Intelligent testing method for conductivity of fracturing proppant

Abstract

The present invention relates to the technical field of oil and gas field development, and in particular to an intelligent testing method for the conductivity of a fracturing proppant, which aims to solve the problems that the existing testing methods are all manual, time-consuming and labor-intensive, and have low test accuracy and long experimental cycles. The intelligent testing method for the conductivity of a fracturing proppant automatically completes data collection through application software, construction equations, and intelligent fuzzy control, and uses a method combining data collection with fuzzy control by a computer, which saves manpower, greatly improves the calculation accuracy and objectivity, overcomes the problems of low test accuracy and long experimental cycles, improves the test accuracy of permeability and conductivity, and strongly supports the development of on-site fracturing technology.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to an intelligent testing method for the conductivity of a fracturing proppant. Background Art

[0002] Fracturing proppant is an important material used in the fracturing process during oil field development. The performance of fracturing proppant is directly related to the fracture conductivity under closing pressure, and plays a very important role in formation fracturing.

[0003] In the SY / T 6302-2019 test method for the conductivity of fracturing proppants, the test methods are all manual, which consumes a lot of time and energy, and has disadvantages such as low test accuracy and long experimental cycle. Summary of the invention

[0004] The invention provides an intelligent testing method for the conductivity of a fracturing proppant, aiming to solve the problems that the existing testing methods are manual, time-consuming and labor-intensive, and have low testing accuracy and long experimental cycles.

[0005] In order to achieve the above object, the present invention provides an intelligent testing method for the conductivity of a fracturing proppant, the method comprising:

[0006] An intelligent testing method for the conductivity of a fracturing proppant, characterized in that the method comprises:

[0007] The API holder is propped with proppant at a concentration of 10 kg / m 2 ;

[0008] Through closed-loop control, the pressure of the press is stabilized;

[0009] After the API flow channel and manifold are vacuumed for more than 30 minutes, liquid saturation is performed at multiple points;

[0010] Apply different closing pressures to the API diversion trough according to the experimental requirements and stabilize the pressure for more than 15 minutes according to the closed-loop control;

[0011] The displacement pump is adjusted at different displacement flow rates. The equations are constructed based on the Darcy equation Forchheimer, the semi-empirical formula Kozeny-Carman equation and the Ergun equation. The flow stability is judged based on the modified Reynolds number Re'. The Kozeny-Carman equation is:

[0012]

[0013] Among them, the Forchheimer Equation equation is:

[0014]

[0015] Among them, C0-constant; ρ w - density of displacement fluid; g- acceleration due to gravity; μ- viscosity of displacement fluid; P E - effective porosity; d p - aperture;

[0016] Among them, the Ergun equation is:

[0017]

[0018] Among them, R e ′-Reynolds number; ρ-displacing fluid density; u-flow rate; P E - effective porosity; μ - displacement fluid viscosity;

[0019] Calculate the permeability and conductivity, where the permeability is calculated as:

[0020]

[0021] The calculation formula of flow conductivity is:

[0022]

[0023] Where, k-permeability, μ-displacement fluid viscosity; Q-flow rate; L-flow length; A-flow cross-sectional area; ΔP-pressure difference; kw f -Flow conductivity.

[0024] In the above-mentioned intelligent testing method for the conductivity of the fracturing proppant, optionally, the pressure of the press is stabilized by closed-loop control, specifically:

[0025] Apply a closing pressure of 3500 kPa to the API diversion trough and maintain the pressure steady for more than 15 minutes.

[0026] In the above-mentioned intelligent test method for the conductivity of fracturing proppants, it is optional that the flow stability judgment is performed according to the corrected Reynolds number Re', specifically:

[0027] When the Reynolds number R e When ′<10, the flow state of the fluid is Darcy flow, that is, laminar flow; when R e When ′>10, the flow state of the fluid reaches the turbulence judgment condition, and the flow rate is intelligently fuzzy controlled.

[0028] The intelligent testing method for the conductivity of fracturing proppants provided by the present invention automatically completes data collection through application software, construction equations, and intelligent fuzzy control, and uses a method that combines data collection with fuzzy control by computer, thereby saving manpower and greatly improving calculation accuracy and objectivity, overcoming the problems of low test accuracy and long experimental cycle, improving the test accuracy of permeability and conductivity, and strongly supporting the development of on-site fracturing technology.

[0029] The construction of the present invention and other objects and advantageous effects thereof will become more apparent through the description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic flow chart of an intelligent testing method for the conductivity of a fracturing proppant provided in an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of intelligent fuzzy control of an intelligent testing method for the conductivity of fracturing proppants provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0034] like Figure 1 As shown, the present invention provides an intelligent testing method for the conductivity of a fracturing proppant, the method comprising:

[0035] Step 110: Place proppant on the API holder, wherein the proppant concentration is 10 kg / m 2 ;

[0036] It should be noted that API is the abbreviation of the American Petroleum Institute, and its standards are implemented.

[0037] Step 120: Stabilize the pressure of the press through closed-loop control, specifically:

[0038] Apply a closing pressure of 3500 kPa to the API diversion trough and maintain the pressure steady for more than 15 minutes.

[0039] It should be noted that PID control is adopted, and the controller forms a closed loop according to the target pressure and the actual pressure, and loads to the target pressure at a rate of 3500kPa / min to stabilize the pressure; compare the target pressure P0 with the real-time detection pressure P i , within 15 minutes | P0-P i |≤0.01MPa is considered stable.

[0040] It should be noted that PID (Proportional Integral Derivative) control is one of the earliest developed control strategies. Among closed-loop control strategies, PID control is widely used in industrial process control due to its simple algorithm, good robustness and high reliability.

[0041] The acquisition control software installed on the computer uses the CAN protocol to fully automatically control the constant pressure of the press, and can carry out short-term and long-term flow capacity test experiments. The Controller Area Network (CAN) is a serial communication protocol bus for real-time applications. It can use twisted pair cables to transmit signals and is one of the most widely used field buses in the world. The CAN protocol is used for communication between different components.

[0042] Step 130: After the API flow channel and the manifold are vacuumed for more than 30 minutes, liquid saturation is performed at multiple points;

[0043] Step 140: applying different closing pressures to the API diversion groove according to experimental requirements and performing pressure stabilization for more than 15 minutes according to closed-loop control;

[0044] Step 150: Adjust the displacement flow rate of the displacement pump, set the flow rate to 2.5 ml / min, construct equations based on the Darcy equation Forchheimer, the semi-empirical formula Kozeny-Carman equation and the Ergun equation, and make a flow stability judgment based on the modified Reynolds number Re', where the Kozeny-Carman equation is:

[0045]

[0046] Among them, the Forchheimer Equation equation is:

[0047]

[0048] Among them, C0-constant; ρ w - density of displacement fluid; g- acceleration due to gravity; μ- viscosity of displacement fluid; P E - effective porosity; d p - aperture;

[0049] Among them, the Ergun equation is:

[0050]

[0051] Among them, R e ′-Reynolds number; ρ-displacing fluid density; u-flow rate; P E - effective porosity; μ - displacement fluid viscosity;

[0052] Specifically, when the Reynolds number R e When ′<10, the flow state of the fluid is Darcy flow, that is, laminar flow; when R e When ′>10, the flow state of the fluid reaches the turbulence judgment condition, and the flow is intelligently fuzzy controlled, such as Figure 2 As shown, Qr represents the input flow and Qk represents the controlled output flow.

[0053] It should be noted that the acquisition control software installed on the computer adjusts the displacement pump to different displacement flow rates through the CAN protocol, and calculates the permeability and conductivity after the flow rate stabilizes.

[0054] Step 160: Calculate the permeability and conductivity, where the calculation formula for the permeability is:

[0055]

[0056] The calculation formula of flow conductivity is:

[0057]

[0058] Where, k-permeability, μ-displacement fluid viscosity; Q-flow rate; L-flow length; A-flow cross-sectional area; ΔP-pressure difference; kw f -Flow conductivity.

[0059] The displacement flow rate of the displacement pump is adjusted to 5 ml / min, and steps 150 and 160 are repeated.

[0060] The displacement flow rate of the displacement pump is adjusted to 10 ml / min, and steps 150 and 160 are repeated.

[0061] The intelligent testing method for the conductivity of fracturing proppants provided by the present invention automatically completes data collection through application software, construction equations, and intelligent fuzzy control, and uses a method that combines data collection with fuzzy control by computer, thereby saving manpower and greatly improving calculation accuracy and objectivity, overcoming the problems of low test accuracy and long experimental cycle, improving the test accuracy of permeability and conductivity, and strongly supporting the development of on-site fracturing technology.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent testing method for the conductivity of a fracturing proppant, characterized in that: The method comprises: The API holder is propped with proppant at a concentration of 10 kg / m 2 ; Through closed-loop control, the pressure of the press is stabilized; After the API flow channel and manifold are vacuumed for more than 30 minutes, liquid saturation is performed at multiple points; Apply different closing pressures to the API diversion trough according to the experimental requirements and stabilize the pressure for more than 15 minutes according to the closed-loop control; The displacement pump is adjusted at different displacement flow rates. The equations are constructed based on the Darcy equation Forchheimer, the semi-empirical formula Kozeny-Carman equation and the Ergun equation. The flow stability is judged based on the modified Reynolds number Re'. The Kozeny-Carman equation is: Among them, the Forchheimer Equation equation is: Among them, C0-constant; ρ w - density of displacement fluid; g- acceleration due to gravity; μ- viscosity of displacement fluid; P E - effective porosity; d p - aperture; Among them, the Ergun equation is: Among them, R e ′-Reynolds number; ρ-displacing fluid density; u-flow rate; P E - effective porosity; μ - displacement fluid viscosity; Calculate the permeability and conductivity, where the permeability is calculated as: The calculation formula of flow conductivity is: Where, k-permeability, μ-displacement fluid viscosity; Q-flow rate; L-flow length; A-flow cross-sectional area; ΔP-pressure difference; kw f -Flow conductivity; The pressure of the press is stabilized by closed-loop control, specifically: Apply 3500kPa closing pressure to the API diversion trough and maintain pressure stability for more than 15 minutes; Among them, PID control is adopted, and the controller forms a closed loop according to the target pressure and the actual pressure, and loads to the target pressure at a rate of 3500kPa / min to stabilize the pressure; compare the target pressure P0 and the real-time detection pressure Pi, and it is considered stable if |P0-Pi|≤0.01MPa within 15 minutes.

2. The intelligent testing method for the conductivity of fracturing proppant according to claim 1, characterized in that: The flow stability judgment based on the corrected Reynolds number Re' is specifically: When the Reynolds number R e When ′<10, the flow state of the fluid is Darcy flow, that is, laminar flow; when R e When ′>10, the flow state of the fluid reaches the turbulence judgment condition, and the flow rate is intelligently fuzzy controlled.

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