川西深层致密碎屑岩气藏储层预测方法

川西深层须家河组致密碎屑岩气藏属近源气藏，具有超深、超压、超致密、低孔隙度、低渗透率和强非均质性的特点，其有利储层分布、储层裂缝发育带预测和含气性识别是制约气藏勘探开发的难点。为此，针对须家河组气藏的特点，基于储层特征分析及储层分类，建立了波阻抗反演与拟声波测井约束波阻抗反演、地震相划分、地震属性分析、地震分频预测等多技术相结合的有利储层横向展布预测方法；采用地质、地震、测井等多学科联合研究的方法，系统地建立了多尺度裂缝发育带预测和裂缝综合评价技术系列；以叠前反演和叠前地震属性提取方法为主，建立了AVO岩石物性参数反演、AVD叠前反演油气预测、Proni吸收滤波、吸收梯度预测、双相介质理论含气性识别、多尺度频率和吸收分析等含气性预测和识别的技术系列。综合利用上述方法，对须家河组致密非均质裂缝性储层进行了有利储层识别、裂缝检测和含气性预测，取得了较好的效果，预测结果与钻井结果吻合。

Prediction of gas reservoir in deeply buried tight clastic rock in west Sichuan

The tight clastic rock gas reservoir in deeply buried Xujiahe formation in west Sichuan is a near-source gas reservoir and characterized by super deep,over-pressured,excessively tight,low porosity,low permeability,and high heterogeneity.The key problems for the exploration and development of such gas reservoirs are the prediction of potential reservoir distribution,fracture development belt,and recognition of gas-bearing area.Aiming at the characteristics of gas reservoir of Xujiahe formation,based on the reservoir characteristics analysis and classification,combining wave impedance inversion and pseudo acoustic logging impedance inversion with seismic facies classification,seismic attributes analysis,seismic frequency division prediction technology,the favorite prediction method for reservoir horizontal distribution was established.Multi-discipline study (geology,seismic,and logging) was adopted to establish prediction technology for multi-scale fracture development belt and synthetic evaluation technology for fractures.The pre-stack inversion and pre-stack seismic attribute extraction method were applied to develop a series of technologies for gas-bearing prediction and recognition,including AVO petro-physical parameters inversion,AVD pre-stack inversion,Proni absorption filtering,absorption gradient prediction, two-phase medium theory analysis, multi-scale frequency and absorption analysis,etc.By synthetically using the above methods,potential reservoir identification,fracture detection, and gas-bearing prediction were carried out on the tight heterogeneity fractured reservoir of Xujiahe formation.Good results have been achieved,which coincides with the drilling results.