Method, apparatus, and device for evaluating dynamic diffusion of natural hydrogen in rock pores

An apparatus for evaluating a natural hydrogen diffusion in rock pores, comprising:

• a non-transitory memory storing computer readable instructions;
• and
• one or more processors in communication with the one or more processors, wherein the instructions, when executed by the one or more processors, causes the apparatus to:
• collect, at a target pressure and a target temperature, rock physics data of a rock to be evaluated using a scanning electron microscopy and a high-pressure mercury intrusion, determine, based on the collected rock physics data of the rock, a full aperture distribution and a pore throat diameter distribution of the rock to be evaluated using adsorption tests, and determine a mineral composition of the rock to be evaluated, to perform a simulation calculation of a natural hydrogen adsorption using a pre-constructed pore model of the rock to be evaluated, and determine, based on the simulation calculation, an average number of hydrogen molecules adsorbed in rock pores of the rock when natural hydrogen in the rock pores is saturated at the target pressure and the target temperature, wherein the pre-constructed pore model is a simulated pore model built using actual pore conditions of the rock to be evaluated, the actual pore conditions comprising the full aperture distribution, the pore throat diameter distribution and the mineral composition of the rock, and a specific surface area, a total pore volume and a pore diameter distribution of the pre-constructed pore model of the rock to be evaluated being approximately equal to results obtained through experimental measurements;
• input, into a pre-constructed ideal model for a natural hydrogen content prediction, lithologic parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the rock pores when the natural hydrogen in the rock pores is saturated at the target pressure and the target temperature, and the target pressure and the target temperature, to obtain a natural hydrogen content V1H2 in the rock pores, wherein the lithologic parameters comprise a pore diameter of the rock to be evaluated, pore type influence coefficients of the rock to be evaluated, and a pore specific surface area of the rock to be evaluated, wherein the pre-constructed ideal model is a linear relationship between the natural hydrogen content V1H2 in the rock pores and influencing factors, and is configured to predict the natural hydrogen content V1H2;
• add one or more gases other than the natural hydrogen to the pre-constructed pore model, and when the pore model saturates at the target pressure and the target temperature, determine a loss content of the natural hydrogen in the rock pores, and determine a diffusion coefficient DTH2 of the natural hydrogen based on a preset diffusion coefficient correction model, wherein the preset diffusion coefficient correction model is a relationship between the diffusion coefficient DTH2 of the natural hydrogen and one or more diffusion coefficients of the one or more gases, and is configured to determine the diffusion coefficient DTH2 of the natural hydrogen;
• and
• generate a diffusion evaluation parameter of the natural hydrogen in the rock pores based on the natural hydrogen content V1H2 in the rock pores, and the loss content of the natural hydrogen and the diffusion coefficient DTH2 of the natural hydrogen, the diffusion evaluation parameter quantitatively representing dynamic diffusion of the natural hydrogen in the rock under geological conditions, wherein the method provides a quantitative evaluation of the dynamic diffusion of the natural hydrogen in the rock pores of the rock by collecting specific rock physics data of the rock and by calculation and simulation using models and the collected specific rock physics data;
• wherein the pre-constructed ideal model for natural hydrogen content prediction is represented as:
• V
• 1
• ⁢
• H
• ⁢
• 2
• =
• ∑
• i
• =
• 1
• n
• K
• i
• (
• aT
• +
• bP
• +
• cD
• +
• dS
• )
• ×
• V
• m
• ×
• N
• N
• A
• ,
• and
• the diffusion coefficient of the natural hydrogen is:
• DT
• H
• ⁢
• 2
• =
• ∑
• i
• =
• 1
• n
• K
• i
• (
• hT
• +
• rP
• +
• kD
• +
• eR
• +
• x
• ⁢
• ∑
• j
• =
• 1
• m
• DT
• j
• )
• ,
• Ki is an ith pore type influence coefficient, n is a total number of the pore type influence coefficients, T is a formation temperature, P is a formation pressure, D is the pore diameter, S is the pore specific surface area, Vm is a gas volume under a standard condition, N is the average number of hydrogen molecules, NA is an avogadro constant, a, b, c and d are fitting constants obtained based on training samples, respectively, R is a pore throat channel diameter of the rock to be evaluated, DTj is a diffusion coefficient of a jth gas of the one or more gases in the rock pores, m is a number of types of the one or more gases, and h, r, k, e and x are fitting constants obtained based on training samples, respectively.