Title

Depressurization extraction technology of natural gas hydrate based on horizontal well perforation

作者

青显林张运祥宋军

单位

西南石油大学机电工程学院，四川成都 610500

Organization

School of Mechanical and Electrical Engineering, Southwest Petroleum University, Chengdu 610500, China

摘要

针对目前天然气水合物降压开采效率较低、产能不足等问题，文中提出了基于水平井射孔和回撤抽提的天然气水合物降压抽采工艺。利用有限元分析软件，建立了天然气水合物降压抽采三维模型，分析抽采过程中储层压力分布和流场变化规律，对日产气量进行估算，并与南海神狐工程试采数据、中海油天然气水合物商业开采标准测算的日产气量进行对比。研究结果表明：采用水平井射孔可显著扩大降压范围、增加产气速率，同时连续的水平井回撤抽提工艺利用了储层降压产气最高效时段，从而在空间和时间上提高了天然气水合物的抽采效率，估算的日产气量远远高于南海神狐工程试采的最高日产气量。该研究确保了天然气水合物商业化开采具有良好的经济性，为后续的开采工艺研究提供了借鉴。

Abstract

To solve the problems of low production efficiency and insufficient yield of natural gas from hydrate reservoir, this paper proposes a gas hydrate depressurization process based on horizontal well perforation arrangement and recursive extraction process. A three?鄄dimensional model of the depressurization and extraction of the Shenhu reservoir in the South China Sea under this method was established by using finite element analysis software. The pressure distribution and the time-varying law of the reservoir during the mining process were analyzed, and the daily gas production was estimated. Finally, the estimated daily gas production was compared with the testing data from Shenhu engineering and the existing commercial standards for natural gas hydrate production calculated by CNOOC. The results show that the use of horizontal well perforation can significantly expand the pressure reduction range and increase the gas production rate. At the same time, the continuous horizontal well retracement extraction process utilizes the most efficient period of reservoir pressure reduction and gas production, thereby improving the efficiency of natural gas hydrate extraction. The daily gas production is far better than the highest single-day gas production efficiency of the trial production, ensuring that the commercial exploitation of natural gas hydrate has good economics, and laying the foundation for subsequent research on mining technology.

关键词：

天然气水合物; 水平井射孔; 抽提; 有限元分析; 经济性; 南海;

Keywords:

gas hydrate; horizontal well perforation; recursive extraction; finite element analysis; economics； South China Sea;

基金项目

DOI

10.6056/dkyqt202006009

基于水平井射孔的天然气水合物降压抽采工艺