川西裂缝性致密碎屑岩气藏高渗区成因机理及预测

川西深层上三叠统须家河组二段致密碎屑岩气藏非均质性极强,裂缝网络与相对优质储层叠加形成的高渗区分布预测是钻井获得高产稳产的技术关键。通过地表露头调查、钻井资料统计分析及地震地质综合研究,剖析了高渗区地质成因机理,认为在砂岩及岩性相变带、相对薄层及地层厚度突变带、优质储层发育区、强构造褶皱变形区、断裂附近等易于形成裂缝及高渗区。通过高渗区储层测井及波阻抗特征、地震响应特征对比分析、模型正演等方法,建立了"杂乱弱反射"地震暗点识别模式,利用吸收处理、像素成像、三维可视化等地震技术手段,预测了高渗区分布,解释了各高渗区地质成因,钻井验证了预测结果。

Genetic Mechanism and Seismic Reservoir Prediction for the High-permeability Block of Fractured Tight Clastic Rock Gas Reservoirs in Western Sichuan

The tight clastic rock gas reservoirs in the second Member of the Upper Triassic Xujiahe Formation of deep formation in Western Sichuan is characterized by strong inhomogeneity.The high-permeability block which is combination of fractured network and relatively high quality reservoir distribution predicted,is the key technology for gaining high and stable yields.Based on observing surface outcrops,drilling data of statistical analysis and seismic profiles,the genetic mechanisms of the high-permeability block are analyzed.The fractured and high-permeability zones are well developed in the facies-varied zone,the break zone of bed thickness,the excellent reservoir block,the strong structural deformation zone and the area near the fault.With contrastive analysis of the characteristic of high efficiency reservoir permeable area logging,wave impedance and seismic response,model forward,etc,the identifying patterns for dim spots of littery reflection and weak reflection are built,the distribution of high-permeability block is predicted,and the geologic origin of the high-permeability block is discussed by the poststack absorbs processing,the body image pixel technology and the three-dimensional(3D) visualization technology.The predicted results are verified by drilling.