延长气田地层水化学特征及气水分布规律

Chemical characteristics of formation water and gas-water distribution regularity in Yanchang gas field

延长气田气藏出水较严重,气、水分布规律认识不明晰,制约了气田开发进程.综合利用各类测试资料,通过统计分析、叠合对比,系统的研究了地层水化学特征及气、水分布规律,研究表明：地层水呈弱酸性,具有高矿化度特征,表现为封闭地层水特点,总矿化度主要集中在7.49 ～391.74 g/L,平均为94.36 g/L,属于氯化钙型,纵向上由浅到深矿化度逐渐增加,平面上相邻井间矿化度相差较大,地层水主要为局部层间滞留水,水体交换弱;控制气、水分布的主要因素为烃源岩、沉积特征、储集层物性等,烃源岩对气、水分布起到关键作用,构造对气、水分布作用不明显.地层水主要分布在烃源岩欠发育区、沉积边缘相带、物性欠佳区.该研究成果可指导研究区井位优选,确定合理的开发对策.

Comprehensively making use of all kinds of testing data, through statistical analysis, superim posed contrast, analysis of formation water chemical characteristics and the gaswater distribution regular ity. Results show that：formation water is faintly acid, formation water salinity is quite high with 7.49 391.74 g/L, average is 94.36 g/L, and water type is CaC12. On the vertical, salinity increases with depth, In the plane, salinity has big difference between adjacent wells, mainly for the retained with weak water exchange;source rock, depositional characteristics and reservoir physical property are the key con trolling factors of gaswater distribution. Source rocks play a key role for gaswater distribution, but struc ture is not important, and formation water is distributed in areas with less developed source rocks, deposit borders and areas of poor properties. This research can be applied for determining a reasonable exploita tion and selecting well site in the development of the gas field.