delineation of highly fractured and cavernous zones in carbonate reservoirs. The behaviour of the indicator showed good agreement with well productivity in the study area and, therefore, made it possible to predict a number of perspective pay zones, presumably associated with in-creased fracturing. At the same time, however, well log estimates of the velocity ratio related to fractured reservoirs exhibited an opposite trend, which mismatched the facts observed in the study area and reported in the literature. This apparent discrepancy is explained by the impact of near-vertical natural macro-fracturing, which, due to different measurement scales, might substantially reduce seismic estimates while producing no impact on well log estimates. In order to describe this phenomenon quantitatively, the weak-anisotropy approximation of P-wave reflection coefficients at a horizontal boundary derived by Rüger for transversely isotropic media with a horizontal axis of symmetry was used. This equation was rewritten in terms of impedances and density and then was analyzed analytically. To express the impact of fractures in terms of fracture density, the simplest model of thin, isolated, penny-shaped fractures was used.


Keywords


simultaneous seismic inversion; acoustic impedance; shear impedance; carbonate rocks; fractured zones

References


Ampilov, Yu. P., Barkov, A. Yu., Yakovlev, I. V., Filippova, K. E., & Priyezzhev, I. I. (2009). Almost everything about seismic inversion. Part 1. Tekhnologii seismorazvedki, 6(4), 3—16 (in Russian).

Levyant, V. B., Khromova, I. Yu., Kozlov, E. A., Kerusov, I. N., Kashcheev, D. E., Kolesov, V. V., & Marmalevskiy, N. Ya. (2010). Methodical recommendations on the use of seismic data for the calculation of hydrocarbon reserves in conditions of carbonate rocks with porosity of a fracture-cavern type. Moscow: Central Geophysical Expedition, 250 p. (in Russian).

Romanenko, M. Yu., Kerusov, I. N., Miroshnichenko, D. E., & Masalkin, Yu. V. (2010). Estimation of the effectiveness of the method for synchronous inversion of seismic data with reference to models of low-contrast reservoirs. Tekhnologii seismorazvedki, 7(2), 55—61 (in Russian).

Tiapkina, A. N., Tyapkin, Yu. K., & Okrepkyj, A. I. (2015). Adequate velocity model as a basis for effective seismic imaging when mapping hydrocarbon traps associated with salt domes. Geofizicheskiy zhurnal, 37(1), 147—164. https://doi.org/10.24028/gzh.0203-3100.v37i1.2015.111333 (in Russian).

Tiapkina, A. N., Tyapkin, Yu. K., & Okrepkyj, A. I. (2014). Advanced methods for seismic imaging when mapping hydrocarbon traps associated with salt domes. Geofizicheskiy zhurnal, 36(3), 86—104. https://doi.org/10.24028/gzh.0203-3100.v36i3.2014.116055 (in Russian).

Tiapkina, A. N., Tyapkin, Yu. K., & Tiapkina, E. Yu. (2017). Combination of improved acquisition system, processing, velocity model and migration for seismic imaging in areas of intense salt tectonics. Geofizicheskiy zhurnal, 39(2), 3—21. https://doi.org/10.24028/gzh.0203-3100.v39i2.2017.97347 (in Russian).

Anno, P. D. (1985). Exploration of the Hunton group, Anadarko basin, using shear waves. 55th SEG Annual Meeting, Expanded Abstracts, 345—348. doi: 10.1190/1.1892649.

Bakulin, A., Grechka, V., & Tsvankin, I. (2000). Estimation of fracture parameters from reflection seismic data — Part I: HTI model due to a single fracture set. Geophysics, 65(6), 1788—1802. doi: 10.1190/1.1444863.

Dong, W., Tura, A., & Sparkman, G. (2003). An introduction — Carbonate geophysics. The Leading Edge, 22(7), 637—638. doi: 10.1190/1.1599688.

Eberli, G. P., Baechle, G. T., Anselmetti, F. S., & Incze, M. L. (2003). Factors controlling elastic properties in carbonate sediments and rocks. The Leading Edge, 22(7), 654—660. doi: 10. 1190/1.1599691.

Fatti, J. L., Smith, G. C., Vail, P. J., Strauss, P. J., & Levitt, P. R. (1994). Detection of gas in sand-stone reservoirs using AVO analysis: A 3D seismic case history using the Geostack technique. Geophysics, 59(9), 1362—1376. doi: 10.1190 /1.1443695.

Gaiser, J., Loinger, E., Lynn, H., & Vetri, L. (2002). Birefringence analysis at Emilio Field for fracture characterization. First Break, 20(8), 505—514. doi: 10.1046/j.1365-2397.2002.00296.x.

Gray, D. (2008). Fracture detection using 3D seismic azimuthal AVO. CSEG Recorder, 33(3), 38—49.

Hampson, D. P., Russell, B. H., & Bankhead, B. (2005). Simultaneous inversion of pre-stack seismic data. 75th SEG Annual Meeting, Expanded Abstracts, 1633—1637. doi: 10.1190/1.2148008.

Hart, B. S., Pearson, R., & Rowling, G. C. (2002). 3D seismic horizon-based approaches to fracture-swarm sweet spot definition in tight-gas reservoirs. The Leading Edge, 21(1), 28—35. doi: 10.1190/1.1445844.

Khromova, I., Link, B., & Marmelevskyi, N. (2011). Comparison of seismic-based methods for fracture permeability prediction. First Break, 29(1), 37—44. doi: 10.3997/1365-2397.2011001.

Konyushenko, À., Shumilyak, V., Solgan, V., Inozemtsev, A., Solovyev, V., & Koren, Z. (2014). Using full-azimuth imaging and inversion in a Belarus salt dome tectonic regime to analyze fracturing in Upper Devonian intersalt and subsalt carbonate reservoirs. First Break, 32(9), 81—88.

Laubach, S. E., Marrett, R. A., Olson, J. E., & Scott, A. R. (1998). Characteristics and origins of coal cleat: A review. International Journal of Coal Geology, 35(1—4), 175—207. doi: 10.1016/S0166-5162(97)00012-8.

Li, Y., Dowton, J., & Goodway, B. (2003). Recent applications of AVO to carbonate reservoirs in the Western Canadian Sedimentary Basin. The Leading Edge, 22(7), 670—674. doi: 10.1190/1.1599694.

Mavko, G., Mukerji, T., & Dvorkin, J. (2009). The rock physics handbook, Second Edition: Tools for Seismic Analysis of Porous Media. Cambridge University Press.

Oliveira, L., Pimentel, F., Peiro, M., Amaral, P., & Christovan, J. (2018). A seismic reservoir characterization and porosity estimation workflow to support geological model update: pre-salt reservoir case study, Brazil. First Break, 36(9), 75—85.

Pardus, Y. C., Conner, J., Schuler, N. R., & Tatham, R. H. (1990). VP /VS and lithology in carbonate rocks: A case study in the Scipio trend in Southern Michigan. 60th SEG Annual Meeting, Expanded Abstracts, 169—172. doi: 10.1190/1.1890101.

Rafavich, F., Kendall, C. H. St. C., & Todd, T. P. (1984). The relationship between acoustic properties and the petrographic character of carbonate rocks. Geophysics, 49(10), 1622—1636. doi: 10.1190/1.1441570.

Rüger, A. (1998). Variation of P-wave reflectivity with offset and azimuth in anisotropic media. Geophysics, 63(3), 935—947. doi: 10.1190/1.1444405.

Rüger, A., & Tsvankin, I. (1997). Using AVO for fracture detection: Analytic basis and practical solutions. The Leading Edge, 16(10), 1429—1434. doi: 10.1190/1.1437466.

Sarg, J. F., & Schuelke, J. S. (2003). Integrated seismic analysis of carbonate reservoirs: From the framework to the volume attributes. The Leading Edge, 22(7), 640—645. doi: 10.1190/1.1599689.

Todorovic-Marinic, D., Mattocks, B., Bale, R., Gray, D., & Dewar, J. (2005). More powerful fracture detection: Integrating P-wave, converted-wave, FMI and everything. 67th EAGE Conference, Extended Abstracts, Paper E038.

Treadgold, G., Campbell, B., McLain, B., Sinc-lair, S., & Nicklin, D. (2011). Eagle Ford shale prospecting with 3D seismic data within a tectonic and depositional system framework. The Leading Edge, 30(1), 48—53. doi: 10.1190/1.3535432.

Tsuneyama, F., Takahashi, I., Nishida, A., & Okamura, H. (2003). VP/VS ratio as a rock frame indicator for a carbonate reservoir. First Break, 21(7), 22—27. doi: 10.3997/1365-2397.2003011.

Vetri, L., Loinger, E., Gaiser, J., Grandi, A., & Lynn, H. (2003). 3D/4C Emilio: Azimuth processing and anisotropy analysis in a fractured carbonate reservoir. The Leading Edge, 22(7), 675—679. doi: 10.1190/1.1599695.




Creative Commons License
Licensed under a Creative Commons Attribution 4.0 International License.

Flag Counter