致密储层应力敏感性分析及裂缝参数优化

Analysis of stress sensitivity and optimization of fracturing parameter for tight reservoirs

 孙元伟 程远方 张卫防 时凤霞 印树明

中国石油大学胜利学院油气工程学院，山东 东营 257061 中国石油大学（华东）石油工程学院，山东 青岛 266580 中国石化胜利西南钻井分公司，山东 东营 257000

College of Petroleum Engineering, College of Shengli, China University of Petroleum, Dongying 257061, China School of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China Southwest Drilling Branch, Shengli Oilfield Company, SINOPEC, Dongying 257000, China

 为准确分析体积压裂后致密储层应力敏感性对其渗流的影响，在考虑致密储层体积压裂改造区域以及未改造区域储层应力敏感性对渗透率影响的基础上，建立了致密储层水平井体积压裂3D渗流模型，采用有限元方法进行求解，进一步研究了储层应力敏感性及裂缝长度对产能和渗透率的影响，并针对应力敏感储层进行裂缝参数优化设计。研究结果表明：当裂缝穿透比大于0.40时，储层应力敏感性对产量影响逐渐增大，裂缝穿透比的影响逐渐减小；应力敏感性主要影响渗透率大小，对渗透率分布形态影响很小，而裂缝穿透比对渗透率分布形态影响很大；随着裂缝穿透比增加，近井地带渗透率下降范围进一步扩展，但增加幅度较小。对应力敏感储层进行裂缝长度优化，当改造区域应力敏感系数为0.010 MPa-1时，裂缝穿透比为0.40的情况下可以取得最佳的增产效果。

 In order to analyze the influence of stress sensitivity on seepage of tight reservoir accurately after volume fracturing, a new 3D seepage model for staged fracturing well considering the effect of stress sensitivity on the permeability of fractured and unfractured zone was established, which was solved by the finite element method; the influence of stress sensitivity and fracture length on production and seepage was analyzed, and the fracture parameter optimization design for the stress sensitive reservoir was carried out. The results show that influence of stress sensitivity on production increases gradually, and the influence of fracture penetration ratio decreases when the penetration ratio is larger than 0.40; the stress sensitivity has big influence on the value of permeability, and contrarily fracture penetration ratio has big influence on permeability distribution; the declining scope of permeability near wellbore zone will extend but the increase is small with the increasing of fracture ratio. Research on the optimizing design for staged fracturing well is presented, which shows that the best development effect is gotten when the stress sensitivity coefficient of the fractured zone is 0.010 MPa-1 and the penetration ratio is 0.40.

10.6056/dkyqt201804018