低渗透应力敏感储层衰竭开发产量递减规律研究  

Production decline law of low permeability stress-sensitive reservoir during depletion development

作　　者：陈民锋 秦立峰[2] 荣金曦 王兆琪 CHEN Minfeng;QIN Lifeng;RONG Jinxi;WANG Zhaoqi(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;College of Petroleum Engineering in China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)石油工程学院,北京102249

出　　处：《复杂油气藏》2022年第3期78-83,共6页Complex Hydrocarbon Reservoirs

摘　　要：准确分析和预测应力敏感储层非稳态条件下的产量变化规律,对高效开发此类油气藏具有重要作用。根据压力敏感储层基本特点,建立相应的不稳定渗流数学模型;在求解过程中采用不等距差分格式和显式处理渗透率的方法,得到每个时间步的高阶差分线性方程组;在证明差分方程组的数值稳定性和收敛性的基础上,采用追赶法求解得到储层中压力分布。根据衰竭开发过程中生产井的产量完全来源于地层的弹性能这一特点,利用地层压力分布求解生产井的产量。研究表明:在不稳定渗流阶段,不同应力敏感系数储层的压力分布差别较小,应力敏感系数大的储层渗流阻力大,产量小;在边界控制流阶段,无因次规整化产量与无因次时间变化关系呈现加速下降的趋势。QC气藏实例分析表明,考虑应力敏感条件的储层,前期不稳定渗流阶段产量相对较大,递减较快,是重要的生产阶段,所述方法可以简便准确地求解应力敏感条件下开发全过程的产量变化动态。The production decline law of stress-sensitive reservoirs under unsteady conditions,which is accurately analyzed and predicted,plays an important role in the efficient development of such reservoirs.Based on the basic characteristics of the pressuresensitive reservoir,the corresponding unstable seepage mathematical model is established.In the solution process,the unequal interval difference scheme and the method of explicitly dealing with the permeability are used to obtain the high-order difference linear equation system for each time step.Based on the numerical stability and convergence of the difference equations,the pressure distribution in the reservoir is solved by the method of catching up.According to the characteristic that the production of producing wells in the process of depletion development is completely derived from the elastic energy of the formation,the production of production wells is calculated by using the distribution of formation pressure.The research shows that in the stage of unstable seepage,the pressure distribution of reservoirs with different stress sensitivity coefficients has little difference,and the reservoirs with larger stress sensitivity coefficients have larger seepage resistance and lower production.In the stage of boundary control flow,the relationship between dimensionless normalized production and dimensionless time variation shows an accelerated downward trend.The case analysis of the QC gas reservoir shows that,considering the stress-sensitive condition of the reservoir,the production in the early unstable seepage stage is relatively large,and the decline is fast,which is an important production stage.The method presented in this paper can easily and accurately solve the production change dynamics in the whole development process under stress-sensitive conditions.

关 键 词：应力敏感 非稳态 不等距差分 压力分布 产量递减 

分 类 号：TE348[石油与天然气工程—油气田开发工程]