基于多分量地震资料的河道砂体刻画及含气性预测技术——以QL地区沙溪庙组为例

Channel sand body characterization and hydrocarbon detection based on multi-component seismic data:A case study of Shaximiao Formation in QL area

四川盆地中部地区中侏罗统沙溪庙组为三角洲前缘沉积,水下分流河道砂体发育,是新一轮非常规天然气勘探开发的新领域。但依靠现有纵波地震资料刻画出的河道砂体边界不清楚、部署的井位产能差异较大,难以满足致密气高效勘探开发的需求。针对勘探与开发的需求以及面临的河道砂体边界刻画不准确、储层含气性预测难等地质问题,利用2020年QL地区新采集的三维三分量地震勘探资料开展了研究,形成了基于多波地震资料融合的河道雕刻技术。该技术较单一纵波可更加清楚地刻画河道边界,补充中、高阻抗河道砂体的识别;形成了基于多波资料的含气预测技术,并利用河道砂体含气后纵波、转换波的地震振幅响应特征及相位特征的差异性,建立了高产气井的多波地震响应模式,从而获得含气性预测成果。该研究成果支撑了区内致密气开发井位部署,为致密气高效开发奠定了基础。

The Middle Jurassic Shaximiao Formation in the central area of Sichuan Basin is a delta front deposit with underwater distributary channel sand bodies,which is a new round of unconventional natural gas exploration and development in this area.However,the boundary of channel sand body depicted by the existing P-wave seismic data is unclear,and the productivity of deployed well locations varies greatly,which is difficult to meet the needs of efficient exploration and development of tight gas.In view of the needs of exploration and development and the geological problems faced,such as inaccurate characterization of river sand body boundary and difficult prediction of reservoir gas content,this paper uses the newly collected three-dimensional and three-component seismic exploration data in QL area in 2020 to carry out the research.The river carving technology based on multi wave seismic data fusion is formed,which depicts the river boundary more clearly than a single P-wave,and complements the identification of medium and high impedance river sand bodies.The gas bearing prediction technology based on multi wave data is formed.Using the differences of seismic amplitude response characteristics and phase characteristics of longitudinal wave and converted wave after gas bearing in river sand body,the multi wave seismic response model of high-yield gas well is established,and the gas bearing prediction results are obtained.The research results support the deployment of tight gas development well location in this area and lay a foundation for efficient development of tight gas.