玛湖井区低伤害滑溜水压裂液性能评价

Performance Evaluation of Low-damage Slick Water Fracturing Fluid in Mahu Well Area

玛湖1井区百口泉组为典型的低孔低渗致密油储层。该井区大规模水力压裂面临3大难题,如压裂液减阻效果差、对储层伤害大;水资源匮乏,油田污水处理困难;缝间剩余油分布,采收率有待提高。针对这些问题,以羟甲基苯乙烯、醋酸乙烯酯、丙烯酰胺、聚乙烯基苄基三甲基氯化铵等为原料,通过分散聚合法制备了减阻剂(JHFR),将其与多功能添加剂(JHFD)复配制得滑溜水压裂液。研究了目标区块的压裂水源、储层岩石的黏土矿物含量对黏土在滑溜水中水化膨胀性能的影响,评价了滑溜水对玛湖致密油藏储层的伤害情况。结果表明,减阻剂JHFR溶解时间(15 s)短,可实现免配直混。由0.1%JHFR和0.2%JHFD组成的滑溜水具有高效减阻(减阻率76.9%)、低油水界面张力(0.89 mN/m)、防膨效果好(防膨率81.12%)等特点,且与玛湖1井区的地层水和返排水的配伍性良好、对岩心渗透率损害程度低,适用于该井区的大规模连续压裂施工。

The Baikouquan formation in the Mahu 1#well area is a typical tight oil reservoir with low porosity and permeability.Large-scale hydraulic fracturing in this well area faces three major problems,such as poor drag reduction effect of fracturing fluid,great damage to reservoir,scarce water resource and difficult treatment of oilfield sewage.Furthermore,the remaining oil distributes between fractures,and the recovery rate needs to be improved.In response to these problems,the drag reducer(JHFR)was prepared by dispersion polymerization using hydroxymethyl styrene,vinyl acetate,acrylamide,polyvinyl benzyl trimethyl ammonium chloride,etc.Then JHFR was compounded with the multifunctional additive(JHFD)to obtain a slick water fracturing fluid.The effects of fracturing water source and the clay mineral content of reservoir rock in target block on the hydration and swelling performance of clay in slick water were studied.And the damage of slick water to the Mahu tight oil reservoir was evaluated.The results showed that the dissolution time(15 s)of drag reducer JHFR was short,and direct mixing could be realized without mixing.The slick water composed of 0.1%JHFR and 0.2%JHFD had the characteristics of high drag reduction(76.9%drag reduction rate),low oil-water interfacial tension(0.89 mN/m),good anti-swelling effect(81.12%anti-swelling rate),etc.The system had good compatibility with the formation water and flowback fluid in the Mahu 1#well area,and had low damage to the core permeability.It was suitable for the large-scale continuous fracturing in this well area.