四川盆地须三段低孔渗储层稳产主控因素及其地震响应特征

Main control factors and seismic response characteristics of low porosity and permeability reservoirs in the third members of Xujiahe Formation in Sichuan Basin

三叠系须家河组砂砾岩储层是四川盆地重要产气层系,近期多口探井在川西地区须家河组须三段获高产油气,揭示须三段砂砾岩具有较好的勘探潜力,但开发井稳产效果较差。为明确须三段稳产、高产的主控因素,落实富气区块,以高品质三维地震数据为基础,精细对比高产井、失利井、稳产井的地震响应特征,结合钻、测井资料,开展孔隙度反演和曲率等地震属性分析,明确了"具有一定连通空间规模(厚度、面积)的储层是稳产的基础,微断裂发育程度是高产的关键"的认识,有效地指导了后续勘探开发。对川西地区须三段井位部署具有重要意义,在对四川盆地其他低孔渗储层进行评价时也可以借鉴推广。

Sandy conglomerate reservoirs of Xujiahe Trias Formation are important gas-producing beds in the Sichuan Basin.Recently,a few exploration wells have obtained high-yield oil and gas in Xujiahe Formation in Western Sichuan,which reveals that sandy conglomerates of Xujiahe Formation have good exploration potential.However development well production is not stable.So we work on the main control factors of the third member of Xujiahe Formation.First we make the comparison of seismic response characteristics of high-yield wells,failure wells,and stable-production wells based on high-quality 3 Dseismic data.Then combined with drilling and logging data,seismic attribute analysis is carried out such as porosity inversion and curvature.It is clear that a certain connected space scale(thickness and area)in reservoirs is the basis of stable production and the development degree of subtle faults is the key of high production,which guides the subsequent exploration and development effectively.This observation has important practical significance for well location deployment of the third members of Xujiahe Formation in Western Sichuan,and it is also worth learning and popularizing for other low porosity and permeability reservoir evaluation in Sichuan Basin.