Productivity calculation method for water-locking gas well

Abstract

The method comprises the following steps: carrying out a gas well rock core water lock experiment, analyzing the relationship between rock core water saturation and permeability damage rate, fitting rock core water lock experiment data, and establishing a water lock permeability damage equation; and coupling the water lock permeability damage equation with the gas well productivity equation according to the water lock characteristics of the gas well, and establishing a water lock gas well productivity model. Darcy and non-Darcy coefficients of the productivity equation are calculated accordingto logging, production, water locking experiment, relative permeability experiment data and the like, the productivity equation of the water locking gas well is determined, and then the productivityof the gas well is calculated to be the unchoked flow. Two factors are considered in the productivity model: 1, water lock damage of different water saturations to reservoir permeability; and 2, the gas-water two-phase flow in the water lock reservoir. The two factors are described through a water lock permeability damage equation and a relative permeability curve equation respectively, and the method is used for accurately calculating the gas well productivity of water lock and gas-water two-phase flow. And a more scientific calculation method is provided for the productivity evaluation of the water-locking gas well.

Description

technical field [0001] The invention relates to the technical field of oil and gas development, in particular to a method for calculating the productivity of a water-locked gas well. Background technique [0002] Natural gas wells tend to form water locks around the wellbore due to water invasion or foreign working fluid injection, which will reduce the seepage channels and permeability of the reservoir around the wellbore. The most direct harm of water lock to gas wells is to reduce the productivity of gas wells. The productivity of gas wells is usually measured and calculated by open flow. The open flow of conventional gas wells is usually calculated based on productivity tests, stable production rates, or complete well logging and well test interpretation data. . However, for gas wells after water lock, the productivity calculation formula before water lock cannot be directly applied because the seepage conditions around the wellbore, that is, the permeability has change...

AI Technical Summary

Problems solved by technology

[0003] The technical problems solved by this patent are: 1. The production capacity calculation method of the water-locked gas well in the prior art requires on-site testing of the production capacity or unstable well test of the water-locked well, which requires a lot of manpower and material resources; 2. The production capacity calculation method of the water-locked gas well in the existing technology needs to shut down the gas well, which affects the normal production of the gas well; 3. The production capacity calculation method of the water-locked gas well in the prior art is the production capacity at a certain moment after the water lock. Continuous, that is, when the penetration rate is continuously reduced, it is impossible to track and calculate

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