致密油储层动态渗吸采油效果及其影响因素

渗吸采油是(弱)亲水致密油藏高效开发的重要技术措施之一,渗吸采油物理模拟是优选渗吸液配方组成和优化渗吸液段塞组合的重要实验手段。针对大庆外围地区致密油藏开发技术需求,以高分子材料学、物理化学和油藏工程等理论为指导,以化学分析、仪器检测和物理模拟等技术为手段,以大庆外围扶余储层地质特征和流体性质为模拟研究对象,开展了动态渗吸采油效果及其影响因素实验研究。结果表明:在渗吸采油实验中,随注液压力升高,渗吸采收率增加;随注液速度增大,渗吸采收率增幅呈现出"先增后减"变化趋势;随渗吸液注入段塞尺寸增加、憋压时间延长和交替注入次数增加,渗吸采收率增加,但增幅逐渐减小。动态渗吸采油实验最优参数推荐:注液速度为0.2 m L/min、段塞尺寸为0.3 PV、憋压时间96 h和交替注入次数为3。与单独注渗吸液或增能剂措施相比较,采取"渗吸液+增能剂"组合方式可以产生协同效应,增强孔隙内油水交渗作用,提高渗吸采油效果。

EFFECTS OF THE DYNAMIC IMBIBITION RECOVERY AND ITS INFLUENCING FACTORS FOR THE TIGHT OIL RESERVOIRS

The imbibition oil recovery is one of the important technical measures which are used to develop efficiently the (weak) hydrophilic tight oil reservoir,and the physical simulation of the imbibition recovery is the important experimental method to optimize the formula compositions and slug combination of the imbibition liquid.Aimed at the development technical requirements of the tight oil reservoir in Daqing peripheral area,guided by the polymer material science,physicochemistry and petroleum engineering,taking the chemical analysis,instrumental test and physical simulation etc.as technical means,and moreover taking the geological features and fluid properties of Fuyu reservoir in Daqing peripheral area as the research objects,the experimental studies on the dynamic imbibition recovery effects and its influencing factors were carried out.The achievements show that in the process of the experiment,with the increase of the injection pressure of the liquid,the imbibition recovery increases as well;with the rise of the injection rate,the imbibition recovery appears the trend of "first increase and then drop";with the increase of the injection slug size,holding pressure time and alternate injection times,the imbibition recovery increases,but the increased degree gradually decreases.The recommendations of the optimal parameters for the dynamic imbibition recovery experiment:the injection rate is 0.2 mL/min,the slug size is 0.3 PV,the holding pressure time should be more than 96h and the alternate injection times should be 3 ones.Comparing with the simulations of the single injection imbibition liquid or energizing agent,the combination between the imbibing liquid and energizing agent can produce synergistic effect,enhance the oil-water percolation effects in the pores and improve the effects of the imbibition recovery.