川西大邑气藏气田水化学特征及其动态运移

THE CHEMICAL CHARACTERISTICS AND ITS DYNAMIC TRANSPORTATION OF GAS FIELD WATER OF DAYI GAS RESERVOIR OF WESTERN SICHUAN

大邑气藏气田水与日俱增,严重影响该气藏的正常生产,为此,对该气藏气田水化学特征、类型、保存条件、分布特征及动态运移进行了研究。引用美国水文地质学家洛瓦克(Novk)相图分析法对大邑气田水进行了分析,与盆地标准剖面对比表明:大邑气藏气田水为须家河组原始沉积水和须下盆雷口坡组的海相水;采用钠氯系数、肖勒系数和脱硫系数判定了大邑气藏气田水保存条件,大邑气藏气田水为封闭性、保存条件好的原始沉积水,分别分布于须家河组和雷口坡组;同时,分析、对比气藏生产动态与气田水相应变化,结果表明:大邑气藏稳产期产出的气田水为须家河组原始沉积水,提产后产出的气田水为海相地层水;而大邑气藏气田水动态变化的过程中,控制大邑构造的断层(沟通了三叠系海相和陆相地层,但未切穿区域盖层)起到了非常重要的通道作用;最后总结了大邑气藏气田水动态运移特征;大邑气藏稳产期的特征表明:有效控水、合理生产压差下气藏可稳定生产。

The gas field water in Dayi is increasing day after day,which have effect on the normal production.So,wecarry out studies on its types,preservation condition,distribution and dynamics migration.First,the gas field waterin Dayi has been analyzed by American hydrogeologists Novk's Phase diagram analysis.It is considered that thegas field water in Dayi is original sedimentary water in Xujiahe formation and marine formation water in Leikoupoformation through comparing standard section of Sichuan Basin.The gas field water in Dayi has been determinedto be original sedimentary water in closed and preservation conditions by using the ratio of natrium and chlorine,Schorer Coefficient and the ratios of desulphurization.The gas field water in Dayi is original sedimentary waterin Xujiahe formation and marine formation water in Leikoupo formation.Meanwhile,analyzing the productionperformance of Dayi gas reservoir and comparing the corresponding change of the gas field water shows that the gasfield water produced on stable production period of gas reservoir is original sedimentary water in Xujiahe formationand is marine formation water in Leikoupo formation after increasing sinter output.During the process of dynamicchange of the gas field water in Dayi,the fault(communicating the Triassic continental and marine strata,but notcutting through regional cap) controlling Dayi gas reservoir plays a channel role.Finally,this paper summarizesdynamics migration of the gas field water in Dayi.The characteristics of Dayi gas reservoir on stable productionperiod show that gas reservoir can be produced stably on the basis of controlling water effectively and reasonableproducing pressure drop.