Numerical simulation method for replacing gas-driven component model

Abstract

The invention relates to a numerical simulation method for replacing a gas-driven component model. The method comprises the following steps of: carrying out PVTi fitting on a target block fluid to obtain PVTi fitted fluid property data; establishing component mechanism models under different permeation rates, and obtaining change rules of a mixed-phase area during oil deposit gas-driven development under the different permeation rates; building a practical component model according to the PVTi fitted fluid property data; obtaining a block practical numerical simulation model according to the change rules of the mixed-phase area during the oil deposit gas-driven development under the different permeation rates; adjusting mixed-phase coefficients in the block practical numerical simulation model to ensure that the differences between the capacity indexes and pressure indexes of the practical component and the block practical numerical simulation model are not higher than 10%, and obtaining reasonable mixed-phase coefficient distribution of a target block; and building a Todd-longstaff practical model, carrying out calculation in the mixed-phase area by using a Todd-longstaff algorithm, and carrying out calculation outside the mixed-phase area by using a common black oil algorithm.

Description

technical field [0001] The invention belongs to the technical field of gas drive oilfield development, in particular to a numerical simulation method for replacing a gas drive component model. Background technique [0002] Gas flooding is one of the important tertiary oil recovery technologies that have been formed in the world. There are many types of gas sources for gas drive, including CO 2 , hydrogen, air, natural gas and flue gas, etc. The mechanism of gas flooding is very complicated. While replenishing energy, a part of the gas can also effectively react physically or chemically with formation crude oil, thereby effectively improving oil displacement efficiency and swept volume. This phenomenon is called miscible, so gas flooding includes miscible drive and immiscible drive. [0003] For gas flooding development methods that can have miscible interactions with formation crude oil, component models are generally used for simulation. The component model can accurate...

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Problems solved by technology

However, in the process of gas drive development, even if the average formation pressure is higher than the miscible pressure, miscibility cannot be effectively achieved in some areas of the reservoir, so the composition model is used in the whole area, and the predicted results in the immiscible area will be relatively low. optimism

At the same time, the calculation speed of the component model will be reduced by about 4-10 times compared with the black oil model. With the gradual increase in the accuracy of the current model, the number of grids and the number of components will increase significantly, resulting in a further decrease in the calculation speed

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