考虑支撑剂运移的压裂停泵压降模型  

Fracturing pump-stopping pressure drop model considering proppant migration

作　　者：王飞 周彤[2] 许佳鑫 管晶晶 索杰林 张士诚[1] 廖凯 邹雨时 Wang Fei;Zhou Tong;Xu Jiaxin;Guan Jingjing;Suo Jielin;Zhang Shicheng;Liao Kai;Zou Yushi(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,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]中国石油化工股份有限公司石油勘探开发研究院,北京100083

出　　处：《石油学报》2023年第4期647-656,共10页Acta Petrolei Sinica

基　　金：国家自然科学基金面上项目(No.51974332)资助。

摘　　要：针对现有压裂停泵压降模型不考虑支撑剂运移、无法解释支撑剂铺置效果的难题,提出适用于主加砂压裂的停泵压降模型,模型考虑了裂缝系统中携砂液-支撑剂靠黏度和速度耦合的水平运移与沉降运动,以及基质系统中压裂液靠黏性力和重力作用的三维流动,通过将裂缝系统与基质系统耦合求解,实现了主加砂压裂停泵过程的支撑剂运移模拟计算,获得的井底压降导数双对数曲线呈现出“厂”字型的形态特征,并按照停泵时间顺序划分为支撑剂沉降、支撑剂水平运移、支撑剂减速运移、支撑剂压实和支撑剂停止运移5个主控阶段。研究结果表明:支撑剂铺置越均匀(主次裂缝内砂量越接近),压降导数曲线越平缓,支撑剂沉降控制期越长,支撑剂减速运移期越短,支撑剂压实控制阶段会呈现出1/4斜率段;支撑剂充填比例越大(缝网总体积越小),压降导数曲线越陡,支撑剂水平运移控制期越短,支撑剂运移控制阶段的压降及导数会呈现重合趋势。选取涪陵页岩气田一口典型压裂水平井逐段开展停泵压降曲线拟合,反演获得各加砂压裂段的支撑裂缝体积与铺砂均匀程度,为定量评价水力压裂加砂效果、认识压后支撑剂运移规律提供了理论依据。In view of the problem that the current fracturing pump-stopping pressure drop model takes no account of proppant migration and cannot explain the proppant laying effect,the paper proposes a set of pump-stopping pressure drop model suitable for main sand fracturing.The model considers the horizontal shifting and settlement movement of sand carrying fluid-proppant relying on the coupling between viscosity and velocity in the fracture system,as well as the three-dimensional flow of fracturing fluid driven by viscous force and gravity in the matrix system.Based on the coupled solution of fracture system and matrix system,it achieves the simulated calculation of proppant migration in the pump-stopping process of main sand fracturing,and the double logarithmic curve of bottom-hole pressure drop derivative presents the morphological characteristics of L-shape.Moreover,it can be divided into five main control stages according to the pump-stopping time sequence,i.e.,proppant settlement,horizontal proppant migration,proppant decelerated migration,proppant compaction and proppant stopping migration.Research shows that the more uniformly the proppant is laid(the closer the sand amount in both the primary and secondary fractures),the more gentle the pressure drop derivative curve,the longer the proppant settlement control period and the shorter the proppant deceleration migration period,and the proppant compaction control stage will show a 1/4 slope section;the larger the proppant filling ratio(the smaller the total volume of fracture network),the steeper the pressure drop derivative curve,the shorter the proppant horizontal migration control period,and the pressure drop and derivative in the proppant migration control stage will tend to coincide.A typical fractured horizontal well in Fuling shale gas field is selected to carry out pump-stopping pressure drop curve fitting in each section sequentially,and the prop-fracture volume and sanding uniformity coefficient of each sand fracturing section are obtained by inversion,thu

关 键 词：主压裂 停泵压降模型 支撑剂运移 支撑裂缝体积 铺砂效果 压降曲线拟合 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]