摘要
常规固结堵漏浆体驻留性差、井筒留塞难。现场采用两级固结堵漏工艺,在固结堵漏浆体前向漏失层注入高黏稠浆体,以提高浆体驻留性。但对堵漏作业过程中井筒压力变化规律认识不清,井筒压力精细控制不足,工艺参数如排量、浆体体积等的确定缺乏理论指导,这些仍然是固结堵漏工艺优化面临的关键问题之一。基于浆体在裂缝中一维径向流动模型,建立了多级固结堵漏动力学模型,提出临界压差和压差比两个参数表征浆体的驻留性。以高黏稠凝胶浆+水泥浆两级固结堵漏工艺为例,分析裂缝宽度、排量、浆体体积及比例对井筒压力的影响,厘清堵漏过程中与环空液面高度变化与井筒压力的关系。研究表明:裂缝宽度越小,堵漏过程中井筒与地层压差、临界压差越大,浆体更容易驻留。增加浆体体积和高黏稠浆体比例,有助于浆体驻留,但实际堵漏应综合考虑浆体驻留、漏层裂缝封固以及成本等多因素。浆体排量越大,压差比越大,不利于浆体驻留。环空液面高度变化可以判断漏失地层井筒压力变化,现场应加强环空液面高度的监测。
Conventional consolidation plugging slurry has poor retention and difficult wellbore plugging.A two-stage consolidation and plugging process was used on site to inject highly viscous slurry into the lost circulation layer before consolidating and plugging the slurry to improve the retention of the slurry.However,unclear understanding of wellbore pressure variation during plugging operations,insufficient precise control of wellbore pressure,and lack of theoretical guidance for determining process parameters such as displacement and slurry volume are still key issues facing optimization of consolidation plugging processes.Based on the one-dimensional radial flow model of slurry in cracks,a dynamic model of two-stage consolidation plugging was built.Two evaluation parameters for the retention of plugging slurry in cracks,the critical pressure and pressure difference ratio were proposed.Taking the two-stage consolidation plugging of high viscous gel slurry+cement slurry as an example,the influence of fracture width,slurry displacement,slurry volume and proportion on wellbore pressure was analyzed.The relationship between the change of annular liquid level height and wellbore pressure during plugging was clarified.The research shows that the smaller the fracture width,the greater the pressure difference between the wellbore and the formation,and the critical pressure difference during the plugging process,and the easier the slurry is to stay.Increasing the volume of slurry and the proportion of highly viscous slurry can contribute to slurry retention,but in actual plugging,multiple factors such as slurry retention,fracture sealing in the lost circulation layer,and cost should be comprehensively considered.The larger the slurry displacement,the greater the pressure differential ratio,which is not conducive to slurry retention.Changes in the annular liquid level can be used to determine changes in wellbore pressure in lost formation,and on-site monitoring of the annular liquid level should be strengthened.
作者
彭力
史野
王韧
龙一夫
蔺艺莹
杨贺卫
郭明红
张现斌
PENG Li;SHI Ye;WANG Ren;LONG Yi-fu;LIN Yi-ying;YANG He-wei;GUO Ming-hong;ZHANG Xian-bin(Tianjin Key Laboratory of Drilling Fluids under Complex Condition,Tianjin 300280,China;Drilling Fluid Technology Services of CNPC Bohai Drilling Engineering Company Limited,Tianjin 300280,China;CNPC Engineering Technology R&D Company Limited,Beijing 102206,China)
出处
《科学技术与工程》
北大核心
2023年第17期7293-7299,共7页
Science Technology and Engineering
基金
天津市科技项目(19PTSYJC00120)
中国石油天然气集团公司前瞻性基础性攻关项目(2021DJ4404)。
关键词
钻井液漏失
两级
固结堵漏
井筒压力
drilling fluid loss
two-stage
consolidation plugging
wellbore pressure
