超深致密砂岩气藏应力敏感性实验研究  

Experimental study on stress sensitivity of ultra-deep tight sandstone gas reservoirs

作　　者：张杜杰 ZHANG Dujie(Petroleum Engineering Technology Research Institute Co.,Ltd.,SINOPEC,Beijing,102206,China;State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,Beijing,102206,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation·Southwest Petroleum University,Chengdu,610500,China)

机构地区：[1]中石化石油工程技术研究院有限公司,北京102206 [2]页岩油气富集机理与有效开发全国重点实验室,北京102206 [3]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500

出　　处：《复杂油气藏》2024年第2期217-224,共8页Complex Hydrocarbon Reservoirs

基　　金：国家重点研发计划项目“井筒稳定性闭环响应机制与智能调控方法”(2019YFA0708303);中国博士后科学基金“深部破碎性地层井壁稳定技术研究”(238316)。

摘　　要：超深致密砂岩气藏储层地质条件特殊、工程作业复杂,建井及生产阶段极易遭受严重的储层损害,储层裂缝应力敏感性损害是超深致密气藏的重要损害形式。以塔里木盆地超深超致密砂岩气藏为研究对象,针对裂缝岩样,开展原状裂缝岩样、重复加载/卸载应力变化路径及钻井液、酸液处理后的裂缝样品的应力敏感性损害实验评价。实验结果显示:超深致密砂岩原状裂缝应力加载过程应力敏感系数介于0.36~0.72,平均0.56,敏感程度中偏强;应力卸载过程介于0.18~0.62,平均0.44,敏感程度中偏弱;循环加载过程中,裂缝渗透率有持续降低的趋势,且有效应力降低后渗透率恢复率极低;油基钻井液处理后致密砂岩裂缝应力敏感性系数介于0.57~0.58,酸液处理后裂缝应力敏感性系数增至0.64~0.69。分析认为,钻井液固相侵入以及工作液处理造成的致密砂岩杨氏弹性模量和抗压强度降低、泊松比增加是工作液加剧裂缝应力敏感性损害的主要机理,敏感性分析显示杨氏模量变化较泊松比变化对裂缝应力敏感程度的影响更显著。研究成果对超致密气藏工作液优选及合理生产压差的制定具有一定借鉴意义。The ultra-deep tight sandstone gas reservoir is prone to severe reservoir damage during well construction and production due to its special geological conditions and complex engineering operations.Fracture stress sensitivity damage is an important form of damage in ultra-deep tight gas reservoirs.Taking the ultra-deep and ultra-tight sandstone gas reservoir in the Tarim Basin as the research object,we carry out the experimental evaluation of stress-sensitive damage on the fractured rock samples in their original state,repeated loading/unloading stress change paths,and treated with drilling fluid and acid solutions.The experimental results show that the stress sensitivity coefficient of the undisturbed sandstone fracture during stress loading ranges from 0.36 to 0.72,with an average of 0.56,and the sensitivity degree is moderately strong.The stress unloading process ranges from 0.18 to 0.62,with an average of 0.44,and the sensitivity is moderately weak.During cyclic loading,fracture permeability tends to decrease continuously,and the recovery rate of permeability is extremely low after effective stress reduction.The fracture stress sensitivity coefficient of tight sandstone after oil-based drilling fluid treatment ranges from 0.57 to 0.58,and the fracture stress sensitivity coefficient increases from 0.64 to 0.69 after acid fluid treatment.It is concluded that the decrease of Young's elastic modulus and compressive strength and the increase of Poisson's ratio caused by solid-phase intrusion of drilling fluids and working fluid treatment are the main mechanisms of working fluid aggravating fracture stress sensitivity damage.Sensitivity analysis shows that the change in Young's modulus significantly affects the degree of fracture stress sensitivity compared to Poisson's ratio.The research results have a certain reference significance for selecting working fluid and the formulation of reasonable production pressure differences in ultra-tight gas reservoirs.

关 键 词：超深 致密砂岩 渗透率 应力敏感 油基钻井液 天然裂缝 

分 类 号：TE371[石油与天然气工程—油气田开发工程]