高温定向井井筒瞬态温度计算模型及其应用  

A mathematical model of wellbore transient temperature of high-temperature directional wells and its application

作　　者：郑友志 辜涛 舒刚[1] 杨谋 余江[1] 伍葳 张占武 赵军 ZHENG Youzhi;GU Tao;SHU Gang;YANG Mou;YU Jiang;WU Wei;ZHANG Zhanwu;ZHAO Jun(Engineering Technology Research Institute,PetroChina Southwest Oil&Gasfield Company,Guanghan,Sichuan 618300,China;National Research and Development Center for High-sulfur Gas Reservoir Exploitation,Guanghan,Sichuan 618300,China;State Key Laboratory for Oil&Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Exploration Department,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China)

机构地区：[1]中国石油西南油气田公司工程技术研究院 [2]国家能源高含硫气藏开采研发中心 [3]“油气藏地质及开发工程”国家重点实验室·西南石油大学 [4]中国石油西南油气田公司勘探事业部

出　　处：《天然气工业》2021年第3期119-126,共8页Natural Gas Industry

基　　金：中国石油天然气集团有限公司重大科技项目“8000 m级复杂超深井优快钻完井技术集成与应用”(编号:2019D-4210);中国石油西南油气田公司博士后科研项目“川渝地区超高温储层固井水泥环关键性能研究”(编号:20190302-16);中国石油西南油气田公司工程技术研究院科研项目“不同工况条件下超高温储层水泥环完整性数值模拟研究”(编号:XNS15JS2019-038)。

摘　　要：四川盆地西部超深天然气井的目的层埋深在8000 m左右,井底原始地温超过150℃,一般都采用定向井的钻井方式钻至目的层。为了准确预测川西地区定向井钻井过程中的井筒瞬态温度、评价温度环境变化对流体性能与压力分布的影响,基于动量与能量守恒原理,考虑该区定向井的井型特点以及井筒—地层各控制区域在径向与轴向的传热机理,建立了定向井井筒—地层瞬态二维传热模型与温度压力耦合下的井筒压力计算模型,应用全隐式有限差分法对数学模型求解,分析了循环时间、排量对井筒温度的影响,进而评价了温度压力耦合下井筒压力与动静态密度随井深的分布变化特征。研究结果表明:①随着循环时间和排量的增加,井筒下部井段流体与近井壁地层温度降低,均低于原始地温,而上部井段流体、近井壁的套管及水泥环温度则高于原始地温;②考虑温度压力耦合下的井筒循环压力、静止密度及当量循环密度数值均小于无温度压力条件下,分别为2.1 MPa、0.065 g/cm3、0.045 g/cm^(3)。结论认为,该研究成果可以为定向钻具服役环境分析、全井段流体性质评价及井筒压力控制提供可靠的判定依据。The target layers of ultradeep natural gas wells in the western Sichuan Basin are at the depth about 8000 m,the bottom hole original temperature is over 150℃,and the drilling mode of directional well is generally adopted here to drill to the target layers.In order to accurately predict the wellbore transient temperature in the drilling process of directional wells in the western Sichuan Basin and evaluate the influences of temperature environmental change on fluid performance and pressure distribution,this paper established a wellbore–formation two-dimensional transient heat transfer model of directional well and a wellbore pressure calculation model of temperature and pressure coupling on the basis of the momentum and energy conservation principles,combined with the characteristics of the directional wells in this area and the radial and axial heat transfer mechanisms in each region under the control of wellbore–formation.Then,this mathematical model was solved using the fully implicit finite difference method.Finally,the influences of circulation time and displacement on the wellbore temperature were analyzed,and the evolution characteristics of fluid density and pressure under temperature and pressure coupling were evaluated.And the following research results were obtained.First,as circulation time and displacement increase,the fluid temperature at the lower hole section and the formation temperature near the wellbore decrease and they are both lower than original formation temperature,while the fluid temperature at the upper section and the casing and cement sheath temperature near the wellbore are higher than the original formation temperature.Second,the wellbore circulation pressure,static density and equivalent circulating density under temperature and pressure coupling are lower than those without temperature and pressure conditions,and they are 2.1 MPa,0.065 g/cm3 and 0.045 g/cm^(3),respectively.In conclusion,the research results can provide a reliable decision basis for analyzing the operational e

关 键 词：定向井 瞬态温度 温度压力耦合 流体性能 井筒压力 四川盆地西部 超深井 

分 类 号：TE24[石油与天然气工程—油气井工程]