川西坳陷深层须家河组裂缝模型含气响应研究

Research on gas bearing response to fracture models of Xujiahe formation in deep west Sichuan depression

(1.成都理工大学网络学院，四川成都618002； 2.中国石油化工股份有限公司西南分公司勘探开发研究院德阳分院，四川德阳618000；3.上海中浦勘查技术研究所，上海200003)

Deyang Branch Institute, Exploration & Production Research Institute, Southwest Branch Co., SINOPEC, Deyang 618000, China

川西坳陷深层须家河组具有储层预测难、裂缝分布描述难、含气性检测难等问题。为了进一步揭示该区裂缝介质的含气响应特征，探索裂缝储层预测与描述的有效方法与技术手段，建立了近似地层原位条件的裂缝储层模型并进行数值模拟，从而分析地震波的传播特性，以指导该区地震资料的处理和解释。其主要研究思路是：首先，基于Hudson裂缝介质理论，采用复杂裂缝性气藏地质模型建立方法,充分利用该区的实际地震资料、测井资料与岩石物理测试参数等信息，建立与地层原位条件近似的各种含气裂缝介质模型；其次，运用各向异性介质地震波全波场正演数值模拟技术对裂缝模型进行数值模拟，获得地震波场数据；最后，从地震波的能量、相位、瞬时信息、频谱特征及吸收衰减属性等角度对获得的地震波场记录进行含气性分析，归纳总结裂缝模型的含气响应特征。研究结果显示，当地震波经过含气裂缝介质时，其振幅、相位、频率均具有明显的异常特征，如“亮点”现象、高频衰减等。利用这些异常特征更有利于川西坳陷深层须家河组的储层解释、裂缝分布描述及含气性检测。

In Xujiahe formation of west Sichuan depression, it is difficult in reservoir prediction, fracture description, and gas bearing detection. In order to reveal the gas bearing response to fractured medium and probe into the effective methods and technologies for predicting and describing fracture reservoir, the fractured reservoir model approximating the original strata condition was established, and the numerical simulation carried out on it. Then, the propagation characteristic of seismic wave was analyzed to guide the data processing and interpretation of the area. The workflows are that, firstly, based on Hudson fracture medium theory and sufficient utilization of actual seismic data, logging data, and petrophysical properties, the geological model method of complex fractured gas reservoir is used to establish all kinds of gas-bearing fractured medium model similar to the original strata condition. Then, the full wave-field numerical simulation technology based on anisotropic seismic wave propagation theory was adopted to simulate those fracture models and obtain the seismic wavefield data. Lastly, from the point of energy, phase, instantaneous information, spectrum signature, absorption and attenuation attribute, gas-bearing analysis was carried out based on the obtained seismic wavefield records, and the gas bearing response of fractured model was concluded. The results indicate that the amplitude, phase and frequency of seismic waves has obvious anomaly when the seismic wave travels through gas-bearing fractured medium, such as bright spot and high frequency attenuation. The anomalies are beneficial to reservoir interpretation, fracture description and gas bearing detection for Xujiahe formation in deep west Sichuan depression.