Coupling numerical simulation method for site selection of underground salt cavern hydrogen storage

Patent metadata

Field	Value
Publication number	US-12131104-B2
Application number	US-202418442107-A
Country	US
Kind code	B2
Filing date	Feb 15, 2024
Priority date	Feb 24, 2023
Publication date	Oct 29, 2024
Grant date	Oct 29, 2024

Abstract

The disclosure relates to the field of underground salt cavern energy storage, and discloses a coupling numerical simulation method for site selection of an underground salt cavern hydrogen storage, which specifically comprises the following. Geological data of an area where the salt cavern hydrogen storage is to be established is obtained. A three-dimensional model is established and grid meshing is performed. An initial coupling field is established and balanced based on the geological model, and then excavation simulation of the salt cavern hydrogen storage is performed. A geological model after excavation and related parameter values thereof are imported into TOUGH2MP software, a stress model in FLAC3D software is coupled with hydraulic and thermal models in the TOUGH2MP software to simulate a stress, hydraulic, and thermal coupling behavior process of rock layers around the salt cavern hydrogen storage in the area, and a coupled simulation result is obtained.

First claim

What is claimed is:

1. A coupling numerical simulation method for site selection of an underground salt cavern hydrogen storage, comprising operations as follows:
S 1 : obtaining geological data of an area where the salt cavern hydrogen storage is to be established, wherein the area where the salt cavern hydrogen storage is to be established in S 1 is an unexploited salt mine;
S 2 : establishing a three-dimensional model and performing grid meshing: establishing a geological model of the area where the single salt cavern hydrogen storage is to be established by using a geo-technical numerical modeling software according to the geological data, and dividing the geological model into computational grids; and performing computational grid densification processing on a peripheral area of a target area of the salt cavern hydrogen storage in the geological model, and selecting a set of computational grids on an inner edge of the target area of the salt cavern hydrogen storage as separate grids;
S 3 : establishing and balancing an initial coupling field based on the geological model, and then performing excavation simulation of the target area of the salt cavern hydrogen storage in the geological model to obtain a geological model after excavation, wherein an excavation area for excavation simulation of the target area of the salt cavern hydrogen storage in the geological model is an internal area of the separate grid in the target area of the salt cavern hydrogen storage;
S 4 : importing the geological model after excavation into a multi-phase flow simulation software, and resetting parameter values of the separate grids in the geological model after excavation in the multi-phase flow simulation software, specifically comprising:
increasing a volume of the separate grid to an actual volume of the target area of the salt cavern hydrogen storage to obtain a hydrogen grid; and
setting a porosity of the hydrogen grid to 0.999, setting a permeability to be significantly greater than a permeability of a surrounding rock salt, setting a hydrogen gas saturation to 1.0, and setting other parameters same as computational grids around the hydrogen grid;
S 5 : coupling a stress model in the geo-technical numerical modeling software with hydraulic and thermal models in the multi-phase flow simulation software, and simulating a stress, hydraulic, and thermal coupling behavior process of a rock layer around the target area of the salt cavern hydrogen storage in the geological model after excavation to obtain a coupled simulation result.

2. The coupling numerical simulation method according to claim 1 , wherein in S 3 , the initial coupling field comprises an initial in-situ stress field, a temperature field, and a seepage field, and establishing and balancing the initial coupling field based on the geological model specifically comprises:
S 31 : setting a constraint boundary of the geological model, applying an overlying rock layer pressure, and establishing the initial in-situ stress field, the temperature field, and the seepage field of the geological model; and
S 32 : performing a balance calculation of the initial in-situ stress field, the temperature field, and the seepage field, and inputting balanced parameter values comprising gravity, temperature, and pore pressure into each of the computational grids in the geological model.

3. The coupling numerical simulation method according to claim 2 , wherein S 5 comprises:
S 51 : initializing settings and synchronously updating initial values of hydraulic and thermal parameters and a simulation time in the geo-technical numerical modeling software and the multi-phase flow simulation software, and simulating and calculating the hydraulic and thermal parameters in the multi-phase flow simulation software, while simulating and calculating a stress in the geo-technical numerical modeling software;
S 52 : importing hydraulic and thermal parameter values obtained after each Newton iteration calculation in the multi-phase flow simulation software in S 51 into the geo-technical numerical modeling software for stress calculation, analyzing and determining whether the rock salt is damaged after obtaining a stress calculation result; in response to being damaged, importing new hydraulic and thermal parameter values caused by change of the stress in the geo-technical numerical modeling software back into the multi-phase flow simulation software to update corresponding hydraulic and thermal parameter values, and performing a next round of Newton iterative calculation; and in response to not being damaged, importing no values back into the multi-phase flow simulation software, that is, directly using the hydraulic and thermal parameter values calculated in the multi-phase flow simulation software for the next round of Newton iteration calculation; and
S 53 : ending the coupling simulation in response to a maximum coupling simulation time reaching the simulation time set in S 51 , and obtaining the coupled simulation result.

4. The coupling numerical simulation method according to claim 3 , wherein in S 1 , the geological data comprises a depth of a roof of a caprock layer, a depth of a roof of a salt layer, a total thickness of the salt layer, a type and a thickness of an interlayer of the salt layer, an average density of the rock salt, an average density of the caprock layer, a floor, and the interlayer, a ground temperature, and a temperature gradient.

5. The coupling numerical simulation method according to claim 4 , wherein the hydraulic parameters in S 51 comprise at least one of porosity, permeability, gravity, pore pressure, and rock pore saturation; and the thermal parameters comprise at least one of temperature, specific heat capacity, and thermal conductivity.

6. The coupling numerical simulation method according to claim 5 , wherein in S 53 , the coupled simulation result comprises rock salt porosity, interlayer permeability, and rock salt creep.

7. The coupling numerical simulation method according to claim 6 , wherein in S 5 , the geo-technical numerical modeling software adopts a creep stress model and adopts a Newton Power law model.

8. The coupling numerical simulation method according to claim 7 , wherein in S 5 , a relative penetration model in the multi-phase flow simulation software adopts a Cauchy model, and a capillary pressure model of each rock layer adopts van Genuchten model.

Assignees

• Univ Sichuan
• Univ Zhengzhou

Inventors

• Hou Zhengmeng
• Fang Yanli
• Liu Jianhua
• Huang Liangchao
• Tang Jianwei
• Ren Li

Classifications

• E21B41/0057

  Disposal of a fluid by injection into a subterranean formation · CPC title

• E21B2200/20

  Computer models or simulations, e.g. for reservoirs under production, drill bits · CPC title

• G06F2111/10

  Numerical modelling · CPC title

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• Y02E60/32

  Hydrogen storage · CPC title