Modeling method and system for clay expansion damaged hydrocarbon reservoir, and spatio-temporal evolution 4D quantitative and intelligent diagnosis method and system for damage degree

Abstract

The invention relates to the technical field of oil field exploration, and discloses a modeling method and system for a reservoir damaged by clay expansion and a method and system for determining the damage degree of the reservoir. The modeling method comprises the steps: determining the Darcy apparent velocity of fluid in a reservoir in a preset area of a to-be-diagnosed well; establishing a mass balance equation of the water molecules in the fluid according to the Darcy apparent velocity of the fluid and the diffusion coefficient of the water molecules in the fluid; according to the Fick diffusion law, establishing a diffusion equation that water molecules in the fluid diffuse into rocks in the reservoir; and according to the diffusion equation and the mass balance equation, determining a spatiotemporal evolution simulation equation of the clay expansion damaged reservoir, wherein the clay is the composition of the rock. The method can quantitatively simulate the four-dimensional spatio-temporal evolution process of reservoir damage characteristics caused by clay expansion, so that reservoir damage quantitative prediction and damage law spatio-temporal deduction are carried out on wells without reservoir damage.

Description

technical field [0001] The invention relates to the technical field of oilfield exploration, in particular to a modeling method and system for clay expansion damage reservoirs and a method and system for determining the degree of reservoir damage. Background technique [0002] In each period of oilfield exploration and development, due to the influence of various internal and external factors, the original physical, chemical, thermodynamic and hydrodynamic equilibrium state of the reservoir will change, which will inevitably make the reservoir near the wellbore wall and even the far wellbore wall The internal permeability of the reservoir is reduced, blocking fluid flow, causing reservoir damage and oil well production decline, or even "shooting" the reservoir. The causes of reservoir damage are diverse and complex, especially during the production process, the reservoir rock storage and seepage space, surface wettability, hydrodynamic field, temperature field, rock type, et...

AI Technical Summary

Problems solved by technology

The core flow test method is to understand the degree of damage through the change of permeability before and after core displacement. Although it is more suitable for studying single-factor reservoir damage, it is difficult to reflect the law of reservoir damage on a large scale

In addition, due to the ideal conditions of the indoor core experiment, the cores used for evaluation are all original state cores, and the dynamic changes of reservoir properties cannot be considered, so the experimental results are quite different from the real damage of the downhole reservoir.

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