低渗透储层具有孔喉细小、孔隙结构复杂、比表面积大,黏土矿物类型丰富等特点,这些特点致使流体在低渗透储层中流动会产生强烈的微流动效应。微流动效应主要包括稀薄效应和不连续效应、表面优势效应、低雷诺数多流态效应、多尺度多相态效应等,这些特殊效应将影响描述流体流动的微分方程及边界状态。孔隙结构特征、黏土矿物产状、润湿性、岩石矿物荷电性等是低渗透储层微流动的影响因素,通过控制这些因素,可以改变流体在低渗透储层中的流动特征,从而控制油、气、水产量。目前已经形成了界面修饰技术、电化学驱油等采油新技术。以微流动机理为基础,结合孔隙结构特征,找出影响低渗透储层流体流动的主控因素,采用具有针对性的开采技术将成为高效开发低渗透油气资源的有效途径。
Low-permeability reservoirs display such characteristics as narrow pore throats,complex pore structure,large specific surface and rich clay minerals.These characteristics will result in strong micro flow effects when fluid flows in low-permeability reservoirs.Partial differential equations and its boundary conditions will be affected by micro flow effects,including rarefied effect and discontinuity,superior surface effect,low Reynolds Number and multiple flow regimes,multi-scale and multiple phases.Pore structure characteristics,clay mineral occurrence,wettability and mineral surface charge are influencing factors for micro flow in low-permeability reservoirs.Oil,gas and water production can be controlled by changing these factors which can affect micro flow characteristics in low-permeability reservoirs.According to these influencing factors,some new technologies are applied for oil production,such as surface modification and electrochemical recovery approach.After identifying the main influencing factors using micro flow mechanism combined with pore structure characteristics,specific technology can be used to develop low-permeability reservoirs efficiently.