洛带气田遂宁组特低渗致密砂岩气藏压裂改造技术应用研究

APPLICATION STUDY OF HYDRAULIC FRACTURING TECHNOLOGY IN TIGHT SANDSTONE RESERVOIR OF SUINING FORMATION WITH ULTRA-LOW PERMEABILITY IN LUODAI GAS FIELD

洛带气田遂宁组气藏埋藏较浅,属典型的特低渗致密气藏。储层为砂泥岩互层或泥岩夹层,单层砂体很薄,微裂缝较发育和非均质性强,长期以来一直被视为“非储层”。文章进行了储层敏感性评价和低伤害压裂液优选研究,提出了以“多层合压或分层压裂、中砂量、中前置液量、中排量、中砂比、强化返排措施”为特色的水力压裂改造技术,取得极为明显的增产效果,平均单井增加无阻流量4.62×104m3/d。遂宁组特低渗致密砂岩气藏压裂改造技术的重大突破,为难动用储量的升级和增储上产做出了关键性贡献,使以前一直被认为是“非储层”的致密气藏成功转化为工业性气藏,并成为川西地区增产效果最好的气藏之一。

Suining Formation gas reservoir in Luodai gas field has relatively shallow burial depth and is a tight sandstone gas reservoir with ultra-low permeability. The reservoir is interbedded sandstone and shale or sandstone with intercalated shale. Single sandbody is very thin with well-developed microfractures and strong heterogeneity and they have long been considered as non-reservoirs. Based on evaluation of reservoir sensitivity and selection of low damage fracturing fluid, a hydraulic fracturing technology is presented, which is characterized by commingled fracturing or separate layer fracturing, moderate sand volume, moderate lead volume, moderate discharge volume, moderate proppant concentration and intensified flowback. The stimulation effects are very good, with an averaged incremental open-flow capacity of single well at 46,200 m3/d. The significant breakthrough of hydraulic fracturing technology in the Suining Formation sandstone reservoir with ultra-low permeability has contributed to the upgrading of the hard-to-produce reserves and reserve addition and production growth, converting the tight sandstone gas reservoirs that have long been considered as non-reservoirs into commercial gas reservoirs. It is one of the best stimulated gas reservoirs in West Sichuan.