【作者】 刘浩瀚；

【导师】 刘志斌；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2013， 博士

【摘要】 随着注水开发进入特高含水阶段,剩余油分布形态及大小发生了巨大的变化,微观孔隙结构中的剩余油如何移动,移动动力条件是什么,水驱油效率如何发生变化等问题已经成为特高含水期油田开发无法回避的关键问题。特高含水期剩余油滴可动条件及水驱油效率变化机理研究对提高油田开发经济效益,保持油田的稳产、增产具有十分重大的意义。第一、论文考察了特高含水期剩余油受力状态影响因素。研究发现孔隙中剩余油滴主要受到浮力、重力、毛细管力、注入压力、摩擦阻力、黏滞力、贾敏效应阻力及附加阻力的作用；从孔隙结构研究现状、孔隙结构的分类、孔隙结构对剩余油受力状态的影响、不同孔隙结构剩余油受力差异四个方面定性分析孔隙结构与剩余油受力状态的关系；依据剩余油滴受力原理,分析了低角度油藏、高角度油藏、正韵律性油藏、反韵律性油藏等油藏类型对剩余油滴受力状态的影响；第二、分析了不同含水期剩余油分布特征。对比分析中低含水期、高含水期、特高含水期剩余油分布特征；第三、分析剩余油滴微观受力特征,结合数学建模方法,提出了特高含水期剩余油滴移动动力条件。研究特高含水期简化孔隙结构下剩余油受力状态,建立特高含水期简化孔隙结构中油滴微观受力状态方程；分析三类简化孔隙结构模型下剩余油滴运动状态；确定不同油藏类型及孔隙结构条件中,单层及多层情形下剩余油滴孔道选择机理；开展三类简化孔隙结构模型下(平行毛管束模型、变截面毛管模型、孔隙网络模型)剩余油滴可动条件研究,确定剩余油滴移动动力条件；第四、开展特高含水期极限水驱油效率室内实验研究。设计实验方案、实验目的、实验内容、实验流程,开展水驱油实验及相渗实验；引入非稳态法对实验数据进行处理分析；研究特高含水期剩余油饱和度分布规律；对比分析现有的剩余油饱和度研究方法,从渗流的角度研究剩余油饱和度分布规律,确定剩余油饱和度随时间及位置变化的新方程；从微观参数入手,研究特高含水期剩余油饱和度分布,确定含水饱和度随微观孔道半径、最大毛管半径等微观参数变化的方程；第五、从不同角度研究特高含水期水驱油效率预测方法。确定特高含水期驱油效率内、外影响因素；统计现有的驱油效率表征方法,主要包括水驱特征曲线法、经验公式法、递减曲线法、现金流法；研究特高含水期基于新型水驱特征曲线、物质平衡原理及GM(1,n)神经网络功能模拟的驱油效率预测方法；第六、开展特高含水期水驱油效率变化机理研究。从油藏工程、实验与数模(牛顿插值原理、灰色神经网络模型)的角度研究特高含水期驱油效率变化机理。更多还原

【Abstract】 When entering the ultra high water cut period, the distribution and size of the remaining oil have been greatly changed. In ultra high water cut oilfield development, the problems, such as what is the moving characteristic of the remaining oil in micro pore structure, what is the dynamic condition of the moving remaining oil, how water flood efficiency changes, etc., play a new and core role and become unavoidable. Study on remaining oil droplet dynamic conditions and water flood efficiency changing mechanisms in the ultra-high water cut period is meaningful to improve economic efficiency and keep stable and high production of oil field.Firstly, influencing factors of remaining oil droplet micro-force status in ultra-high water cut period have been investigated. Study shows the main forces of remaining oil droplet in pore network structure are buoyancy, gravity, capillary force, injection pressure, the frictional resistance force of the rock, viscous force, the resistance force of Jamin effect, etc.; the influences of pore structure related parameters (study status of pore structure, classification and analysis of pore structure models, influences of pore structure on remaining oil force state, force difference in different pore structure) on the micro force status of remaining oil droplet have been qualitatively analyzed; the influences of different reservoir types (low angle pore structure oil reservoir, high angle pore structure oil reservoir, oil reservoir with positive rhythm and anti-rhythmic oil reservoir) on the micro force status of remaining oil droplet have been studied;Secondly, remaining oil distribution characteristics in different water cut period have been compared and analyzed, including typical characteristics of remaining oil distribution in low-middle water cut stage, high water cut stage and ultra high water cut stage.Thirdly, according to the micro forces analysis of remaining oil droplet and establishment of mathematical models, dynamic conditions of moving remaining oil droplet in ultra high water cut stage have been proposed, including micro force status of remaining oil droplet in three different types of pore structure models; establishment of micro force status equation of remaining oil droplet in simplified pore structures; description of moving status of remaining oil droplet in three different types of pore structure models; capillary selecting mechanism of remaining oil droplet in different reservoir types and simplified pore structures; dynamic conditions and Threshold conditions of moving oil droplet in three simplified pore structures-parallel, variable cross-section and pore network capillary model.Fourthly, indoor experiments have been running to study the limited water flood efficiency in ultra high water cut period, including experimental design, purpose, content and process; running water flooding experiment and relative permeability experiments; processing and analysis of the experimental data with transient method. Remaining oil saturation during ultra high water cut stage has been studied, including comparisons of present calculation methods of remaining oil saturation; study of remaining oil saturation distribution pattern from the perspective of seepage and establishment of remaining oil saturation distribution equation with time and place change; study of remaining oil saturation distribution adapted to ultra high water cut stage from the perspectives micro parameters and establishment of remaining oil saturation distribution equation with micro parameters like capillary radius and maximum capillary radius change.Fifthly, predicting methods of water flood efficiency in ultra high water cut stage have been studied from different perspectives:internal and external influencing factors of water flood efficiency in ultra high water cut stage have been studied; present oil displacement efficiency predicting methods, including Water drive characteristic curve method, Empirical formula method, Decline curve method and Cash flow method, have been investigated; four kinds of new water flood efficiency predicting methods in ultra high water cut stage based on new type of water drive characteristic curve, material balance equation, and GM(l,n) and ANN functional simulation separately have been discussed in-depth.Sixthly, changing mechanisms of water flood efficiency in ultra high water cut period have been studied. For one thing, studying of changing mechanisms of water flood efficiency in ultra high water cut period from the perspective of reservoir engineering; for another, studying of changing mechanisms of water flood efficiency in ultra high water cut period from the perspective of experiments and numerical simulations, such as Newton interpolation principle and GM (1, n)-Neural network model.更多还原