A test method for gas-water relative permeability of tight rock core

Abstract

The invention discloses a method for testing gas-water relative permeability of a dense core. The method comprises the following steps: (1) preparing an experimental core, measuring the porosity and the klinkenberg permeability of the core, and determining the minimum return pressure of weakening a slippage effect; (2) establishing water saturation in the core by utilizing formation water or simulation formation water; (3) arranging the core in a core holding unit, applying confining pressure to the original effective stress or reservoir overburden pressure and constant displacement pressure p1, applying return pressure p2 at the core outlet, and measuring the gas flow of the core; (4) measuring the gas flow of the core under different water saturations, and calculating the gas-phase effective permeability and gas-phase relative permeability of the core; (5) establishing 100 percent of water saturation in the core, and measuring the accumulated water yield of the core in unit time; and (6) calculating the water-phase effective permeability and water-phase relative permeability of the core. The method disclosed by the invention can be used for really reflecting the gas seepage conditions under in-situ conditions and simulating the underground production state and has wide market prospects.

Description

technical field [0001] The invention relates to a test method for gas-water relative permeability of tight rock cores in the process of oil and natural gas exploration and development, which reflects the gas seepage situation under in-situ conditions. Background technique [0002] When there is multiphase fluid flow in rock pores, there will be interaction, interference and influence among the fluids of each phase. As a direct indicator of the ability of a certain fluid to pass through rocks, relative permeability measures the flow ability of each phase of fluid. Porosity, permeability and relative permeability are the basic measurement parameters in development experiments. The existing methods for obtaining relative permeability mainly include experimental testing and theoretical calculation. The relative permeability curve is the basis of reservoir engineering and reservoir numerical simulation. With the continuous discovery of low-permeability-tight gas reservoirs and ...

AI Technical Summary

Problems solved by technology

[0011] The object of the present invention is to provide a kind of testing method of gas-water relative permeability of tight rock core, this method can adopt formation water or simulated formation water to establish the water saturation of tight rock core below irreducible water and measure the gas phase under this state Permeability, by applying back pressure, plays a role in correcting permeability, weakening the slippage effect of gas seepage, making the gas-water relative permeability curve more perfect, and more truly reflecting the gas seepage situation under in-situ conditions and simulating downhole production status It overcomes the shortcomings of the existing two-phase fluid relative permeability test method, such as large experimental error, inability to use formation water or simulated formation water to establish a low water saturation, inability to correct permeability, time-consuming, etc., and has broad market prospects

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