基于PEBI网格的考虑诱导裂缝的聚合物驱压力动态研究  

Pressure transient of polymer flooding considering induced fractures based on PEBI grid

作　　者：钟会影[1] 沈文霞 藏秋缘 许严芮 ZHONG Huiying;SHENWenxia;ZANG Qiuyuan;XU Yanrui(Key Laboratory of Enhanced Oil and Gas Recovery of Ministry of Education,Northeast Petroleum University,Daqing 163318,Heilongjiang,China;Downhole Service Company,PetroChina Daqing Oilfield Company,Daqing 163311,Heilongjiang,China)

机构地区：[1]东北石油大学提高油气采收率教育部重点实验室,黑龙江大庆163318 [2]中国石油大庆油田分公司井下作业分公司,黑龙江大庆163311

出　　处：《岩性油气藏》2022年第3期164-170,共7页Lithologic Reservoirs

基　　金：中国博士后科学基金“考虑诱导裂缝闭合的黏弹性聚合物驱压力降落特征研究”(编号:2019M661250);黑龙江省博士后经费项目“二类油层黏弹性聚合物驱注入井压力动态解释方法研究”(编号:LBH-Z19050)联合资助。

摘　　要：通过PEBI网格变尺度剖分方法,考虑注聚井在注入过程中会产生诱导裂缝的情况,综合聚合物溶液黏浓关系、剪切效应、渗透率下降以及吸附机理,建立了考虑诱导裂缝的聚合物驱垂直裂缝井数学模型。采用有限体积法对数学模型进行离散,从而得到井底压力数值解,进而绘制压力及压力导数双对数曲线并对其影响因素进行分析。研究结果表明:(1)聚合物驱垂直裂缝井试井曲线可以分为5个流动阶段:纯井筒储集阶段、双线性流阶段、线性流阶段、椭圆流阶段与径向流阶段;聚合物浓度主要影响试井曲线后期阶段,浓度越大,双线性流及非牛顿径向流阶段曲线越靠上。(2)诱导裂缝半长越小,压力和压力导数曲线上翘越明显;通过与水驱诱导裂缝闭合压力动态曲线的对比,基于混合PEBI网格考虑诱导裂缝聚合物驱数值计算方法能够准确描述诱导裂缝闭合后的压力动态。(3)当裂缝闭合速度因子(delpat)为0时,裂缝瞬间闭合,压力发生突变,在压力导数图中表现为一个明显峰值;delpat越大,裂缝闭合速度越慢,压力导数的峰值越高,曲线越靠右。Based on PEBI grid method,by considering the situation that the polymer injection well will produce induced fractures during the injection process,and taking into account the rheology of polymer solution,shear thinning,permeability reduction and adsorption mechanism,a mathematical model of polymer flooding considering vertical induced fractures was established.The finite volume method was used to discrete the mathematical model,and then the numerical solution of bottom hole pressure was obtained.The double logarithmic curve of pressure and pressure derivative was plotted and the influencing factors were analyzed.The results show that:(1)The well test curve of polymer flooding for vertically fractured well can be divided into five flow stages:pure wellbore storage stage,bilinear flow stage,linear flow stage,elliptical flow stage and radial flow stage.Polymer concentration mainly affects the later stage of well test curve.The higher the concentration,the more upward the curves at the bilinear flow stage and non-Newtonian radial flow stage.(2)The shorter the half-length of induced fractures,the more obvious the upward curve of pressure and pressure derivative.Compared with the pressure dynamic curves considering induced fracture closure in water drive,the numerical calculation method of polymer flooding considering induced fracture based on hybrid PEBI grid can accurately describe the pressure transient after induced fracture closure.(3)When the value of the fracture closure velocity factor(delpat)is 0,the fracture closes instantaneously and the pressure change suddenly,it is shown as an obvious peak in the pressure derivative diagram.The larger the delpat is,the slower the closure velocity is,the lower the derivative peak is,and the more the curve shifts to the right.

关 键 词：PEBI网格 聚合物驱 诱导裂缝 数值试井 裂缝闭合 压力动态 

分 类 号：TE319[石油与天然气工程—油气田开发工程] P632[天文地球—地质矿产勘探]