Drilling fluid waste heat power generation system and method

Abstract

The invention provides a drilling fluid waste heat power generation system and method. The system comprises a drilling fluid waste heat power generation device and a drilling fluid circulating cooling device. The drilling fluid waste heat power generation device comprises a heat exchanger, a turbine, a condenser, a working medium collector and a working medium liquid pump which are sequentially connected, and further comprises a power generator connected with the turbine. The drilling fluid circulating cooling device comprises a heat exchanger shared with the drilling fluid waste heat power generation device, and further comprises a drilling fluid cooling device, a drilling fluid circulating device and a drilling fluid pump which are sequentially connected with the heat exchanger. The circulating temperature of the drilling fluid can be effectively reduced under the condition that the well site space is limited, and waste heat of the drilling fluid can be effectively utilized for power generation.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling fluid waste heat utilization, and in particular to a drilling fluid waste heat power generation system and method. Background Art

[0002] During deep well drilling, the bottom hole temperature is high, generally exceeding 150°C, and sometimes even exceeding 180°C, which has a great impact on bottom hole instruments, especially precision instruments such as rotary guides. Since these instruments have many internal electronic components and are extremely sensitive to temperature, they will fail if they are in a high temperature environment for a long time. At this time, the drill needs to be pulled out for replacement, and the loss of drilling time is huge due to the high daily cost of these high-end instruments. At the same time, the treatment agent in the drilling fluid will also withstand the test of long-term high temperature, and will undergo serious degradation or other reactions at high temperatures, resulting in deterioration of the drilling fluid performance.

[0003] Under deep well conditions, the temperature of the drilling fluid returning to the surface is high, about 60-90°C. Oil-based drilling fluid consumes heat mainly in the form of evaporation, which increases the well site temperature while reducing the water content in the drilling fluid. As a low-temperature heat source, it is currently urgent to find an effective technology that can utilize the waste heat of the drilling fluid while reducing the temperature of the drilling fluid at the bottom of the well. Summary of the invention

[0004] In order to solve the technical problem of how to reduce the temperature of drilling fluid at the bottom of the well while reducing the utilization of drilling fluid, the present invention proposes a drilling fluid waste heat power generation system and method.

[0005] In a first aspect, an embodiment of the present invention provides a drilling fluid waste heat power generation system, comprising:

[0006] The drilling fluid waste heat power generation device comprises a heat exchanger 1, a turbine 2, a generator 11, a condenser 12, a working fluid collector 13 and a working fluid liquid pump 3; the heat exchanger 1 is used to perform heat exchange between the circulating working fluid and the drilling fluid flowing out from the drilling fluid ground inlet and outlet 7, and utilize the waste heat of the drilling fluid to convert the circulating working fluid from liquid to gas; the turbine 2 is used to utilize the gaseous circulating working fluid output by the heat exchanger 1 to perform mechanical expansion work to drive the generator 11 to generate electricity; the condenser 12 is used to cool and condense the circulating working fluid discharged by the turbine 2 into liquid circulating working fluid, and store it in the working fluid collector 13; the working fluid liquid pump 3 is used to pump the liquid circulating working fluid stored in the working fluid collector 13 into the heat exchanger 1 for continued circulation;

[0007] The drilling fluid circulation cooling device includes a heat exchanger 1 shared with the drilling fluid waste heat power generation device, and also includes a drilling fluid cooling device 4, a drilling fluid circulation device 5 and a drilling fluid pump 6; the drilling fluid cooling device 4 is used to further cool the drilling fluid output by the heat exchanger 1; the drilling fluid circulation device 5 is used to purify, store and adjust the performance of the drilling fluid after being cooled by the drilling fluid cooling device 4; the drilling fluid pump 6 is used to pump the drilling fluid in the drilling fluid circulation device 5 into the well through the drilling fluid ground inlet and outlet 7 for continued circulation.

[0008] In some implementations, the heat exchanger 1 includes at least one of a drilling fluid waste heat radiator and a drilling fluid low-temperature waste heat exchanger.

[0009] In some implementations, the drilling fluid waste heat radiator includes a heat exchange tube 16 and an inner tube arranged in the heat exchange tube 16, the heat exchange tube 16 is provided with a circulating working fluid inlet 17 for liquid circulating working fluid to flow in and a circulating working fluid 18 for gaseous circulating working fluid to flow out; the inner tube is provided with a high-temperature drilling fluid inlet 14 for drilling fluid to flow in and a high-temperature drilling fluid outlet 19 for drilling fluid to flow out; the heat exchange tube 16 is connected to a plurality of heat exchange plates 15, and the heat exchange plates 15 are used to perform heat exchange between the circulating working fluid in the heat exchange tube 16 and the drilling fluid in the inner tube.

[0010] In some implementations, the heat exchange fins are columnar heat exchange fins or sheet-shaped heat exchange fins.

[0011] In some implementations, the spacing between adjacent heat exchange fins is greater than or equal to 10 centimeters.

[0012] In some implementations, the cooling method adopted by the drilling fluid cooling device 4 includes at least one of air cooling, water cooling, and heat pump cooling.

[0013] In some implementations, the drilling fluid circulation device 5 includes a combination of at least two of the following equipment: a vibrating screen, a desander, a desilter, a centrifuge, a circulation tank, a reserve tank, a weighting pump, a solid recovery device, and a feed port.

[0014] In some implementations, the drilling fluid cooling device 4 is connected to the input end of the turbine 2, and the turbine 2 is also used to perform mechanical expansion and work using the gaseous circulating working fluid output by the drilling fluid cooling device 4;

[0015] Alternatively, the drilling fluid cooling device 4 is connected to the input end of the condenser 12, and the condenser 12 is also used to cool the gaseous circulating working fluid output by the drilling fluid cooling device 4 and condense it into liquid circulating working fluid.

[0016] In some implementations, a first coupling 8, a gearbox 9, and a second coupling 10 are sequentially provided between the turbine 2 and the generator 11; the first output end of the turbine 2 is connected to the first coupling 8; the first coupling 8 is also connected to the input shaft of the gearbox 9; the output shaft of the gearbox 9 is connected to the second coupling 10; and the second coupling 10 is connected to the generator 11.

[0017] In a second aspect, an embodiment of the present invention provides a drilling fluid waste heat power generation method based on the above-mentioned drilling fluid waste heat power generation system, comprising:

[0018] The drilling fluid flowing through the drilling fluid surface inlet and outlet 7 enters the heat exchanger 1 and dissipates heat to the liquid circulating medium. The cooled drilling fluid enters the drilling fluid cooling device 4 and is further cooled. Then, the drilling fluid circulating device 5 purifies, stores and adjusts the performance of the drilling fluid further cooled by the drilling fluid cooling device 4. Finally, the drilling fluid pump 6 pumps the drilling fluid in the drilling fluid circulating device 5 into the well through the drilling fluid surface inlet and outlet 7 for continued circulation.

[0019] The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat exchanger 1 by absorbing the heat emitted by the drilling fluid in the heat exchanger 1; the gaseous circulating working fluid enters the turbine 2 for mechanical expansion and work, thereby driving the generator 11 to generate electricity; after working, the circulating working fluid discharged from the turbine 2 is cooled and condensed into a liquid circulating working fluid in the condenser 12, and stored in the working fluid collector 13, and then the working fluid liquid pump 3 pumps the liquid circulating working fluid in the working fluid collector 13 into the heat exchanger 1 for continued circulation.

[0020] One or more embodiments of the present invention bring at least the following beneficial effects:

[0021] The present invention can effectively reduce the circulation temperature of the drilling fluid under space constraints at the well site and effectively utilize the waste heat of the drilling fluid to generate electricity through the connection method of each device in the drilling fluid waste heat power generation device and the drilling fluid circulation cooling device, as well as the corresponding modification of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0023] Figure 1 A schematic diagram of a drilling fluid waste heat power generation system provided by an embodiment of the present invention;

[0024] Figure 2A schematic diagram of a heat exchanger provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] 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 only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0026] Embodiment 1

[0027] This embodiment provides a drilling fluid waste heat power generation system, including a drilling fluid waste heat power generation device and a drilling fluid circulation cooling device.

[0028] like Figure 1As shown, the drilling fluid waste heat power generation device includes a heat exchanger 1, a turbine 2, a generator 11, a condenser 12, a working fluid collector 13 and a working fluid liquid pump 3. The heat exchanger 1 is used to perform heat exchange between the circulating working fluid and the drilling fluid flowing out of the drilling fluid ground inlet and outlet 7, and convert the circulating working fluid from a liquid state to a gaseous state by using the waste heat of the drilling fluid. The turbine 2 is used to perform mechanical expansion work by using the gaseous circulating working fluid output by the heat exchanger 1 to drive the generator 11 to generate electricity. Specifically, a first coupling 8, a gear box 9 and a second coupling 10 are sequentially arranged between the turbine 2 and the generator 11. The first output end of the turbine 2 is connected to the first coupling 8; the first coupling 8 is also connected to the input shaft of the gear box 9; the output shaft of the gear box 9 is connected to the second coupling 10; and the second coupling 10 is connected to the generator 11. The condenser 12 is used to cool the circulating working medium discharged from the turbine 2 and condense it into a liquid circulating working medium, and store it in the working medium collector 13. The working medium liquid pump 3 is used as the circulating power source of the drilling fluid waste heat power generation device, and is used to pump the liquid circulating working medium stored in the working medium collector 13 into the heat exchanger 1 for continuous circulation. The circulation process of the circulating working medium in the drilling fluid waste heat power generation device is as follows: the liquid circulating working medium absorbs heat from the drilling fluid in the heat exchanger 1 to generate steam with a certain pressure and temperature, and the steam enters the turbine 2 for mechanical expansion and work, thereby driving the generator 11 to generate electricity or drive other power machinery to work through the power transmission of the first coupling 8, the gear box 9, and the second coupling 10; the circulating working medium discharged from the turbine 2 releases heat to the cooling water in the condenser 12 in the condenser 12, condenses into a liquid state, is stored in the working medium collector 13, and finally returns to the heat exchanger 1 with the help of the working medium liquid pump 3 to continue circulation.

[0029] like Figure 1As shown, the drilling fluid circulation cooling device includes a heat exchanger 1 shared with the drilling fluid waste heat power generation device, and also includes a drilling fluid cooling device 4, a drilling fluid circulation device 5 and a drilling fluid pump 6. The drilling fluid cooling device 4 is used to further cool the drilling fluid output by the heat exchanger 1. The drilling fluid circulation device 5 is used to purify, store and adjust the performance of the drilling fluid after cooling by the drilling fluid cooling device 4. Specifically, the drilling fluid circulation device 5 includes a combination of at least two devices selected from the group consisting of a vibrating screen, a desander, a desilter, a centrifuge, a circulation tank, a reserve tank, a weighting pump, a solid recovery device, and a feed port. The drilling fluid pump 6 is used to pump the drilling fluid in the drilling fluid circulation device 5 into the well through the drilling fluid ground inlet and outlet 7 for continued circulation. The drilling fluid pump 6 is the main power source in the drilling fluid circulation cooling device, and can be divided into a low-pressure pump and a high-pressure pump. The low-pressure pump can make the fluid pressure of the drilling fluid reach 0 to 30 MPa. The high-pressure pump can make the fluid pressure of the drilling fluid reach 0-60Mpa. The drilling fluid circulation process of the drilling fluid circulation cooling device refers to the drilling fluid flowing out from the drilling fluid ground inlet and outlet 7, which is cooled down in turn through the heat exchanger 1 and the drilling fluid cooling device 4, and then purified, stored and performance adjusted by the drilling fluid circulation device 5, and then enters the wellbore through the drilling fluid pump 6, the faucet, the drill pipe, etc., and finally reaches the bottom of the well along the drill pipe, the bottom-hole precision instruments, the drill bit, etc., and then returns from the bottom of the well through the downhole annulus to the drilling fluid ground inlet and outlet 7 to enter the heat exchanger 1.

[0030] In one implementation, the heat exchanger includes at least one of a drilling fluid waste heat radiator and a drilling fluid low-temperature waste heat exchanger. Figure 2As shown, the drilling fluid waste heat radiator includes a heat exchange tube 16 and an inner tube arranged in the heat exchange tube 16. The heat exchange tube 16 is provided with a circulating medium inlet 17 for the inflow of liquid circulating medium and a circulating medium 18 for the output of gaseous circulating medium. The inner tube is provided with a high-temperature drilling fluid inlet 14 for the inflow of drilling fluid and a high-temperature drilling fluid outlet 19 for the outflow of drilling fluid. The heat exchange tube 16 is connected with a plurality of heat exchange fins 15. The heat exchange fins 15 are used to perform heat exchange between the circulating medium in the heat exchange tube 16 and the drilling fluid in the inner tube. The heat exchange fins 15 can be columnar heat exchange fins or sheet heat exchange fins. Since the drilling fluid returned from the bottom of the well carries a large amount of solid phase, and the particle size of the solid phase particles varies from 0.1 μm to 10 cm, the spacing between adjacent heat exchange fins 15 is greater than or equal to 10 cm or the heat exchange fins 15 are connected in an easy-to-disassemble manner, so as to facilitate the cleaning of solid phase particles. The drilling fluid waste heat radiator adopts an internal and external dual circulation mode. Internal circulation: the high-temperature drilling fluid returned from the drilling fluid ground inlet and outlet 7 is input into the inner tube through the high-temperature drilling fluid inlet 14, and heat exchange is performed with the circulating medium through the inner tube wall and the heat exchange plate 15 in the inner tube, and then connected to the drilling fluid cooling device 4 through the high-temperature drilling fluid outlet 19; the circulating medium in the heat exchange tube 16 enters through the circulating medium inlet 17, and heat exchanges with the high-temperature drilling fluid through the inner tube wall and the heat exchange plate 15, and then output to the turbine 2 through the circulating medium outlet 18.

[0031] In one implementation, the drilling fluid cooling device 4 uses air cooling, water cooling, heat pump cooling and other cooling methods to further reduce the temperature of the drilling fluid returning to the bottom of the well, protect the downhole precision instruments and equipment, and solve the problem that the number of heat exchangers is insufficient or the drilling fluid temperature at the outlet is lower than the working temperature of the circulating working medium due to the limitation of the drilling site, so that the drilling fluid temperature cannot be reduced to the temperature required for effectively protecting the downhole precision instruments. The air cooling method is to cool the drilling fluid by using a large number of fans to form a strong wind. The water cooling method is to use a large amount of circulated clean water to close the contact with the pipeline where the drilling fluid is located to achieve heat exchange and cool the drilling fluid. The heat pump cooling method is to use a heat pump to transfer the heat energy in the drilling fluid to the power generation device or the heat dissipation device. The drilling fluid cooling device 4 in this embodiment is connected to the input end of the turbine 2, and the turbine 2 is also used to use the gaseous circulating working medium output by the drilling fluid cooling device 4 to perform mechanical expansion work. Alternatively, the drilling fluid cooling device 4 is connected to the input end of the condenser 12, and the condenser 12 is also used to cool the gaseous circulating working medium output by the drilling fluid cooling device 4 and condense it into a liquid circulating working medium.

[0032] In one implementation, the circulating working fluid generally uses a working fluid with a boiling point of 0 to 30°C for the ORC Rankine cycle. The circulating working fluid can use a circulating working fluid with a high boiling point, such as water, to achieve cooling or waste heat power generation. The circulating working fluid can also use a working fluid with a lower boiling point, such as carbon dioxide or liquid air or liquid nitrogen, etc. The boiling point of the working fluid is as low as -196°C, which can achieve heat source power generation above 10°C. For safety reasons, when a working fluid with a lower boiling point is used, the working fluid liquid pump 3 needs to be replaced with a supercritical gas turbine for a cryogenic working fluid. Both the heat exchanger 1 and the working fluid collector 13 need to be modified accordingly, such as adding protective equipment and using a pressure vessel with high-efficiency thermal insulation and heat insulation for storing cryogenic working fluids, the protective equipment including a pressure limiting valve and a safety valve. At the same time, the pipeline used to transport the circulating working fluid in the drilling fluid waste heat power generation device uses a cryogenic pipe, and a throttle valve is provided on the cryogenic pipe.

[0033] The system provided in this embodiment can increase the amount of waste heat power generation and reduce carbon emissions. Taking a vertical depth of 4000m to 5000m deep extended displacement well or horizontal well as an example, the bottom hole temperature is 180℃, the surface outlet temperature is 90℃, and the drilling fluid waste heat power generation system is used. A well can save 90,720 yuan in electricity bills per day. If the drilling time from directional drilling is 50 days, the rotary directional drilling time is 40 days, and the drilling fluid waste heat power generation system is used, the drilling fluid temperature drops to 40℃ after heat exchange, the drilling fluid exchange displacement is 20L / s, and the specific heat capacity of water is 4200J / kg.℃. By calculation, the recovered drilling fluid waste heat is 1.45×1013J. Calculated at an electric energy conversion efficiency of 10%, the generated electricity is 4.032×105kWh. The current national implementation is the difference in peak electricity charges. Calculated at 0.6 yuan / kWh, the electricity bill savings are 241,920 yuan. According to 1kWh = 860kCal, 1kg standard coal heat = 7000kCal, converted to 1kWh of electricity = 860 / 7000 = 0.1229kg standard coal heat, generating one kilowatt-hour of electricity is equivalent to consuming 323g standard coal. Further, according to the "carbon (C)" emission coefficient of "carbon dioxide (CO2)" generated by the complete combustion of 1 ton of standard coal, each ton of standard coal brings 2.4567 tons of carbon dioxide emissions, and the carbon dioxide emissions of generating one kilowatt-hour of electricity are 793.5141g CO2, so each extended reach well or horizontal well reduces carbon emissions by 480.076t.

[0034] The system provided in this embodiment can reduce the economic losses caused by the failure of high-end instruments such as rotary steering. The pure drilling time of a single well with rotary steering is 40 days. If this technology is not used, it may be necessary to replace the drill bit, or it may be necessary to replace other more advanced (higher temperature resistant) instruments, which may increase the use time of the rotary steering drilling tool by 30 to 40 days. Calculated at a daily fee of 200,000 yuan / day, the daily cost loss of replacing the drilling tool due to the high temperature downhole is 200,000 yuan / day×35 days=7 million yuan.

[0035] The system provided in this embodiment can reduce construction costs. Unlike the commonly used low-temperature waste heat power generation system that can achieve utilization value at a water temperature of about 80°C, the system provided in this embodiment mainly saves the daily cost of cooling the drilling fluid. The daily cost of cooling the drilling fluid is about 200,000 yuan for 15 days, and the system provided in this embodiment can realize device power generation, reduce carbon emissions, and significantly reduce construction costs.

[0036] In summary, the present invention reduces carbon emissions through waste heat power generation, reduces economic losses caused by failure of high-end instruments such as rotary guides, improves drilling construction efficiency, and reduces construction costs.

[0037] The system provided in this embodiment realizes the circulation process of the circulating medium through the connection between the heat exchanger 1, the turbine 2, the generator 11, the condenser 12 and the condensate reservoir 13, and realizes the use of the waste heat of the drilling fluid to generate electricity. In addition, by connecting the ground inlet and outlet 7 of the drilling fluid to the heat exchanger 1, the heat exchanger 1 is connected to the drilling fluid cooling device 4, the drilling fluid cooling device 4 is connected to the drilling fluid circulation device 5, the drilling fluid circulation system 5 is connected to the drilling fluid pump 6, and the drilling fluid pump 6 is connected to the ground inlet and outlet 7 of the drilling fluid, a circulating cooling of the drilling fluid is formed, which effectively solves the problem that the number of heat exchangers is insufficient due to the limitation of the drilling site or the drilling fluid temperature at the outlet is lower than the working temperature of the circulating medium, thereby failing to reduce the drilling fluid temperature to the temperature required to effectively protect the bottom hole precision instruments.

[0038] Embodiment 2

[0039] This embodiment provides a drilling fluid waste heat power generation method based on the drilling fluid waste heat power generation system according to the first embodiment, comprising:

[0040] The drilling fluid flowing through the drilling fluid surface inlet and outlet 7 enters the heat exchanger 1 and dissipates heat to the liquid circulating medium. The cooled drilling fluid enters the drilling fluid cooling device 4 and is further cooled. Then, the drilling fluid circulating device 5 purifies, stores and adjusts the performance of the drilling fluid further cooled by the drilling fluid cooling device 4. Finally, the drilling fluid pump 6 pumps the drilling fluid in the drilling fluid circulating device 5 into the well through the drilling fluid surface inlet and outlet 7 for continued circulation.

[0041] The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat exchanger 1 by absorbing the heat emitted by the drilling fluid in the heat exchanger 1; the gaseous circulating working fluid enters the turbine 2 for mechanical expansion and work, thereby driving the generator 11 to generate electricity; after working, the circulating working fluid discharged from the turbine 2 is cooled and condensed into a liquid circulating working fluid in the condenser 12, and stored in the working fluid collector 13, and then the working fluid liquid pump 3 pumps the liquid circulating working fluid in the working fluid collector 13 into the heat exchanger 1 for continued circulation.

[0042] The method provided in this embodiment can reduce the surface drilling fluid temperature from 80°C to 90°C at the outlet to 30°C to 40°C; at the same time, the circulating temperature of the drilling fluid at the bottom of the well can be reduced to 10°C to 20°C, effectively protecting the precision instruments at the bottom of the well and slowing down the degradation of the drilling fluid treatment agent, solving the problem of space limitation at the well site and the problem of difficulty in utilizing waste heat.

[0043] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely illustrative.

[0044] It should be noted that, in this article, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0045] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A drilling fluid waste heat power generation system, It is characterized in that include: A drilling fluid waste heat power generation device comprises a heat exchanger (1), a turbine (2), a generator (11), a condenser (12), a working fluid collector (13) and a working fluid liquid pump (3); the heat exchanger (1) is used to perform heat exchange between a circulating working fluid and drilling fluid flowing out of a drilling fluid ground inlet and outlet (7), and utilize the waste heat of the drilling fluid to convert the circulating working fluid from a liquid state into a gaseous state; the turbine (2) is used to utilize the gaseous circulating working fluid output by the heat exchanger (1) to perform mechanical expansion work to drive the generator (11) to generate electricity; the condenser (12) is used to cool the circulating working fluid discharged by the turbine (2) to condense it into a liquid circulating working fluid, and store it in the working fluid collector (13); the working fluid liquid pump (3) is used to pump the liquid circulating working fluid stored in the working fluid collector (13) into the heat exchanger (1) for continued circulation; The drilling fluid circulation cooling device comprises a heat exchanger (1) used in common with the drilling fluid waste heat power generation device, and also comprises a drilling fluid cooling device (4), a drilling fluid circulation device (5) and a drilling fluid pump (6); the drilling fluid cooling device (4) is used to further cool the drilling fluid output by the heat exchanger (1); the drilling fluid circulation device (5) is used to purify, store and adjust the performance of the drilling fluid after being cooled by the drilling fluid cooling device (4); the drilling fluid pump (6) is used to pump the drilling fluid in the drilling fluid circulation device (5) into the well through a drilling fluid ground inlet and outlet (7) for continued circulation.

2. The drilling fluid waste heat power generation system according to claim 1, It is characterized in that The heat exchanger (1) comprises at least one of a drilling fluid waste heat radiator and a drilling fluid low-temperature waste heat exchanger.

3. The drilling fluid waste heat power generation system according to claim 2, It is characterized in that The drilling fluid waste heat radiator comprises a heat exchange tube (16) and an inner tube arranged in the heat exchange tube (16); the heat exchange tube (16) is provided with a circulating working medium inlet (17) for liquid circulating working medium to flow in and a circulating working medium (18) for gaseous circulating working medium to flow out; the inner tube is provided with a high-temperature drilling fluid inlet (14) for drilling fluid to flow in and a high-temperature drilling fluid outlet (19) for drilling fluid to flow out; the heat exchange tube (16) is connected to a plurality of heat exchange fins (15), and the heat exchange fins (15) are used to perform heat exchange between the circulating working medium in the heat exchange tube (16) and the drilling fluid in the inner tube.

4. The drilling fluid waste heat power generation system according to claim 3, It is characterized in that The heat exchange fins are columnar heat exchange fins or sheet-shaped heat exchange fins.

5. The drilling fluid waste heat power generation system according to claim 3, It is characterized in that The distance between adjacent heat exchange fins is greater than or equal to 10 cm.

6. The drilling fluid waste heat power generation system according to claim 1, It is characterized in that The cooling method adopted by the drilling fluid cooling device (4) includes at least one of air cooling, water cooling and heat pump cooling.

7. The drilling fluid waste heat power generation system according to claim 1, It is characterized in that The drilling fluid circulation device (5) comprises a combination of at least two of the following equipment: a vibrating screen, a desander, a desilter, a centrifuge, a circulation tank, a reserve tank, a weighting pump, a solid recovery device, and a feed port.

8. The drilling fluid waste heat power generation system according to claim 1, It is characterized in that The drilling fluid cooling device (4) is connected to the input end of the turbine (2), and the turbine (2) is also used to use the gaseous circulating working fluid output by the drilling fluid cooling device (4) to perform mechanical expansion and work; Alternatively, the drilling fluid cooling device (4) is connected to the input end of the condenser (12), and the condenser (12) is also used to cool the gaseous circulating working fluid output by the drilling fluid cooling device (4) to condense it into liquid circulating working fluid.

9. The drilling fluid waste heat power generation system according to claim 1, It is characterized in that A first coupling (8), a gear box (9) and a second coupling (10) are arranged in sequence between the turbine (2) and the generator (11); the first output end of the turbine (2) is connected to the first coupling (8); the first coupling (8) is also connected to the input shaft of the gear box (9); the output shaft of the gear box (9) is connected to the second coupling (10); and the second coupling (10) is connected to the generator (11).

10. A drilling fluid waste heat power generation method based on the drilling fluid waste heat power generation system according to any one of claims 1 to 9, It is characterized in that include: The drilling fluid flowing through the drilling fluid surface inlet and outlet (7) enters the heat exchanger (1) and dissipates heat to the liquid circulating medium. The cooled drilling fluid enters the drilling fluid cooling device (4) and is further cooled. The drilling fluid circulating device (5) then purifies, stores and adjusts the performance of the drilling fluid that has been further cooled by the drilling fluid cooling device (4). Finally, the drilling fluid pump (6) pumps the drilling fluid in the drilling fluid circulating device (5) through the drilling fluid surface inlet and outlet (7) into the well for continued circulation. The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat exchanger (1) by absorbing the heat emitted by the drilling fluid in the heat exchanger (1); the gaseous circulating working fluid enters the turbine (2) to undergo mechanical expansion and perform work, thereby driving the generator (11) to generate electricity; after performing work, the circulating working fluid discharged from the turbine (2) is cooled and condensed into a liquid circulating working fluid in the condenser (12), and stored in the working fluid collector (13); then the working fluid liquid pump (3) pumps the liquid circulating working fluid in the working fluid collector (13) into the heat exchanger (1) for continued circulation.

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