高含水期砂岩油田周期注水机理及应用研究

【作者】 殷代印；

【导师】 翟云芳；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2001， 博士

【摘要】 本文通过室内岩心驱油实验、理论分析、矿场资料解剖等多方面的研究,系统全面地阐述了周期注水过程中,毛管力、弹性力改善非均质砂岩油田开发效果的宏观作用机理和微观作用机理。综合考虑了毛管力、弹性力和重力的影响,建立起非均质砂岩油藏周期注水数学模型,推导出模型的数值解。在模型中,分别考虑了驱动力、毛管力和重力引起的流动项,然后根据各流动项在周期注水过程中的流动特点,提出一种新的流动系数取值方法,克服了常规注水时普遍采用“上游”权系数方法带来的缺陷,并对数值解进行了稳定性分析,使该模型能够准确描述周期注水过程中毛管力作用引起的吸渗现象和弹性力引起的附加窜流现象。在上述理论研究的基础上,编制了相应的周期注水数值模拟软件。软件编制过程中,针对普通数模软件模拟周期注水时存在的其它问题,充分考虑了地下流体在周期注水不同阶段的渗流特点,改进了相对渗透率曲线和毛管力曲线的处理方法,提高了周期注水动态指标的计算精度,采收率提高幅度值与矿场实际值符合程度较高。应用该模拟软件定量分析了毛管力、弹性力、重力、原油粘度、油层韵律性、油层纵向非均质性、垂向渗透率等油藏客观因素对周期注水效果的影响,及周期注水方式、油水井工作制度、周期注水开始时间等主观因素对周期注水效果的影响,确定出了适合周期注水的油藏类型和合理的周期注水方式。结论是,毛管力的作用是第一位的,弹性力的作用是第二位的,水湿油层更适合周期注水。为了验证理论计算结果,进行了室内实验和现场实际周期注水效果评价计算。根据非均质砂岩油田地质特点,设计了平面非均质和纵向非均质岩心实验物理模型,进行了周期注水和常规注水驱油实验,结果表明,对于水湿岩心,采收率提高幅度为1.5%-2.5%;对于油湿岩心,采收率提高幅度为1.0%左右,验证了毛管力是周期注水的主要影响因素之一。最后,结合大庆油田三个周期注水试验区的生产实际进行了周期注水开发效果评价,实践表明水湿油层周期注水效果较好,可以提高采收率1.5%以上,而油湿油层周期注水效果较差,提高采收率低于1.0%。同时分析对比了不同周期注水方式下的优缺点,给出了合理的间注周期和注水波动幅度,为非均质砂岩油田周期注水方案的制订提高了理论依据和参考。更多还原

【Abstract】 This chapter set forth in detail that capillary force and elastic force improve macroscopic and microscopic action mechanisms of heterogeneous sandstone field development effectiveness by a lot of aspect such as laboratory core oil displacement experiment, theory analysis and lease information interpretation etc in the course of cyclic water injection, consider overall capillary force, elastic force and gravity’s influences, establishes cyclic water injection mathematical model in heterogeneous sandstone reservoirs, the model considers flow items caused respectively by displacement pressure, capillary force and gravity. According to flow character of each flow item in the course of cyclic water injection, then it sets forth a new method to obtain flow coefficient which overcomes the default of generously used “upstream”weight coefficient method , based on which it derives numerical solution of theoretical model and carries out stability analysis .The model can describe accurately absorptive percolation phenomena caused by capillary force and additional channeling flow phenomena caused by elastic force and work out cyclic water injection numerical simulation software correspondingly。In the course of working out software, aiming at the defects which exists in common numerical simulation software, this chapter considers sufficiently underground liquids’seepage flow characters in different cyclic water injection period, improves treatment methods of relative permeability curves and capillary force curves, increases calculation precision of cyclic water injection dynamic indexes, the magnitude that recovery efficiency increases accords in more highly degree with lease actual values.。It applies the simulation software to analyze quantitatively how objective factors such as capillary force、elastic force、gravity、oil viscosity、oil reservoir rhythmic nature、oil reservoir longitudinal heterogeneity、vertical permeability etc and subjective factors such as cyclic water injection manners、oil well and water well work system、cyclic water injection starting time etc influence cyclic water injection effectiveness, to confirm reservoir types and reasonable water injection manners that are suitable to cyclic water injection。The conclusion is: capillary force is in first ,elastic force is in second , water-wet oil reservoir is more suitable to cyclic water injection。In order to verify calculation results in theory ,it carries out shop experiment and on-site actual cyclic water injection effectiveness evaluation calculation。In terms of geologic characters in heterogeneous sandstone reservoirs, it designs plane heterogeneous and vertical heterogeneous core experiment physical model, carries out cyclic water injection and conventional water injection experiments, results show that the magnitude recovery efficiency increases is 1.5%-2.5% to water-wet core , to oil-wet core the value is about 1.0%, and verify capillary force is one of main influential factors in cyclic water injection.。At last, combining production practices in three cyclic water injection experiment areas in DAQING Oil Field, the chapter carries out cyclic water injection development effectiveness evaluation, practices shows that in water-wet oil reservoirs cyclic water injection’s effect is better than in oil-wet oil reservoir, the former may increase recovery efficiency about 1.5%, while the latter may increase recovery efficiency less than 1.5%。At the same time, it analyzes and contrasts different cyclic water injection manners’shortcomings and advantages, gives reasonable interval water injection cycle and water injection amplitude of fluctuation and provides foundation and reference in theory for setting down cyclic water injection projects in heterogeneous sandstone fields。更多还原