川东高峰场地区凉高山组致密砂岩甜点储层地质特征及地震综合预测技术

Seismic geological characteristics and exploration prospect of tight sandstone in Lianggaoshan Formation of Gaofengchang block,eastern Sichuan Basin,China

近年来随着国家油气需求进一步增加,致密储层逐渐成为研究热点,川东地区凉高山组是典型的致密砂岩储层,具有层系多、河道规模大、砂体厚、生储组合好和烃源丰富等优点,具有较好的勘探前景,但也存在储层岩性致密、孔渗低、勘探程度低等难题。针对这些问题,从地震地质资料入手,详细分析凉高山组纵横向砂岩储层地震地质特征。研究发现:优势砂体发育在凉高山组中上部,中下部烃源岩发育好,水下分流河道及河口坝为主要储集体,河道宽度大,河道沙坝呈块状非连续性分布,油气保存条件较好。储层甜点区受相带控制特征明显,远离通天断层的向斜区、河道中沙坝、裂缝发育区为最有利的勘探区域。

In recent years,as the national oil and gas demand has further increased,tight reservoirs have gradually become a research hotspot. The Lianggaoshan Formation in eastern Sichuan Basin is a typical tight sandstone reservoir,which has the advantages of multiple layers,large scale of river channels,thick sand bodies,good source-reservoir assemblage and abundant hydrocarbon sources,and has good prospects for exploration.However,there are also problems such as tight reservoir lithology,low porosity and permeability,and low degree of exploration. In response to these problems,this article starts with seismic geological data and analyzes in detail the seismic geological characteristics of vertical and horizontal sandstone reservoirs in the Lianggaoshan Formation,and the research finds that dominant sand bodies are developed in the middle and upper parts of Lianggaoshan Formation,source rocks are well developed in the middle and lower parts of Lianggaoshan Formation. The underwater distributary channels and estuary dams are the main reservoirs,the channel width is large,and the channel sand dams are distributed in blocky discontinuity,and the oil and gas preservation conditions are good. Reservoir sweet spots are obviously controlled by facies belts,and syncline areas far away from the Tongtian fault,sand bars in river channels,and fracture-developed areas are the most favorable exploration areas.