致密气藏水平井多级多段压裂新技术及应用

XC气田JS气藏是川西侏罗系低渗致密气藏的典型代表,为使难动用储量通过水平井技术得到经济有效的开发,试验探索了不同钻井方式、不同完井方式、不同改造方式下的增产效果,并最终认为套管封隔器分级压裂是提高水平井效果的必须技术。但是随着产能对水平井分段数逐步提高的需求,由于滑套极差等因素影响,在139.7mm套管内分段数仅能达到7～10级。针对该情况,通过在封隔器分级压裂的每级间采用限流压裂工艺,提出了水平井多级多段压裂新技术,该技术能在现有技术的基础上有效提高了水平井的分段压裂数。水平井多级多段压裂新技术在XC气田JS难动用储量层实施8口井,平均单井获得天然气无阻流量19.4846×104m3/d,是邻井直井压裂增产的7.97倍,是以往封隔器常规分段压裂效果的1.9倍,增产效果明显提高。该技术在采用较少封隔器的情况下可以提高水平井分段数,而不会增加井下工具成本,同时可以降低施工风险。目前该技术在水平井中已经实现了15段的分段数,通过该技术的应用,139.7mm套管内水平井的分段数可由目前的7～10段提高到20～30段,该新技术的应用将对水平井开发非常规天然气技术提供有益的参考。

MULTI-STAGE FRACTURING TECHNOLOGY AND ITS APPLICATION IN HORIZONTAL WELL OF TIGHT GAS RESERVOIR

JS gas pool of XC gas field is the typical Jurassic low-permeability tight gas reservoirs,in order to effectively develop the difficult-to-produce reserves through the horizontal well technology,the effects of increasing production under the different drilling,completion and transformation ways have been tested,and the packer graduation fracturing is the best technology to enhance the horizontal well production rate.But with the improvement of off-take potential demand for the horizontal well partition number,due to the factors such as poor sliding sleeve,the number of segments in 139.7mm casing can only reach 7.For this condition,the new multi-level multi-stage fracturing technology of the horizontal well was proposed by using packer limited-entry fracturing technique.On the basis of existing technology,the technology could improve the number of staged fracturing effectively.The multi-level multi-stage fracturing technology of horizontal well were applied in 8 wells of JS difficult-to-produce reserves,the average single well natural gas open-flow capacity was 19.4846 × 10 4 m 3 /d,the yield has improved obviously.In case of using less packers,the technology could increase the number of horizontal well segments without increasing the cost of downhole tools and could reduce the construction risk.At present,the technology in horizontal wells has been achieved the number of segments 15,the new technology would provide a useful reference for unconventional natural gas development.