天然气泡沫体系流度控制能力影响因素

Influencing factors of fluidity control ability of natural gas foam system

大量现场应用发现,泡沫驱作为一种有效提高采收率的方式,合适的注入参数可使其最大程度地发挥泡沫的流度控制能力。选取APG-10为起泡剂、DG为稳泡剂、天然气为气相制备天然气泡沫。对起泡剂质量浓度、稳泡剂质量浓度、天然气泡沫注入流速、天然气泡沫体积分数、含油饱和度5个因素,设计正交试验,确定最优天然气泡沫体系配方及最佳注入参数。分析不同因素对流度控制能力的影响;引入标准偏差描述驱替过程中阻力系数的波动幅度;探究最佳注入参数在不同渗透率地层中的适应性。在渗透率为100 mD的多孔介质中,最佳注入参数为6000 mg/L APG-10+400 mg/L DG;当天然气泡沫体积分数为70%,天然气泡沫注入流速为4 mL/min时,天然气泡沫的流度控制能力最强,阻力系数为57.04。在渗透率适应性研究中,多孔介质渗透率在3000 mD以内时,随着渗透率增加,天然气泡沫流度控制能力增强。

Foam flooding,as an effective way to improve oil recovery,has been widely used in major oil fields in China.It is found from numerous field applications that suitable injection parameters can give the fluidity control ability of foam flood⁃ing to full play.APG-10 was selected as foaming agent,DG as foam stabilizer,and natural gas as gas phase to prepare natu⁃ral gas foam.Orthogonal experiments with regards to mass concentration of foaming agent,mass concentration of foam stabi⁃lizer,injection flow rate of natural gas foam,volume fraction of natural gas foam,and oil saturation were designed to deter⁃mine the optimal formula of natural gas foam system and the best injection parameters.The influence of different factors on the fluidity control ability was analyzed.The standard deviation was introduced to describe the fluctuation range of the resis⁃tance coefficient during the displacement.Further,the adaptability of optimal injection parameters in formations with differ⁃ent permeability was explored.In the porous media with a permeability of 100 mD,the optimal injection parameters were 6000 mg/L APG-10+400 mg/L DG.When the volume fraction of natural gas foam was 70%and the injection flow rate of natural gas foam was 4 mL/min,the fluidity control ability of natural gas foam was the strongest and the resistance coeffi⁃cient was 57.04.In the study of permeability adaptability,when the permeability of porous media was within 3000 mD,the fluidity control ability of natural gas foam grows as the permeability increases.