西斜坡区萨二、三油层油气保存条件

Conditions of oil and gas preservation in S_(2,3) oil layer in west slope region

通过西斜坡区嫩一段泥岩盖层封闭特征,研究萨二、三油层地层水保存条件和侧向遮挡条件,阐述其油气藏形成与保存条件的作用,分析了油气在纵向和侧向上的保存条件,结果表明:西斜坡区嫩一段泥岩盖层具有中等至较好的封闭能力;西斜坡区萨二、三油层油气在纵向上只有保存在一般浓缩亚区才能阻止氧化和菌解作用的破坏;其油气侧向遮挡条件不发育,主要是一些低幅度的鼻状构造和面积较小的背斜圈闭,还有一些地层超覆,砂岩上倾尖灭和断层遮挡可为油气聚集提供侧向遮挡条件.

Through the study of sealing characteristics of K1n1 mudstone caprock,preservation conditions of formation water and later seal condition of S 2,3 oil layer in west slope region,this paper deals with the vertical and lateral preservation characteristics of S 2,3 oil layer in west slope region.The effect of preservation conditions of the formation and preservation of oil or gas reservoirs has been discussed,so we arrive at a conclusion that the mudstone caprock of K1n1 to possesses moderate and good sealing ability.The oil or gas preservation conditions are good.Only oil or gas of S 2,3 oil layer was preserved in general concentration subarea,it can stop the destruction of oxidization and degradation.Lateral seal condition of S 2,3 oil layer in west slope region did not develop.They are mainly nose structures whose scope is low and anticlines with small sizes.Some strata overlap,sandstone updip pinch out and fault seal can also provide lateral seal for oil or gas to accumulate.