摘要
煤层气井排采过程中,压裂裂缝导流能力大小变化,直接影响压降漏斗扩展范围,进而影响煤层气井产气量的高低。以晋煤集团寺河矿3号煤制作煤片,以兰州石英砂为支撑剂,运用FCES-100裂缝长期导流能力评价仪,在实验室物理模拟了排采过程中煤储层压裂裂缝的导流能力变化规律。实验结果认为:煤层气井排采过程中压裂裂缝导流能力具有较强的应力敏感性,如果控制排采降压连续缓慢稳定进行,可以使压降漏斗充分扩展前应力敏感对导流能力的伤害较小;在水力压裂施工中可以通过增加砂比来减小支撑剂嵌入的影响,对于深井选用更高强度支撑剂可以克服支撑剂破碎引起的伤害;不稳定和断续排采可造成压裂裂缝导流能力快速下降,只有坚持排采降压的"连续、缓慢、稳定"进行,才能避免应力敏感和流速敏感带来的储层伤害,确保煤层气井开发取得好的效果。
During the process of drainage to coalbed methane（CBM） well,the change of conductivity of hydraulic frac- tures directly affects the extending range of pressure drop funnel, which can further influence the gas production level. The change regular pattern of fractures conductivity in coal reservoir during the process of drainage was simulated physically in the laboratory by means of the FCES-100 fracture long-term flow conductometer, and by using coal sam- ples made by No. 3 coal of Sihe Mine in Jincheng Anthracite Mining Group and Lanzhou sand as the proppant. Accord- ing to the analysis of the experiment, the conductivity of hydraulic fractures has a fairly strong stress sensitivity during the process of drainage, which controls the reservoir pressure dropping slowly and ensures that before the pressure drop funnel is fully extended, the stress sensitivity does less damage to the conductivity. Increasing sand ratio is considered to decrease the effect of proppant embedment and selecting higher-strength proppant aims to overcome the damage of its break in deep well. Instability and intermittent drainage is another important reason for the rapid decreasing of frac- ture conductivity, and only by adhering to draining continuously, slowly and stably can the damage of stress sensitivity and drainage velocity sensitivity be avoided and ensure coalbed methane wells development with good results achieved.
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2014年第1期124-128,共5页
Journal of China Coal Society
基金
国家自然科学基金资助项目(40972109
41002047)
关键词
导流能力
压裂裂缝
煤层气井
排采
闭合压力
conductivity
hydraulic factures
coalbed methane well
drainage
closure pressure
