Method and system for determining damage radius of oil and gas reservoir water blocking

Abstract

The invention provides a method for determining the damage radius of oil and gas reservoir water blocking. The determining method includes the steps that aqueous phase movement speed is determined according to capillary force Pc and a displacement effect on aqueous phase by differential pressure delta P between liquid phase pressure in a shaft and formation pressure; the water amount of the aqueous phase entering a reservoir stratum is determined according to the aqueous phase movement speed and the contact sectional area between the aqueous phase and the reservoir stratum; the radius of the aqueous phase invading into the reservoir stratum is calculated according to the water amount of the aqueous phase entering the reservoir stratum, the pore channel sectional area of the reservoir stratum and porosity. The invention further provides a system for determining the damage radius of the oil and gas reservoir water blocking. The determining method can forecast accurately the invading radius of the gas well water blocking without the need for rock core experiments and well testing, and can calculate dynamic invading radiuses in kinds of operation, so that the system is easy to operate and small in calculation error. The water blocking damage radius of long-period operation measures can be described accurately, and the defect that the water blocking damage radius can not be obtained through a routine experimental method is remedied.

Description

technical field [0001] The invention relates to an evaluation technology of water lock damage in oil and gas reservoirs, in particular to a method and system for determining the radius of water lock damage in oil and gas reservoirs. Background technique [0002] Water lock damage is an important factor affecting the productivity of gas wells. Due to the small pores of low-permeability gas reservoirs, they will enter the reservoir under the action of capillary force after contact with external water. When the pores are smaller, the capillary force is greater, and the radius of the water phase entering the reservoir is larger. In the process of self-priming, on the one hand, the more water inhaled, the greater the resistance it suffers; on the other hand, due to the effect of viscous resistance, the gas cannot be discharged quickly, and the self-inhaled water gradually pushes the gas along the direction of self-priming, so that The increased gas pressure limits the rate of wa...

AI Technical Summary

Problems solved by technology

When the well killing or operation time is too long, and the water phase invasion radius is large, the conventional perforation method may not be able to test the real productivity, and large-scale plugging removal and production stimulation measures are required

It is difficult to dynamically judge the degree and radius of water lock damage based on current experimental methods, and there is a lack of necessary technical support when formulating specific operation measures

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