压裂直井的三维半结构网格表征与求解方法  

Three-dimensional fine characterization and numerical simulation methods for fractured vertical wells

作　　者：刘辉 廖新维[1] 李则骅 于伟 LIU Hui;LIAO Xinwei;LI Zehua;YU Wei(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,P.R.China;Cockrell School of Engineering,University of Texas at Austin,Austin 78731,USA;The 11th Oil Production Plant of PetroChina Changqing Oilfield,Qingyang 745000,Gansu Province,P.R.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]得克萨斯大学奥斯汀分校科克雷尔工程学院,美国奥斯汀78731 [3]中石油长庆油田分公司第十一采油厂,甘肃庆阳745000

出　　处：《深圳大学学报（理工版）》2024年第6期643-652,共10页Journal of Shenzhen University(Science and Engineering)

基　　金：国家自然科学基金资助项目(U1762210,52074322)。

摘　　要：为模拟直井压裂后形成的三维裂缝的复杂形态和空间渗流特征,提出一种精确表征三维裂缝的新方法.首先,利用计算机辅助设计技术建立压裂直井的三维几何模型,明确裂缝、储层和井的空间几何关系;然后,根据三维裂缝复杂几何形态及其与井筒的空间相交方式,以及空间渗流特征,提出三维半结构网格节点约束算法和网格剖分方法,并实现混合离散求解;最后,利用所提方法对现场一口压裂直井P进行单井模拟,分析其井底压力和压力空间分布特征,并反演得到一套储层和裂缝的压裂评价参数.研究结果表明,裂缝的三维几何形态对直井P的压力空间分布具有显著的影响,井P在垂向上的压力分布具有明显的非均匀性.该研究有助于理解压裂过程中裂缝的三维形态以及裂缝对井底压力和空间渗流特征的影响,从而提高复杂压裂井的产量.To model the complex three-dimensional fracture morphology and spatial seepage characteristics formed after fracturing,a novel method for accurately representing three-dimensional fractures is introduced.First,computer-aided design(CAD)techniques are used to construct three-dimensional geometric model of the fractured vertical well and clarify the spatial geometric relationship among fractures,reservoirs,and wells,etc.Second,a 3D semi-structured grid node constraint algorithm and mesh generating method are proposed based on the complex geometric shape of the 3D fractures,their intersection with the wellbore,and their spatial seepage characteristics;and hence a mixed discrete solution method is implemented.Finally,the proposed method is used to simulate an actual fractured vertical well,of which the bottom-hole pressure and the characteristics of spatial pressure distribution are analyzed,and a set of inversion parameters for reservoir and fractures is obtained.The results indicate that the 3D fracture geometry significantly influences the spatial pressure distribution of well P,with noticeable non-uniformity in the vertical pressure distribution.The research helps in understanding the impacts of the 3D fracture morphology on the bottom-hole pressure and spatial flow characteristics during the fracturing process,thus improving the production of complex fractured wells.

关 键 词：油田开发 油藏数值模拟 压裂直井 计算机辅助设计 三维半结构网格 单井模拟 压力空间分布 

分 类 号：TE312[石油与天然气工程—油气田开发工程]