小尺度缝洞型碳酸盐岩储集体地震预测技术
——以四川盆地台内GS18井区灯影组四段储层为例

Seismic prediction technology of small scale fractured-cave carbonate reservoir: taking the intra-platform reservoir of the fourth Member of Dengying Formation in GS18 wellblock, Sichuan Basin as an example

李春梅,彭才,韦柳阳,别静,王紫笛,李雯琪,何小会

LI Chunmei, PENG Cai, WEI Liuyang, BIE Jing, WANG Zidi, LI Wenqi, HE Xiaohui

中国石油东方地球物理公司西南物探研究院，四川 成都 610000

Southwest Geophysical Research Institute, BGP Inc., CNPC, Chengdu 610000, China

四川盆地灯影组为一套岩溶缝洞型碳酸盐岩储层。由于储层埋藏深度大、风化岩溶时间短，使得储层非均质性强、缝洞尺度小，常规地震技术预测储层困难。文中以GS18井区灯影组四段台内气藏为例，采用双高处理思路，进行低频保幅噪声压制、沿层速度分析及一体化速度优化、OVT域各向异性叠前时间偏移，获得高分辨率高保真地震资料。在高品质地震资料基础上，通过单井分析、模型正演、分频、分方位等技术手段，开展了断裂精细刻画及小尺度缝洞展布预测。研究成果有效指导了四川盆地GST台内区井位部署及钻井调整。

Dengying Formation in Sichuan Basin is a set of karst fracture-cave carbonate reservoirs. Due to the large burial depth and short weathering karst time, the reservoir has strong heterogeneity and small size of fracture and cave, so it is difficult to predict by conventional seismic technology. Taking the intra-platform gas reservoir of the fourth Member of Dengying Formation in GS18 wellblock area as an example, the “double-high” processing idea is adopted to carry out the low-frequency amplitude-preserving noise suppression, the velocity analysis along the layer and the integrated velocity optimization, the OVT domain anisotropic prestack time migration, and finally the high-resolution and high-fidelity seismic data are obtained. On the basis of high quality seismic data, by means of single well analysis, model forward modeling, frequency division and azimuth division, the fine characterization of faults and the distribution prediction of small scale fractures and cavities are carried out. The research results have effectively guided the well placement and drilling adjustment of GST intra-platform in Sichuan Basin.

10.6056/dkyqt202202008