摘要
针对鄂尔多斯盆地致密砂岩油藏岩石致密、非均质性强、常规压裂工艺形成的裂缝形态单一而无法实现储层立体改造,开展了非常规压裂技术多簇压裂裂缝均衡起裂及延伸行为规律研究。利用大尺寸真三轴模拟实验系统,基于量纲分析法(π定理)物理模拟实验相似准则设计,经多次实验配比、养护、力学测试等方法,得到了与目标层位相近岩石力学参数的人工养护岩体,利用30 cm×30 cm×30 cm的人工试样系统开展了非常规体积压裂物理模拟实验。以常规压裂工艺为参照,通过改变实验条件及设计参数,模拟了水力脉冲预处理、簇间暂堵、限流法、循环加卸载和脉冲间歇压裂5种非常规体积压裂工艺下的压裂裂缝均衡起裂与延伸行为,明确了不同压裂工艺对应的多簇压裂裂缝均衡起裂及扩展延伸规律。对比常规压裂对压裂裂缝存在应力干扰而抑制其扩展,5种非常规体积压裂方法均能减小多簇压裂裂缝间的应力干扰,有利于裂缝均匀起裂扩展,获得复杂裂缝和更大的改造体积,其中簇间暂堵压裂工艺获得复杂缝网的效果最好。形成并完善了体积压裂多簇裂缝均衡起裂与延伸控制技术,有助于提高非常规致密油气藏整体改造、立体动用程度。
For the tight sandstone reservoirs in the Ordos Basin,where the rock is compact,heterogeneous and the fracture shapes formed by conventional fracturing techniques are monolithic,a 3D reconstruction of the reservoir cannot be achieved.We have carried out the research on the law of balanced fracture initiation and extension of multi-cluster fracturing fractures in unconventional fracturing technology.Using the large size true triaxial simulation experiment system,based on the dimensional analysis method(π theorem)physical simulation experiment similarity criterion design,through multiple experimental proportioning,curing,mechanical testing and other methods,the artificial curing rock mass with mechanical parameters similar to the target layer is obtained,and a 30 cm×30 cm×30 cm artificial sample system was used to carry out the physical simulation experiment of unconventional volumetric fracturing.Taking the conventional fracturing technology as a reference,by changing the experimental conditions and design parameters,the non-equilibrium initiation and extension behaviors of fracturing fractures under five unconventional volume fracturing technologies,namely hydraulic pulse pretreatment,temporary plugging between clusters,flow limiting method,cyclic loading and unloading and pulse intermittent fracturing,were simulated,and the non-equilibrium initiation and extension laws of multicluster fractures were clarified.Compared with conventional fracturing,which has stress interference on the fracture and inhibits the fracture expansion,five unconventional volume fracturing methods can reduce the stress interference of multi-cluster fracturing,which is conducive to the uniform fracture initiation and expansion,and it is easier to obtain complex fractures and larger reconstruction volume.Among them,the effect of complex fracture networks is the best for inter-cluster block fracturing.It has developed and refined a balanced fracture and extension control technique for multiple cluster fractures in bulk fracturing,which has helped to improve the degree of 3D reconstruction of unconventional tight oil and gas reservoirs.
作者
孔祥伟
严仁田
许洪星
李松
KONG Xiangwei;YAN Rentian;XU Hongxing;LI Song(School of Petroleum Engineering,Yangtze University,Wuhan 430100,China;Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University),Wuhan 430100,China;Development Division of PetroChina Southwest Oil and Gasfield Company,Chengdu 610041,China;CCDC Changqing Down Hole Technology Company,Xi'an 710018,China;Engineering Research Institute of PetroChina Southwest Oil and Gasfield Company,Chengdu 610017,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2023年第7期1123-1136,共14页
Natural Gas Geoscience
基金
国家自然科学基金“超深裂缝地层溢流多相流动机理及气体侵入类型识别研究”(编号:52274001)
中国石化科技部项目“川西中浅层致密砂岩气藏体积压裂关键技术”(编号:P22047)
中国石油集团川庆钻探工程公司项目“压裂靶向暂堵关键施工参数优化设计技术及现场试验”“多靶向暂堵压裂优化设计与评价技术”联合资助.
关键词
真三轴
相似准则
暂堵
多簇裂缝
均衡起裂及扩展
True triaxial
Similarity criterion
Temporary blocking
Multiple clusters of fractures
Balanced fracture initiation and expansion
作者简介
孔祥伟(1982-),男,黑龙江大庆人,博士(后),副教授,博士生导师,主要从事油气井力学、储层改造等井工程力学研究.E-mail:76922591@qq.com.
