海底天然气水合物储层复杂地层钻进取芯数值模拟  

Numerical Simulation on Drilling of Submarine Gas Hydrate in Complicated Formation

作　　者：卫成效 金永平 刘德顺 万步炎 何术东 WEI Chengxiao;JIN Yongping;LIU Deshun;WAN Buyan;HE Shudong(National-Local Joint Engineering Laboratory of Marine Mineral Resources Exploration Equipment and Safety Technology,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学海洋矿产资源探采装备与安全技术国家地方联合工程实验室,湖南湘潭411201

出　　处：《矿业工程研究》2024年第3期11-19,共9页Mineral Engineering Research

基　　金：国家自然科学基金资助项目(51779092);国家重点研发计划资助项目(2016YFC0300502);湖南省研究生科研创新资助项目(CX20210985);湖南创新型省份建设专项经费资助项目(2020GK1021,2019SK2271,2019GK1010,2019GK1012)。

摘　　要：海底天然气水合物由于其特殊的成藏机理,其分布大多与海底构造地层相关,而天然气水合物的赋存状态同样影响着海底沉积物的性质,因此其储层往往是可预见性差、可钻性差及稳定性差的复杂地层.针对天然气水合物储层的软硬互层,利用有限元软件Abaqus/CAE,建立搭载在海底钻机上的金刚石钻头对天然气水合物储层钻进取芯的有限元仿真模型,对钻进过程进行模拟分析.通过在钻头上施加不同的钻进参数,获得金刚石钻头随钻进参数变化的运动规律,以及不同钻进参数下水合物储层不同位置的应力状态;通过对应力状态进行分析,得到岩芯受扰动的变化规律.结果表明:金刚石钻头在穿过不同地层时运动状态可分为3个阶段,钻头的平均钻速随着钻压与转速的增加而增加;不同地层的岩芯失效率大不相同,水合物层岩芯的失效率为10%~15%,其上覆土层岩芯的失效率为25%~45%,而且失效率受钻压的影响较为明显.The distribution of submarine gas hydrates is mostly related to the submarine structural strata due to its special accumulation mechanism.The occurrence state of natural gas hydrate also affects the properties of seabed sediments,so its reservoirs are often complex formations with poor predictability,poor drill ability,and poor stability.This paper,using the finite element software Abaqus/CAE,targeting at the soft and hard interbeds of natural gas hydrate reservoirs,a finite element model of the diamond drill bit mounted on the deep-sea drilling-rig drill a complex marine gas hydrate reservoir is built to simulate and analyze the drilling process.During the drilling,by applying different drilling parameters to the bit,it obtains the variation of diamond bit motion with drilling parameters,and stress states at different positions of hydrate reservoirs under different drilling parameters.Through the analysis of stress state,the variation law of core disturbance is obtained.The results show that the motion of a diamond bit through different formations can be divided into three stages,the average bit rate increases with the increase of bit weight and rotational speed.The core failure rate varies greatly from formation to formation,the failure rate of hydrate core is about 10%to 15%,while the failure rate of the overlying rock core is about 25%to 45%.Failure rate is obviously affected by weight on bit.

关 键 词：海底天然气水合物 复杂地层 有限元模型 钻速 应力状态 

分 类 号：TE52[石油与天然气工程—油气田开发工程]