辫状河含气砂岩储层预测

鄂尔多斯盆地苏西地区盒8 段及山1 段为辫状河沉积，其含气储层与围岩纵波阻抗相近，利用常规叠后资料
不能有效识别含气储层；同时，山1 段砂体为中-弱振幅不连续地震反射，其同相轴无法在全区进行合理追踪，难以
预测砂体的平面展布特点。针对以上问题，根据辫状河地质沉积特点，建立辫状河地震响应模式。利用含气储层和围
岩泊松比差异明显的特点，尝试应用叠前AVO 资料来识别含气储层。借鉴地震沉积学理论和方法，提出将AVO 属性
体岩性化，以便于后续的岩性解释。采用切片方法合理获取山1 段砂体地震反射等时面。研究结果表明：正演和生产
实践均验证了AVO 属性体岩性化这一方法的合理性和实用性。应用该方法对研究区盒8 段和山1 段含气储层进行了
有效的识别，具有等时意义的地震切片属性准确地反映了含气储层空间发育及平面展布特点。

Gas-bearing Reservoir Prediction of Braided River

The He 8 and Shan 1 members belonging to braided-river deposition are pay zones of Sulige western region，
Ordos basin. The ranges of P-wave impedance of gas-bearing reservoir and surrounding rocks of these two members are
overlapping. The gas reservoir could not be feasibly recognized by conventional post-stack seismic data. Also，due to the
discontinuous mid-weak amplitude of seismic reflection，the seismic event of Shan1 member can′t be picked in the whole work
area，leading to difficulty in obtaining the plane view of its sandstone distribution. Attempting to solve the problems above，
we established the seismic response characterization of braided-river according to its sedimentary model. As the difference
of Poisson ratio of gas-bearing reservoir and surrounding rocks are distinct，the AVO seismic data were utilized to identify
gas-bearing reservoir. The conception of lithological converting has been proposed with reference to the theory of seismicsedimentology.
The AVO attribute volume was converted to lithological volume，which provides convenience for the subsequent
interpretation work. The isochronous surface of Shan1 member seismic reflection can be obtained with the aid of slicing method.
The result shows that the feasibility of lithological converting of AVO attribute volume has been demonstrated by forward
modeling and practical application. This series of method is capable of recognizing gas-bearing reservoir of He 8 and Shan 1
members，and the evolutional history and plane distribution character of the gas-bearing reservoir are clearly delineated by the
slices with isochronous significance.