裂缝预测技术在玛湖地区页岩油勘探中的应用

Application of fracture prediction technology in shale-oil exploration in Mahu area

准噶尔盆地玛湖地区二叠系风城组页岩油层发育大量天然裂缝,裂缝的发育程度决定了单井的产量,但是仅凭叠后地震资料难以准确预测裂缝尺度、发育特征和分布规律。为此,依托GeoEast系统总结出一套利用叠前、叠后资料开展地震裂缝预测的技术思路:首先,从单井出发,结合岩心、成像资料确定裂缝发育段;其次,通过叠后资料相干体、曲率属性识别一级和次级大尺度断裂,同时运用五维地震解释技术的振幅各向异性属性识别小尺度微裂缝;最后,充分结合宽方位叠前资料、叠后地震资料信息,预测裂缝密度及方向,明确了风城组页岩油层裂缝分布规律。综合预测出研究区内三个裂缝发育区,该预测结果为玛湖地区页岩油水平井部署提供了支持。

A large number of natural fractures are developed in shale-oil reservoir of the Permian Fengcheng Formation in the Mahu area,Junggar Basin.The development degree of fractures determines the production of a single well.However,it is difficult to accurately predict the scale,development characteristics,and distribution law of the fractures only by post-stack seismic data.On the basis of GeoEast software,this paper studies a single well and determines fracture development sections by rock core and imaging data.In addition,making full use of wide-azimuth pre-stack and post-stack seismic data,five-dimensional seismic interpretation technology,the study identifies large-scale faults and small-scale micro-fractures,clarifies fracture distribution law,and predicts fracture strength and direction.Finally,three fracture development areas in the study area are comprehensively predicted.The fracture prediction results provide certain support for the deployment of shale-oil horizontal wells in the Mahu area.