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There are abundant nanopores in the organic matter of shales. Gas flow in nano-pores leads to micro-scale effect that can't be described by flowing law of macro fluid. The Lattice Boltzmann Method was applied to simulate gas flow in the nano-channels of organic matter and the effect of slippage, diffusion and adsorption/desorption were considered. The simulation result shows that the compressibility effect of gas leads to the nonlinear pressure distribution along the channels, and the larger the pressure difference, the more serious the nonlinear distribution. To some extent, the enhancement of rarefaction effect weakens nonlinear degree caused by the compressibility effect. With increasing Knudsen number and the pressure differential on the two ends, the slip velocity on the boundary increases, and the velocity vertical to the channel is not zero, increasing the exchange of kinetic energy between gas molecules in channels and molecules at boundary. Slippage effect and adsorption/desorption effect have a significant contribution to the gas mass flow in nano-channels of organic matter. Key words: organic matter, nanopore, Lattice Boltzmann Method, micro-scale effect, boundary slip velocity

Based on the theory of scaling criteria, a physical experimental model of fractured-vuggy cell which meets the geometric similarity, kinematic similarity, dynamic similarity and characteristic parameters similarity was designed. The factors affecting fluid flow and water flooding characteristics, and the EOR features of different displacing modes were studied by experiments. The experimental results show that: Oil and water displacement effect caused by the density difference between oil and water is the main mechanism of water flooding; Injection rate has no effect on the remaining oil and water-cut; Fracture-vuggy connection is the dominant factor controlling water-free recovery, ultimate limit of remaining oil and water-cut variation in the fractured-vuggy cell; Oil-water viscosity ratio has an important effect on oil production rate, oil replacement ratio and economic limit remaining oil; When the filling degree is low, it has no effect on remaining oil, but when the filling degree is high, the remaining oil contains both “attic oil” and the oil existing in porous media; Foam flooding after water flooding enhances oil recovery by starting the attic oil at the top of vugs, and the remaining oil is in the center of the vugs after foam flooding; Polymer flooding after water flooding enhances the economic limit recovery by increasing the oil production rate and oil draining ratio, but it has no effect on the limit remaining oil of water flooding. Key words: fractured-vuggy reservoir, water flooding experiment, fractured-vuggy cell, scaling theory, fractured-vuggy configuring relation, remaining oil, enhanced oil recovery

According to the characteristics of overpressure carbonate reservoirs of the Kenkiyak pre-salt oil field in the littoral Caspian Basin, cores were made artificially and the stress sensibility of matrix cores and cores with non-packed, semi-packed and fully packed fractures were analyzed. The method of gas measurement was used in the experiment. The confining pressure of the sample cores was first increased and then decreased. When the confining pressure became stable, porosity and permeability data from each pressure point were obtained to analyze stress sensibility of cores. The results showed that the stress sensibility of these four types of cores with a descending order is cores with non-packed fractures, cores with semi-packed fractures, cores with packed fractures, and matrix cores. With the decrease in packing degree of core fractures, the stress sensitivity of core permeability increased and the recovery degree of permeability decreased; the recovery degree of porosity and permeability of the matrix cores and cores with fully packed fractures was high with the recovery of pressure and these two types of cores showed elastic-plastic features. By contrast, the recovery degree of porosity and permeability of cores with partly packed and unpacked fractures was lower and these two types of cores showed plastic features. With the increase of confining pressure, the variation of porosity and permeability showed relatively regular exponential variations. Key words: carbonates, abnormally high pressure, stress sensitivity, fracture packing, permeability variation