天然气工业2025，Vol.45Issue(4)：85-97,13.DOI:10.3787/j.issn.1000-0976.2025.04.007
页岩气加密井水力压裂增能与老井压力恢复机理
Mechanisms of old well pressure buildup and energy increase by hydraulic fracturing of infill wells in shale gas reservoirs:A case study on Fuling national shale gas demonstration area
摘要
Abstract
Well interference in the process of hydraulic fracturing in shale reservoirs(also called as frac hit)is often regarded as an negative effect that only leads to wellbore integrity failure and single well productivity drop.During the hydraulic fracturing of infill wells in Fuling national shale gas demonstration area,however,some adjacent old wells exhibit such phenomena as wellbore pressure buildup and production increase.To further understand these phenomena,based on the idea of geology-engineering integration,this paper establishes a geomechanical model of hydraulic fracturing of a tridimensional infill well group with the multi-layer tridimensional infill well group X1 in the main part of Fuling national shale gas demonstration area as the research object.Then,the four-dimensional geo-stress evolution in the old wells after the fracturing and its influence on the propagation of the complex fractures induced by infill wells in different layers are analyzed.And combined with on-site monitoring curves of hydraulic fracturing construction,the intrinsic mechanisms of the hydraulic fracturing of infill wells to increase the energy of old wells are revealed.The following results are obtained.First,hydraulic fracturing of infill wells activates the natural fracture zones,forming a high-permeability channel for efficient pressure replenishment between the infill well(high formation pressure)and the old well(low formation pressure),so that the liquid supply capacity of the old well is supplemented,and its productivity is restored effectively under the combined effect of the pressure difference and high-permeability zone between the infill well and the old well.Second,controlling the well spacing can realize the positive communication of fractures between the old and the new well,and increase the fracture length and width at the front end of the fracture in the old well,which not only reduces the resistance to seepage but also supplements the pressure around the old well.Third,if the old well has been exploited for too long time,the fracture width at the front end of the fracture will be limited,which hinders the effective reduction of the resistance to seepage,restricts the productivity recovery of the old well,and damages the productivity of the infill well.In conclusion,the further understanding on the mechanisms of the hydraulic fracturing by infill well in shale gas reservoirs to restore the productivity of old well can provide a theoretical basis for the prevention and control of frac hits in fractured shale reservoirs and the production recovery of old wells,and are of important significance to the large-scale,safe and efficient development of shale gas in the Sichuan Basin.关键词
涪陵国家级页岩气示范区/立体井组压裂/井间干扰/压裂增能/天然裂缝带/压力恢复机理Key words
Fuling national shale gas demonstration area/Tridimensional well group fracturing/Well interference/Energy increase by fracturing/Natural fracture zone/Pressure buildup mechanism分类
石油、天然气工程引用本文复制引用
唐煊赫,杨海心,滕格格,何永生,朱海燕,王大江,李奎东,肖佳林,刘立之,冯宁鑫,孔繁昇..页岩气加密井水力压裂增能与老井压力恢复机理[J].天然气工业,2025,45(4):85-97,13.基金项目
国家自然科学基金青年基金项目"深层页岩缝口暂堵压裂多簇复杂裂缝交错扩展机理研究"(编号:52204005)、国家自然科学基金面上项目"页岩气立体加密井组压裂复杂裂缝扩展与井间干扰机理研究"(编号:52374004)、国家自然科学基金联合基金重点项目"四川深层页岩智能传控靶向复合压裂基础研究"(编号:U20A20265). （编号:52204005）
