低渗透裂缝型碳酸盐岩酸压气井动态特征分析  

Dynamic Characteristic Analysis for Acid Fracturing Gas Well of Low Permeability Fractured Carbonate Reservoir

作　　者：史文洋 程时清 姚约东[1] 冯乃超 顾少华 SHI Wen-yang;CHENG Shi-qing;YAO Yue-dong;FENG Nai-chao;GU Shao-hua(State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum(Beijing), Beijing 102249, China;Research Institute of Petroleum Exploration & Development, Beijing 100083, China;SINOPEC Petroleum Exploration and Production Research Institute, Beijing 100083, 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]中国石油勘探开发研究院,北京100083 [3]中国石化石油勘探开发研究院,北京100083

出　　处：《科学技术与工程》2020年第22期8948-8956,共9页Science Technology and Engineering

基　　金：国家自然科学基金(11872073)。

摘　　要：低渗透裂缝型碳酸盐岩基质低孔低渗、天然裂缝发育,目前存在的酸压气井动态特征模型没有同时考虑储层基质低孔低渗引起的非达西渗流以及储层裂缝发育造成的储层应力敏感效应。为了分析低渗透裂缝型碳酸盐岩气藏酸压后渗流特征和产量递减规律,建立了考虑酸压改造程度、酸压改造范围、流体低速非达西流动、储层应力敏感的酸压气井渗流模型。首先针对气体拟压力形式的非线性非齐次的渗流方程进行Laplace空间变换,在Laplace空间利用摄动理论线性方程解的叠加原理进行求解,其次基于Duhamel叠加原理考虑了井储和表皮对渗流的影响,采用Stehfest数值反演方法得到实空间酸压气井不稳定产量和压力解,最后基于典型曲线特征分析了四类因素对酸压气井产量递减和井底压力动态特征的影响。结果表明:低渗透裂缝型碳酸盐岩酸压气井存在8个流动阶段,基质-裂缝窜流具有减缓产量递减速率的作用;低速非达西在生产中后期对产量递减影响明显,会削弱窜流对产量递减的补偿作用且明显降低气井产能;应力敏感在生产后期对产量递减的影响凸显,对气井递减率和产能影响较小;改造程度越高,产量递减率越大且产能下降越明显;改造范围越大,气井递减速率越稳产。结论认为:实际低渗透裂缝型碳酸盐岩气藏产能分析中,低速非达西渗流对产能的影响大于应力敏感对气井产能的影响;若以保持酸压气井稳定的产量递减速率为目标,增大改造范围比增大改造程度更重要。Existing models of dynamic characteristics of acid fracturing gas wells do not consider non-Darcy flow caused by low porosity and permeability of the reservoir matrix and reservoir stress-sensitive effects caused by reservoir fracture.In order to analyze the flow regimes and the production decline of acid fracturing gas well of low permeability fractured carbonate reservoirs,the dynamic characteristic analysis model was used to investigate the effects of acid fracturing,stress sensitivity,low-velocity non-Darcy flow on the production decline.Firstly,a Laplace transformation was performed for the nonlinear and non-homogeneous seepage equation in the form of gas pseudo-pressure.In the Laplace domain,the perturbation theory was used for linearization,and the seepage equation was solved by the superposition principle of linear equation solving.Secondly,the effects of wellbore storage and skin were considered by the Duhamel superposition principle,and the Stehfest numerical inversion method was used to obtain the transient production and pressure solution in the real-time domain.Finally,these effects on production decline and the dynamic characteristics were analyzed.The results show that there are eight flow regimes in low permeability fractured carbonate reservoir after acid fracturing,and the effect of inter-porosity flow can reduce the rate of production decline.Meanwhile,low-velocity non-Darcy flow significantly affects the rate of production decline in the middle and late production stages,which will reduce the influence of inter-porosity flow and production performance The effect of stress sensitivity on the production decline is prominent in the late production stage,which has little effect on gas productivity and production decline rate.Thirdly,the higher the acid fracturing degree,the faster the rate of production decline is,and the more obvious the decline in production performance is.The bigger the acid fracturing area,the stronger the ability to stabilize production is.It is concluded that the impact of l

关 键 词：低渗透储层 裂缝型碳酸盐岩 酸压气井 产量递减 低速非达西渗流 应力敏感 

分 类 号：TE371[石油与天然气工程—油气田开发工程]