南海涠洲中低渗油藏SMG深部调驱体系研究

Research on SMG deep profile control system of Weizhou medium and low permeability reservoir in South China Sea

目的针对涠洲12-1油田中低渗油藏注水开发效果差,注入凝胶调剖容易导致注入压力过高产生欠注,泡沫驱泡沫体积及半衰期受高温高盐环境影响大等实际问题,提出使用合成粒径可控,性质稳定且具有优秀的注入能力以及耐温耐盐性能的SMG微球作为深部调驱剂,以期满足现场进一步增产需求。方法利用扫描电镜、激光粒度仪以及物理模拟实验针对SMG深部调驱体系的水化膨胀性能、注入性能、封堵性能和提高采收率效果进行分析。结果SMG具有良好的膨胀及封堵性能,其初始粒径为0.71μm,7天后粒径膨胀速度减缓,达到5.32μm,最终粒径膨胀倍数约7倍。岩心渗透率在69.8×10^(-3)~308.0×10^(-3)μm^(2)时,封堵率均在90%以上,且随着岩心渗透率的增加,SMG的阻力系数、封堵率呈小幅度波动后逐步下降趋势,实验组中最高采收率增幅为15.49%。结论注入SMG可以实现深部滞留,有效封堵高渗层大孔喉,改善储层非均质性,改变驱替液流向及压力分布,提高波及面积,从而提高采收率;并且注入SMG的时机越早,增压调驱能力越强,提高采收率效果越好。

Objective Aiming at the poor development effect of water injection in the medium-low permeability reservoir of Weizhou 12-1 oilfield,the under-injection caused by high injection pressure easily due to the injection gel conditioning,and the foam volume and half-life of foam repellent are greatly affected by the high temperature and high salt environment,etc.,we propose to use the synthesized SMG microspheres,which are controllable in size,stable in nature,and have excellent injection ability and temperature and salt resistance,as the deep driving agent,so as to satisfy the further increase of the production in the field.Methods The hydration swelling performance,injection performance,plugging performance and recovery enhancement effect of SMG deep profile control system were analyzed by scanning electron microscope,laser particle size meter and physical simulation experiments.Results SMG has good swelling and plugging performance,with an initial particle size of 0.71μm,expansion slows down after seven days,and a final particle size swelling multiple of 5.32μm,the final particle size expansion ratio was about 7 times.When the core permeability was in the range of 69.8×10^(-3)-308.0×10^(-3)μm^(2),the plugging rate was above 90%in all cases.The resistance coefficient and plugging rate of SMG showed a small fluctuation and then gradually decreased with the increase of core permeability.The highest recovery increase in the experimental group was 15.49%.Conclusions The injection of SMG can achieve deep retention,effectively seal the large pore throat of high permeability,improve the reservoir inhomogeneity.It can change the flow direction and pressure distribution of the drive fluid,increase the wave area to improve the oil recovery,and the earlier the timing of SMG injection,the stronger the ability of pressurization and flooding,the better the recovery enhancement effect.