【作者】 王学武；

【导师】 黄延章； 杨正明；

【作者基本信息】 中国科学院研究生院（渗流流体力学研究所） ， 流体力学， 2010， 博士

【摘要】 本文以大庆外围特低渗透油藏为研究对象,结合常规压汞、恒速压汞、核磁共振和物理模拟实验等方法,研究了特低渗透油藏微观孔隙结构特征,并从微观角度出发,阐述了单相流体非线性渗流特征和油水两相渗流规律。研究结果表明：1.对于特低渗透储层,喉道分布、孔喉比和分选性是决定储层物性的关键因素。随着渗透率的增大,喉道分选性变差,并且平均喉道半径与渗透率在对数坐标系中具有较好的线性关系。可动流体百分数和可动流体孔隙度和渗透率具有较好的半对数关系,是储层评价的重要参数。2.研究了特低渗透岩心应力敏感性和水敏性,认为特低渗透储层敏感性与渗透率具有较好相关关系,并且普遍表现出较强的应力敏感性和水敏性。从微观角度分析了喉道半径和粘土矿物对其影响,认为喉道半径越小,粘土矿物含量越高,应力敏感程度和水敏程度越强。并且分析了应力敏感程度对产能的影响。3.测试了大庆外围特低渗透岩芯在低流速下的渗流曲线,根据微观喉道分布,结合毛管模型,计算了不同驱替压力梯度下吸附边界层的厚度。研究表明,特低渗透岩芯渗流曲线具有非线性特征,表现在其视渗透率不是常数,而是随压力梯度的增加而增大,并逐渐趋近一定值。随着驱替压力梯度的增大,吸附边界层厚度变小,并且其在低压力梯度下变化明显,这是影响非线性渗流的关键。4.分析了特低渗透岩心油水相渗特征及束缚水和残余油下的非线性渗流特征。提出了可动油饱和度参数及其测试方法,分析了不同渗透率、不同润湿性、不同驱替压力、不同含水阶段的可动油和残余油分布规律。5.建立了考虑非线性渗流的压裂井产能公式、产量递减公式和水驱特征公式,分析了非线性渗流参数及储层物性参数对其影响。并分析了典型区块的生产规律。更多还原

【Abstract】 In this dissertation, combining with mercury, constant rate mercury injection, nuclear magnetic resonance and physics simulation, the micro pore structure character of ultra-low permeability reservoir. Then, from the microscopic point of view, the percolation flow law of the single phase and two phase fluids percolation are studied. The main research results are as followed:1. Throat distribution, pore-throat ratio and sorting coefficient are the main factors that control reservoir properties. The sorting coefficient increases with permeability, and the relationship between the average throat radius and permeability are linear in logarithmic coordinates. The relationship between movable fluid percentage, movable fluid porosity and permeability are linear in semi-logarithmic coordinates, and movable fluid percentage and movable fluid porosity are important parameter of reservoir evaluation.2. The stress sensitivity and water sensitivity are strong in ultra-low permeability reservoir. The influence factors by throat radius and clay are analyzed. The degree of stress sensitivity and water sensitivity are higher with the smaller radius of throat and the higher clay content, and the production capacity is analyzed considering stress sensitivity.3. The flow characteristics at low velocity were studied by the self-designed micro-flux measuring instrument. Considering the throat distribution and capillary model, the thickness of fluid boundary layer under different pressure gradient was calculated, the mechanism and influencing factors of nonlinear percolation were discussed. The study showed that the percolation curve of ultra-low rocks was nonlinear, and apparent permeability was not a constant, which increased with pressure gradient. The absorption boundary layer decreased with the increase of pressure gradient, and changed significantly especially in low pressure gradient, which was the essence of bringing nonlinear percolation.4. The character of oil/water relative permeability, nonlinear percolation character at irreducible water state and residual oil state of ultra-low permeability cores are analyzed. A new method of testing movable oil saturation was established, and the difference between movable fluid and movable oil was analyzed. The main influencing factors of the movable oil saturation including wettability, displacement pressure and water cut were studied.5. Considering the character of nonlinear percolation, the formulae of calculating vertical fracture well productivity for steady-state flow, production decline equation and water-drive characteristic equation are put forward. The influence factors by nonlinear percolation parameters and reservoir properties parameters are studied, and production law of typical blocks are analyzed.更多还原