摘要
天然气水合物具有巨大的潜在经济和环境价值,其开发利用对国家能源安全和实现国家碳达峰碳中和的“双碳目标”具有战略意义。我国天然气水合物资源主要分布于南海海域,海洋环境的复杂性和隐蔽性使工程测量数据具有较大不确定性,影响钻井安全。目前未见有水合物储层井壁稳定可靠度研究。为定量评估在我国南海神狐海域水合物储层钻井风险,基于水合物储层钻井井壁稳定解析理论和南海神狐海域具体地质条件,结合可靠度分析方法中的改进一次二阶矩法和响应面法,研究南海神狐海域水合物储层钻井井壁失稳概率分布特征,分析该海域井壁失稳概率及安全钻井液压力窗口对主要参数均值和不确定性的敏感性,结果表明:(1)若测量数据足够精确,在我国南海神狐海域水合物储层进行钻井活动的安全性较高,安全钻井液压力窗口也较大。测量数据的不确定性增大将使井壁失稳概率显著升高,缩窄安全钻井液压力窗口。(2)较低的钻井液温度对降低井壁失稳概率略有帮助,且能明显地扩大安全钻井液压力窗口。(3)5个主要参数的均值和不确定性对井壁失稳概率的影响次序相同,均为初始地应力>初始内摩擦角>弹性模量比>初始黏聚力>初始弹性模量。实际工程中对初始地应力数据精确测量,能够显著提高水合物储层钻井井壁稳定性。
Natural gas hydrates have significant economic and environmental potential,and their exploitation and utilization are of strategic significance for national energy security and realizing“dual carbon goals”of peak carbon and carbon neutrality.The majority of hydrates in China is distributed in the South China Sea.The complexity and concealment of the marine environment result in highly uncertainty of engineering measurement data,which affects drilling safety.However,there is a lack of reliability analysis for wellbore stability in hydrate reservoirs.Based on the analytical model of wellbore stability in hydrate reservoirs and the specific geological conditions of the Shenhu area in the South China Sea,the reliability analysis methods including the advanced first-order second-moment method and the response surface method are employed to quantitatively assess the probability of wellbore instability during drilling,and to analyze the sensitivity of the wellbore instability probability and safe drilling fluid pressure window to the mean and uncertainty of the main parameters.The research results indicate that:(1)If the measurement data are accurate enough,the drilling in hydrate reservoirs in the Shenhu area of the South China Sea is highly safe and the safe drilling fluid pressure window is also large.However,the increased uncertainty of measurement data can significantly increase the probability of wellbore instability and narrow the safe drilling fluid pressure window.(2)A lower drilling fluid temperature can slightly reduce the probability of wellbore instability and significantly increase the safe drilling fluid pressure window.(3)The mean and uncertainty of the five main parameters have the same order of influence on the probability of wellbore instability,that is:initial in situ stress>initial internal friction angle>elastic modulus ratio>initial cohesion>initial elastic modulus.Accurate measurement of initial in situ stress in practical engineering can significantly improve the wellbore stability in hydrate reservoirs.
作者
黄佳佳
蒋明镜
王华宁
HUANG Jia-jia;JIANG Ming-jing;WANG Hua-ning(College of Civil Engineering,Tongji University,Shanghai 200092,China;Zhejiang Electric Power Design Institute,China Energy Engineering Group,Hangzhou,Zhejiang 310012,China;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;School of Civil Engineering,Suzhou University of Science and Technology,Suzhou,Jiangsu 215009,China;School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第5期1505-1516,共12页
Rock and Soil Mechanics
基金
国家自然科学基金(No.12272274,No.51890911)
同济大学土木工程防灾国家重点实验室自主课题(No.SLDRCE19-A-06)
海南省重点研发计划项目(No.ZDYF2021SHFZ264)
中国工程科技发展战略海南研究院重大咨询研究项目(No.21-HN-ZD-02-5)。
关键词
天然气水合物
井壁稳定性
可靠度
南海神狐海域
响应面法
改进一次二阶矩法
natural gas hydrate
wellbore stability
reliability
Shenhu area in the South China Sea
response surface method
advanced first order second moment method
作者简介
第一作者:黄佳佳,男,1991年生,博士,主要从事含水合物地层井壁稳定等方面的研究。E-mail:huangjiajia_civil@tongji.edu.cn;通讯作者:蒋明镜,男,1965年生,博士,教授,主要从事深海能源土宏微观数值分析等方面的研究。E-mail:mingjing.jiang@tongji.edu.cn。
