天然气水合物试采井筒-土壤三维非线性耦合模型研究  

Study on 3D nonlinear coupling wellbore-soil model of natural gas hydrate production test

作　　者：畅元江[1] 黄帅[1] 王康[1] 孙宝江[2] 李昊[2] 孙焕钊 陈国明[1] CHANG Yuanjiang;HUANG Shuai;WANG Kang;SUN Baojiang;LI Hao;SUN Huanzhao;CHEN Guoming(Center for Offshore Engineering and Safety Technology,China University of Petroleum(East China),Qingdao 266580,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石油大学(华东)海洋油气装备与安全技术研究中心,山东青岛266580 [2]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《中南大学学报（自然科学版）》2022年第3期942-951,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学重点基金资助项目(51890914)。

摘　　要：常规二维模型用于研究水合物井筒稳定性时,不能反映地层沉降变形对井筒的影响,为此,考虑渗流场、应力场和井筒内外压力场的多场耦合作用,研究水合物分解引起的储层特征参数在近井界面区域的时变特征;采用流固耦合理论,建立天然气水合物井筒-土壤三维非线性耦合模型,并以南海某水合物井为例,对井筒稳定性影响因素进行分析。研究结果表明:井筒稳定性主要影响因素为轴向应力;随着生产压差提高和试采时间延长,井筒的轴向应力逐渐增加,且轴向应力在试采初期增加较明显,随着试采进行逐渐趋于平稳;若生产压差为10 MPa,则安全试采仅能维持15 d,若生产压差不超过8 MPa,则安全试采可达60 d以上。The conventional 2D model can not reflect the influence of formation settlement deformation on wellbore stability when it is used to study hydrate wellbore stability.In this paper,considering the multi-field coupling effect of seepage field,stress field and pressure field inside and outside wellbore,the time-varying characteristics of reservoir characteristic parameters caused by hydrate decomposition near wellbore interface were studied,a 3D nonlinear coupling model of natural gas hydrate wellbore-soil was established.A hydrate well in the South China Sea was taken as an example,and the influencing factors of wellbore stability were analyzed.The results show that the wellbore stability is dominated by its axial stress.With the increase of production pressure difference and the extension of production test time,the axial stress of wellbore increases gradually,and the axial stress increases obviously in the early stage of production test,and tends to be stable with the progress of production test.If the production pressure difference is 10 MPa,the safe trial production can only last 15 d,and if the production pressure difference is less than 8 MPa,the safe trial production can last more than 60 d.

关 键 词：天然气水合物 三维非线性 多场耦合 井筒稳定性 

分 类 号：TE58[石油与天然气工程—油气田开发工程]