蜀南地区DTC区块中二叠统茅口组高产气井地震响应及裂缝预测研究

针对蜀南地区DTC区块中二叠统茅口组储层孔渗条件差、非均质性强的特点，开展了茅口组主力产层段茅三段高产井地震反射特征及裂缝定量预测研究。结合邻区勘探成果，通过对研究区多口高产井的储层精细标定，总结出高产井储层段的地震波形特征为低频强振幅的波谷响应，横向上波谷呈现较强的扭曲错动现象，包括波谷反射不连续，并伴有波形分叉、合并或呈楔形、复波等，为茅口组顶部古风化壳物性横向非均质性强、低速缝洞系统的特征响应。以此为基础，利用基于叠前方位各向异性(AVAZ)技术对茅三段裂缝发育特征进行了预测和刻画，经与钻井、前期叠后裂缝预测结果反复比对，最终认为利用AVAZ技术进行裂缝预测，结果更加可靠，更加适用于蜀南地区海相碳酸盐岩的裂缝预测。 关键词 蜀南地区 茅口组 地震响应 叠前方位各向异性 裂缝预测基金项目：国家十三五重大专项（编号：2016ZX05052001，2016ZX05047-002-05）、中国石油集团公司重大专项编号：2016E-0604）、中国石油科技创新基金研究项目（2016D-5007-0107）联合资助 第一作者简介：吴仕虎（1981— ），博士研究生。研究方向：石油地质与地球物理综合研究。E-mail：shihuwu@petrochina.com.cn

Study on Seismic Response to Production Intervals with High Productivity and Fracture Prediction of the Middle Permian Maokou Formation in the DTC Block, Shunan Area, Sichuan Basin

This paper deals with seismic response to production interval with high productivity and fracture prediction of the third member of Middle Permian Maokou formation, with very low porosity and permeability and strong heterogeneity, in the DTC block, Shunan Area, Sichuan Basin. Together with neighboring exploration achievements, we firstly carried out fine calibration between synthetic seismograms and through-well seismic profiles to analyze and summarize the seismic response to production intervals with high productivity, the result shows that those production intervals with high productivity are characterized by wave trough with low frequency and strong amplitude, and laterally have characteristic of relatively strong distortion and dislocation, including discontinuous trough reflection accompanying waveform divarication, amalgamation, or showing wedge-shaped and composite waveform and so on, they are probably seismic response to fault damage zone, paleo weathering crust with strong lateral heterogeneity, and low velocity cave-fractured reservoir. And then, with the help of AVAZ technique, based on prestack seismic data, we conducted fracture identification and its distribution prediction for the third member of Moukou formation, after repeated comparison among drilling data, previous prediction results using poststack data, final result indicates that, in our study area, the fracture prediction result using AVAZ technique is more accurate and more suitable than others