【作者】 张继成；

【导师】 宋考平；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2008， 博士

【摘要】 截至2007年底,大庆油田聚合物驱油区块已达30多个,其中有14个区块已完成注聚过程,今后将有更多区块应用聚合物驱油技术并陆续面临聚驱后挖潜问题。为了高效开采比例高达40%以上的聚驱后剩余原油储量,本文开展了聚驱后剩余油识别方法及其分布规律的研究。建立了一套集室内驱油实验、核磁共振、岩心磨片荧光分析、密闭取心分析、测井解释和快速数值模拟于一体的聚驱后剩余油潜力和分布规律的评价和识别方法;对大庆油田已完成注聚区块开发现状进行了评价,包括含水率、采出程度、剩余油潜力等;分析了渗透率变异系数、聚合物分子量、聚合物溶液浓度、注入聚合物溶液段塞大小等因素对聚合物驱效果和剩余油潜力的影响规律;研究了聚合物驱提高采收率的机理;对现有相对渗透率曲线进行了分类,定义了I型、II型、III型三种相对渗透率曲线;提出了相对渗透率特征曲线,并给出了其方程;建立了一种计算单个网格块相对渗透率曲线的方法;对北一二排西进行了数值模拟研究;给出了聚驱后微观和宏观剩余油的类型以及分布规律;对不同的剩余油,提出了适宜的继续挖潜措施。研究表明,大庆油田14个已完成注聚区块的采出程度为52.8%,地下仍然存在大量剩余油,聚驱后继续挖潜十分必要。岩心渗透率变异系数越大、聚合物分子量越大、聚合物溶液浓度越大、聚合物溶液段塞尺寸越大,聚驱采收率就越大,剩余油饱和度就越低。聚合物驱既可以提高驱油效率,又能够提高波及系数。建立的计算网格块相对渗透率曲线的方法,可实现在数值模拟中对每个网格块计算得到一条相对渗透率曲线,从而提高数值模拟的水平和效率。聚驱后微观剩余油主要包括簇状、盲端、角隅和膜状剩余油;宏观剩余油类型主要包括韵律段上部、连通差型、注采不完善型、分流线部位、采出井端、二线受效型、射孔不完善型、断层附近、成片分布差油层和无效驱替等剩余油。对聚驱后不同单元、不同部位、不同微相、不同类型的剩余油,应采用不同的挖潜措施,有效地进行聚驱后继续提高采收率工作。宏观剩余油主要以综合调整措施挖潜为主,微观剩余油以二元驱、三元驱、泡沫复合驱等化学驱提高采收率技术挖潜为主。本文研究成果具有一定理论意义和较高实用推广价值。更多还原

【Abstract】 By the end of 2007, there are already more than 30 polymer flooding areas in Daqing oilfield, 14 of which have completed polymer injection. In the future, there will more and more areas adopting polymer flood and then facing the problem of potential tapping. There is more than 40% of OOIP still remained in reservoir after polymer displacement. In order to effectively recover this amount of remaining oil, this paper demonstrated a study on the identifying method and distribution rule of the remaining oil after polymer flooding.This paper developed a set of method for identifying and evaluating potential and distribution rule of the remaining oil after polymer flooding, which incorporates laboratory experiment, nuclear magnetic resonance, fluorescence of slice of core, natural core analysis, log interpretation and numerical simulation as a whole and capable system. For the second, current situation of areas completed polymer flooding was evaluated, including water cut, recovery percent and remaining potential, etc.. For the third, this paper investigated influence of permeability variation coefficient, molecular weight of polymer, concentration of polymer solution and polymer slug size on flooding effect and remaining potential. For the fourth, mechanism of polymer enhancing recovery was studied. For the fifth, this paper defined 3 types of relative permeability curve, i.e., I-, II- and III-type, constructed eigen curve and corresponding equation and proposed a method for calculating relative permeability curve for every grid block in reservoir simulation. For the sixth, numerical simulation of remaining oil distribution after polymer flooding was made for western Beiyierpai area. For the last, this paper concluded microscopic and macroscopic distribution rule of remaining oil and proposed suitable potential tapping measures for different type of remaining oil.Evaluation shows that recovery percent of the 14 areas is 52.8%, a great deal of oil remained underground, and so continuous potential tapping is very necessary. The greater variation coefficient, molecular weight, concentration and polymer slug size, the larger recovery efficient and the lower remaining oil saturation. Polymer flooding can increase both displacing and sweeping efficiency and thus enhance oil recovery. Method for calculating relative permeability curve for every grid block can help increase the art and efficiency of numerical simulation. Microscopic remaining oil after polymer flooding mainly includes cluster, dead-end, cant and film type. Macroscopic remaining oil includes the upper part of rhythmic interval, poor connection, imperfect injection-production, branch stream line, near producing well, the second row of producing wells, imperfect perforation, near fault, large area of poor layer and ineffective displacement, etc.. For remaining oil in different layer unit, location, facies and of type, we should take different suitable measures to tap potential and futher enhance recovery after polymer flooding. Macroscopic remaining oil should be tapped mainly by globally optimized adjustment and microscopic oil by chemical processes such as polymer/surfactant, polymer/surfactant/alkaline and foam combination flooding.This study is of certain theoretical significance and value of field-scale application.更多还原