DH低渗气藏储层渗流特征实验研究
发布时间：2018-11-06 12:01
【摘要】：低渗气藏不同于常规气藏,因其低孔低渗的特点,其渗流特征往往与常规气藏差别较大。DH气藏X3层平均渗透率2.05mD,属低渗储层；X4层平均渗透率0.1mD、X5层平均渗透率0.068mD,均属致密低渗透储层,储层中的流体流动存在独特的渗流机理。因此本文主要采用室内物理模拟方法,分别针对气藏主力产层X3、X4和X5层开展单相渗流、两相渗流以及水锁效应机理研究,为该气田开发方案设计提供机理认识及基础参数。为此,研究的重点包括(1)重点针对目标气藏的低渗层位开展20组岩心的单相气体低速渗流测试,研究评价DH气藏滑脱效应影响。(2)利用实验室自研异常高压岩心驱替装置(200℃,200MPa),在真实地层条件下开展7组岩心的应力敏感测试(最高温度174.2℃,最高压力95.7MPa),研究评价开发过程中气藏压力下降导致的渗透率应力敏感程度。(3)DH气藏边底水较强,采气过程中随地层压力的下降会出现强水驱现象,造成气水两相渗流。针对储层这一渗流特征,首先建立高温高压水驱气相渗测试方法,分别在常温常压和高温高压(151.8～174.2℃,37.12～54.1MPa)两种条件下开展8组岩心的水驱气相渗曲线测试。(4)在实际气井开关井时,近井区容易产生高含水饱和度带造成水锁现象,为评价水锁效应伤害程度,对此创新性建立测试水锁效应及水锁气解封启动压力的测试方法(专利申请中),并开展6组岩心的水锁伤害测试研究。本文研究取得的主要成果如下：(1)DH气藏产生滑脱效应的临界压力较小,应在0.125MPa以下,对一般气藏来讲废弃压力应高于此值,因此实际生产中可不考虑气体滑脱效应,只做机理研究。(2)DH气藏X3层应力敏感平均中等偏弱,其它两层中等偏强,而且储层中应力敏感程度一般砂砾岩比砂岩强,低渗透砂岩比高渗透砂岩强。(3)DH气藏储层岩心高温高压水驱气相渗与地面常规相渗测试结果相比,平均束缚水饱和度低3%,等渗点左移8%左右,水驱效率低6-8%,水驱残余气饱和度高5%左右,差异较大。(4)水锁实验结果显示DH气藏水淹排水后气相渗透率整体下降幅度在6-15%之间,水锁气解封启动压力在0.3-3.7MPa之间,但实验岩心较短,因此启动压力梯度很大,水锁后解除水锁的难度较大。
[Abstract]:Low permeability gas reservoir is different from conventional gas reservoir, because of its low porosity and low permeability, its percolation characteristic is often different from that of conventional gas reservoir. The average permeability of X3 layer in DH gas reservoir is 2.05 mD, which belongs to low permeability reservoir. The average permeability of layer X _ 4 is 0.1mDX _ (5). The average permeability of layer X _ 5 is 0.068mD, which belongs to dense and low permeability reservoirs, and the fluid flow in the reservoir has a unique percolation mechanism. Therefore, this paper mainly adopts the method of indoor physical simulation to study the mechanism of single-phase seepage, two-phase seepage and water lock effect for the main production zones X3X _ 4 and X _ 5 of the gas reservoir, which provides the mechanism understanding and basic parameters for the design of the development plan of the gas field. Therefore, the key points of the research include: (1) to carry out 20 groups of single-phase gas low-velocity percolation tests for the low permeability layer of the target gas reservoir. The effect of slippage effect on DH gas reservoir is studied and evaluated. (2) using laboratory self-developed abnormal high-pressure core displacement device (200 鈩，
本文编号：2314200
[Abstract]:Low permeability gas reservoir is different from conventional gas reservoir, because of its low porosity and low permeability, its percolation characteristic is often different from that of conventional gas reservoir. The average permeability of X3 layer in DH gas reservoir is 2.05 mD, which belongs to low permeability reservoir. The average permeability of layer X _ 4 is 0.1mDX _ (5). The average permeability of layer X _ 5 is 0.068mD, which belongs to dense and low permeability reservoirs, and the fluid flow in the reservoir has a unique percolation mechanism. Therefore, this paper mainly adopts the method of indoor physical simulation to study the mechanism of single-phase seepage, two-phase seepage and water lock effect for the main production zones X3X _ 4 and X _ 5 of the gas reservoir, which provides the mechanism understanding and basic parameters for the design of the development plan of the gas field. Therefore, the key points of the research include: (1) to carry out 20 groups of single-phase gas low-velocity percolation tests for the low permeability layer of the target gas reservoir. The effect of slippage effect on DH gas reservoir is studied and evaluated. (2) using laboratory self-developed abnormal high-pressure core displacement device (200 鈩，
本文编号：2314200
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