Pilot experiment for underground in-situ pyrolysis of tar-rich coal in the northern Shaanxi Province
DUAN Zhonghui;YANG Fu;WANG Zhendong;MA Li;DUAN Xiaoqing;CAO Husheng;CHEN Liang
陕北富油煤地下原位热解先导试验在国内外尚属首次,开创了富油煤、油页岩等原位转化新方向,引起了行业内外广泛关注。富油煤地下原位热解的研究尚处于起步阶段,缺少现场工程数据的系统研究。
通过现场先导试验,明确富油煤地下原位热解的地质条件和工程难点,总结陕北富油煤地下原位热解开采进展,探讨下一步技术攻关方向。
结果表明:(1)先导试验区具有煤层稳定、煤质条件好、煤焦油产率高、生油潜力大、煤系富水性弱、隔水层厚度大等优越的原位热解地质条件,但煤层孔隙连通性差、导流能力低、煤层导热能力差、高效加热难度大、煤层改造难度大、体积造缝要求高等因素影响到工程效果。(2) 开展综合地质评价有利于规避地层水、断层等不利因素对地下热解过程的影响,可控冲击波致裂技术有助于地下煤层裂缝连通,井下高效电加热器稳定运行是高效产油的关键。(3) 经过一个月加热运行,成功提取出全球第一桶地下原位热解油,初步打通了富油煤地下原位热解开采技术路径,获取了产油的地下温度、压力等工艺参数。先导试验存在加热周期短、产油量低、耗能高,缺少项目运行的系统性技术评价,需从研发高效井下电加热器、地下煤层体积造缝、热解−气化一体化、热能综合利用及集成CCS等方面继续升级技术,实现降本增效,综合提高富油煤地下原位热解开采的经济性、安全性和可靠性。
The breakthrough of the pilot experiment for underground in-situ pyrolysis of tar-rich coal in the northern Shaanxi has added new vitality to the research on in-situ conversion of fossil energy such as tar-rich coal and oil shale, and the results have attracted wide attention both inside and outside the industry. The research on underground in-situ pyrolysis of tar rich coal is still in its infancy, lacking systematic research on field engineering data.
Based on the pilot experiment, the main geological conditions and engineering difficulties have been clarified, and the progress of underground in-situ pyrolysis has been summarized. The next technical breakthrough directions are also discussed.
The results show that: (1) The superior geological conditions of the pilot experiment area, such as stable coal seams, good coal quality, high tar yield of coal seams, large oil generation potential, weak water-rich coal measures and large thickness of aquiclude. However, there are some factors affecting the engineering implementation, such as poor connectivity of coal seam pores, low diversion capacity, poor thermal conductivity of coal seams, difficulty in efficient heating, difficulty in coal reservoir reconstruction, and high requirements for volume .fracturing; (2) Comprehensive geological evaluation is conducive to avoiding the influence of unfavorable factors such as formation water and faults on the underground pyrolysis process. Controllable shock wave fracturing technology is helpful for the connectivity of underground coal seams. The stable operation of efficient underground electric heaters is the key to efficient oil production. (3) After one month of heating operation, the world's first barrel of underground in-situ pyrolysis oil was extracted, which opened up the technical path of underground in-situ pyrolysis extraction of tar-rich coal and initially obtained the underground temperature, pressure and other process parameters for efficient oil production. The pilot experiment has a short heating cycle, low oil production and high energy consumption, lacks a technical systematic evaluation of project operation.It is necessary to continue upgrading technologies in terms of developing efficient underground electric heaters, underground coal seam volume fracturing, pyrolysis-gasification integration, comprehensive utilization of heat energy and integrated CCS, so as to comprehensively improve the economy, safety and reliability of underground in-situ pyrolysis extraction of tar-rich coal.
tar-rich coal;underground in-situ pyrolysis;pilot experiment;pyrolytic-gasification integration;northern Shaanxi Province
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会