Experimental test method of competitive dissolution of CO<2> in oil-water mixture system

Abstract

The invention discloses an experimental test method of competitive dissolution of CO<2> in an oil-water mixture system. The experimental test method of competitive dissolution of CO<2> in the oil-water mixture system comprises the steps of: configuring a crude oil sample and a formation water sample, wherein injected gas is industrial CO<2> gas; injecting the formation water sample, an oil sampleand the CO<2> gas in a sample preparation device; discharging the oil sample, recording the volume of crude oil discharged from a separator and the volume of CO<2> in a gasometer, and calculating thegas-oil ratio after CO<2> is dissolved by the crude oil; recording the volume of formation water discharged from the separator and the volume of CO<2> in the gasometer, and calculating the gas-water ratio after CO<2> is dissolved in water phase; and, gradually increasing displacement pressure, repeating the step, so that the volume of dissolved CO<2> in the crude oil and the formation water samplein series of pressure conditions is obtained, and furthermore, calculating the dissolved CO<2> gas-water ratio GWR in the water phase and the dissolved CO<2> gas-oil ratio GOR in the oil phasein each pressure condition. The experimental test method disclosed by the invention is reliable in principle, simple and applicative, can precisely evaluate and compare the dissolving condition when CO<2> is contacted with the crude oil and the formation water at the same time in a true reservoir condition, and has wide market application prospect.

Description

technical field [0001] The invention relates to CO under high temperature and high pressure conditions in the field of oil and gas exploration and development 2 The invention relates to an experimental test method for competitive dissolution in an oil-water mixed system, belonging to the technical field of gas drive enhanced recovery. Background technique [0002] There are many types of oilfields in my country, and the geological conditions are relatively complex. The reservoirs are mainly continental clastic rock deposits, usually characterized by small-scale sand bodies, scattered distribution, low permeability and poor heterogeneity of the reservoirs. In the initial stage of oilfield development, most of the reservoirs were developed by water flooding. The heterogeneity of the reservoirs led to a rapid increase in the water cut of the water flooding reservoirs, with a low recovery rate of about 30-35%, and a large amount of remaining oil remained in the formation. Gas f...

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Problems solved by technology

However, the existing experimental test methods are mostly used to explore the CO 2 Solubility characteristics in single-phase oil and wa

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