In last years, the share of hard-to-recover oil reserves, concentrated in low-permeability carbonate reservoirs, where fractures mainly provide permeability, is increasing significantly. To date, fields of this type are located on the territory of the Russian Federation in Eastern Siberia, the Timan-Pechora region, the Caucasus, etc. The difficulties in developing such reservoirs are due to the irregular distribution of fractures and caverns, which are the main ways of fluid filtration and form the basis of the capacitive space of the fracture reservoir type. Rosneft Oil Company implements an extensive innovative program, using a technology for separating scattered and reflected waves on the base of the Gaussian beam method which is developing in Corporate Research and Design Complex
(RN-KrasnoyarskNIPIneft). The new technology has a high and uniform resolution, which makes it possible to obtain clear diffraction images of the fine structure of fractured-cavernous reservoirs. In this paper, we describe this technology. And present results of its verification on a synthetic model, describing a carbonate fractured-cavernous reservoir. Statistical characteristics of the model and corresponding images in scattered waves are compared, analyzed and discussed. The results prove, that some statistical characteristics are saved, in particular, the characteristic size of the heterogeneity of the near-fault zone. A systematic change in the parameters of the geological model was used to study how they display in seismic images by comparing their statistical characteristics. The application of the technology will increase the efficiency of the promotion of exploration and production drilling at the fields of Rosneft Oil Company with a difficult geological structure. First, it will be possible to reduce the geological risks associated with missed tectonic disturbances that limit the reservoir and directly affects the assessment of hydrocarbon reserves. Next, the technology allows localization of zones, associated with improved filtration and capacitance properties with high accuracy, which is of fundamental importance for geological modeling of complex reservoirs and subsequent successful drilling.
References
1. Kutovenko M.P., Protasov M.I., Cheverda V.A., Gaussian beams true-amplitude seismic imaging of multi-component data (In Russ.), Tekhnologii seysmorazvedki, 2010, no. 4, pp. 3 – 13.
2. Protasov M.I., Cheverda V.A., True amplitude seismic imaging of multicomponent walk-away VSP data (In Russ.), Tekhnologii seysmorazvedki, 2012, no. 3, pp. 31-41.
3. Protasov M.I., Cheverda V.A., Using Gaussian beams to build true-amplitude images (In Russ.), Tekhnologii seysmorazvedki, 2006, no. 4, pp. 3 – 10.
4. Kostin V.I., Lisitsa V.V., Reshetova G.V. et al., A finite-difference method for the numerical simulation of seismic wave propagation through multiscale media (In Russ.), Vychislitelʹnye metody i programmirovanie, 2011, V. 12, pp. 321 – 329.
5. Kostin V., Lisitsa V., Reshetova G. et al., Local time-space refinement for simulation of elastic wave propagation in multi-scale media, Journal of Computational Physics, 2015, V. 281, pp. 669 – 689.
6. Lisitsa V.V., Pozdnyakov V.A. et al., Scattered seismic responses: simulation and imaging. Part 1. Two-dimensional media (In Russ.), Tekhnologii seysmorazvedki, 2013, no. 1, pp. 46-58.
7. Tveranger J., Skar T., Braathen A., Incorporation of fault zones as volumes in reservoir models, Bolletino di Geofisica Teorica e Applicata, 2004, V. 45(1), pp. 316–318.
