摘要
五探1井是部署在四川盆地东部达州—开江古隆起上的一口风险探井,主探寒武系、震旦系,设计井深7 570 m。该井志留系以下地层的地质不确定性强、风险度高,寒武系可能钻遇大段膏盐层、纵向上压力系统复杂、预测井底温度达到175℃、井底液柱压力超过140 MPa并含有硫化氢等,给井身结构设计带来了很大的挑战。为此,借鉴国内外盐下超深井钻井的成功经验,在分析钻井工程面临的难点和风险的基础上,结合该井的压力系统特点、膏盐层蠕变特性,优化设计井身结构,并进行了现场应用。结果表明:(1)基于裸眼段防漏、防喷和防压差卡钻等约束条件,确定井身结构必封点5个、套管层次6层;(2)压力衰竭的石炭系岩性致密,压差卡钻和漏失的风险低,可以不做为必封点;(3)为寒武系膏盐层专门设计一层套管,以实现盐层专打,套管抗挤强度160 MPa预防挤毁;(4)五探1井安全钻达设计地层,完钻井深为8 060 m。结论认为,为实现川东地区盐下安全钻井而确定5个必封点、六开非常规井身结构是合理的,该井的成功完钻为上述古隆起后续深层天然气钻探提供了经验和借鉴。
Well Wutan 1 is a wildcat well deployed in the Dazhou–Kaijiang paleo-uplift, eastern Sichuan Basin and its design depth is 7 570 m. The Cambrian and Sinian strata are its main exploration targets, and the strata below the Sinian in this well are geologically uncertain with a high risk. A large section of gypsum-salt layer may be encountered in the Cambrian and the longitudinal pressure system is complex. It is predicted that the bottomhole temperature is up to 175 ℃, and the bottomhole liquid column pressure exceeds 140 MPa, and there is hydrogen sulfide. As a result, the casing program design is confronted with great challenges. In this paper, the difficulties and risks of drilling engineering were analyzed. Then, a casing program was designed and optimized referring to the successful drilling experience of subsalt ultra-deep wells at home and abroad, combined with the pressure system characteristics of Well Wutan 1 and the creep performance of gypsum-salt layers. Finally, the casing program was applied on site. And the following research results were obtained. First, in order to prevent leakage, blowout and pressure difference induced pipe sticking in the open hole section, it is determined that the casing program shall be in the pattern of six-section casing with 5 setting positions. Second, no setting position is needed in the Carboniferous pressure depleted reservoir for it is lithologically tight and pressure difference induced pipe sticking and leakage is less risky. Third, for achieving salt layer specialization, one section of casing is specially designed for the Cambrian gypsum-salt layer and its collapse strength is 160 MPa to prevent collapse by salt creep. Fourth, Well Wutan 1 is drilled successfully to the expected strata and its total depth is 8 060 m. In conclusion, the unconventional six-section casing program with 5 setting points to ensure the subsalt drilling safety in the eastern Sichuan Basin is rational. The successful drilling of Well Wutan 1 provides experiences and references for the follow-up deep-seated gas exploration in the Dazhou–Kaijiang paleo-uplift.
作者
邹灵战
毛蕴才
刘文忠
汪海阁
郭建华
邓传光
郑有成
黄洪春
李杰
乐宏
陈刚
Zou Lingzhan;Mao Yuncai;Liu Wenzhong;Wang Haige;Guo Jianhua;Deng Chuanguang;Zheng Youcheng;Huang Hongchun;Li Jie;Yue Hong;Chen Gang(CNPC Engineering Technology Research Institute Co.,Ltd.,Beijing 102206,China;PetroChina Exploration ＆ Production Company,Beijing 100083,China;PetroChina Southwest Oil ＆ Gasfield Company,Chengdu,Sichuan 610051,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2018年第7期73-79,共7页
Natural Gas Industry
基金
中国石油天然气股份有限公司重大科技专项"西南油气田上产300亿立方米勘探开发关键技术研究与应用"(编号:2016E-0608)
中国石油西南油气田公司重大科技专项"川东地区天然气勘探开发关键技术研究与应用"(编号:2016ZD01)
关键词
超深井
复杂压力系统
膏盐层
含硫化氢
井身结构
四川盆地
川东地区
达州—开江古隆起
五探1井
Ultra-deep well
Complex pressure system
Gypsum-salt layer
Hydrogen sulfide bearing
Casing program
Sichuan Basin
Eastern Sichuan Basin
Dazhou-Kaijiang paleo-uplift
Well Wutan 1
