实时变黏压裂液在宁武盆地煤层气井的应用

APPLICATION OF REAL-TIME THICKENING FRACTURING FLUID SYSTEM IN CBM WELLS AT NINGWU BASIN

宁武盆地石炭系上统太原组9号煤层在区域内分布稳定,含气量较高,是该区块煤层气勘探开发的主力层位。前期改造过程中多采用活性水压裂液体系,但由于煤层的松散、弱胶结、高滤失性等特点,存在地面施工压力高、波动大、易砂堵等问题,施工成功率仅55.6%,严重影响改造效果。室内研究形成了一种适用于煤层气井压裂的可实时变黏压裂液体系稠化剂HT-1,其具有施工全程黏度可控、在线混配、连续施工、低温破胶、破胶液残渣含量低等特点,提高了压裂液效率和携砂性能,降低了压裂液破胶液对煤层的伤害。现场应用表明,这种可实时变黏压裂液体系在施工过程中性能良好,能够满足设计要求,为该地区煤层气勘探开发提供了重要的技术保障。

9~# coal seam in taiyuan group of carboniferous system at NingW u basin is featured with stable distribution in the region and high gas content. It is the main target layer of coalbed methane exploration and development at the block. During the early-stage reservoir stimulation,the fracturing fluid systemwith activated water was used. But due to the loose,weakly cemented,and high filtration coal seams,problems like high and large-fluctuation surface pressure,and sand plugging often led to an operation success ration of only 55. 6%,seriously affecting the stimulation effects. Through experimental study a kind of realtime thickening agent HT-1 was developed which was suitable for fracturing in coalbed methane gas wells. Its viscosity can be controlled during the whole operation,it can be mixed on-line,continuously operated,broken at low temperatures,and low gel breaking liquid residue. It will improve the efficiency of fracturing fluid and sand carrying,reduce the damage to the coal beds. Field application shows that this frac fluid system has supreme performance,able to meet the design requirements,providing an important technical guarantee for the coalbed methane exploration and development in this area.