克拉苏气田超致密砂岩气储层水锁损害

发布时间：2019-06-25 20:40

【摘要】：超致密砂岩微米、纳米级孔喉发育且连通性差,气层具有毛细管压力高、黏土矿物含量高、含水饱和度低等特征,水锁是这类气藏重要的损害方式。现有的水锁损害评价标准存在未建立初始含水饱和度、地层水盐析、水敏伤害与水锁伤害叠加耦合、渗透率测试具有系统误差、评价不全面等问题,文中以克拉苏气田克深9井区K1bs组超致密砂岩为研究对象,利用核磁成像技术实时监测岩样毛细管自吸过程,运用高温钝化、高速离心、恒压驱替、核磁共振等手段建立该类气藏水锁损害评价方法,并据此进行室内实验,对比评价蒸馏水、质量分数8%的KCl溶液与破胶压裂液等流体对超致密砂岩气层基质的损害程度。结果表明,气层孔喉半径越小,流体黏度越大、矿化度越高,初始含水饱和度与束缚水饱和度差异越大,气层水锁损害越强。
[Abstract]:Ultra-tight sandstone micron, nanometer pore throat development and poor connectivity, gas reservoir has the characteristics of high capillary pressure, high clay mineral content, low water saturation and so on. Water lock is an important damage mode of this kind of gas reservoir. The existing evaluation standards of water lock damage have some problems, such as unestablished initial water saturation, formation water salting out, superimposed coupling of water sensitive damage and water lock damage, systematic error in permeability test, incomplete evaluation and so on. In this paper, the ultra-tight sandstone of K1bs formation in well Kesheng 9 of Klassou gas field is taken as the research object, the capillary self-priming process of rock samples is monitored in real time by nuclear magnetic imaging technology, high temperature passivation, high speed centrifugation and constant pressure displacement are used. The evaluation method of water lock damage of this kind of gas reservoir was established by nuclear magnetic resonance (NMR), and the laboratory experiments were carried out to compare and evaluate the damage degree of distilled water, 8% KCl solution and gel fracturing fluid to the matrix of ultra-tight sandstone gas reservoir. The results show that the smaller the pore throat radius is, the greater the fluid viscosity is, the higher the salinity is, the greater the difference between initial water saturation and bound water saturation is, and the stronger the damage of gas reservoir water lock is.
【作者单位】：西南石油大学地球科学与技术学院;西南石油大学油气藏地质及开发工程国家重点实验室;中国石油塔里木油田油气工程研究院;
【基金】：国家自然科学基金项目“页岩气储层纳米尺度非均质性研究”(51674211)、“致密气藏储层干化、提高气体渗流能力的基础研究”(51534006)
【分类号】：TE258

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