气体钻井空井压井井筒气液两相瞬态流动数学模型  

A mathematical model for gas–liquid transient flow in wellbore during empty well killing in gas drilling

作　　者：魏纳[1] 孟英峰[1] 吴鹏程[2] 李皋[1] 方强[1] 李鹏杰[1] 陶祖文 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.西南石油大学 [2]中国石油西南油气田公司勘探事业部 [3]中石化西南石油工程有限公司井下作业分公司

出　　处：《天然气工业》2017年第6期64-71,共8页Natural Gas Industry

基　　金：国家重点研发计划项目(编号:2016YFC0304008);"油气藏地质及开发工程"国家重点实验室开放基金项目(编号:PLN1309;PLN1418);国家自然科学基金项目(编号:51204140;51334003)

摘　　要：气体钻井钻遇高压、高产气层后往往要进行压井作业,空井压井期间,随着压井液的注入,井筒环空气液两相流动与地层渗流产气发生耦合作用,目前国内外对此研究都很少。为此,基于地层瞬态渗流理论和井筒气液两相流动理论,建立了气体钻井空井压井过程中地层瞬态产气与井筒气液两相瞬态耦合流动数学模型及其数值求解方法。实例模拟计算结果表明:(1)气体钻井空井压井是由气相空井筒—瞬态气液两相流动—纯压井液井筒的物理过程,同时也是一个地层瞬态渗流与井筒气液两相瞬态流动耦合的过程;(2)成功的压井作业需要井口回压、泵排量、压井液密度等关键参数的共同配合,其中控制好井口回压是保证压井作业获得成功的关键。结论认为,研究成果首次量化了气体钻井压井过程,对气体钻井空井压井施工参数的优化设计具有指导意义。When high-pressure or high-yield gas layers are encountered during gas drilling, it is generally necessary to carry out well killing operation. In the course of empty well killing, a coupling effect occurs between a gas–liquid flow in wellbore annulus and gas seepage through porous media in reservoirs as the killing fluid is injected. However, this effect is rarely studied in China and abroad. In this paper, a mathematical model for such a coupling flow was established according to the theories of both formation transient seepage and wellbore gas–liquid flow, and its numerical solution method was developed. Case simulation indicates that empty well killing in gas drilling is a physical process of gas phase from gas only first to a transient gas–liquid flow and to killing fluids finally left in the wellbore, as well as a coupling process of transient seepage from reservoirs and a gas–liquid transient flow. In order to realize successful well killing, it is necessary to coordinate key parameters jointly, such as wellhead backpressure, pumping rate and killing fluid density, among which, wellhead backpressure is the key to the success of well killing operation. Based on the research, the well killing process in gas drilling is, for the first time, quantified. The research results are of instructive significance to the optimal design of empty well killing parameters in gas drilling.

关 键 词：气体钻井 压井液 空井压井 井控 地层瞬态产气 瞬态气液两相流动 井口回压 施工参数 

分 类 号：TE242[石油与天然气工程—油气井工程]