地震-地质导向技术在盆缘复杂构造带的应用——以南川区为例

Application of seismic-geological steering technology in complex structural belt along basin margin-A case study of Nanchuan area

南川页岩气田位于川东南盆缘构造带,目标层系五峰组—龙马溪组经过多期构造运动改造,地层变形强烈,断裂、褶皱发育,地层产状变化剧烈,水平井的地质导向工作难度大。为保证水平井顺利入窗,提高靶窗钻遇率,本文以地震-地质一体化导向技术为研究目标。建立了层控、断控、井控的“三控”特色速度建模技术,得到较为可靠的深度域数据体。以深度域地震数据为基础,建立工区构造模型、地质模型,立体把控目的层空间展布形态,优化了靶点深度和水平段地层产状的预测方法。综合分析认为,地震-地质导向技术在水平井精准着窗、靶窗平稳穿行等导向关键环节均呈现了良好的指示意义。是复杂构造带油气效益勘探开发行之有效的技术方法,值得在同类型区块推广应用。

Nanchuan shale gas field is located in the southeastern margin of the Sichuan Basin structural belt.The target reservoir O3w-S1l have undergone multiple tectonic movements and transformations,with strong deformation of strata,developed faults and folds,and dramatic changes in strata occurrence,making it difficult to geosteer for horizontal wells.In order to ensure that horizontal wells enter windows smoothly and improve the drilling encounter rate of target windows,this article takes seismic-geological integrated guidance technology as the research goal.A“three-control”characteristic velocity modeling technology of layer control,fault control,and well control was established to obtain a more reliable depth domain data body.Based on the depth-domain seismic data,a construction model and geological model of the working area were established to 3D control the spatial distribution of the target layer and optimize the prediction method of target depth and stratigraphic occurrence in horizontal sections.Comprehensive analysis shows that seismic-geological guidance technology has good indicative significance in key guidance links such as accurate windowing of horizontal wells and smooth passage through target windows.It is an effective technical method for oil and gas exploration and development in complex structural belts and is worth promoting and applying in similar blocks.