A thermal balance design method and system for underground circuits

Abstract

The present invention relates to the technical field of thermal balance design of downhole instruments for oil drilling, and in particular to a thermal balance design method and system for downhole circuits. The method comprises calculating the area S of a circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of a single component in the circuit board. 和 Dual constraints, both heat generation and area, are set. Within these constraints, the number and type of sensor components are selected, the component combinations are determined, and the layout and distribution of the sensor components on the circuit board are completed. The system includes an acquisition module, a calculation module, and a layout module. This method and system effectively solves the problem of optimizing the layout of sensor components, which cannot be quantified through quantitative calculation, and can achieve temperature rise control for downhole instruments.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal balance design of downhole instruments for oil drilling, and in particular to a thermal balance design method and system for downhole circuits. Background Art

[0002] With the increasing complexity of oil and gas exploration and development objects, well depths are constantly increasing, and high temperature and high pressure are becoming more common. The ultra-deep (7000m), high temperature (above 175°C), and high pressure (above 140MPa) target layers pose higher challenges to drilling equipment and tools. The demand for downhole instruments that can withstand high temperatures of 175°C and above is growing.

[0003] Considering the heat generation of the instrument itself, if downhole instruments are required to withstand temperatures exceeding 175°C, the temperature rating of electronic components, chips, and other components must reach 200°C or higher, approaching the upper limit of their thermal resistance. Therefore, developing downhole circuit thermal balance design to control and reduce the temperature rise of components is a key technical approach to improving the temperature resistance of downhole instruments. Current thermal balance designs for downhole instruments primarily suppress temperature rise by improving the thermal conductivity of sealants and distributing heat-generating components.

[0004] In the prior art, a Chinese invention patent document with publication number CN107864550A and publication date of March 30, 2018, is proposed. The technical solution disclosed in the patent document is as follows: a method for manufacturing a circuit board based on microelement thermal balance, wherein a hollow plate is stacked on the insulating substrate, and the hollow pattern of the hollow plate corresponds to the conductive pattern of the prefabricated circuit board; a metal conductive material is magnetron sputtered on the hollow plate of the composite structure, and after the hollow plate is removed, a circuit layer is formed on the insulating substrate; and a circuit layer is covered on the circuit layer. Insulating layer; attaching the high thermal conductivity sheet on the bottom surface of the circuit layer; then covering the outer surface of the high thermal conductivity sheet with a graphite heat absorption and heat storage plate; aligning and stacking multiple manufactured circuit boards in sequence along their thickness direction; placing multiple aligned and stacked circuit boards in a mixing and pressing groove, buried through holes, and a baking plate; evacuating the processing room, introducing Ar into the processing room, and removing the glue by ions; after the circuit board is hot-melted, placing a high-frequency sub-board and a copper block in the mixing and pressing groove and the buried through hole respectively, and stacking copper foil at the bottom, and then pressing them together to firmly bond the high-frequency sub-board, copper block, copper foil and circuit board together.

[0005] In the prior art, a Chinese invention patent document with publication number CN114264692A and publication date of April 1, 2022 has been proposed. The technical solution disclosed in the patent document is as follows: a method for simultaneously measuring the thermal conductivity and emissivity of micro-nano materials. The measurement method mainly includes: (1) using a dual hot wire structure to simultaneously measure the thermal conductivity and emissivity of polymer composite fibers. (2) gluing the two ends of the sample to be tested to the center position of two parallel platinum wires (dual hot wires) respectively, comparing the changes in the average temperature rise of the hot wires before and after being attached to the sample to be tested, obtaining the heat conducted by the heating end hot wire to the test wire and the heat obtained by the receiving end hot wire, and determining the thermal conductivity and emissivity of the test wire. (3) Measure the thermal conductivity of a single platinum wire (λ = 71.7 W•m -1 •K -1 ) and emissivity (ε=0.14) are consistent with the reference values; the thermal conductivity and emissivity of the polymer composite fiber are measured to be 1.67W•m -1 •K -1 and 0.45.

[0006] In the prior art, a Chinese invention patent document with publication number CN114221470A, published on March 22, 2022, discloses the following technical solution: a motor cooling structure comprising a housing and a rotor. The housing is provided with a coolant inlet, a housing flow channel, and a coolant outlet. A rotor cavity is provided in the middle of the rotor, and a liquid-spinning hole is provided on the rotor sidewall. The coolant inlet, housing flow channel, rotor cavity, liquid-spinning hole, and coolant outlet are sequentially connected. Coolant enters the housing through the coolant inlet and cools the motor housing as it flows through the housing flow channel. The coolant continues to flow from the housing flow channel into the rotor cavity in the middle of the rotor, cooling the rotor. The coolant then flows through the axial flow channel of the rotor punching to cool the rotor assembly. It is then ejected from the pressure plate outlet to cool the windings and ultimately discharged from the coolant outlet of the housing. During the flow of the coolant, the rotor and windings of the motor are sequentially cooled, effectively reducing the temperature of the motor and helping it maintain efficient operation.

[0007] During actual use of the above technical solutions, the following problems will arise: the above technical solutions all achieve temperature rise control through additional cooling mechanisms and a large amount of simulation analysis, which is not suitable for downhole drilling instruments. At the same time, there is a lack of quantitative design methods for thermal balance of drilling instruments. The guidance method for the dispersed layout of heating devices is mainly based on experience, lacks quantitative evaluation and calculation basis, and it is difficult to guide the optimization of the layout of device components. Summary of the Invention

[0008] To solve the above technical problems, the present invention proposes a thermal balance design method and system for downhole circuits, which can effectively solve the problem of optimizing the layout of the guide components that cannot be quantified by quantitative calculation, and can realize the temperature rise control of downhole instruments.

[0009] The present invention is achieved by adopting the following technical solutions:

[0010] A thermal balance design method for underground circuits, characterized by comprising the following steps:

[0011] Calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of each component in the circuit board. 和 ;

[0012] Set the dual constraints of heat output and area, select the number and type of components under these constraints, and determine the combination of components:

[0013] ;

[0014] Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself;

[0015] According to S 需 ≥Q 和 / (T×h×λ) principle, complete the layout and distribution of the device components on the circuit board, and complete the thermal balance design of the downhole instrument;

[0016] Where T is the temperature rise control target; h is the circuit board sealing height; and λ is the thermal conductivity of the sealant.

[0017] If the number of combinations is greater than or equal to 1, then in the combination mode that meets the necessary components, the area and S 和 Under the minimum constraint condition, that is, , determine the number and type of unique device components.

[0018] The specific calculation method of the area S of the circuit board is:

[0019] S= L×D,

[0020] Where L is the length of the board boundary, and D is the width of the board boundary.

[0021] The specific calculation method of the effective heat transfer Q that can be achieved by a single circuit board is:

[0022] Q=S×T×h×λ,

[0023] Where S is the area of the circuit board, T is the temperature rise control target, h is the height of the circuit board sealant, and λ is the thermal conductivity of the sealant.

[0024] The heat generation power and Q of a single component in the circuit board 和 The calculation method is:

[0025] Q 和 =Q 自 +I 2 R, Q 自 is the heat generation power of a single device component in the downhole working state, R is the resistance of the external connection wire around the device component, and I is the current passing through;

[0026] Therefore, the dual constraints are:

[0027] .

[0028] A system for thermal balance design of underground circuits, characterized by comprising:

[0029] An acquisition module is used to obtain parameters of the circuit board and parameters of individual components;

[0030] The calculation module is used to calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heating power and Q of a single component in the circuit board based on the parameters obtained by the acquisition module. 和 ;

[0031] The layout module is used to select the number and type of components that can be carried on a single circuit board based on the dual constraints of heat generation and area, determine the combination of components, and then calculate the number and type of components based on S 需 ≥Q 和 / (T×h×λ) principle, the layout and distribution of the device components on the circuit board are completed, where the dual constraints are:

[0032] .

[0033] It also includes an optimization module, which is used to meet the combination mode of the necessary components. Principle, determine the number and type of unique device components.

[0034] The parameters of the circuit board include the boundary size of the circuit board and the thermal conductivity of the sealant.

[0035] The parameters of the single component include the heating power of the single component in the downhole working state is Q 自 , the external connection resistance around the device component is R and the current passing through it is I.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention can achieve quantitative design of the thermal balance of downhole instrument circuits. By adopting a full-process closed-loop calculation method, accurate analysis of each circuit component is achieved, which is conducive to discovering and breaking through key weaknesses, improving the temperature resistance of downhole instruments, and meeting the needs of high-temperature environments. At the same time, it reduces the need for simulation iterative calculations, shortens the design and development cycle by about 5%, and reduces development costs.

[0038] 2. The present invention proposes a method for quantitative calculation using the heating power of the device components and the heat dissipation efficiency per unit area, which can quantitatively guide the optimal layout of the device components and realize the temperature rise control of the downhole instrument.

[0039] 3. The dual constraints established in this invention determine the combination of components. Furthermore, specific principles are used to determine the distribution and arrangement of individual components on the circuit board, finalizing the design of the circuit board. This principle ensures that heat generated by the components can be dissipated promptly within the target temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0041] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0042] Example 1

[0043] As a basic embodiment of the present invention, the present invention includes a thermal balance design method for downhole circuits, comprising the following steps:

[0044] Calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of each component in the circuit board. 和 .

[0045] Set the dual constraints of heat output and area, select the number and type of components under these constraints, and determine the combination of components:

[0046] ;

[0047] Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself.

[0048] According to S 需 ≥Q 和 / (T×h×λ) principle is followed to complete the layout and distribution of the components on the circuit board and the thermal balance design of the downhole instrument; where T is the temperature rise control target; h is the circuit board sealing height, and λ is the thermal conductivity of the sealant.

[0049] Example 2

[0050] As a preferred embodiment of the present invention, the present invention includes a thermal balance design method for downhole circuits, comprising the following steps:

[0051] Calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of each component in the circuit board. 和 .

[0052] Set the dual constraints of heat output and area, select the number and type of components under these constraints, and determine the combination of components:

[0053] ;

[0054] Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself.

[0055] According to S 需 ≥Q 和 / (T×h×λ) principle, the layout and distribution of the device components on the circuit board are completed, and the thermal balance design of the downhole instrument is completed.

[0056] Where T is the temperature rise control target; h is the circuit board sealing height; and λ is the thermal conductivity of the sealant.

[0057] If too many combinations are selected, that is, the number of combinations is greater than or equal to 1, then the combination mode that meets the necessary components is selected. Principle, determine the number and type of unique device components.

[0058] Example 3

[0059] As another preferred embodiment of the present invention, the present invention includes a system for thermal balance design of downhole circuits, comprising:

[0060] The acquisition module is used to obtain the parameters of the circuit board and the parameters of individual components.

[0061] The calculation module is used to calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heating power and Q of a single component in the circuit board based on the parameters obtained by the acquisition module.和 .

[0062] The layout module is used to select the number and type of components that can be carried on a single circuit board based on the dual constraints of heat generation and area, determine the combination of components, and then calculate the number and type of components based on S 需 ≥Q 和 The layout and distribution of the components on the circuit board are completed according to the principle of / (T×h×λ); the dual constraints are:

[0063] .

[0064] Optimization module, the optimization module is used to meet the combination mode of the necessary components, Principle, determine the number and type of unique device components.

[0065] Example 4

[0066] As the best embodiment of the present invention, refer to the attached Figure 1 The present invention includes a thermal balance design method for downhole circuits. The circuit board of the downhole instrument while drilling is often installed in a closed electronic compartment. The compartment is encapsulated with a thermally conductive sealant to fix the circuit board and completely fill the gaps in the compartment. The compartment is located on the drill collar, and the entire drill collar is surrounded by the drilling fluid in the well. The drilling fluid and the drill collar can be considered to be at the same temperature. Therefore, the heat exchange between the circuit board and the outside world is transferred by the thermally conductive sealant to the metal drill collar and the drilling fluid. The thermal balance design method specifically includes the following steps:

[0067] Calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of each component in the circuit board. 和 .

[0068] When designing a PCB board, based on the analysis of the drill collar's stress strength, the board's boundary dimensions will be determined in advance: L meters in length and D meters in width. Then the area of a single circuit board is S=L×D, in square meters.

[0069] Assume the system temperature rise control target is T°C, which is the temperature difference between the PCB and the metal drill collar; the sealant thermal conductivity is λ, measured in watts per meter degree (W / (m·K)); and the PCB sealant height is h meters, which is the thermal conduction distance between the PCB and the metal drill collar. Thermal conductivity refers to the amount of heat transferred through a 1-square-meter area over a given period of time under stable heat transfer conditions, given a 1-degree (K) temperature difference across the two surfaces of a 1-meter-thick material. Here, K can be replaced by °C. The temperature rise control target and PCB sealant height are both design inputs.

[0070] Based on the assumptions, the effective heat transfer that a single circuit board can achieve is Q=S×T×h×λ, expressed in watts.

[0071] In order to achieve the set temperature rise control target, the thermal power Q of a single circuit board itself is 热 ≤Q, which ensures that the heat generated by the circuit board can be transferred to the drilling fluid in time for circulation, ensuring that the system temperature rise does not exceed the set T value.

[0072] According to the manual of the device components, we know that the heat generation power of a single device component in the underground working state is Q 自 The resistance of the external wiring around the device component is R, and the current passing through it is I, so the total heat power of a single device component is Q 和 =Q 自 +I 2 R.

[0073] To ensure the temperature rise control target, according to the effective heat transfer calculation formula, the area of ​​the single component that needs to be laid out on the circuit board is S 需 ≥Q 和 / (T×h×λ).

[0074] Set dual constraints of heat output and area, select the number and type of components under these constraints, and determine the combination of components. Type refers to different types of components, such as resistors and capacitors. There are multiple types of products with the same function. The dual constraints are:

[0075] ,

[0076] Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself.

[0077] If too many combinations are selected, that is, the number of combinations is greater than or equal to 1, then in the combination mode that meets the necessary components, the area and S 和 Under the minimum constraint condition, that is, , determine the number and types of unique components. Essential components are determined based on different circuit design requirements. Some components are unique to different circuit designs and are considered essential. Some components are considered optional if multiple components can achieve the same function.

[0078] According to S 需 ≥Q 和 / (T×h×λ) principle is followed to complete the layout and distribution of the components on the circuit board, thereby completing the thermal balance design of the downhole instrument.

[0079] Take the downhole while-drilling instrumentation currently involved in this work as an example. The circuit board is 25 cm long and 6 cm wide, and the height of the circuit board sealant is 6 cm. The sealant has a thermal conductivity of 200 W / m.°C, and the target temperature rise is 10°C.

[0080] A single circuit board is available for efficient heat transfer:

[0081] Q=S×T×h×λ=0.25×0.06×10×0.06×200=1.8W.

[0082] The heat output of a single component operating underground is approximately 0.1-0.3W, and the number of components can be selected from 6 to 18. The area of a single component is 0.003 m2. Based on the area distribution size restrictions, the maximum number of components that can be selected is 0.25 × 0.06 / 0.003 = 5. Taking into account the dual restriction principle, five components are selected. The heat transfer within the 0.003 m2 area is 0.003 × 10 × 0.06 × 200 = 0.36W, which is greater than the component's own heat output and meets the thermal conductivity requirements. Therefore, based on the component type, five components are laid out on the circuit board, completing the circuit thermal balance design.

[0083] A system used in the above-mentioned thermal balance design method for downhole circuits, the system may include:

[0084] The acquisition module is used to acquire the parameters of the circuit board and the parameters of the individual components. The parameters of the circuit board include the boundary size of the circuit board and the thermal conductivity of the sealant. The parameters of the individual components include the heat generation power of the individual components in the underground working state, Q 自 , the external connection resistance around the device component is R and the current passing through it is I.

[0085] The calculation module is used to calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heating power and Q of a single component in the circuit board based on the parameters obtained by the acquisition module. 和 .

[0086] The layout module is used to select the number and type of components that can be carried on a single circuit board based on the dual constraints of heat generation and area, determine the combination of components, and then calculate the number and type of components based on S 需 ≥Q 和 The layout and distribution of the components on the circuit board are completed according to the principle of / (T × h × λ). The dual constraints are:

[0087] .

[0088] Optimization module, the optimization module is used to meet the combination mode of the necessary components, Principle, determine the number and type of unique device components.

[0089] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, which all fall within the scope of protection of the present invention.

Claims

1. A thermal balance design method for downhole circuits, characterized by: The following steps are involved: Calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heat generation power and Q of each component in the circuit board. 和 ; Set the dual constraints of heat output and area, select the number and type of components under these constraints, and determine the combination of components: ； Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself; If the number of combinations is greater than or equal to 1, then in the combination mode that meets the necessary components, the area and S 和 Under the minimum constraint condition, that is, , determine the number and type of unique device components; According to S 需 ≥Q 和 / (T×h×λ) principle, complete the layout and distribution of the device components on the circuit board, and complete the thermal balance design of the downhole instrument; Where T is the temperature rise control target; h is the circuit board sealing height; and λ is the thermal conductivity of the sealant.

2. A thermal balance design method for downhole circuits according to claim 1, characterized in that: The specific calculation method of the area S of the circuit board is: S=L×D, Where L is the length of the board boundary, and D is the width of the board boundary.

3. The thermal balance design method for underground circuits according to claim 1, characterized in that: The specific calculation method of the effective heat transfer Q that can be achieved by a single circuit board is: Q=S×T×h×λ, Where S is the area of the circuit board, T is the temperature rise control target, h is the height of the circuit board sealant, and λ is the thermal conductivity of the sealant.

4. The thermal balance design method for underground circuits according to claim 1, characterized in that: The heat generation power and Q of a single component in the circuit board 和 The calculation method is: Q 和 =Q 自 +I 2 R, The Q 自 is the heat generation power of a single device component in the downhole working state, R is the resistance of the external connection wire around the device component, and I is the current passing through; Therefore, the dual constraints are: 。 5. A system for thermal balance design of underground circuits, characterized by: include: An acquisition module is used to obtain parameters of the circuit board and parameters of individual components; The calculation module is used to calculate the area S of the circuit board, the effective heat transfer Q that can be achieved by a single circuit board, and the heating power and Q of a single component in the circuit board based on the parameters obtained by the acquisition module. 和 ; The layout module is used to select the number and type of components that can be carried on a single circuit board based on the dual constraints of heat generation and area, and determine the combination of components; Optimization module, used to meet the combination mode of necessary components in terms of area and S 和 Under the minimum constraint condition, that is, , determine the number and type of unique device components; Layout module, also used according to S 需 ≥Q 和 / (T×h×λ) principle, the layout and distribution of the device components on the circuit board are completed; The dual constraints are: ； Where i represents the i-th component, n represents the total number of components on a single circuit board, S 需 S is the area that a single device component needs to be laid out on the circuit board. 和 is the area of the components in the circuit board, Q 热 is the heat power of a single circuit board itself.

6. The system for thermal balance design of underground circuits according to claim 5, characterized in that: The parameters of the circuit board include the boundary size of the circuit board and the thermal conductivity of the sealant.

7. The system for thermal balance design of underground circuits according to claim 5, characterized in that: The parameters of the single component include the heating power of the single component in the downhole working state is Q 自 , the external connection resistance around the device component is R and the current passing through it is I.

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