Gas phase threshold pressure gradient experiment test system and method and data processing method

Abstract

The invention discloses a gas phase threshold pressure gradient experiment test system and method and a data processing method. The obtained gas phase threshold pressure gradient prediction model hashigh prediction precision and high adaptability. The influence of the gas phase continuity on the gas phase threshold pressure gradient is reflected by the relative movable gas saturation. With the designed gas phase threshold pressure gradient experiment test system, gas phase threshold pressure gradients of rock samples with different physical properties under different relative movable gas saturations are tested according to the provided gas phase threshold pressure gradient experiment method. After the experimental test, the gas phase continuity of a rock sample is characterized by the relative movable gas saturation of the rock sample and a prediction model of the gas phase threshold pressure gradient of a water flooding gas reservoir is established.

Description

technical field [0001] The invention relates to the technical field of gas reservoir exploitation, in particular to an experimental testing system, method and data processing method of gas phase threshold pressure gradient. Background technique [0002] Most of the gas reservoirs that have been discovered and developed in my country are water drive gas reservoirs, and the edge and bottom water connected to the gas reservoirs will invade the gas reservoirs during the development of the gas reservoirs, and gas-water two-phase flow widely exists in the reservoirs. The threshold pressure gradient of gas phase is the critical pressure gradient of gas phase flow when gas-water two phases coexist. The threshold pressure gradient of the gas phase will increase the seepage resistance of the gas phase in the reservoir and affect the seepage law of the gas-water two-phase. Therefore, an accurate description of the change law of the gas-phase threshold pressure gradient is an important...

AI Technical Summary

Problems solved by technology

The first type of model does not comprehensively consider the influence of rock permeability and gas phase continuity on the gas phase threshold pressure gradient, and the model has poor adaptability

The second type of model uses water saturation to represent the continuity of the gas phase, without considering the influence of irreducible water saturation and residual gas saturation on the continuity of the gas phase, so the model cannot accurately describe the variation law of the gas phase threshold pressure gradient with the gas phase continuity

Therefore, water saturation does not accurately reflect the continuity of the gas phase in porous media

[0012] From Table 1, although the Li Qi model, Yang Chaopeng model and Tian W-B model comprehensively considered rock permeability and gas phase continuity, they used water saturation to represent gas phase continuity, and did not consider irreducible water saturation and gas phase continuity. The influence of residual gas saturation on gas-phase continuity makes the model unable to describe the influence of gas-phase continuity on gas-phase threshold pressure gradient well, and also makes it difficult for the single gas-phase flow region (S w wc ) and single aqueous phase flow region (S w >1-S gr ) is meaningless ( figure 1 )

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