致密油藏压裂水平井压力响应特征研究  

Study on pressure response characteristics of fractured horizontal wells in tight oil reservoir

作　　者：孙壮壮 王胡振[1,2] 刘天城 钟会影 谭桢来[1] 万宏宇 Sun Zhuangzhuang;Wang Huzhen;Liu Tiancheng;Zhong Huiying;Tan Zhenlai;Wan Hongyu(Department of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,China;Key Laboratory of Reservoir Stimulation,CNPC,Daqing 163318,China)

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318 [2]中国石油集团公司油气藏改造重点实验室,黑龙江大庆163318

出　　处：《能源与环保》2023年第5期144-149,155,共7页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：中国博士后科学基金(2019M661250);大庆市指导性科技计划项目(zd-2021-51)。

摘　　要：为了提高致密油藏压裂井数值试井裂缝描述精细程度,采用混合单元有限元方法建立考虑启动压力梯度的单相数值试井模型。验证数学模型准确性的基础上,研究了裂缝网格尺寸对数值计算结果的影响、启动压力梯度和裂缝参数对压裂水平井压降曲线的影响。结果表明,混合单元有限元离散裂缝数值试井模型具有较高的准确性;地层渗透率1×10^(-3)μm^(2)条件下,不考虑和考虑井筒储集效应,压裂水平井数值计算时推荐的裂缝网格尺寸上限为0.5 m和5.0 m,过大的网格尺寸会产生“假井筒储集效应”;启动压力梯度对压裂水平井压力响应影响较大,支裂缝参数的影响弱于主裂缝参数;裂缝导流能力较低时,裂缝参数对压力响应影响较弱。裂缝导流能力越低,裂缝参数对试井曲线的影响越小,裂缝特征越不明显。To improve the accuracy of fracture description in numerical well testing of fracturing wells in tight oil reservoirs,a mixed element finite element method was used to establish a single-phase numerical well testing model considering the starting pressure gradient.On the basis of verifying the accuracy of the mathematical model,the influence of the fracture grid size on the numerical calculation results,the influence of the starting pressure gradient and the fracture parameters on the pressure drop curve of the fracturing horizontal well were studied.The results show that the mixed element finite element discrete fracture numerical well testing model has high accuracy;under the condition of formation permeability of 1×10^(-3)μm^(2),without considering or considering the wellbore storage effects,the upper limit of fracture grid size recommended in the numerical calculation of fractured horizontal wells is 0.5 m and 5 m.Too large grid size will produce"false wellbore storage effect";the starting pressure gradient has a great influence on the pressure response of the fracturing horizontal well,and the influence of the branch fracture parameters is weaker than that of the main fracture parameters;when the fracture conductivity is low,the fracture parameters have a weak influence on the pressure response.The lower the fracture conductivity,the smaller the impact of fracture parameters on the well testing curve,and the less obvious the fracture characteristics.

关 键 词：致密油藏 压裂水平井 数值试井 有限单元法 压力响应特征 

分 类 号：TE357.6[石油与天然气工程—油气田开发工程]