Laboratory Researches On Gas Injection And Porous Flow Mechanics For Low Permeability Reservoirs

In this paper, laboratory researches on gas injection and porous flow mechanics in low permeability reservoirs are studied for the practical problems that occurred during the development of reservoirs, which are accomplished on the base of predecessors' work. The main research results are gotten as follows:1 I had consulted a large number of Chinese and foreign documents. These results of my researching work have extensive suitability to low permeability reservoirs. All analysis methods and the experimental techniques have been applied according to rule, the theory and actual unified. Some foundational and the practical conclusions are obtained.2 Basis to low permeate large-scale Yushulin oil field of Daqing, there are a series of experiment researches about CO₂ displacement in fine tube, in long core, in formular simulation and in microcosmic experiments. After all of those, a conclusion can be drawn that CO₂ miscible flooding can be developed in reservoir condition, the experimented MMP (minimum miscible pressure) of CO₂ and natural gas are obtained by laboratory tests. The enhanced oil recoveries under different pressures have been gained for low permeability oil reservoirs.3 Through long core experiments some conclusions are obtained as follows:(1)The new craft mode of carbon dioxide miscible flooding is put forward and its result in oil physical simulation is provided. The experiment and numerical simulation result show: CO₂ flooding can improve the oil recovery rate by a large margin. The influences of water on CO₂ miscible flooding can be reduce greatly if there is at last one 0.1 HCPV gas section during water alternate gas injection. This way can raise recovery ratio to be most heavy.(2)The effect of water flooding is not good. In order to advance oil recovery ratio greatly, a series of experiment researches about natural gas displacement are done that include tests in fine tube, in long core and the water alternate gas injection. After these tests mechanisms and factors of effect on oil recovery ratio are analyzed. A conclusion can be drawn that natural gas immiscible flooding can be developed in reservoir...