苏里格气区盒8段地层古今构造特征及其对气水分布的控制作用

Ancient and modern tectonic characteristics of 8th member of Xiashihezi Formation in Sulige Gasfield,Ordos Basin,China and their control effects on gas-water distribution

苏里格气区构造上位于鄂尔多斯盆地伊陕斜坡西部,近年来的勘探开发表明该区盒8段储层有近1/3的探井不同程度地产水.盒8上亚段的产气、产水井主要分布在布拉格苏木—乌审旗一带,盒8下亚段则主要分布在毛脑海庙—雷龙湾的北部及东北部地区.剖面上气水分布关系复杂,多个不同含气性的渗流单元相互叠置,气水分异作用不明显.分析认为:古今区域构造背景对盒8段储层内气水宏观分布具有较重要的控制作用,表现为东部相对富气、西部相对富水,而局部构造对气水分布的控制作用并不明显;K1末盒8段地层的构造面貌比较复杂,气、水多产出于构造平缓的斜坡带上.多因素的分析表明,气源条件、沉积特征、储层非均质性是影响气水分布的首要因素,在这一背景下,构造演化特征控制了气水分布的宏观格局.

Geological tectonic of Sulige gas field belongs to the west of Yishaan slope in Ordos Basin,China.The recent exploration and development has revealed that nearly one third of explortation wells of 8th member of Xiashihezi Formation start producing water in various degree.The gas and water producing wells of the upper submember of He-8 mainly distribute in Braggsuppan-Wushenqi zone,and those of the lower submember of He-8 mainly distribute in the north and northeast of Maonaohaimiao-Leilongwan zone.On section,the gas-water distribution relationship is complex,which shows the mutual superposition among the multiple seepage units with different gas saturations,and shows the indistinct differentiation between gas and water.It is held that ancient and modern tectonic background dominates the macro gas-water distribution of He-8 member,which display that,gas is richer in the eastern area,water is richer in the western area,and local structures have unapparent control on the gas-water distribution.The tectonic feature of in He-8 reservoir in the end of early Cretaceous is complex,and the produced gas and water is mainly from the gently slope zone.The analysis of multiple factors shows that the primary factors of influencing gas-water distribution are gas source conditions,sedimentary characteristics and reservoir heterogeneity.Under such background,tectonic evolution characteristics dominate the macro pattern of gas-water distribution.