CN-122024873-A - Hydrate generation kinetic model establishment method considering different gas-liquid contact modes

CN122024873ACN 122024873 ACN122024873 ACN 122024873ACN-122024873-A

Abstract

The invention discloses a method for establishing a hydrate generation kinetic model by considering different gas-liquid contact modes, and belongs to the technical field of sea bottom sealing and storage of carbon dioxide by a hydrate method. The method comprises the steps of establishing an equivalent capillary model based on a porous medium pore structure, respectively deducing a specific surface area expression of hydrate controlled by spherical crown liquid drops and controlled by gas columns in a capillary by considering reservoir wettability and hydrate membrane coverage rate, establishing a comprehensive specific surface area expression by associating contributions of two gas-liquid contact modes through critical liquid phase saturation, coupling the expression into a classical hydrate reaction kinetic model, constructing a new hydrate generation kinetic model, determining key parameters in the model through fitting a simulation prediction result and experimental data, and verifying rationality and accuracy of the model through experiments. The invention provides a more reasonable model foundation for optimizing dynamic prediction and sealing quantity evaluation of hydrate generation in the hydrate method carbon dioxide submarine sealing technology.

Inventors

YU TAO
XIA YONGQIANG
SONG YONGCHEN
JIANG LANLAN
CHEN BINGBING
YANG MINGJUN
YANG LEI
ZHANG LUNXIANG
LING ZHENG

Assignees

大连理工大学

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (10)

1. The method for establishing the hydrate generation kinetic model by considering different gas-liquid contact modes is characterized by comprising the following steps of: S1, determining porosity and particle radius of a porous medium, and obtaining mathematical expressions of capillary length and capillary radius based on the assumption that the pore volume of a porous medium unit body is equal to the volume of a cylindrical capillary model; s2, according to the mathematical expression in S1, considering reservoir wettability, calculating the number of spherical crown liquid drops in a capillary, and simultaneously introducing a hydrate film coverage rate, so as to establish a hydrate generation specific surface area expression controlled by the spherical crown liquid drops; s3, establishing a hydrate generation specific surface area expression controlled by a gas column based on the migration mode of carbon dioxide plumes in a porous medium according to the mathematical expression of S1; S4, establishing a hydrate generation specific surface area expression considering different gas-liquid contact modes according to the two hydrate generation specific surface area expressions obtained in S2 and S3 by acquiring critical liquid phase saturation and associating the contribution of the two gas-liquid contact modes of spherical crown liquid drops and a gas column to the hydrate generation specific surface area; s5, coupling the hydrate generation specific surface area expression taking different gas-liquid contact modes into consideration in the S4 into a classical hydrate reaction kinetic model, so as to obtain a hydrate generation kinetic model taking different gas-liquid contact modes into consideration; And S6, determining key parameters in the hydrate generation kinetic model considering different gas-liquid contact modes based on fitting analysis of simulation prediction results and experimental data, and verifying rationality and accuracy of the hydrate generation kinetic model after determining the key parameters through experiments.
2. The method for establishing a kinetic model of generating hydrate taking different gas-liquid contact modes into consideration according to claim 1, wherein in S1, mathematical expressions of the capillary length L and the capillary radius R are respectively: ; ; wherein r g is the average radius of the porous medium particles, phi is the porosity of the unit body, and the formula is V s is the volume of the porous medium unit body.
3. The method for establishing a kinetic model of hydrate formation taking into account different gas-liquid contact modes according to claim 1, wherein in S2, the expression of the specific surface area a ss_droplet of hydrate formation controlled by spherical crown droplets is specifically as follows: ; Wherein S A is liquid phase saturation, S As is start liquid phase saturation, C droplet is hydrate film coverage index controlled by liquid drops, S H is hydrate saturation, n is the ratio of vertical distance to capillary radius, θ is contact angle, r g is average radius of porous medium particles, and phi is unit porosity.
4. The method for establishing a kinetic model of hydrate formation taking into account different gas-liquid contact modes according to claim 1, wherein in S3, the expression of the specific surface area a ss_column of hydrate formation controlled by a gas column is specifically as follows: ; Wherein S A is liquid phase saturation, C column is gas column controlled hydrate film coverage index, S H is hydrate saturation, r g is average radius of porous medium particles, and phi is unit porosity.
5. The method for establishing a kinetic model of generating hydrate taking into account different gas-liquid contact modes according to claim 1, wherein in S4, an expression of a specific surface area a ss of generating hydrate taking into account different gas-liquid contact modes is specifically as follows: ; Wherein S A obtained after A ss_droplet and A ss_column are equal is the critical liquid phase saturation S Ac ;S A , S As is the starting liquid phase saturation, C droplet is the hydrate film coverage index controlled by liquid drops, S H is the hydrate saturation, n is the ratio of the vertical distance to the capillary radius, θ is the contact angle, r g is the average radius of porous medium particles, φ is the unit porosity, and C column is the hydrate film coverage index controlled by gas column.
6. The method for creating a kinetic model of hydrate formation taking into account different gas-liquid contact modes according to claim 5, wherein in S5, the classical kinetic model of hydrate reaction is Kim-Bishnoi kinetic model, and the specific surface area expression is coupled thereto, thereby obtaining a kinetic model of hydrate formation taking into account different gas-liquid contact modes: ; Wherein k 0 is an initial kinetic constant, ΔE is a reaction activation energy, R is a gas constant, T is a local temperature, M H is a hydrate molar mass, P g is a local gas pressure, P e is a phase equilibrium pressure, and R h is a hydrate generation rate.
7. The method for establishing a kinetic model of generating hydrate by considering different gas-liquid contact modes according to claim 1, wherein in S6, experimental data comprise temperature and pressure of a hydrate generating system, mean absolute percentage error MAPE and a determination coefficient R 2 are adopted for evaluation during fitting analysis, and key parameters comprise contact angle, ratio and starting liquid phase saturation.
8. A computer program product comprising computer program/instructions which, when executed by a processor, is capable of implementing a method for creating a kinetic model of hydrate formation taking into account different gas-liquid contact modes according to any one of claims 1 to 7.
9. A computer-readable storage medium, wherein a computer program is stored on the storage medium, and when the computer program is executed by a processor, the method for creating a dynamic model of hydrate formation taking into account different gas-liquid contact modes according to any one of claims 1 to 7 is implemented.
10. A computer electronic device comprising a memory and a processor; the memory is used for storing a computer program; the processor is configured to implement the hydrate formation kinetic model building method according to any one of claims 1 to 7, in consideration of different gas-liquid contact modes, when executing the computer program.

Description

Hydrate generation kinetic model establishment method considering different gas-liquid contact modes Technical Field The invention belongs to the technical field of sea bottom sealing and storage of carbon dioxide by a hydrate method, and particularly relates to a method for establishing a hydrate generation kinetic model by considering different gas-liquid contact modes. Background The carbon dioxide concentration in the atmosphere is rising year by year, and the global warming caused by the rise obstructs the urban process, and brings serious challenges to human life and social development. Carbon dioxide geological sequestration technology is one of the effective means to alleviate this problem, with hydrate-process carbon dioxide subsea sequestration technologies exhibiting prominence. Submarine reservoirs generally have low-temperature and high-pressure environments, and after carbon dioxide is injected, water molecules form a cage-shaped structure through hydrogen bonds, so that free-state dioxide is captured to form solid hydrates. Under standard conditions, one cubic meter of hydrate is capable of storing about 160 cubic meters of carbon dioxide. The technology relies on widely distributed submarine reservoirs, has the advantages of high sealing density and high safety, has great application potential in the aspects of efficiently sealing carbon dioxide and relieving global warming, and provides a reliable technical path for coping with weather crisis. The sea bottom sequestration technology of carbon dioxide by the hydrate method faces a core contradiction. On one hand, the generation of the hydrate can lead to the reduction of the permeability of a deposition layer, and the pores can be effectively blocked, so that the risk of carbon dioxide leakage is reduced, and the blocking safety is improved, on the other hand, the rapid reduction of the permeability also causes a technical application bottleneck, reduces an effective seepage channel of fluid, remarkably restricts the subsequent transportation of carbon dioxide and water, and generates a self-inhibition effect on the further growth of the hydrate. Therefore, accurately predicting the growth process of the hydrate is a precondition for optimizing the carbon dioxide sequestration scheme and balancing the sequestration safety and the sequestration efficiency. Various mathematical models have been developed to describe the kinetic behavior of hydrate formation. For the hydrate reaction process in the porous medium, a complex coupling process of fluid seepage, heat transfer and mass transfer is involved. The specific surface area is a key parameter for controlling the hydrate reaction and represents the ratio of the gas-liquid mass transfer area in the porous medium unit body to the unit body volume. Reservoir wettability influences the gas-liquid contact mode by changing the occurrence pattern of liquid water. Meanwhile, different gas-liquid contact modes in the porous medium influence the gas-liquid mass transfer area, and the generation mechanism and the generation form of the hydrate are controlled. However, most hydrate generation kinetic models ignore the influence of different gas-liquid contact modes on hydrate generation, which reduces the reliability and predictability of the model under complex reservoir conditions, thereby limiting the large-scale application of the hydrate-method carbon dioxide subsea sequestration technology. Disclosure of Invention The invention aims to overcome the defects in the prior art and provide a method for establishing a hydrate generation kinetic model by considering different gas-liquid contact modes, so that the accuracy of the prediction of the sealing quantity in the large-scale numerical simulation of the hydrate method carbon dioxide submarine sealing technology is improved, and the application of the technology in an actual sealing field is promoted. The specific technical scheme adopted by the invention is as follows: In a first aspect, the present invention provides a method for establishing a kinetic model of hydrate formation taking into account different gas-liquid contact modes, specifically including: S1, determining porosity and particle radius of a porous medium, and obtaining mathematical expressions of capillary length and capillary radius based on the assumption that the pore volume of a porous medium unit body is equal to the volume of a cylindrical capillary model; s2, according to the mathematical expression in S1, considering reservoir wettability, calculating the number of spherical crown liquid drops in a capillary, and simultaneously introducing a hydrate film coverage rate, so as to establish a hydrate generation specific surface area expression controlled by the spherical crown liquid drops; s3, establishing a hydrate generation specific surface area expression controlled by a gas column based on the migration mode of carbon dioxide plumes in a porous medium according to the mat