页岩油流动的储层条件和机理

页岩油藏经过分段压裂水平井的储层改造，其高效开发和持续稳产与基质中页岩油的动用情况密切相关。虽然赋存原油的泥页岩储集孔隙尺寸小、渗透率极低，但如果砂岩-页岩互层的纹层结构发育，页岩油仍有望达到商业化开采所需的可动用储层条件。目前烃类流体在纹层状泥页岩储层中流动机理尚不明确，普遍应用于常规油藏级数值模拟的双重介质模型和等效介质模型无法反映烃类流体在纹层状页岩油储层中流动的微观复杂特征，所得的宏观渗流模拟结果是不可靠的。根据陆相页岩储层的特征，建立了宏观页岩油藏的储层概念模型，分析了纹层状页岩储层的流体流动机理；考虑纹层物性、流体粘度和裂缝间距等影响因素，模拟了弹性开采过程中页岩储层条件和裂缝分布对页岩油可动性的作用规律，验证了页岩油藏弹性开采过程中窜流机制的存在和砂岩纹层渗透率的重要性，证明了天然裂缝和压裂缝加强纹层间流体传递的重要作用。

Reservoir conditions and mechanism of shale oil flow

With the development of horizontal wells through multi-stage hydraulic fracturing techniques,the shale oil production rate and its decline rate are closely related to the flow ability of shale oil in the matrixes.Although the shale re-servoir rich in crude oil is characterized by fine pores and extremely low permeability,it is possible to accomplish commercial production of shale oil if the laminated texture (featuring sandstone alternating with shale) is well developed.The mechanism of shale oil flow in laminated formations is not clear yet.The commonly applied dual-media or equivalent permeability methods in field-scale reservoir simulations cannot be used to describe the microscopic phenomena of shale oil flow in laminated reservoirs,and consequently the simulated shale oil production is not reliable.Therefore,we established a macroscopic conceptual model for shale oil reservoirs based on the features of continental shale reservoirs,and analyzed the flow mechanisms of shale oil in laminated reservoirs.Besides,the effects of laminated texture properties and fracture distribution on shale oil flow in shale reservoirs during primary production were investigated through simulation.The simulated results verify the presence of transverse flow and the significant control of laminated sandstone intervals' permeability on the overall reservoir permeability,and demonstrate the important role of both natural and artificial fractures in enhancing fluid communication within the laminated reservoirs.