Method and Device for Determining Pumping Rate to Improve Proppant Placement Efficiency

Description

TECHNICAL FIELD

The present application relates to the technical field of oil and gas extraction, and more particularly, to a method and device for determining pumping rate to improve proppant placement efficiency.

BACKGROUND OF THE INVENTION

The objective of hydraulic fracturing in unconventional reservoirs is to create fractures with sufficient conductivity in low- or ultra-low-permeability formations. The conductivity of the fracture is generally achieved by pumping proppants of a certain mesh size into the fracture. The placement efficiency of the proppant directly determines the conductivity of the fracture and consequently affects the productivity enhancement after stimulation.

When determining proppant placement requirements, the pumping rate must be considered. An insufficient pumping rate may fail to create effective fractures, while an excessively high pumping rate may render the fracture inoperative.

At present, no effective solution has been proposed to efficiently and accurately determine the appropriate pumping rate.

SUMMARY OF THE INVENTION

The objective of the present application is to provide a method and device for determining pumping rate to improve proppant placement efficiency, which enables accurate determination of a reasonable pumping rate and thereby enhances proppant placement efficiency.

The method and device for determining pumping rate to improve proppant placement efficiency are implemented as follows:

A method for determining pumping rate to improve proppant placement efficiency, comprising:

• • acquiring the mesh size of the proppant as the predetermined mesh size;
  • acquiring the bulk density of the proppant with the predetermined mesh size, the density of the carrier fluid, and the viscosity of the carrier fluid at reservoir temperature;
  • determining the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average fracture width during pumping;
  • acquiring a preset proppant concentration (sand ratio) for the predetermined mesh size;
  • retrieving a pre-established pumping rate calculation model corresponding to the predetermined mesh size of the proppant;
  • inputting the bulk density of the proppant, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip, the average fracture width, and the sand ratio into the pumping rate calculation model for the predetermined mesh size, and computing the pumping rate for the proppant with the predetermined mesh size.

In one embodiment, the mesh size of the proppant comprises at least one of the following: 30/50, 40/70, 70/140, 100/200.

In one embodiment, the pumping rate calculation model for a predetermined mesh size of the proppant includes:

When the predetermined mesh size of the proppant is 30/50, the corresponding pumping rate calculation model is expressed as:

Q p ⁢ 3 ⁢ 0 / 5 ⁢ 0 = 1 . 9 ⁢ 6 ⁢ L f ⁢ 3 ⁢ 0 / 5 ⁢ 0 ⁢ W f ⁢ 3 ⁢ 0 / 5 ⁢ 0 ⁢ lg ⁢ ( α 3 ⁢ 0 / 5 ⁢ 0 m 3 ⁢ 0 / 5 ⁢ 0 ⁢ ρ s ⁢ 3 ⁢ 0 / 5 ⁢ 0 ρ l ⁢ 3 ⁢ 0 / 5 ⁢ 0 ) ⁢ e - n 3 ⁢ 0 / 5 ⁢ 0 ⁢ μ 3 ⁢ 0 / 5 ⁢ 0

• • wherein: Q_p30/50 represents the pumping rate of the proppant with a mesh size of 30/50; L_f30/50 represents the distance from the wellbore to the fracture tip after the 30/50 mesh proppant enters the fracture; W_f30/50 represents the average fracture width during pumping for the 30/50 mesh proppant; α_30/50 represents the proppant concentration (sand ratio) during pumping for the 30/50 mesh proppant; m_30/50 represents the sand ratio coefficient for the 30/50 mesh proppant; ρ_s30/50 represents the bulk density of the 30/50 mesh proppant; ρ_l30/50 represents the density of the carrier fluid for the 30/50 mesh proppant; n_30/50 represents the viscosity coefficient for the 30/50 mesh proppant; μ_30/50 represents the viscosity of the carrier fluid for the 30/50 mesh proppant at reservoir temperature.

The calculation model for the proppant pumping rate corresponding to a predetermined proppant mesh size of 40/70 is expressed as follows:

Q p ⁢ 4 ⁢ 0 / 7 ⁢ 0 = 1 . 2 ⁢ 3 ⁢ L f ⁢ 4 ⁢ 0 / 7 ⁢ 0 ⁢ W f ⁢ 4 ⁢ 0 / 7 ⁢ 0 ⁢ lg ⁢ ( α 40 / 70 m 4 ⁢ 0 / 7 ⁢ 0 ⁢ ρ s ⁢ 40 / 70 ρ l ⁢ 4 ⁢ 0 / 7 ⁢ 0 ) ⁢ e - n 40 / 70 ⁢ μ 4 ⁢ 0 / 7 ⁢ 0

• • wherein: Q_p40/70 represents the pumping rate of the proppant with a mesh size of 40/70; L_f40/70 represents the distance from the wellbore to the fracture tip after the 40/70 mesh proppant enters the fracture; W_f40/70 represents the average fracture width during pumping for the 40/70 mesh proppant; α_40/70 represents the proppant concentration (sand ratio) during pumping for the 40/70 mesh proppant; m_40/70 represents the sand ratio coefficient for the 40/70 mesh proppant; ρ_s40/70 represents the bulk density of the 40/70 mesh proppant; ρ_l40/70 represents the density of the carrier fluid for the 40/70 mesh proppant; n_40/70 represents the viscosity coefficient for the 40/70 mesh proppant; μ_40/70 represents the viscosity of the carrier fluid for the 40/70 mesh proppant at reservoir temperature.

The calculation model for the proppant pumping rate corresponding to a predetermined proppant mesh size of 70/140 is expressed as follows:

Q p ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 = 0 . 4 ⁢ 7 ⁢ L f ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ W f ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ lg ⁡ ( α 70 / 140 m 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ ρ s ⁢ 70 / 140 ρ l ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ) ⁢ e - n 70 / 170 ⁢ μ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0

• • wherein: Q_p70/140 represents the pumping rate of the proppant with a mesh size of 70/140; L_f70/140 represents the distance from the wellbore to the fracture tip after the 70/140 mesh proppant enters the fracture; W_f70/140 represents the average fracture width during pumping for the 70/140 mesh proppant; α_70/140 represents the proppant concentration (sand ratio) during pumping for the 70/140 mesh proppant; m_70/140 represents the sand ratio coefficient for the 70/140 mesh proppant; ρ_s70/140 represents the bulk density of the 70/140 mesh proppant; ρ_l70/140 represents the density of the carrier fluid for the 70/140 mesh proppant; n_70/140 represents the viscosity coefficient for the 70/140 mesh proppant; μ_70/140 represents the viscosity of the carrier fluid for the 70/140 mesh proppant at reservoir temperature;

The calculation model for the proppant pumping rate corresponding to a predetermined proppant mesh size of 100/200 is expressed as follows:

Q p ⁢ 100 / 200 = 1 . 4 ⁢ 1 ⁢ L f ⁢ 100 / 200 ⁢ W f ⁢ 100 / 200 ⁢ lg ⁡ ( α 100 / 200 m 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0 ⁢ ρ s ⁢ 100 / 200 ρ l ⁢ 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0 ) ⁢ e - n 100 / 200 ⁢ μ 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0

• • wherein: Q_p100/200 represents the pumping rate of the proppant with a mesh size of 100/200; L_f100/200 represents the distance from the wellbore to the fracture tip after the 100/200 mesh proppant enters the fracture; W_f100/200 represents the average fracture width during pumping for the 100/200 mesh proppant; α_100/200 represents the proppant concentration (sand ratio) during pumping for the 100/200 mesh proppant; m_100/200 represents the sand ratio coefficient for the 100/200 mesh proppant; ρ_s100/200 represents the bulk density of the 100/200 mesh proppant; ρ_l100/200 represents the density of the carrier fluid for the 100/200 mesh proppant; n_100/200 represents the viscosity coefficient for the 100/200 mesh proppant; μ_100/200 represents the viscosity of the carrier fluid for the 100/200 mesh proppant at reservoir temperature.

In one embodiment, after calculating the pumping rate of the proppant with the predetermined mesh size, the method further includes:

• • obtaining a preset upper limit of the fracturing displacement;
  • determining whether the calculated proppant pumping rate for the predetermined mesh size exceeds the preset upper limit of the fracturing displacement;
  • if the calculated pumping rate of the proppant with the predetermined mesh size exceeds the preset upper limit, modifying the mesh size of the proppant and recalculating the pumping rate for the adjusted mesh size until the resulting pumping rate falls below the preset upper limit of the fracturing displacement.

In one embodiment, determining the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture and determining the average width of the injected fracture includes:

• • calculating the average width of the injected fracture according to the following formula:

W = 2 ⁢ ( P - σ ) · l E

• • wherein: W represents the average fracture width during pumping; P represents the fluid pressure inside the fracture; σ represents the normal stress on the fracture surface; l represents the fracture face deformation length; E represents the Young's modulus;

The distance from the wellbore to the fracture tip is calculated according to the following formula:

L = V · γ H · W

• • wherein: L represents the distance from the wellbore to the fracture tip; V represents the volume of fracturing fluid; γ represents the efficiency of the fracturing fluid; H represents the fracture height.

A device for determining the pumping rate to improve proppant placement efficiency, comprising:

• • a first acquisition module, configured to acquire the mesh size of the proppant as the predetermined mesh size;
  • a second acquisition module, configured to acquire the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature;
  • a determination module, configured to determine the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture;
  • a third acquisition module, configured to acquire a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size;
  • a retrieval module, configured to retrieve a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size;
  • a calculation module, configured to input the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip after the proppant enters the fracture, the average width of the injected fracture, and the proppant-to-liquid ratio for the predetermined mesh size into the calculation model to calculate the pumping rate of the proppant with the predetermined mesh size.

An electronic device, comprising a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements the steps of the above method.

A computer-readable storage medium, on which a computer program/instructions are stored, wherein the program/instructions, when executed by a processor, implement the steps of the above method.

The pumping rate determination method for improving proppant placement efficiency provided in the present application comprises: acquiring the mesh size of the proppant as the predetermined mesh size; then acquiring the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature; determining the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture; further acquiring a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size; retrieving a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size; and inputting the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip after the proppant enters the fracture, the average width of the injected fracture, and the proppant-to-liquid ratio into the calculation model to calculate the pumping rate of the proppant with the predetermined mesh size. That is, by determining the pumping rate based on parameters such as the bulk density of the proppant, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature, the method solves the technical problem in the prior art of being unable to accurately determine the pumping rate, and achieves the technical effect of accurately determining a reasonable pumping rate to improve proppant placement efficiency.

DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The accompanying drawings described below only show some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any inventive effort.

FIG. 1 is a flowchart of one embodiment of the pumping rate determination method for improving proppant placement efficiency provided in the present application;

FIG. 2 is a schematic diagram showing the relationship between viscosity and pumping rate under different proppant mesh sizes provided in the present application;

FIG. 3 is a hardware block diagram of an electronic device implementing the pumping rate determination method for improving proppant placement efficiency provided in the present application;

FIG. 4 is a schematic diagram of the module structure of one embodiment of the device for determining the pumping rate to improve proppant placement efficiency provided in the present application.

SPECIFIC EMBODIMENTS

To enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. It is apparent that the described embodiments are merely a part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present application.

It should also be noted that certain software, components, models, etc., mentioned in the embodiments of this specification may refer to existing industry solutions, and such references shall be deemed illustrative only. Their purpose is solely to demonstrate the feasibility of implementing the technical solution of the present application, and it does not imply that the applicant has adopted or must adopt these solutions.

Considering that the main factors affecting the efficiency of proppant placement in fractures include the slurry velocity, slurry viscosity, proppant-to-liquid ratio, fracture width, and proppant particle size, it is necessary to optimize the design of proppant mesh size (particle size), density, carrier fluid density/viscosity, and pumping rate during hydraulic fracturing to maximize hydrocarbon production. Based on this, the present embodiment proposes a method for designing and adjusting the proppant pumping rate to improve in-fracture proppant placement efficiency. This method enables accurate design of the proppant pumping rate for unconventional hydraulic fracturing and also allows adjustment of the rate by changing proppant particle size, density, carrier fluid density, and viscosity, thus providing a theoretical basis and design guidance for efficient conductivity creation in unconventional reservoirs.

FIG. 1 is a flowchart of one embodiment of the method for determining the pumping rate to improve proppant placement efficiency provided in the present application. Although the present application provides method steps or device structures as shown in the embodiments or drawings, based on routine knowledge or without requiring inventive effort, more or fewer operational steps or functional modules may be included in the described method or device. For steps or structures that are not logically causally related, the execution order or module configuration is not limited to that shown in the embodiments or drawings. In practical applications of the method or modular structure in devices or terminal products, the process may be executed sequentially or in parallel (for example, in a parallel processor, multithreaded, or even distributed processing environment) based on the embodiments or drawings.

Specifically, as shown in FIG. 1, the above method for determining the pumping rate to improve proppant placement efficiency may include the following steps:

• • Step 101: Acquire the mesh size of the proppant as the predetermined mesh size;
  • Wherein, the proppant mesh size may include, but is not limited to, at least one of the following: 30/50, 40/70, 70/140, and 100/200.
  • Step 102: Acquire the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature;
  • Step 103: Determine the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture;
  • That is, based on the consideration of the bulk density of the proppant, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature, the geometric dimensions of the hydraulic fracture are also taken into account to design the pumping rate calculation model, thereby improving the accuracy of the determined pumping rate.
  • Step 104: Acquire a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size;
  • Step 105: Retrieve a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size;

Specifically, the above pumping rate calculation model for proppants with predetermined mesh sizes may be defined for different mesh sizes, for example:

• • 1) When the predetermined mesh size of the proppant is 30/50, the corresponding pumping rate calculation model may be expressed as:

Q p ⁢ 3 ⁢ 0 / 5 ⁢ 0 = 1 . 9 ⁢ 6 ⁢ L f ⁢ 3 ⁢ 0 / 5 ⁢ 0 ⁢ W f ⁢ 3 ⁢ 0 / 5 ⁢ 0 ⁢ lg ⁡ ( α 30 / 50 m 3 ⁢ 0 / 5 ⁢ 0 ⁢ ρ s ⁢ 30 / 50 ρ l ⁢ 3 ⁢ 0 / 5 ⁢ 0 ) ⁢ e - n 30 / 50 ⁢ μ 3 ⁢ 0 / 5 ⁢ 0

• • wherein: Q_p30/50 represents the pumping rate of the proppant with a mesh size of 30/50; L_f30/50 represents the distance from the wellbore to the fracture tip after the 30/50 mesh proppant enters the fracture; W_f30/50 represents the average fracture width during pumping for the 30/50 mesh proppant; α_30/50 represents the proppant concentration (sand ratio) during pumping for the 30/50 mesh proppant; m_30/50 represents the sand ratio coefficient for the 30/50 mesh proppant; ρ_s30/50 represents the bulk density of the 30/50 mesh proppant; ρ_l30/50 represents the density of the carrier fluid for the 30/50 mesh proppant; n_30/50 represents the viscosity coefficient for the 30/50 mesh proppant; μ_30/50 represents the viscosity of the carrier fluid for the 30/50 mesh proppant at reservoir temperature;
  • 2) When the predetermined mesh size of the proppant is 40/70, the corresponding pumping rate calculation model may be expressed as:

Q p ⁢ 4 ⁢ 0 / 7 ⁢ 0 = 1 . 2 ⁢ 3 ⁢ L f ⁢ 4 ⁢ 0 / 7 ⁢ 0 ⁢ W f ⁢ 4 ⁢ 0 / 7 ⁢ 0 ⁢ lg ⁡ ( α 40 / 70 m 4 ⁢ 0 / 7 ⁢ 0 ⁢ ρ s ⁢ 40 / 70 ρ l ⁢ 4 ⁢ 0 / 7 ⁢ 0 ) ⁢ e - n 40 / 70 ⁢ μ 4 ⁢ 0 / 7 ⁢ 0

• • wherein: Q_p40/70 represents the pumping rate of the proppant with a mesh size of 40/70; L_f40/70 represents the distance from the wellbore to the fracture tip after the 40/70 mesh proppant enters the fracture; W_f40/70 represents the average fracture width during pumping for the 40/70 mesh proppant; α_40/70 represents the proppant concentration (sand ratio) during pumping for the 40/70 mesh proppant; m_40/70 represents the sand ratio coefficient for the 40/70 mesh proppant; ρ_s40/70 represents the bulk density of the 40/70 mesh proppant; ρ_l40/70 represents the density of the carrier fluid for the 40/70 mesh proppant; n_40/70 represents the viscosity coefficient for the 40/70 mesh proppant; μ_40/70 represents the viscosity of the carrier fluid for the 40/70 mesh proppant at reservoir temperature.
  • 3) When the predetermined mesh size of the proppant is 70/140, the corresponding pumping rate calculation model may be expressed as:

Q p ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 = 0 . 4 ⁢ 7 ⁢ L f ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ W f ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ lg ⁡ ( α 70 / 140 m 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ⁢ ρ s ⁢ 70 / 140 ρ l ⁢ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0 ) ⁢ e - n 70 / 140 ⁢ μ 7 ⁢ 0 / 1 ⁢ 4 ⁢ 0

• • wherein: Q_p70/140 represents the pumping rate of the proppant with a mesh size of 70/140; L_f70/140 represents the distance from the wellbore to the fracture tip after the 70/140 mesh proppant enters the fracture; W_f70/140 represents the average fracture width during pumping for the 70/140 mesh proppant; α_70/140 represents the proppant concentration (sand ratio) during pumping for the 70/140 mesh proppant; m_70/140 represents the sand ratio coefficient for the 70/140 mesh proppant; ρ_s70/140 represents the bulk density of the 70/140 mesh proppant; ρ_l70/140 represents the density of the carrier fluid for the 70/140 mesh proppant; n_70/140 represents the viscosity coefficient for the 70/140 mesh proppant; μ_70/140 represents the viscosity of the carrier fluid for the 70/140 mesh proppant at reservoir temperature;
  • 4) When the predetermined mesh size of the proppant is 100/200, the corresponding pumping rate calculation model may be expressed as:

Q p ⁢ 100 / 200 = 1 . 4 ⁢ 1 ⁢ L f ⁢ 100 / 200 ⁢ W f ⁢ 100 / 200 ⁢ lg ⁡ ( α 100 / 200 m 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0 ⁢ ρ s ⁢ 100 / 200 ρ l ⁢ 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0 ) ⁢ e - n 100 / 200 ⁢ μ 1 ⁢ 0 ⁢ 0 / 2 ⁢ 0 ⁢ 0

• • wherein: Q_p100/200 represents the pumping rate of the proppant with a mesh size of 100/200; L_f100/200 represents the distance from the wellbore to the fracture tip after the 100/200 mesh proppant enters the fracture; W_f100/200 represents the average fracture width during pumping for the 100/200 mesh proppant; α_100/200 represents the proppant concentration (sand ratio) during pumping for the 100/200 mesh proppant; m_100/200 represents the sand ratio coefficient for the 100/200 mesh proppant; ρ_s100/200 represents the bulk density of the 100/200 mesh proppant; ρ_l100/200 represents the density of the carrier fluid for the 100/200 mesh proppant; n_100/200 represents the viscosity coefficient for the 100/200 mesh proppant; μ_100/200 represents the viscosity of the carrier fluid for the 100/200 mesh proppant at reservoir temperature.

The specific values of m_30/50 n_30/50 m_40/70 n_40/70 m_70/140 n_70/140 m_100/200 and n_100/200 may be determined based on actual conditions and experimental results, and are not limited by the present application.

The distance from the wellbore to the fracture tip and the average width of the injected fracture for the proppant with the predetermined mesh size may include:

• • S1: Calculating the average width of the injected fracture according to the following formula:

W = 2 ⁢ ( P - σ ) · l E

• • wherein: W represents the average fracture width during pumping; P represents the fluid pressure inside the fracture; σ represents the normal stress on the fracture surface; l represents the fracture face deformation length; E represents the Young's modulus;
  • S2: Calculating the distance from the wellbore to the fracture tip according to the following formula:

L = V · γ H · W

• • wherein: L represents the distance from the wellbore to the fracture tip; V represents the volume of fracturing fluid; γ represents the efficiency of the fracturing fluid; H represents the fracture height.
  • Step 106: Input the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip, the average width of the injected fracture, and the proppant-to-liquid ratio into the corresponding pumping rate calculation model, and calculate the pumping rate of the proppant with the predetermined mesh size.

Since an excessively low pumping rate cannot achieve the desired fracture effect and an excessively high pumping rate may lead to fracture instability, after calculating the pumping rate of the proppant with the predetermined mesh size, a preset upper limit of the fracturing displacement may be obtained. It is then determined whether the calculated pumping rate exceeds the preset limit. If it does, the mesh size of the proppant is adjusted, and the pumping rate is recalculated using the adjusted mesh size until the resulting value is below the preset limit. That is, if the resulting pumping rate is not appropriate, the mesh size of the proppant is modified, which in turn alters the proppant bulk density, carrier fluid density, viscosity at reservoir temperature, fracture geometry, and proppant-to-liquid ratio, thus enabling dynamic adjustment of the pumping rate.

A specific embodiment is provided below to illustrate the above-described method. However, it should be noted that this embodiment is presented solely for better illustration and should not be construed as an undue limitation on the present application.

In this embodiment, a proppant pumping rate design model is provided. The design model is established based on the consideration of factors affecting proppant placement efficiency in the fracture, such as slurry flow velocity, slurry viscosity, proppant-to-liquid ratio, fracture width, and proppant particle size, as well as the influence of hydraulic fracture geometry.

This is mainly because the primary factors affecting the efficiency of proppant placement within fractures include slurry flow velocity, slurry viscosity, proppant-to-liquid ratio, fracture width, and proppant particle size. Therefore, in order to maximize hydrocarbon production, hydraulic fracturing requires precise design of proppant particle size (mesh size), density, carrier fluid density/viscosity, and pumping rate.

Specifically, a method for designing and regulating the pumping rate to improve in-fracture proppant placement efficiency is provided. This method enables accurate determination of the pumping rate for unconventional hydraulic fracturing and allows the adjustment of pumping rate by changing proppant particle size, density, carrier fluid density, and viscosity, thus providing a theoretical basis and design reference for the efficient establishment of fracture conductivity in unconventional reservoirs.

The proposed proppant pumping rate design model is expressed as follows:

Q p ⁢ 30 / 50 = 1.96 L f ⁢ 30 / 50 ⁢ W f ⁢ 30 / 50 ⁢ lg ⁡ ( α 30 / 50 m 30 / 50 ⁢ ρ s ⁢ 30 / 50 ρ l ⁢ 30 / 50 ) ⁢ e - n 30 / 50 ⁢ μ 30 / 50 Q p ⁢ 40 / 70 = 1.23 L f ⁢ 40 / 70 ⁢ W f ⁢ 40 / 70 ⁢ lg ⁡ ( α 40 / 70 m 40 / 70 ⁢ ρ s ⁢ 40 / 70 ρ l ⁢ 40 / 70 ) ⁢ e - n 40 / 70 ⁢ μ 40 / 70 Q p ⁢ 70 / 140 = 0.47 L f ⁢ 70 / 140 ⁢ W f ⁢ 70 / 140 ⁢ lg ⁡ ( α 70 / 140 m 70 / 140 ⁢ ρ s ⁢ 70 / 140 ρ l ⁢ 70 / 140 ) ⁢ e - n 70 / 140 ⁢ μ 70 / 140 Q p ⁢ 100 / 200 = 1.41 L f ⁢ 100 / 200 ⁢ W f ⁢ 100 / 200 ⁢ lg ⁡ ( α 100 / 200 m 100 / 200 ⁢ ρ s ⁢ 100 / 200 ρ l ⁢ 100 / 200 ) ⁢ e - n 100 / 200 ⁢ μ 100 / 2000

• • wherein: α_30/50 represents the proppant concentration (sand ratio) during pumping for the 30/50 mesh proppant; m_30/50 represents the sand ratio coefficient for the 30/50 mesh proppant; ρ_s30/50 represents the bulk density of the 30/50 mesh proppant; ρ_l30/50 represents the density of the carrier fluid for the 30/50 mesh proppant; n_30/50 represents the viscosity coefficient for the 30/50 mesh proppant; μ_30/50 represents the viscosity of the carrier fluid for the 30/50 mesh proppant at reservoir temperature; α_40/70 represents the proppant concentration (sand ratio) during pumping for the 40/70 mesh proppant; m_40/70 represents the sand ratio coefficient for the 40/70 mesh proppant; ρ_s40/70 represents the bulk density of the 40/70 mesh proppant; ρ_l40/70 represents the density of the carrier fluid for the 40/70 mesh proppant; n_40/70 represents the viscosity coefficient for the 40/70 mesh proppant; μ_40/70 represents the viscosity of the carrier fluid for the 40/70 mesh proppant at reservoir temperature; α_70/140 represents the proppant concentration (sand ratio) during pumping for the 70/140 mesh proppant; m_70/140 represents the sand ratio coefficient for the 70/140 mesh proppant; ρ_s70/140 represents the bulk density of the 70/140 mesh proppant; ρ_l70/140 represents the density of the carrier fluid for the 70/140 mesh proppant; n_70/140 represents the viscosity coefficient for the 70/140 mesh proppant; μ_70/140 represents the viscosity of the carrier fluid for the 70/140 mesh proppant at reservoir temperature; α_100/200 represents the proppant concentration (sand ratio) during pumping for the 100/200 mesh proppant; m_100/200 represents the sand ratio coefficient for the 100/200 mesh proppant; ρ_s100/200 represents the bulk density of the 100/200 mesh proppant; ρ_l100/200 represents the density of the carrier fluid for the 100/200 mesh proppant; n_100/200 represents the viscosity coefficient for the 100/200 mesh proppant; μ_100/200 represents the viscosity of the carrier fluid for the 100/200 mesh proppant at reservoir temperature; Q_p100/200 represents the pumping rate of the proppant with a mesh size of 100/200; L_f100/200 represents the distance from the wellbore to the fracture tip after the 100/200 mesh proppant enters the fracture; W_f100/200 represents the average fracture width during pumping for the 100/200 mesh proppant; Q_p40/70 represents the pumping rate of the proppant with a mesh size of 40/70; L_f40/70 represents the distance from the wellbore to the fracture tip after the 40/70 mesh proppant enters the fracture; W_f40/70 represents the average fracture width during pumping for the 40/70 mesh proppant; Q_p70/140 represents the pumping rate of the proppant with a mesh size of 70/140; L_f70/140 represents the distance from the wellbore to the fracture tip after the 70/140 mesh proppant enters the fracture; W_f70/140 represents the average fracture width during pumping for the 70/140 mesh proppant; Q_p100/200 represents the pumping rate of the proppant with a mesh size of 100/200; L_f100/200 represents the distance from the wellbore to the fracture tip after the 100/200 mesh proppant enters the fracture; W_f100/200 represents the average fracture width during pumping for the 100/200 mesh proppant; lg is the common logarithm (base 10).

The determination of the distance from the wellbore to the fracture tip and the average width of the injected fracture for a given proppant mesh size may be performed as follows:

• • S1: Calculate the average width of the injected fracture using the following equation:

W = 2 ⁢ ( P - σ ) · l E

• • Where W is the average fracture width; P is the fluid pressure within the fracture; σ is the normal stress on the fracture surface; l is the deformation length; and E is the Young's modulus.
  • S2: Calculate the distance from the wellbore to the fracture tip using the following equation:

L = V · γ H · W

• • Where L is the distance from the wellbore to the fracture tip; V is the fracturing fluid volume; γ is the fluid efficiency; and H is the fracture height.

In practice, the mesh size of the proppant (for example, 30/50) may first be selected, followed by acquisition of the bulk density of the proppant, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature. Subsequently, the distance from the wellbore to the fracture tip and the average fracture width are obtained. Based on a target proppant-to-liquid ratio, the corresponding pumping rate is calculated. If the resulting pumping rate exceeds the upper limit of the fracturing displacement, the mesh size (for example, from 30/50 to 40/70) may be changed to reduce the bulk density, increase the carrier fluid density, or increase the carrier fluid viscosity at reservoir temperature. The pumping rate is then recalculated until it falls below the upper limit. FIG. 2 illustrates a schematic diagram showing the relationship between viscosity and pumping rate for different proppant mesh sizes.

In the above example, a method for designing and adjusting the proppant pumping rate to improve in-fracture proppant placement efficiency is provided. The method enables accurate design of pumping rates for unconventional hydraulic fracturing, and allows regulation of pumping rate by adjusting proppant particle size, proppant density, carrier fluid density, and carrier fluid viscosity, thereby providing theoretical and design support for constructing high-conductivity fractures in unconventional reservoirs.

The method described in the above embodiments may be implemented on a mobile terminal, computer terminal, or a similar computing device. Taking an electronic device as an example, FIG. 3 is a hardware block diagram of the electronic device for implementing the proppant pumping rate determination method to improve proppant placement efficiency, as provided in the present application. As shown in FIG. 3, the electronic device 10 may include one or more processors 02 (only one shown), wherein the processor may include, but is not limited to, a microcontroller (MCU) or a field-programmable gate array (FPGA); a memory 04 for storing data; and a transmission module 06 for communication functionality. Those skilled in the art will understand that the structure shown in FIG. 3 is merely illustrative and does not limit the electronic device. For example, the device 10 may include more or fewer components than shown, or may be configured differently from the structure illustrated.

The memory 04 may be used to store software programs and modules of application software, such as the program instructions/modules corresponding to the method for determining the pumping rate to improve proppant placement efficiency in the embodiments of the present application. The processor 02 executes various functional applications and data processing by running the software programs and modules stored in the memory 04, thereby implementing the above-mentioned method. The memory 04 may include high-speed random access memory, and may also include non-volatile memory such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state storage. In some instances, the memory 04 may further include memory remotely located with respect to the processor 02, which may be connected to the electronic device 10 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, intranet, local area network (LAN), mobile communication network, or any combination thereof.

The transmission module 06 is used to receive or transmit data via a network. Specific examples of the network may include wireless networks provided by the communication service provider of the electronic device 10. In one example, the transmission module 06 includes a Network Interface Controller (NIC), which may connect to other network devices via a base station to communicate with the Internet. In one example, the transmission module 06 may be a Radio Frequency (RF) module for wireless communication with the Internet.

At the software level, the above device for determining the pumping rate to improve proppant placement efficiency may include, as shown in FIG. 4:

• • First acquisition module 401, used to acquire the mesh size of the proppant as the predetermined mesh size;
  • Second acquisition module 402, used to acquire the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature;
  • Determination module 403, used to determine the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture;
  • Third acquisition module 404, used to acquire a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size;
  • Retrieval module 405, used to retrieve a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size;
  • Calculation module 406, used to input the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip after the proppant enters the fracture, the average width of the injected fracture, and the proppant-to-liquid ratio into the calculation model to calculate the pumping rate of the proppant with the predetermined mesh size.

In one embodiment, the mesh size of the proppant may include but is not limited to at least one of the following: 30/50, 40/70, 70/140, and 100/200.

In one embodiment, the calculation model for the pumping rate of the proppant with the predetermined mesh size may include:

When the predetermined mesh size of the proppant is 30/50, the corresponding pumping rate calculation model is expressed as:

Q p ⁢ 30 / 50 = 1.96 L f ⁢ 30 / 50 ⁢ W f ⁢ 30 / 50 ⁢ lg ⁡ ( α 30 / 50 m 30 / 50 ⁢ ρ s ⁢ 30 / 50 ρ l ⁢ 30 / 50 ) ⁢ e - n 30 / 50 ⁢ μ 30 / 50

• • wherein: Q_p30/50 represents the pumping rate of the proppant with a mesh size of 30/50; L_f30/50 represents the distance from the wellbore to the fracture tip after the 30/50 mesh proppant enters the fracture; W_f30/50 represents the average fracture width during pumping for the 30/50 mesh proppant; α_30/50 represents the proppant concentration (sand ratio) during pumping for the 30/50 mesh proppant; m_30/50 represents the sand ratio coefficient for the 30/50 mesh proppant; ρ_s30/50 represents the bulk density of the 30/50 mesh proppant; ρ_l30/50 represents the density of the carrier fluid for the 30/50 mesh proppant; n_30/50 represents the viscosity coefficient for the 30/50 mesh proppant; μ_30/50 represents the viscosity of the carrier fluid for the 30/50 mesh proppant at reservoir temperature;
  • When the predetermined mesh size of the proppant is 40/70, the corresponding pumping rate calculation model for the proppant is expressed as follows:

Q p ⁢ 40 / 70 = 1.23 L f ⁢ 40 / 70 ⁢ W f ⁢ 40 / 70 ⁢ lg ⁡ ( α 40 / 70 m 40 / 70 ⁢ ρ s ⁢ 40 / 70 ρ l ⁢ 40 / 70 ) ⁢ e - n 40 / 70 ⁢ μ 40 / 70

• • wherein: Q_p40/70 represents the pumping rate of the proppant with a mesh size of 40/70; L_f40/70 represents the distance from the wellbore to the fracture tip after the 40/70 mesh proppant enters the fracture; W_f40/70 represents the average fracture width during pumping for the 40/70 mesh proppant; α_40/70 represents the proppant concentration (sand ratio) during pumping for the 40/70 mesh proppant; m_40/70 represents the sand ratio coefficient for the 40/70 mesh proppant; ρ_s40/70 represents the bulk density of the 40/70 mesh proppant; ρ_l40/70 represents the density of the carrier fluid for the 40/70 mesh proppant; n_40/70 represents the viscosity coefficient for the 40/70 mesh proppant; μ_40/70 represents the viscosity of the carrier fluid for the 40/70 mesh proppant at reservoir temperature.

When the predetermined mesh size of the proppant is 70/140, the corresponding pumping rate calculation model for the proppant is expressed as follows:

Q p ⁢ 70 / 140 = 0.47 L f ⁢ 70 / 140 ⁢ W f ⁢ 70 / 140 ⁢ lg ⁡ ( α 70 / 140 m 70 / 140 ⁢ ρ s ⁢ 70 / 140 ρ l ⁢ 70 / 140 ) ⁢ e - n 70 / 140 ⁢ μ 70 / 140

• • wherein: Q_p70/140 represents the pumping rate of the proppant with a mesh size of 70/140; L_f70/140 represents the distance from the wellbore to the fracture tip after the 70/140 mesh proppant enters the fracture; W_f70/140 represents the average fracture width during pumping for the 70/140 mesh proppant; α_70/140 represents the proppant concentration (sand ratio) during pumping for the 70/140 mesh proppant; m_70/140 represents the sand ratio coefficient for the 70/140 mesh proppant; ρ_s70/140 represents the bulk density of the 70/140 mesh proppant; ρ_l70/140 represents the density of the carrier fluid for the 70/140 mesh proppant; n_70/140 represents the viscosity coefficient for the 70/140 mesh proppant; μ_70/140 represents the viscosity of the carrier fluid for the 70/140 mesh proppant at reservoir temperature;
  • When the predetermined mesh size of the proppant is 100/200, the corresponding pumping rate calculation model for the proppant is expressed as follows:

Q p ⁢ 100 / 200 = 1.41 L f ⁢ 100 / 200 ⁢ W f ⁢ 100 / 200 ⁢ lg ⁡ ( α 100 / 200 m 100 / 200 ⁢ ρ s ⁢ 100 / 200 ρ l ⁢ 100 / 200 ) ⁢ e - n 100 / 200 ⁢ μ 100 / 2000

• • wherein: Q_p100/200 represents the pumping rate of the proppant with a mesh size of 100/200; L_f100/200 represents the distance from the wellbore to the fracture tip after the 100/200 mesh proppant enters the fracture; W_f100/200 represents the average fracture width during pumping for the 100/200 mesh proppant; α_100/200 represents the proppant concentration (sand ratio) during pumping for the 100/200 mesh proppant; m_100/200 represents the sand ratio coefficient for the 100/200 mesh proppant; ρ_s100/200 represents the bulk density of the 100/200 mesh proppant; ρ_l100/200 represents the density of the carrier fluid for the 100/200 mesh proppant; n_100/200 represents the viscosity coefficient for the 100/200 mesh proppant; μ_100/200 represents the viscosity of the carrier fluid for the 100/200 mesh proppant at reservoir temperature.

In one embodiment, determining the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture and the average width of the injected fracture may include:

• • Calculating the average width of the injected fracture according to the following formula:

W = 2 ⁢ ( P - σ ) · l E

• • wherein: W represents the average fracture width during pumping; P represents the fluid pressure inside the fracture; σ represents the normal stress on the fracture surface; l represents the fracture face deformation length; E represents the Young's modulus;
  • The distance from the wellbore to the fracture tip is calculated according to the following formula:

L = V · γ H · W

• • wherein: L represents the distance from the wellbore to the fracture tip; V represents the volume of fracturing fluid; γ represents the efficiency of the fracturing fluid; H represents the fracture height.

In one embodiment, after calculating the pumping rate of the proppant with the predetermined mesh size, the above-mentioned proppant placement efficiency improvement-based pumping rate determination device may further acquire a preset upper limit of the fracturing pumping rate; determine whether the calculated pumping rate of the proppant with the predetermined mesh size exceeds the preset upper limit; in the case where the calculated pumping rate exceeds the upper limit, change the mesh size of the proppant and recalculate the pumping rate of the proppant with the adjusted mesh size until the calculated pumping rate is lower than the preset upper limit.

The embodiments of the present application further provide a specific implementation of an electronic device capable of performing all steps of the method for determining the pumping rate to improve proppant placement efficiency described in the above embodiments. The electronic device specifically includes: a processor, a memory, a communications interface, and a bus. The processor, memory, and communications interface communicate with each other via the bus. The processor is configured to invoke a computer program stored in the memory, and by executing the computer program, the processor implements all the steps of the above method for determining the pumping rate to improve proppant placement efficiency. For example, the processor executes the computer program to implement the following steps:

• • Step 1: Acquire the mesh size of the proppant as the predetermined mesh size;
  • Step 2: Acquire the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature;
  • Step 3: Determine the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture;
  • Step 4: Acquire a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size;
  • Step 5: Retrieve a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size;
  • Step 6: Input the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip after the proppant enters the fracture, the average width of the injected fracture, and the proppant-to-liquid ratio into the pumping rate calculation model to calculate the pumping rate of the proppant with the predetermined mesh size.

The embodiments of the present application further provide a computer-readable storage medium capable of performing all steps of the method for determining the pumping rate to improve proppant placement efficiency described in the above embodiments. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements all the steps of the method for determining the pumping rate to improve proppant placement efficiency described in the above embodiments. For example, the processor executes the computer program to implement the following steps:

• • Step 1: Acquire the mesh size of the proppant as the predetermined mesh size;
  • Step 2: Acquire the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature;
  • Step 3: Determine the distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture, and the average width of the injected fracture;
  • Step 4: Acquire a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size;
  • Step 5: Retrieve a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size;
  • Step 6: Input the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, the carrier fluid viscosity at reservoir temperature, the distance from the wellbore to the fracture tip after the proppant enters the fracture, the average width of the injected fracture, and the proppant-to-liquid ratio into the pumping rate calculation model to calculate the pumping rate of the proppant with the predetermined mesh size.

From the above description, it can be seen that in the embodiment of the present application, the mesh size of the proppant is first acquired as the predetermined mesh size. Then, the bulk density of the proppant with the predetermined mesh size, the carrier fluid density, and the carrier fluid viscosity at reservoir temperature are obtained. The distance from the wellbore to the fracture tip after the proppant with the predetermined mesh size enters the fracture and the average width of the injected fracture are further determined. Subsequently, a preset proppant-to-liquid ratio for the proppant with the predetermined mesh size is obtained, and a pre-established calculation model for the pumping rate of the proppant with the predetermined mesh size is retrieved. The bulk density, carrier fluid density, carrier fluid viscosity at reservoir temperature, distance to the fracture tip, average fracture width, and the proppant-to-liquid ratio are then input into the calculation model to obtain the pumping rate of the proppant with the predetermined mesh size. That is, by determining the pumping rate in conjunction with parameters such as the bulk density of the proppant, carrier fluid density, and carrier fluid viscosity at reservoir temperature, the problem in the prior art of being unable to accurately determine the pumping rate is solved, thereby achieving the technical effect of accurately determining a reasonable pumping rate to enhance the placement efficiency of the proppant.

Each embodiment in this specification is described in a progressive manner. The same or similar parts among the various embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for hardware+software implementation embodiments, since they are essentially similar to method embodiments, the description is relatively brief. Please refer to the description of the method embodiments for relevant parts.

The foregoing has described specific embodiments of the present specification. Other embodiments fall within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in an order different from that in the embodiments and still achieve the expected results. Additionally, the processes illustrated in the figures do not necessarily require the illustrated particular order or sequential order to achieve the intended results. In some implementations, multitasking and parallel processing may be possible or advantageous.

Although the present application provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative labor. The step sequence listed in the embodiments is merely one of many possible execution sequences and does not represent the only execution order. In practical implementation of the device or client product, the method may be executed sequentially as shown in the embodiment or figure, or in parallel (for example, in an environment with parallel processors or multithreaded processing).

Although the embodiments of this specification provide method operation steps as described in the embodiments or flowcharts, additional or fewer steps may be included based on conventional or non-creative means. The step order listed in the embodiments is only one of the many possible execution sequences and does not represent the only sequence. In practice, the method may be executed sequentially as illustrated in the embodiments or drawings, or executed in parallel (for example, in a parallel processor or multithreaded processing environment, or even in a distributed data processing environment). The terms “include,” “comprise,” or any variation thereof are intended to cover non-exclusive inclusion, so that a process, method, product, or device that includes a set of elements is not limited to those elements but may include other elements not expressly listed, or elements inherent to such process, method, product, or device. In the absence of further limitations, the inclusion of the aforementioned elements does not exclude the presence of additional identical or equivalent elements.

For ease of description, the above-described devices are divided into various modules based on function. Of course, in the implementation of this specification, the functions of each module may be implemented in one or more software and/or hardware units, or the same function may be realized by a combination of multiple sub-modules or sub-units. The described device embodiments are merely illustrative. For example, the division of the described units is merely based on logical function. Other division methods are possible in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not executed. Moreover, the interconnections or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, and can be electrical, mechanical, or other forms.

It is also known to those skilled in the art that, apart from implementing the controller in the form of purely computer-readable program code, it is entirely possible to implement the same functions by logically programming the method steps using logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), embedded microcontrollers, and the like. Therefore, such a controller can be regarded as a hardware component, and the internal means for implementing various functions can also be regarded as structures within the hardware component. Alternatively, the means for implementing various functions can be regarded as software modules for implementing the method or as structures within the hardware components.

The present application is described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present application. It should be understood that each process and/or block in the flowcharts and/or block diagrams can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device create means for implementing the functions specified in the flowchart process or processes and/or block diagram block or blocks.

Those skilled in art should understand that the embodiments of this specification may be provided as a method, system, or computer program product. Therefore, the embodiments of this specification may take the form of entirely hardware implementations, entirely software implementations, or implementations combining software and hardware. Moreover, the embodiments of this specification may take the form of a computer program product implemented on one or more computer-usable storage media having computer-usable program code embodied thereon, including but not limited to magnetic disks, CD-ROMs, optical memory, and the like.

The embodiments of this specification may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform particular tasks or implement particular abstract data types. The embodiments of this specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communication network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.

Each embodiment in this specification is described in a progressive manner. The same or similar parts among the various embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for system embodiments, since they are essentially similar to method embodiments, the description is relatively brief. Please refer to the description of the method embodiments for relevant parts. In the description of this specification, references to terms such as “an embodiment,” “some embodiments,” “an example,” “a specific example,” or “some examples” mean that specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this specification. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined appropriately in one or more embodiments or examples. Moreover, under the premise of not being contradictory, the technical personnel in the field may combine and integrate the different embodiments or examples and their features described in this specification.

The above description is only illustrative of the embodiments of this specification and is not intended to limit the embodiments. Those skilled in the art can make various modifications and changes to the embodiments of this specification. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the embodiments of this specification shall be included within the scope of the claims of this specification.