摘要
岩石可压性评价是储层压裂改造层位优选、压后产能评估的重要基础工作。准中4区块致密砂岩储层埋藏深、物性差,亟需通过压裂改造提高工业产能。因此,以董2井北三维区侏罗系致密砂岩为例,基于岩石三轴实验建立了致密砂岩断裂能密度—弹性模量的拟合公式,采用矿物成分法和弹模-泊松比法确定了研究区不同深度岩石脆性指数,采用岩石破裂准则确定了研究区不同深度的裂缝发育指数。以断裂能密度表征致密砂岩断裂韧性,以裂缝发育指数表征储层天然裂缝发育程度,综合考虑岩石脆性、断裂韧性、地应力环境和天然裂缝发育程度的影响,采用层次分析法计算了各因素权重,建立了适合深层致密砂岩的可压性评价方法。研究结果表明,可压裂性指数大于0.55时,可压性好;可压裂性指数介于0.50～0.55之间时,可压性一般;可压裂性指数小于0.50时,可压性差;研究区D7井的最佳压裂层位为4145～4160 m、4470～4480 m、5290～5330 m,D8井的最佳压裂层位为5120～5330 m、5350～5365 m,D701井的最佳压裂层位为3900～3910 m、4430～4440 m、4455～4465 m、5125～5135 m。
Fracrability evaluation is the basis for the optimization of fracturing level and the evaluation of productivity after fracturing.The tight sandstone reservoirs in block 4 in central Junggar Basin are buried deep and poor in physical property,and it is urgent to improve the industrial productivity by fracturing.Therefore,the fracture property of the Jurassic tight sandstone of Dong 2 well north area is studied as an example.Based on the experimental data of the rock triaxial test,the fitting formula of fracture energy density and elastic modulus of tight sandstone is established.Brittleness index of rocks at different depths in the study area is determined by mineral composition method and elastic modulus-Poisson ratio method.The fracture development index of different depths in the study area is determined by the criterion of rock fracture.Fracture energy density is used to characterize the fracture toughness of tight sandstone,and the fracture development index is used to characterize the development degree of natural fractures.Considering the influence of rock brittleness,fracture toughness,in-situ stress and development degree of natural fractures,the weight of each parameter is calculated by analytic hierarchy process,and a new quantitative fracrability evaluation of deep and tight sandstone reservoirs is established.The results show that when the fracrability index is greater than 0.55,the reservoir can be fractured well,when the fracrability index is between 0.50~0.55,the fractured reservoir is moderate,and when the fracrability index is less than 0.50,the fractured reservoir is poor.In the study area,the optimal fracturing horizons of Well D7 are 4145~4160 m,4470~4480 m,5290~5330 m,Well D8 are 5120~5330 m,5350~5365 m,and Well D701 are 3900~3910 m,4430~4440 m,4455~4465 m,5125~5135 m.
作者
曾治平
刘震
马骥
张春磊
李静
刘振
孙鲁宁
ZENG Zhiping;LIU Zhen;MA Ji;ZHANG Chunlei;LI Jing;LIU Zhen;SUN Luning(Research Institute of Exploration and Development of Shengli Oilfield,Sinopec,Dongying 257015,Shandong,China;China Petroleum Engineering&Construction Corp.Beijing Company,Beijing 100085,China;Institute of Geological Mechanics and Engineering,China University of Petroleum,Qingdao 266580,Shandong,China)
出处
《地质力学学报》
CSCD
2019年第2期223-232,共10页
Journal of Geomechanics
基金
国家科技重大专项(2016ZX05002-002)
国家自然科学基金(41272141)
关键词
致密砂岩
可压裂性
可压裂性指数
岩石脆性
断裂韧性
天然裂缝
tight sandstone
fracrability
fracrability index
rock brittleness
fracture toughness
natural fractures
