Prediction and identification of gas-bearing properties of tight sandstone reservoirs through simultaneous pre-stack inversion:A case study of block S in Sulige gas field
ZHANG De-Ming(), LIU Zhi-Gang, ZANG Dian-Guang, LIAO Xian-Feng, LIU Zhi-Yi, LIU Guo-Bao
Southwest Institute of Geophysical Exploration,BGP Inc.,China National Petroleum Corporation,Chengdu 610036,China
Owing to the small impedance difference with surrounding rock and complex gas-water relationships,it is difficult to identify high-quality reservoirs in block S in the Sulige gas field through the post-stack P-wave impedance inversion.According to the petrophysical analysis of the study area,the pre-stack parameter vp/vs ratio can be used to effectively identify lithology and gas-bearing properties.This study firstly determined the seismic response characteristics of the reservoirs through forward modeling.Secondly,it conducted petrophysical modeling and the prediction of shear-wave velocities using the Xu-White model suitable for sandstone and mudstone and accordingly established a petrophysical model.Thirdly,the CRP gathers were optimized using the processing methods such as linear denoising and residual amplitude compensation.Finally,the thickness and gas-bearing properties of the reservoirs in block S in the Sulige gas field were quantitatively predicted through simultaneous pre-stack inversion.The results are as follows.(1)The top boundary of the reservoirs in the study area shows the seismic reflection characterized by strong trough reflection,while the bottom boundary of the reservoirs shows unapparent seismic reflection;(2)The vp/vs ratio of less than 1.68 can be used to effectively determine sandstone.This combined with the P-wave impedance of less than 12200 g·cm-3 ·m·s-1 can be used to predict the reservoirs in the study area. Moreover, a vp/vs of less than 1.57 can be used to identify the gas-bearing properties;(3)Reservoir distribution and the predicted gas-bearing range have similar trends but differ locally.The development degree of reservoirs is not necessarily positively correlated with the gas content.The method proposed in this paper is expected to provide strong technical support for delineating the favorable gas-bearing reservoir area and deploying well locations in the future.
张德明, 刘志刚, 臧殿光, 廖显锋, 刘志毅, 刘国宝. 基于叠前同时反演的致密砂岩储层预测及含气性识别——以苏里格S区块为例[J]. 物探与化探, 2022, 46(3): 645-652.
ZHANG De-Ming, LIU Zhi-Gang, ZANG Dian-Guang, LIAO Xian-Feng, LIU Zhi-Yi, LIU Guo-Bao. Prediction and identification of gas-bearing properties of tight sandstone reservoirs through simultaneous pre-stack inversion:A case study of block S in Sulige gas field. Geophysical and Geochemical Exploration, 2022, 46(3): 645-652.
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