致密油藏直井体积压裂非稳态渗流问题  

Non-steady Flow of Volume Fracturing for Vertical Well in Tight Oil Reservoir

作　　者：谢伟伟 张艳[2] 丁一萍[1] XIE Wei-wei;ZHANG Yan;DING Yi-ping(Petroleum Exploration & Development Institute, SINOPEC, Beijing 100083, China;School of Energy Resources, China University of Geosciences, Beijing 100083, China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《科学技术与工程》2021年第21期8857-8862,共6页Science Technology and Engineering

基　　金：国家重大科技专项(2016ZX05033)。

摘　　要：针对致密油藏直井体积压裂的非稳态渗流问题,建立了考虑启动压力梯度和压敏效应的两区复合模型,利用稳态逐次逼近非稳态的半解析方法进行求解,分析致密油藏直井体积压裂后压力传播规律,以及影响压力传播的主要因素。计算结果表明:当存在启动压力梯度和压敏效应时,流体渗流阻力增大,压力传播速度减缓,压力传播半径变小,最终导致井底流压降低,井口流量减少。对于两区复合模型,压裂改造区内渗流阻力小,压力传播速度快,体积压裂改造范围越大,压力传播速度越快,压力传播半径越大。对于定井底流压情形,改造区域半径越大,油井产能越高,但是当改造半径大于一定值后,改造半径的扩大对于提升油井产能的作用不再明显。For non-steady flow problem of fracture network reconstruction vertical well in tight oil reservoirs,a two-region composite seepage model considering the pressure gradient and pressure-sensitive was built,and the model was solved using a semi-analytical method of steady-state successive approach to unsteady-state solution.The results show that the existence of pressure gradient and pressure-sensitive effect slow down the well bottom pressure and pressure propagation speed for the reason that pressure gradient and pressure-sensitive increase the formation flow resistance.In two-region composite seepage model,pressure propagation speed in fracture reconstruction region is faster than pressure propagation speed in non-fracture reconstruction zone.The larger fracture reconstruction radius,the larger pressure propagation radius is.For constant-pressure production,with increase of fracture reconstruction region radius,well production rate increases,while its increasing rate is decreasing.

关 键 词：致密油藏 体积压裂 启动压力梯度 压敏 稳态逐次替换方法 

分 类 号：TE341[石油与天然气工程—油气田开发工程]