Organization
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
Xinjiang Oilfield Company, PetroChina, Karamay 834000, China
Project Management Department, Shaanxi Yanchang Petroleum(Group) Co., Ltd., Yan′an 716000, China
Oil Production Division, China Oilfield Service Limited, Tianjin 300450, China
摘要
页岩油藏岩石孔隙结构复杂，纳米孔发育，有机质丰度高，导致页岩油储层中流体渗流规律不符合经典达西定律，且页岩油在无机和有机纳米孔中的传输机理尚不明确。文中结合润湿特性，考虑边界层、液体吸附、界面滑移、应力敏感以及强流体￣壁面作用力导致的原油物性变化，建立了纳米尺度流体传输模型，研究了不同烷烃分子在纳米孔中的传输机理。结果表明：多因素耦合的页岩油微尺度传输模型可以合理描述页岩油传输特征；微尺度效应对长链烷烃分子影响更加明显，在计算纳米孔发育的页岩储层渗透率时需考虑不同烷烃分子的影响；界面滑移及物性变化是导致微尺度现象的主要机理；页岩油应力敏感效应不同于常规尺度，不仅与力学属性、有效应力等因素有关，微尺度效应也产生直接影响。所建模型可应用于页岩储层渗透率预测，能为页岩油藏生产动态分析、产能预测和生产制度制定提供理论支撑。
Abstract
The pore structure of shale reservoir is complex, which is mainly composed of nanopores and rich in organic matter, resulting in that the transport behaviors of oil in shale reservoirs do not obey the classical Darcy law. Besides, transport behaviors of shale oil in organic and inorganic pores remain mystery. To explore the transport behaviors of crude oil in nanopores, the transport model for oil in nanopores is established combing the wettability, boundary layer, liquid adsorption, velocity slip, stress sensitivity, and changes in oil physical properties that caused by the strong interactions between liquid and wall surface. The results show that the transport model coupled multi?鄄factors can be applied to describe the shale oil transport behaviors. The microscale effect has more obvious impacts on n?鄄alkane molecules with longer chain length, and the molecule structure should be taken into consideration when the permeability of shale reservoir is calculated. Meanwhile, the boundary slip and the varying physical properties are two dominant factors of microscale phenomenon. The stress sensitivity effect of shale oil reservoirs is different from that of conventional, it is related to the mechanical properties and the effective stress, as well as the microscale effects. The model provides a guidance for shale oil production performance analysis, productivity prediction and production system preparation.
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