CN-121996880-A - Carbonate rock rough slit H based on power law acid liquor+Mass transfer coefficient calculation method

Abstract

The invention discloses a carbonate rock rough slit H + mass transfer coefficient calculation method based on power law acid liquor, which comprises the steps of 1) deriving a mass transfer coefficient calculation method based on boundary layer theory and a two-dimensional convection diffusion differential equation, and 2) constructing an H + mass transfer coefficient calculation method by taking the power law characteristic of the acid liquor into consideration and correcting. Compared with the prior art, the H + mass transfer coefficient calculation method provided by the invention considers the power law characteristic of the acid liquor, and is more suitable for the actual situation of a field non-Newtonian acid liquor system.

Inventors

• CHEN CHI
• FANG JINHUI
• WANG ZHIHAO
• ZHANG HENG
• GUO JIANCHUN
• TAN XING
• LAI JIE
• WANG KUN
• REN JICHUAN
• LIU KUN
• YANG WENHAO

Assignees

• 西南石油大学

Dates

Publication Date

20260508

Application Date

20251231

Claims (6)

1. 1. A carbonate rock rough slit H + mass transfer coefficient calculation method based on power law acid liquor comprises the following steps: 1) Deriving a mass transfer coefficient calculation method based on boundary layer theory and a two-dimensional convection diffusion differential equation; 2) And (3) taking the acid liquor power law characteristics into consideration and correcting to construct an H + mass transfer coefficient calculation method.
2. 2. The mass transfer coefficient calculating method according to claim 1, wherein the mass transfer coefficient calculating method in step 1) is as follows: The diffusion boundary layer thickness equation is: the mass transfer coefficient and boundary layer thickness are related as follows: Wherein, the Is a mass transfer boundary layer, t is time, x and z respectively represent axial directions, u and w respectively represent speeds along the x direction and z, D is a material diffusion coefficient, and k g is a mass transfer coefficient.
3. 3. The mass transfer coefficient calculation method according to claim 1, comprising in step 2): 21 Taking the power law characteristic of the acid liquor into consideration to construct an acid liquor shear stress equation; 22 Substituting initial conditions, and solving to obtain the thickness of the boundary layer; 23 Substituting the boundary layer thickness into the mass transfer coefficient calculation equation in the step 1) to obtain an H + mass transfer coefficient calculation expression based on the power law acid liquor.
4. 4. The mass transfer coefficient calculation method according to claim 3, wherein the acid shear stress equation in the step 21) is: (16) Wherein, the Is that Wall shear stress at the location; Is viscosity; is the flow rate of the main flow area, and x is the coordinate.
5. 5. The mass transfer coefficient calculation method according to claim 3, wherein the boundary layer thickness expression in said step 22) is: 。
6. 6. The mass transfer coefficient calculating method according to claim 3, wherein the power law acid solution-based H + mass transfer coefficient calculating expression in step 23) is: Wherein L is the seam width; Is a rheological index; Consistency coefficient, ρ is density, μ is viscosity.

Description

Carbonate rock rough slit H + mass transfer coefficient calculation method based on power law acid liquor Technical Field The invention relates to the field of oil and gas field development, in particular to a carbonate rock rough slit H + mass transfer coefficient calculation method based on power law acid liquor. Background Carbonate reservoirs are one of the key fields of global oil and gas exploration and development, and the reservoir space takes slits and holes as main expression forms, so that the development degree and connectivity of the slits directly determine the productivity level of the reservoirs. The acidification transformation is used as a core technology for increasing the yield of the carbonate reservoir, and the acid liquor is injected into the reservoir, so that the slit wall surface is eroded by utilizing the chemical reaction of the acid liquor and the carbonate, the expansion of the slit width and the non-uniform etching are realized, and the permeability and the diversion capacity of the reservoir are improved. Acid fracturing simulation is used as an important technical module in acid fracturing technology, and the accuracy of the result influences the quality of the carbonate reservoir reconstruction effect, so that the yield of oil and gas exploitation is influenced. In the calculation of an acid pressure model, the reaction speed of H + and the mass transfer speed of H + jointly represent the acid rock reaction boundary, so that the simulation accuracy is affected, and the overall reaction speed of limestone-HCL is mainly controlled by mass transfer, so that a related acid etching experiment is required to be carried out to calculate the mass transfer coefficient k g of H +. The mass transfer coefficient calculation formula in the prior art is suitable for calculating the mass transfer coefficient of the acid rock reaction H + of the flat plate, but the power law characteristic parameter of the acid liquor is not systematically integrated. In the acidification construction, non-Newtonian acid liquid systems such as gelled acid, thickening acid and the like added with a thickening agent are widely adopted. A significant feature of such acid solutions is that they exhibit typical power law fluid characteristics, decreasing viscosity with increasing shear rate. Therefore, on the basis of rough slit mass transfer calculation, the method for calculating the mass transfer coefficient by taking rheological parameters and roughness coupling action into consideration is established by integrating the acid liquid power law characteristic, so that the method is suitable for the application requirements of a field non-Newtonian acid liquid system, and theoretical support is provided for the accurate design of acidification transformation. Disclosure of Invention In view of the above, the invention provides a method for calculating mass transfer coefficients of carbonate rock rough slits H + based on power law acid liquor, so as to make up for the defects in the prior art. A carbonate rock rough slit H + mass transfer coefficient calculation method based on power law acid liquor comprises the following steps: 1) Deriving a mass transfer coefficient calculation method based on boundary layer theory and a two-dimensional convection diffusion differential equation; 2) Taking the acid liquor power law characteristic into consideration and correcting to construct an H + mass transfer coefficient calculation method; further, the mass transfer coefficient calculation method in the step 1) is as follows: The diffusion boundary layer thickness equation is: the mass transfer coefficient and boundary layer thickness are related as follows: Wherein, the Is a mass transfer boundary layer, t is time, x and z respectively represent axial directions, u and w respectively represent speeds along the x direction and z, D is a material diffusion coefficient, and k g is a mass transfer coefficient. Further, step 2) includes: 21 Taking the power law characteristic of the acid liquor into consideration to construct an acid liquor shear stress equation; 22 Substituting initial conditions, and solving to obtain the thickness of the boundary layer; 23 Substituting the boundary layer thickness into the mass transfer coefficient calculation equation in the step 1) to obtain an H + mass transfer coefficient calculation expression based on the power law acid liquor. Further, the acid shear stress equation in the step 21) is: (16) Wherein, the Is thatWall shear stress at the location; Is viscosity; is the flow rate of the main flow area, and x is the coordinate. Further, the boundary layer thickness expression in the step 22) is: 。 Further, the mass transfer coefficient calculation expression of the H + based on the power law acid solution in the step 23) is as follows: Wherein L is the seam width; Is a rheological index; Consistency coefficient, ρ is density, μ is viscosity. Compared with the prior art, the inventi