摘要
定向井穿越复合盐膏层,易遭遇溢流、井漏、井塌、阻卡等钻井复杂情况。联系伊拉克米桑油田盐膏层地质实际,在盐岩层定向钻井的井壁稳定性问题研究中引入瞬时弹性分析法和有限元分析法,推导建立了瞬时弹性坍塌压力、破裂压力及控制井眼盐岩蠕变收缩的钻井液密度计算模型。通过对米桑油田X井盐岩岩心进行三轴蠕变实验测试,利用模型计算分析了X井盐岩层的坍塌压力、破裂压力及安全钻井液密度。结果表明,盐膏层水平与垂直方向力学性质差别明显,各向异性突出,弹性模量低,水平方向泊松比高,盐膏层的安全钻井液密度窗口为2. 31～2. 50 g/cm^3。研究成果应用于米桑油田盐岩层钻井方案设计,有效解决了井壁稳定问题。
While directional well crossing the compound salt-gypsum layer,the complicated drilling conditions of overflow,well leak,well collapse,blocking and shrinkage are frequent.Based on the geological conditions of salt-gypsum bed in Missan Oilfield,the methods of instantaneous elastic analysis and finite element analysis are used to study the wellbore stability of directional drilling in salt formation,and calculation model of drilling fluid density for instantaneous elastic collapse pressure,fracture pressure and creep controlling of wellbore salt rock is established.Triaxial creep test of salt core in well X of Missan Oilfield is carried out,and the collapse pressure,fracture pressure and safe drilling fluid density of salt rock formation in well X are calculated and analyzed by using this model.The research results show that the mechanical properties of salt-paste layer differ significantly between horizontal and vertical directions,with prominent anisotropy,low elastic modulus and high poisson′s ratio in horizontal directions.The calculation results show that the salt-paste safe drilling fluid density window ranges from 2.31 to 2.50 g cm 3.The research results have been successfully applied to the design of drilling scheme when drilling into salt-rock formation in Missan oilfield,effectively solving the problem of borehole wall stability and ensuring site operation safely.
作者
吴怡
卢运虎
刘书杰
王名春
洪国滨
吴晓冬
WU Yi;LU Yunhu;LIU Shujie;WANG Mingchun;HONG Guobin;WU Xiaodong(CNOOC Research Institute Co.Ltd.,Beijing 100028,China;College of Petroleum Engineering,China University of Petroleum,Beijing 102249,China)
出处
《重庆科技学院学报（自然科学版）》
CAS
2019年第1期63-67,共5页
Journal of Chongqing University of Science and Technology：Natural Sciences Edition
基金
国家科技重大专项"海外重点油气田开发钻采关键技术"(2017ZX05032004)
关键词
盐岩层
定向井
井壁稳定性
钻井液密度
计算模型
salt rock layer
directional well
wellbore stability
drilling fluid density
computational model
