高浓度聚合物微观驱油特征及流变性研究

【作者】 何冬月；

【导师】 李英； 曹绪龙；

【作者基本信息】 山东大学 ， 化学工程， 2009， 硕士

【摘要】 聚合物驱油技术是国内各大油田进行三次采油的重要手段。本文通过室内试验和理论分析,主要研究了高浓度聚合物微观驱油机理,通过不同浓度条件下微观模型驱油实验,验证聚合物在高浓度条件下提高采收率的程度。通过对不同浓度聚合物以及粘度相当的甘油、黄原胶进行流变性能测试,研究高浓度条件下聚合物溶液流变性以及高浓聚合物的流变效应对提高采收率的贡献。(1)微观驱油特征描述对不同浓度聚合物溶液的微观模型驱油过程进行了多状态二维图象、三维图象CT扫描;对不同浓度聚合物溶液分别进行了非均质平板模型驱油的多状态二维图象DR扫描,并进行相关的图象处理;同一模型下不同浓度溶液分段塞注入,各驱替状态下进行二维和三维CT扫描。通过微观驱油实验的驱替过程和实验结果研究高浓度聚合物驱油作用机理。(2)聚合物弹性和粘性对提高采收率的贡献研究本文选取了胜利油田现场常用的几种聚合物,与甘油、黄原胶作为被研究对象,用流变仪研究了几种物质溶液的剪切稳态流变特性。对比在相同粘度下这三种体系粘性与弹性的对应关系:选定粘弹性相对较好的聚合物开展驱油实验,研究在连续驱替条件下聚合物驱油效果;研究纯粘性的甘油以及弹性较小而粘性较大的黄原胶在连续驱替条件下的驱油效果;根据以上结果确定弹性和粘性各自在提高采收率过程中所起的作用。(3)高浓度聚合物溶液流变特性研究研究了高浓度聚合物溶液体相流变特征,研究不同类型的聚合物在不同浓度、不同剪切速率条件下的稳态剪切流变性;研究了不同种类聚合物动态粘弹性特征;得到聚合物在不同浓度下粘性模量、弹性模量、复合模量、相位角、复合粘度等体向流变特征参数。研究了高浓度聚合物溶液界面流变特征。研究聚合物不同浓度下的界面复合粘弹模量、粘性模量、弹性模量、相位角、界面张力。不同聚合物浓度下的驰豫特征参数。研究了高浓度聚合物溶液拉伸流变特征。研究聚合物在不同浓度下的拉伸流变特性;对比不同种类聚合物在相同浓度条件的拉伸流变特性。(4)高浓聚合物粘弹效应对提高采收率的影响研究通过对室内长细管模型中不同类型聚合物的沿程压力分布及采出液粘度变化进行监测,研究聚合物溶液在多孔介质中的运移特征;采用单管岩心研究在不同渗透率条件下,模拟水驱后聚合物溶液对驱油效果的影响;采用双管并联岩心试验,研究不同类型聚合物溶液对驱油效果的影响。以上研究表明,高浓度聚合物驱在驱油机理上不能简单的定义为提高波及系数和改善流度比,因为聚合物溶液本身不是普通粘性流体,而是具有粘弹性的流体,尤其是对于高浓度的聚合物溶液来说,其流变特性对于提高最终采收率的影响是不容忽视的。更多还原

【Abstract】 Polymer flooding is the most important approach to improve oil recovery in our country. The micro-displacement mechanism and the displacement ability of polymer at high concentration was studied in this paper.(1) Characterization of micro-displacementPolymer solutions of different concentrations of the micro-model of oil displacement process has been multi-state two-dimensional image scanning and Three-dimensional image scanning by CT .Different concentrations of polymer solution is carried out in non-homogeneous plate model of flooding of the multi-state two-dimensional DR image scanning. Through the micro-drive oil displacement experiment process studied high-concentration polymer flooding mechanism.(2) Polymer elasticity and viscosity of the contribution of enhanced oil recovery This study selected the victory of several polymers commonly used in oil field.Steady and dynamic rheology of polymers at different concentrations were studied.Storage moduli、loss moduli、complex muduli、phase angle and complex viscosity were studied at different concentrations.Interfacial rheology of polymers at high concentrations were studied.Interfacial complex moduli、loss moduli、storage moduli、phase angle、interfacial tension and relaxation parameters at different concentrations were also studied.Elongational rheology of polymers at high concentration were studied.Elongational rheology of different polymers at different concentrationswere studied in detail.(3)Effects of viscosity and elasticity of polymer on enhanced oil recoveryIn this paper, high-concentration polymer solution rheological characteristics was studied.The steady and dynamic rheology of polymers、glycerol and xanthan which are the most commonly used in shengli oil field were studied. By comparing viscosity and elasticity of these polymers, the best polymer was chosen as the diplacement agent.By studying the flooding effects under continuous flooding conditiongs and comparing the flooding effects of viscous glycerol and xanthan By studying the pressure of polymer flooding in long thin tube and determing the performance of produced liquid, migrations of polymer solutions in porous media were studied.The displacement efficiency of polymers after water flooding was studied by single-tube core at different permeabilities.The displacement efficiencies of different polymers were studied by twin-tube parallel experiments.So some conclusions can be got that the flooding mechamism of polymer at high concentration doesn’t come from enhancement of sweep efficiency and mobility ratio,because polymer behaves as visco-elastic fluid rather than common viscous fluid.Rheology of polymers plays an important role in enhancing oil recovery.更多还原