Closed drilling fluid cooling equipment and cooling method

Abstract

The invention relates to the technical field of drilling fluid cooling, in particular to closed type drilling fluid cooling equipment and a cooling method, and aims to solve the problems of drilling fluid performance disturbance, constraint of natural environment and water source conditions and high operation power consumption caused by existing cooling equipment. The closed type drilling fluid cooling equipment comprises a cooling liquid cooling system, a heat convection module and a drilling fluid circulating system. The cooling liquid cooling system is communicated with the convective heat exchange module, and the drilling fluid circulating system is communicated with the convective heat exchange module; the cooling liquid cooling system comprises a cooling tower, a cooling-water machine and an air compressor; the cooling tower and the cooling-water machine are used for cooling the cooling liquid, and the air compressor is used for injecting air into the cooling liquid. Comprehensive refrigeration is carried out through various refrigeration devices, disturbance to drilling fluid performance is avoided by adopting the dividing wall type heat exchanger, constraints of natural environment and water source conditions are eliminated, and refrigeration modes can be flexibly selected according to refrigeration requirements so as to reduce operation power consumption.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid cooling, and in particular to closed drilling fluid cooling equipment and a cooling method. Background Art

[0002] There are three main types of drilling fluid cooling equipment commonly used in high-temperature wells: the first type is air-cooled open-type drilling fluid cooling equipment. When working, the sand pump draws the high-temperature drilling fluid to the upper spray system, and sprays the high-temperature drilling fluid downward onto the filler layer through the nozzle to form a layer of water film. The electric fan on the top of the equipment forcibly draws the cold air outside the tank into the tank, and performs contact heat exchange with the high-temperature drilling fluid in the filler. The heated air is discharged out of the tank through the fan. The advantages of the equipment are simple structure and low energy consumption. The disadvantage is that the drilling fluid is in an open cycle, and strong winds will carry part of the water and treatment agent in the drilling fluid system. The drilling fluid has about 2m 3 / h consumption will cause great disturbance to the performance of drilling fluid, increase the difficulty and cost of drilling fluid maintenance. The second type is spray direct cooling closed drilling fluid cooling equipment, generally called mud cooling tower, the working principle is the same as the conventional closed cooling tower, the sand pump transports the high-temperature drilling fluid to the heat exchange tube (tube), and the circulating air or spray water exchanges heat with the drilling fluid to achieve the cooling effect. The advantages are closed circulation of drilling fluid, no loss of drilling fluid, no disturbance in performance, and low energy consumption. The disadvantage is that it depends on water source conditions. The cooling source for cooling comes entirely from clean water (fresh water), which cannot be used in extremely cold and water-scarce areas. In addition, the cooling effect is poor in high temperature environment, and the solid particles of drilling fluid are easy to adhere to the inner wall of the tube, affecting the cooling effect. Once the pipe is blocked, it cannot be cleaned and maintained on site. The third type is the spray indirect cooling closed drilling fluid cooling equipment. First, a closed cooling tower is used to cool the cooling medium (clean water or ethylene glycol aqueous solution). In the heat exchanger (plate heat exchanger or heat pipe heat exchanger), the cooling medium and the drilling fluid are convectively exchanged to achieve the purpose of cooling the drilling fluid. This cooling equipment can solve the problems of scaling in the drilling fluid pipe and on-site maintenance. However, like the second cooling equipment, the cold source comes from clean water, and there are problems such as dependence on water sources and poor cooling capacity in high-temperature environments. Therefore, the existing drilling fluid cooling equipment generally has the following problems: open cooling equipment disturbs the performance of drilling fluid; spray cooling equipment is constrained by the natural environment and water source conditions and cannot achieve full-condition operation; and the operating power consumption is large. Summary of the invention

[0003] The purpose of the present invention is to provide a closed drilling fluid cooling equipment and a cooling method to solve the problems that the existing cooling equipment causes drilling fluid performance disturbance, is constrained by natural environment and water source conditions, and has high operating power consumption.

[0004] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0005] A closed drilling fluid cooling equipment comprises a coolant cooling system, a convection heat exchange module and a drilling fluid circulation system; the coolant cooling system is connected to the convection heat exchange module, and the drilling fluid circulation system is connected to the convection heat exchange module; the coolant cooling system comprises a cooling tower, a chiller and an air compressor; the cooling tower and the chiller are used to cool the coolant, the air compressor is used to inject air into the coolant, the cooling tower is configured as a closed cooling tower, and the chiller is configured as an air-cooled chiller; the convection heat exchange module comprises a partition wall heat exchanger.

[0006] Furthermore, the coolant cooling system also includes a coolant insulation box; the cooling tower and the chiller respectively form a circulation loop with the coolant insulation box, which is used to cool the coolant in the coolant insulation box; the air compressor is connected to the coolant insulation box, which is used to inject air into the coolant in the coolant insulation box; the coolant insulation box is connected to the partition heat exchanger to form a circulation loop.

[0007] Furthermore, the coolant cooling system also includes a first circulating pump and a second circulating pump; the first circulating pump is arranged between the cooling tower and the coolant insulation tank, and is used to drive the coolant to circulate between the cooling tower and the coolant insulation tank; the second circulating pump is arranged between the chiller and the coolant insulation tank, and is used to drive the coolant to circulate between the chiller and the coolant insulation tank.

[0008] Furthermore, the coolant cooling system also includes a coolant circulation pump, which is arranged between the coolant insulation box and the partition wall heat exchanger to drive the coolant to circulate between the coolant insulation box and the partition wall heat exchanger.

[0009] Furthermore, the air compressor is communicated with the partitioning heat exchanger for injecting air into the coolant entering the partitioning heat exchanger.

[0010] Furthermore, the drilling fluid circulation system includes a first drilling fluid tank, a second drilling fluid tank and a drilling fluid circulation pump; the first drilling fluid tank, the second drilling fluid tank, the drilling fluid circulation pump and the partition heat exchanger are connected end to end in sequence to form a circulation loop.

[0011] Furthermore, the drilling fluid circulation system also includes a third drilling fluid tank, a drilling mud pump and a wellbore; the first drilling fluid tank, the second drilling fluid tank, the third drilling fluid tank, the drilling mud pump and the wellbore are connected end to end in sequence to form a circulation loop.

[0012] Furthermore, the closed drilling fluid cooling equipment also includes a control module, which is used to control the start and stop of the first circulation pump, the second circulation pump, the coolant circulation pump and the drilling fluid circulation pump.

[0013] Another aspect of the present invention provides a closed drilling fluid cooling method, using the above-mentioned closed drilling fluid cooling equipment, comprising the following steps:

[0014] Drilling fluid circulation: The drilling mud pump extracts the drilling fluid from the third drilling fluid tank and injects it into the wellbore, and then returns it from the wellhead. The drilling fluid returned from the wellhead enters the first drilling fluid tank and the second drilling fluid tank in turn for solid phase treatment, and the treated drilling fluid enters the third drilling fluid tank;

[0015] Convection heat exchange: When the temperature of the drilling fluid returned from the wellbore exceeds the set temperature, the coolant circulation pump and the drilling fluid circulation pump are started, the coolant circulation pump draws the coolant in the coolant insulation box to the partition heat exchanger, and the drilling fluid circulation pump draws the drilling fluid in the second drilling fluid tank to the partition heat exchanger; after heat exchange, the coolant and drilling fluid return to the coolant insulation box and the first drilling fluid tank respectively;

[0016] Coolant cooling: The coolant cooling system automatically operates according to the set temperature to stabilize the coolant temperature in the coolant insulation box at the set temperature.

[0017] Furthermore, in the cooling step of the coolant:

[0018] When the water supply is sufficient and the ambient temperature is below 0℃, as the cooling demand increases, air compressor refrigeration, air compressor and chiller combined refrigeration are used in turn;

[0019] When the water source is sufficient and the ambient temperature is between 0℃ and 30℃, as the cooling demand increases, air compressor refrigeration, air compressor and chiller refrigeration, air compressor and chiller and cooling tower refrigeration are used in turn;

[0020] When the water supply is sufficient and the ambient temperature is not lower than 30℃, as the cooling demand increases, cooling tower refrigeration, cooling tower and chiller combined refrigeration are used in turn;

[0021] In the absence of water source, when the ambient temperature is below 30℃, as the cooling demand increases, air compressor refrigeration, air compressor and chiller combined refrigeration are used in turn;

[0022] In the absence of water source, when the ambient temperature is higher than 30℃, a water chiller is used for cooling.

[0023] Based on the above technical solutions, the technical effects that can be achieved by the present invention are:

[0024] The closed drilling fluid cooling equipment provided by the present invention comprises a coolant cooling system, a convection heat exchange module and a drilling fluid circulation system; the coolant cooling system is connected to the convection heat exchange module, and the drilling fluid circulation system is connected to the convection heat exchange module; the coolant cooling system comprises a cooling tower, a chiller and an air compressor; the cooling tower and the chiller are used to cool the coolant, the air compressor is used to inject air into the coolant, the cooling tower is configured as a closed cooling tower, and the chiller is configured as an air-cooled chiller; the convection heat exchange module comprises a partition wall heat exchanger.

[0025] The closed drilling fluid cooling equipment provided by the present invention performs comprehensive refrigeration through a variety of refrigeration equipment, and adopts a partition-type heat exchanger to avoid direct contact between the drilling fluid and the coolant, thereby avoiding the disturbance of the cooling equipment on the performance of the drilling fluid. The use of chillers and air compressors for refrigeration is free from the constraints of the natural environment and water source conditions. The cooling tower, chiller and air compressor are flexibly started according to the refrigeration demand to achieve refrigeration in the most economical way, thereby reducing the operating power consumption. In particular, the air compressor injects air into the coolant to form a gas-liquid two-phase flow, which is conducive to increasing the flow rate, thereby forming turbulence in the partition-type heat exchanger to increase the convective heat transfer coefficient, thereby achieving the effect of improving the cooling efficiency and reducing the operating power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic structural diagram of a closed drilling fluid cooling device provided in an embodiment of the present invention.

[0028] Icons: 110-cooling tower; 120-water chiller; 130-air compressor; 140-coolant insulation box; 150-first circulation pump; 160-second circulation pump; 170-coolant circulation pump; 210-partition heat exchanger; 310-first drilling fluid tank; 320-second drilling fluid tank; 330-third drilling fluid tank; 340-drilling mud pump; 350-wellbore; 360-drilling fluid circulation pump. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0032] Existing drilling fluid cooling equipment has problems such as open cooling equipment disturbing the drilling fluid performance, spray cooling equipment being constrained by the natural environment and water source conditions, being unable to achieve full-condition operation, and high operating power consumption.

[0033] In view of this, the present invention provides a closed drilling fluid cooling equipment, including a coolant cooling system, a convection heat exchange module and a drilling fluid circulation system; the coolant cooling system is connected to the convection heat exchange module, and the drilling fluid circulation system is connected to the convection heat exchange module; the coolant cooling system includes a cooling tower 110, a chiller 120 and an air compressor 130; the cooling tower 110 and the chiller 120 are used to cool the coolant, the air compressor 130 is used to inject air into the coolant, the cooling tower 110 is configured as a closed cooling tower 110, and the chiller 120 is configured as an air-cooled chiller 120; the convection heat exchange module includes a partition wall heat exchanger 210.

[0034] The closed drilling fluid cooling equipment provided by the present invention performs comprehensive refrigeration through a variety of refrigeration equipment, and adopts a partition-type heat exchanger 210 to avoid direct contact between the drilling fluid and the coolant, thereby avoiding the disturbance of the cooling equipment on the performance of the drilling fluid. The use of a chiller 120 and an air compressor 130 for refrigeration is free from the constraints of the natural environment and water source conditions. The cooling tower 110, the chiller 120 and the air compressor 130 are flexibly started according to the refrigeration demand to achieve refrigeration in the most economical way, thereby reducing the operating power consumption. In particular, the air compressor 130 injects air into the coolant to form a gas-liquid two-phase flow, which is conducive to increasing the flow rate, thereby forming turbulence in the partition-type heat exchanger 210 to increase the convective heat transfer coefficient, thereby achieving the effect of improving the cooling efficiency and reducing the operating power consumption.

[0035] The following combination Figure 1 The structure and shape of the closed drilling fluid cooling equipment provided in this embodiment are described in detail:

[0036] In an optional solution of this embodiment, the cooling liquid cooling system includes a cooling tower 110, a chiller 120, an air compressor 130, a cooling liquid insulation box 140, a first circulation pump 150, a second circulation pump 160 and a cooling liquid circulation pump 170. Figure 1 As shown, with the coolant insulation tank 140 as the center, a total of three circulation loops are formed. Specifically, the cooling tower 110, the first circulation pump 150 and the coolant insulation tank 140 form a first coolant cooling circulation loop, the cooling tower 110 and the coolant insulation tank 140 are connected by two pipelines, and the first circulation pump 150 is connected in series to one of the pipelines to drive the coolant to circulate between the cooling tower 110 and the coolant insulation tank 140; the chiller 120, the second circulation pump 160 and the coolant insulation tank 140 form a second coolant cooling circulation loop, the chiller 120 and the coolant insulation tank 140 are connected by two pipelines. The partition wall heat exchanger 210 and the coolant insulation tank 140 are connected by two pipes, and the second circulation pump 160 is connected in series to one of the pipes to drive the coolant to circulate between the chiller 120 and the coolant insulation tank 140; the partition wall heat exchanger 210, the coolant circulation pump 170 and the coolant insulation tank 140 form a coolant heat exchange circulation loop, and the partition wall heat exchanger 210 and the coolant insulation tank 140 are connected by two pipes, and the coolant circulation pump 170 is connected in series to one of the pipes to drive the coolant to circulate between the partition wall heat exchanger 210 and the coolant insulation tank 140.

[0037] At the same time, the air compressor 130 is connected to the coolant insulation box 140 and the partition-type heat exchanger 210, respectively, and is used to inject air into the coolant insulation box 140 and the partition-type heat exchanger 210, respectively. The air compressor 130 injects air into the coolant insulation box 140 to cool the coolant, and at the same time forms a gas-liquid two-phase flow with the coolant to accelerate the flow rate and form turbulence, so that the coolant between the cooling tower 110 and the coolant insulation box 140, and between the chiller 120 and the coolant insulation box 140 accelerates the flow rate and forms turbulence, thereby improving the convective heat transfer coefficient and improving the cooling efficiency. Similarly, the air compressor 130 injects air into the coolant entering the partition-type heat exchanger 210 to form a gas-liquid two-phase flow, thereby improving the convective heat transfer coefficient, improving the cooling efficiency and reducing the operating power consumption. Specifically, the coolant circulation pump 170 draws coolant from the coolant insulation box 140 into the partition wall heat exchanger 210 . After the coolant passes through the coolant circulation pump 170 , the air compressor 130 injects air into the coolant to form a gas-liquid two-phase flow, and then the gas-liquid two-phase flow enters the partition wall heat exchanger 210 .

[0038] In this embodiment, the chiller 120 uses air as a cold source, and its operation is not affected by the ambient temperature. It has three working modes, including a natural cold source mode, a hybrid cooling mode, and a mechanical cooling mode. The natural cold source mode is equivalent to air cooling by a fan structure, the hybrid cooling mode is equivalent to dehumidification of an air conditioner, and the mechanical cooling mode corresponds to air conditioning refrigeration, that is, using a compressor for refrigeration. Specifically, the chiller 120 uses an air-cooled magnetic levitation chiller.

[0039] In this embodiment, the cooling tower 110 uses a countercurrent closed cooling tower to ensure the refrigeration effect, improve the refrigeration efficiency and avoid disturbing the drilling fluid performance. The coolant is closed-circulated in the cooling tower 110, which has the advantages of no loss and no pollution. Cooling is mainly carried out by external circulating water spraying.

[0040] In the optional solution of this embodiment, the partition heat exchanger 210 is configured as a detachable plate heat exchanger for easy maintenance and replacement. The heat exchange plate material is a high thermal conductivity ceramic material. Compared with metal materials, ceramic materials can be applied to any mud system and will not cause the problem of reduced heat exchange efficiency due to corrosion of the plate material.

[0041] In this embodiment, an exhaust valve is provided at an appropriate position in the coolant cooling system to discharge an appropriate amount of air filled into the drilling fluid to maintain a constant pressure, thereby avoiding a continuous increase in system pressure as air is filled in, causing safety problems and preventing the air from effectively mixing with the drilling fluid to form turbulence.

[0042] In an optional solution of this embodiment, the drilling fluid circulation system includes a first drilling fluid tank 310, a second drilling fluid tank 320, a third drilling fluid tank 330, a drilling mud pump 340, a wellbore 350 and a drilling fluid circulation pump 360. Figure 1 As shown, the first drilling fluid tank 310, the second drilling fluid tank 320, the third drilling fluid tank 330, the drilling mud pump 340 and the wellbore 350 are connected in sequence to form a drilling fluid working circulation loop; at the same time, the first drilling fluid tank 310, the second drilling fluid tank 320, the drilling fluid circulation pump 360 and the partition wall heat exchanger 210 are connected in sequence to form a drilling fluid heat exchange circulation loop.

[0043] In an optional solution of this embodiment, the closed drilling fluid cooling equipment further includes a control module, which is used to control the start and stop of the first circulation pump 150, the second circulation pump 160, the coolant circulation pump 170 and the drilling fluid circulation pump 360. Accordingly, a temperature sensor can be set at the position where the drilling fluid enters and exits the wellbore 350 to monitor the drilling fluid temperature, thereby providing parameters for the operation of the control module; in addition, a temperature sensor can be set in the coolant insulation box 140 to detect the coolant temperature in real time. Specifically, the control module can be set as a PLC.

[0044] In this embodiment, the coolant can be selected from clean water or ethylene glycol aqueous solution according to the ambient temperature. Clean water is suitable for the case where the ambient temperature is higher than 0°C, and ethylene glycol aqueous solution can be used for the case where the ambient temperature is not greater than 0°C. The temperature of the coolant is usually stably controlled at about 30°C to ensure that the drilling fluid can be cooled in a timely and effective manner. When the air compressor 130 injects air into the coolant and fully mixes it, a gas-liquid two-phase flow is formed, which has the characteristics of fast flow rate, and turbulence can be formed in the partition wall heat exchanger 210 to have a higher convective heat transfer coefficient, thereby improving the heat exchange efficiency, reducing the operating power consumption and the actual working time of the equipment.

[0045] The working process of the closed drilling fluid cooling equipment provided in this embodiment is as follows:

[0046] During high-temperature drilling, the drilling mud pump 340 extracts the drilling fluid from the third drilling fluid tank 330 and injects it into the wellbore 350. After circulating in the wellbore 350, the drilling fluid returns from the wellhead. The drilling fluid returned from the wellhead enters the first drilling fluid tank 310 and the second drilling fluid tank 320 in turn for solid phase treatment, and the treated drilling fluid returns to the third drilling fluid tank 330. When the temperature of the drilling fluid returned from the wellbore 350 exceeds the set temperature or the bottom hole circulation temperature exceeds the high temperature resistance limit of the downhole tool, in order to ensure the smooth implementation of the drilling operation, the coolant circulation pump 170 and the drilling fluid circulation pump 360 are started at the same time, so that the coolant in the coolant insulation box 140 and the drilling fluid in the second drilling fluid tank 320 enter the partition wall heat exchanger 210 for heat exchange to reduce the temperature of the drilling fluid, thereby ensuring the normal progress of the drilling operation. As the convective heat exchange proceeds, the temperature of the drilling fluid will rise. When the temperature of the drilling fluid rises to the set temperature, the coolant cooling system starts to cool the drilling fluid. When the temperature of the drilling fluid in the third drilling fluid tank 330 drops to the set temperature, the convective heat exchange stops, and the coolant circulation pump 170, the air compressor 130 and the drilling fluid circulation pump 360 stop working. As the drilling operation proceeds, the temperature of the drilling fluid in the third drilling fluid tank 330 rises to the set temperature and then continues to convective heat exchange, and this reciprocating cycle is repeated to control the temperature of the drilling fluid.

[0047] Specifically, when the temperature of the drilling fluid returned from the wellbore 350 exceeds 68°C, convection heat exchange is performed to reduce the temperature of the drilling fluid; or when the temperature of the drilling fluid entering the well is higher than 50°C, convection heat exchange is performed to reduce the temperature of the drilling fluid. When the temperature of the drilling fluid entering the well is reduced to 45°C, convection heat exchange is stopped, and the temperature of the drilling fluid entering the well is the temperature of the drilling fluid in the third drilling fluid tank 330. In addition, the temperature setting can set the temperature of the drilling fluid entering the well according to the selected wellbore 350 circulation temperature calculation model to ensure that the downhole temperature can ensure the normal drilling work.

[0048] It should be noted that when the drilling fluid and the coolant exchange heat, the air compressor 130 works simultaneously to form a gas-liquid two-phase flow to improve the heat exchange efficiency, reduce the drilling fluid temperature in time, and ensure the normal progress of the drilling work.

[0049] In this embodiment, when the temperature of the coolant drops to 25°C, the coolant is no longer cooled. As the coolant and the drilling fluid perform convection heat exchange, when the drilling fluid temperature is higher than 30°C, the coolant begins to be cooled, and the drilling fluid temperature is maintained between 25°C and 30°C in this way. When cooling the coolant, one or more of the cooling tower 110, the chiller 120 and the air compressor 130 are selected to work according to the water source conditions and the ambient temperature. That is, the working state of the cooling tower 110, the chiller 120 and the air compressor 130 is determined according to the temperature of the coolant in the coolant insulation box 140 to ensure that the temperature of the coolant is within the set range, and a quick response can be made when convection heat exchange is required to cool the drilling fluid. Flexible selection of refrigeration equipment according to the situation can reduce power consumption and maintain the temperature of the coolant in the best way. Specifically, the control module controls the working state of each circulation loop according to the temperature information to select the cooling method with the lowest energy consumption under the premise of meeting the cooling demand.

[0050] Based on the closed drilling fluid cooling equipment provided in this embodiment, a closed drilling fluid cooling method is proposed, using the above-mentioned closed drilling fluid cooling equipment, including the following steps:

[0051] Drilling fluid circulation: The drilling mud pump 340 extracts the drilling fluid in the third drilling fluid tank 330 and injects it into the wellbore 350. The drilling fluid circulates in the wellbore 350 and then returns to the wellhead. The drilling fluid returned from the wellhead enters the first drilling fluid tank 310 and the second drilling fluid tank 320 in turn for solid phase treatment. The treated drilling fluid enters the third drilling fluid tank 330.

[0052] Convection heat exchange: When the temperature of the drilling fluid returned from the wellbore 350 exceeds the set temperature, the coolant circulation pump 170 and the drilling fluid circulation pump 360 are started, the coolant circulation pump 170 extracts the coolant in the coolant insulation tank 140 to the partition wall heat exchanger 210, and the drilling fluid circulation pump 360 extracts the drilling fluid in the second drilling fluid tank 320 to the partition wall heat exchanger 210; the coolant and the drilling fluid return to the coolant insulation tank 140 and the first drilling fluid tank 310 respectively after heat exchange;

[0053] Cooling of the coolant: The cooling system automatically operates according to the set temperature to stabilize the temperature of the coolant in the coolant insulation box 140 at the set temperature.

[0054] Specifically, the coolant cooling step includes the following situations:

[0055] When the water source is sufficient and the ambient temperature is below 0°C, as the cooling demand increases, two modes are used in sequence: air compressor 130 cooling and air compressor 130 and chiller 120 cooling together. When the chiller 120 is cooling, the natural cold source mode, mixed cooling mode, and mechanical cooling mode can be used in sequence to cooperate with the air compressor 130 according to the increase in cooling demand. Among them, the air compressor 130 can inject air into the coolant insulation box 140 when the ambient temperature is not higher than 30°C to fully mix the air and the coolant, thereby reducing the coolant temperature.

[0056] When the water source is sufficient and the ambient temperature is between 0°C and 30°C, as the cooling demand increases, three modes are used in sequence: air compressor 130 cooling, air compressor 130 and chiller 120 cooling together, and air compressor 130 and chiller 120 and cooling tower 110 cooling together. Specifically, when the air compressor 130 and chiller 120 cool together, the chiller 120 uses the natural cold source mode for cooling; when the air compressor 130 and chiller 120 and cooling tower 110 cool together, the chiller 120 can use the natural cold source mode, the mixed cooling mode, and the mechanical cooling mode for cooling in sequence according to the increase in the cooling demand.

[0057] When the water source is sufficient and the ambient temperature is higher than 30°C, as the cooling demand increases, the cooling tower 110 and the cooling tower 110 and the chiller 120 are used in sequence. When the chiller 120 is cooling, the mixed cooling mode and the mechanical cooling mode can be used in sequence to cooperate with the cooling tower 110 according to the increase in the cooling demand. At this time, the ambient temperature is higher than the set temperature of the coolant, and it is impossible to directly cool down by air cooling, so the natural cold source mode is not used.

[0058] In the absence of a water source, when the ambient temperature is lower than 30°C, as the cooling demand increases, two modes are used in sequence: air compressor 130 cooling, and air compressor 130 and chiller 120 cooling together. When the air compressor 130 and chiller 120 cool together, the chiller 120 can cool in sequence using the natural cooling source mode, the mixed cooling mode, and the mechanical cooling mode according to the increase in the cooling demand.

[0059] In the absence of a water source, when the ambient temperature is not lower than 30°C, the chiller 120 is used for cooling. At this time, the chiller 120 can sequentially use a mixed cooling mode and a mechanical cooling mode for cooling according to the increase in the cooling demand.

[0060] The closed drilling fluid cooling equipment and cooling method provided in this embodiment have the following advantages:

[0061] 1. It can be applied to any working conditions and is not restricted by ambient temperature and water source conditions.

[0062] 2. The cooling process of the drilling fluid is a closed cycle of inter-wall convection heat exchange. There is no loss of drilling fluid during the convection heat exchange process and there is no disturbance to the performance of the drilling fluid.

[0063] 3. The cooling medium is a gas-liquid two-phase flow of coolant and air that is fully mixed. The flow rate in the heat exchanger is fast and turbulence can be formed, so it has a higher convective heat transfer coefficient.

[0064] 4. The convection heat exchange process can be automated. When the temperature of the drilling fluid entering the well is higher than the set temperature, the coolant circulation pump 170, the air compressor 130 and the drilling fluid circulation pump 360 are started, and the drilling fluid and the cooling medium begin to convection heat exchange. When the temperature of the drilling fluid entering the well drops to a certain range below the set temperature, the coolant circulation pump 170, the air compressor 130 and the drilling fluid circulation pump 360 are shut down, and this process is repeated, thereby stabilizing the temperature of the drilling fluid entering the well at a low temperature, avoiding idling of the equipment, and reducing operating power consumption.

[0065] 5. The operating parameters of the convective heat transfer process can be automatically selected. According to the set drilling fluid inlet temperature, the optimal coolant circulation displacement, air compressor 130 air volume and drilling fluid circulation displacement are automatically selected based on the convective heat transfer calculation model.

[0066] 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. A closed drilling fluid cooling equipment, characterized in that: It includes a coolant cooling system, a convection heat exchange module and a drilling fluid circulation system; The cooling liquid cooling system is in communication with the convection heat exchange module, and the drilling fluid circulation system is in communication with the convection heat exchange module; The coolant cooling system comprises a cooling tower (110), a chiller (120) and an air compressor (130); The cooling tower (110) and the water chiller (120) are used to cool the coolant, the air compressor (130) is used to inject air into the coolant, the cooling tower (110) is configured as a closed cooling tower, and the water chiller (120) is configured as an air-cooled water chiller; The countercurrent heat exchange module includes a partitioning heat exchanger (210).

2. The closed drilling fluid cooling equipment according to claim 1, characterized in that: The coolant cooling system also includes a coolant insulation box (140); The cooling tower (110) and the chiller (120) respectively form a circulation loop with the coolant insulation box (140) for cooling the coolant in the coolant insulation box (140); The air compressor (130) is in communication with the coolant insulation box (140) and is used to inject air into the coolant in the coolant insulation box (140); The coolant insulation tank (140) is connected to the partition heat exchanger (210) to form a circulation loop.

3. The closed drilling fluid cooling equipment according to claim 2, characterized in that: The coolant temperature reduction system further comprises a first circulation pump (150) and a second circulation pump (160); The first circulation pump (150) is disposed between the cooling tower (110) and the coolant insulation tank (140), and is used to drive the coolant to circulate between the cooling tower (110) and the coolant insulation tank (140); The second circulation pump (160) is arranged between the water chiller (120) and the coolant insulation tank (140), and is used to drive the coolant to circulate between the water chiller (120) and the coolant insulation tank (140).

4. The closed drilling fluid cooling equipment according to claim 3, characterized in that: The coolant cooling system further comprises a coolant circulation pump (170), which is arranged between the coolant insulation box (140) and the partition-type heat exchanger (210) and is used to drive the coolant to circulate between the coolant insulation box (140) and the partition-type heat exchanger (210).

5. The closed drilling fluid cooling equipment according to claim 4, characterized in that: The air compressor (130) is in communication with the partition-type heat exchanger (210) and is used to inject air into the coolant entering the partition-type heat exchanger (210).

6. The closed drilling fluid cooling equipment according to claim 5, characterized in that: The drilling fluid circulation system comprises a first drilling fluid tank (310), a second drilling fluid tank (320) and a drilling fluid circulation pump (360); The first drilling fluid tank (310), the second drilling fluid tank (320), the drilling fluid circulation pump (360) and the partitioning heat exchanger (210) are connected end to end in sequence to form a circulation loop.

7. The closed drilling fluid cooling equipment according to claim 6, characterized in that: The drilling fluid circulation system further includes a third drilling fluid tank (330), a drilling mud pump (340) and a wellbore (350); The first drilling fluid tank (310), the second drilling fluid tank (320), the third drilling fluid tank (330), the drilling mud pump (340) and the wellbore (350) are connected end to end in sequence to form a circulation loop.

8. The closed drilling fluid cooling equipment according to claim 7, characterized in that: It also includes a control module, which is used to control the start and stop of the first circulation pump (150), the second circulation pump (160), the coolant circulation pump (170) and the drilling fluid circulation pump (360).

9. A closed drilling fluid cooling method, using the closed drilling fluid cooling equipment as claimed in claim 8, characterized in that: The steps include: Drilling fluid circulation: the drilling mud pump (340) extracts the drilling fluid in the third drilling fluid tank (330) and injects it into the wellbore (350), and then returns it from the wellhead. The drilling fluid returned from the wellhead enters the first drilling fluid tank (310) and the second drilling fluid tank (320) in sequence for solid phase treatment, and the treated drilling fluid enters the third drilling fluid tank (330); Convective heat exchange: when the temperature of the drilling fluid returned from the wellbore (350) exceeds the set temperature, the coolant circulation pump (170) and the drilling fluid circulation pump (360) are started, the coolant circulation pump (170) draws the coolant in the coolant insulation box (140) into the partition wall heat exchanger (210), and the drilling fluid circulation pump (360) draws the drilling fluid in the second drilling fluid tank (320) into the partition wall heat exchanger (210); After heat exchange between the coolant and the drilling fluid, the coolant returns to the coolant insulation box (140) and the first drilling fluid tank (310) respectively; Cooling of the coolant: The coolant cooling system automatically operates according to the set temperature to stabilize the temperature of the coolant in the coolant insulation box (140) at the set temperature.

10. The closed drilling fluid cooling method according to claim 9, characterized in that: In the cooling liquid cooling step: When the water source is sufficient and the ambient temperature is below 0°C, as the cooling demand increases, the air compressor (130) is used for cooling, and the air compressor (130) and the water chiller (120) are used for cooling together in sequence; When the water source is sufficient and the ambient temperature is between 0°C and 30°C, as the cooling demand increases, the air compressor (130) is used for cooling, the air compressor (130) and the water chiller (120) are used together for cooling, and the air compressor (130) and the water chiller (120) and the cooling tower (110) are used together for cooling in sequence; When the water source is sufficient and the ambient temperature is higher than 30° C., as the cooling demand increases, the cooling tower (110) is used for cooling, and the cooling tower (110) and the chiller (120) are used for cooling together in sequence; In the absence of a water source, when the ambient temperature is lower than 30° C., as the cooling demand increases, the air compressor (130) is used for refrigeration, and the air compressor (130) and the water chiller (120) are used for refrigeration together; In the absence of a water source, when the ambient temperature is not lower than 30° C., the water chiller (120) is used for refrigeration.

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