深水钻井最大允许气侵溢流量的计算方法
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摘要
深水钻井对井控提出了更高的要求,气侵的早期监测便成为深水井控研究的热点。由于溢流量预警值为经验值,使得现有泥浆池增量法在水深较深、原始地层压力较高的井中应用的普适性和可靠性较差。为此,通过引入最大允许关井套压和环空气体上升位置,计算不同溢流量条件下的压井风险,建立了基于气侵的溢流量预警值反算方法,以此来保证在现有井控设备、施工参数和地层参数等确定的条件下进行更为精确可靠的气侵溢流监测。同时引入含可信度地层压力预测方法对溢流量预警值反算方法进行改进,最大限度地降低了因地层压力预测不准而导致的气侵监测误差。实例计算结果表明,该方法充分考虑了气侵后气体上升位置和压井风险,能够大大提高深水钻井气侵早期监测的准确率和可靠性,对于实现因井而异的溢流量预警值设计和降低气侵监测成本有实际意义。同时提出推荐采用精度更高更稳定的进出口流量计对泥浆池增量进行监测,以满足半潜式钻井平台的测量精度。
Deepwater drilling requires more rigorous well control. Accordingly, proactive gas invasion detection is a hot topic in research of deepwater well control. The warning overflow value is an empiric value, so the existing pit-gain method is less applicable and reliable for the wells with a high initial reservoir pressure in deep water. In this paper, the well-killing risks under different overflow conditions were calculated with consideration to the maximum allowable shut-in casing pressure and the annulus gas-ascending position. Then, a back calculation method was developed on the basis of the warning overflow value of gas invasion so as to monitor gas invasion overflow more accurately and reliably with the existing well control equipment, construction parameters and formation parameters. Furthermore, this method was improved by integrating the credibility formation pressure prediction method to minimize the gas invasion monitoring errors caused by inaccurate formation pressure prediction. Practical calculation shows that this method takes the annulus gas-ascending positions and well-killing risks into full account, so the accuracy and reliability of proactive gas invasion detection in deepwater drilling are improved greatly. This method plays a practical role in designing well-specific warning overflow value and reducing gas invasion monitoring costs. Finally, it was recommended to monitor the pit gain by using the import and export flow meters of higher accuracy and stability so as to satisfy the measurement accuracy of semi-submersible drilling platforms.
Deepwater drilling requires more rigorous well control. Accordingly, proactive gas invasion detection is a hot topic in research of deepwater well control. The warning overflow value is an empiric value, so the existing pit-gain method is less applicable and reliable for the wells with a high initial reservoir pressure in deep water. In this paper, the well-killing risks under different overflow conditions were calculated with consideration to the maximum allowable shut-in casing pressure and the annulus gas-ascending position. Then, a back calculation method was developed on the basis of the warning overflow value of gas invasion so as to monitor gas invasion overflow more accurately and reliably with the existing well control equipment, construction parameters and formation parameters. Furthermore, this method was improved by integrating the credibility formation pressure prediction method to minimize the gas invasion monitoring errors caused by inaccurate formation pressure prediction. Practical calculation shows that this method takes the annulus gas-ascending positions and well-killing risks into full account, so the accuracy and reliability of proactive gas invasion detection in deepwater drilling are improved greatly. This method plays a practical role in designing well-specific warning overflow value and reducing gas invasion monitoring costs. Finally, it was recommended to monitor the pit gain by using the import and export flow meters of higher accuracy and stability so as to satisfy the measurement accuracy of semi-submersible drilling platforms.
引文
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[13]Zuber N and Findlay JA.Average volumetric concentration in two-phase flow systems[J].Journal of Heat Transfer,1965,87(4):453-468.
[14]宋洵成,管志川.深水钻井井筒全瞬态传热特征[J].石油学报,2011,32(4):704-708.Song Xuncheng,Guan Zhichuan.Full transient analysis of heat transfer during drilling fluid circulation in deep-water wells[J].Acta Petrolei Sinica,2011,32(4):704-708.
[15]董星亮,曹式敬,唐海雄,陈建兵.海洋钻井手册[M].北京:石油工业出版社,2011.Dong Xingliang,Cao Shijing,Tang Haixiong,Chen Jianbing.Offshore drilling manual[M].Beijing:Petroleum Industry Press,2011.
[16]柯珂,管志川,周行.深水探井钻前含可信度的地层孔隙压力确立方法[J].中国石油大学学报:自然科学版,2009,33(5):61-67.Ke Ke,Guan Zhichuan,Zhou Hang.An approach to determining pre-drilling formation pore pressure with credibility for deep water exploration wells[J].Journal of China University of Petroleum:Edition of Natural Science,2009,33(5):61-67.
[17]许玉强,管志川,张洪宁,张会增.基于含可信度地层压力剖面的精细井身结构设计方法[J].中国石油大学学报:自然科学版,2014,38(6):72-77.Xu Yuqiang,Guan Zhichuan,Zhang Hongning,Zhang Huizeng.Methods for precise casing design based on formation pressure profiles with different credibility[J].Journal of China University of Petroleum:Edition of Natural Science,2014,38(6):72-77.
[2]Chen Wei.Status and challenges of Chinese deepwater oil and gas development[J].Petroleum Science,2011,8(4):477-484.
[3]何小胡,钟泽红,董贵能,姚哲,吴迅达.莺琼盆地新近系海流的研究新进展及深水油气勘探的启示[J].天然气勘探与开发,2015,38(1):5-8.He Xiaohu,Zhong Zehong,Dong Guineng,Yao Zhe,Wu Xunda.Neogene ocean current in Yingqiong Basin:Implication of deepwater oil and gas exploration[J].Natural Gas Exploration&Development,2015,38(1):5-8.
[4]谢玉洪.南海北部自营深水天然气勘探重大突破及其启示[J].天然气工业,2014,34(10):1-8.Xie Yuhong.A major breakthrough in deepwater natural gas exploration in a self-run oil/gas field in the northern South China Sea and its enlightenment[J].Natural Gas Industry,2014,34(10):1-8.
[5]曹式敬.“海洋石油981”超深水钻井装置防喷器系统可靠性分析[J].中国海上油气,2013,25(1):46-48.Cao Shijing.Analysis on the reliability of subsea BOP and control system for ultra-deepwater drilling unit HYSY981[J].China Offshore Oil and Gas,2013,25(1):46-48.
[6]陈平,马天寿.深水钻井溢流早期监测技术研究现状[J].石油学报,2014,35(3):602-612.Chen Ping,Ma Tianshou.Research status of early monitoring technology for deepwater drilling overflow[J].Acta Petrolei Sinica,2014,35(3):602-612.
[7]卓鲁斌,葛云华,汪海阁.深水钻井早期井涌检测方法及其未来趋势[J].石油钻采工艺,2009,31(1):22-26.Zhuo Lubin,Ge Yunhua,Wang Haige.Early kick detection methods for deepwater drilling and its future development[J].Oil Drilling&Production Technology,2009,31(1):22-26.
[8]任美鹏,李相方,徐大融,尹邦堂.钻井气液两相流体溢流与分布特征研究[J].工程热物理学报,2012,33(12):2120-2125.Ren Meipeng,Li Xiangfang,Xu Darong,Yin Bangtang.Research of kick and distribution features of gas-liquid two phase flow during drilling[J].Journal of Engineering Thermophysics,2012,33(12):2120-2125.
[9]任美鹏,李相方,刘书杰,耿亚楠,朱磊,尹邦堂.深水钻井井筒气液两相溢流特征及其识别方法[J].工程热物理学报,2011,32(12):2068-2072.Ren Meipeng,Li Xiangfang,Liu Shujie,Geng Yanan,Zhu Lei,Yin Bangtang.The characteristics and identification method of gas-liquid two flow overflow in deepwater drilling[J].Journal of Engineering Thermophysics,2011,32(12):2068-2072.
[10]隋秀香,梁羽丰,李轶明,尹邦堂,李相方.基于多普勒测量技术的深水隔水管气侵早期监测研究[J].石油钻探技术,2014,42(5):90-94.Sui Xiuxiang,Liang Yufeng,Li Yiming,Yin Bangtang,Li Xiangfang.Early monitoring of the gas-cut in deepwater riser based on doppler measuring system[J].Petroleum Drilling Techniques,2014,42(5):90-94.
[11]孙连伟,管志川,梁海明,江梦娜.井身结构变化及尾管回接对井控的影响分析[J].石油钻探技术,2013,41(6):34-39.Sun Lianwei,Guan Zhichuan,Liang Haiming,Jiang Mengna.Effects of casing program change and liner tieback on well control[J].Petroleum Drilling Techniques,2013,41(6):34-39.
[12]高永海,孙宝江,王志远,曹式敬,宋林松,程海清.深水钻探井筒温度场的计算与分析[J].中国石油大学学报:自然科学版,2008,32(2):58-62.Gao Yonghai,Sun Baojiang,Wang Zhiyuan,Cao Shijing,Song Linsong,Cheng Haiqing.Calculation and analysis of wellbore temperature field in deepwater drilling[J].Journal of China University of Petroleum:Edition of Natural Science,2008,32(4):58-62.
[13]Zuber N and Findlay JA.Average volumetric concentration in two-phase flow systems[J].Journal of Heat Transfer,1965,87(4):453-468.
[14]宋洵成,管志川.深水钻井井筒全瞬态传热特征[J].石油学报,2011,32(4):704-708.Song Xuncheng,Guan Zhichuan.Full transient analysis of heat transfer during drilling fluid circulation in deep-water wells[J].Acta Petrolei Sinica,2011,32(4):704-708.
[15]董星亮,曹式敬,唐海雄,陈建兵.海洋钻井手册[M].北京:石油工业出版社,2011.Dong Xingliang,Cao Shijing,Tang Haixiong,Chen Jianbing.Offshore drilling manual[M].Beijing:Petroleum Industry Press,2011.
[16]柯珂,管志川,周行.深水探井钻前含可信度的地层孔隙压力确立方法[J].中国石油大学学报:自然科学版,2009,33(5):61-67.Ke Ke,Guan Zhichuan,Zhou Hang.An approach to determining pre-drilling formation pore pressure with credibility for deep water exploration wells[J].Journal of China University of Petroleum:Edition of Natural Science,2009,33(5):61-67.
[17]许玉强,管志川,张洪宁,张会增.基于含可信度地层压力剖面的精细井身结构设计方法[J].中国石油大学学报:自然科学版,2014,38(6):72-77.Xu Yuqiang,Guan Zhichuan,Zhang Hongning,Zhang Huizeng.Methods for precise casing design based on formation pressure profiles with different credibility[J].Journal of China University of Petroleum:Edition of Natural Science,2014,38(6):72-77.