Drilling fluid waste heat utilization system and method based on drilling well site

Abstract

The invention provides a drilling fluid waste heat utilization system based on a drilling well site, which is arranged at a drilling well outlet and comprises a drilling fluid waste heat utilization device and a drilling fluid waste heat utilization power generation device, the drilling fluid waste heat utilization device comprises a heat dissipation circulation tank, a circulation tank group and a drilling fluid working medium pump which are connected in sequence; the drilling fluid waste heat utilization power generation device comprises a heat dissipation circulation tank, a turbine, a power generator, a condenser, a condensate reservoir and a working medium liquid pump. The heat exchange area of the drilling fluid can be increased, the contact heat exchange time with the drilling fluid can be prolonged, and the problems that due to drilling well site space limitation, cooling of the drilling fluid on the ground is insufficient, and waste heat of the drilling fluid is difficult to utilize are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal energy utilization, and in particular to a system and method for utilizing waste heat of drilling fluid based on a drilling well site. Background Art

[0002] During deep well drilling, the high temperature at the bottom of the well has a significant impact on the precision instruments at the bottom of the well. Some components need to be pulled out of the well for replacement, which increases the rental cost of high-end instruments, reduces drilling efficiency, and increases working hours. The treatment agents in the drilling fluid will undergo severe degradation or other reactions at high temperatures, causing the drilling fluid performance to deteriorate.

[0003] The cooling technology used in drilling adopts natural cooling, water cooling, and air cooling. The cooling efficiency of the natural cooling method is low and it is usually used when the bottom temperature of the well is not high. The water cooling method wastes a lot of water resources. The air cooling method requires high energy consumption. The water cooling method and the air cooling method alone cannot meet the bottom temperature cooling requirements of high-temperature wells, so they are usually required to cooperate to reduce the ground drilling fluid temperature from 80℃ to 90℃ at the outlet to about 40℃. However, the cost is high, the area is large, and there is no power generation effect, which wastes the high-temperature heat at the bottom of the well.

[0004] The drilling fluid returned from the wellhead carries a large amount of coarse solid particles. At present, most drilling fluid cooling devices are washed by the coarse particles of unpurified drilling fluid, which reduces their durability. In addition, most drilling fluid cooling devices are either too large and limited in use due to space constraints at the well site; or the contact time is too short and the drilling fluid cooling capacity is low. At present, there is an urgent need to find an effective technology that can reduce the high temperature of drilling fluid and utilize the waste heat of drilling fluid without being restricted by well site space. Summary of the invention

[0005] In order to solve the technical problem that the heat exchanger is in short contact with the drilling fluid due to space limitations at the drilling site, the drilling fluid is not sufficiently cooled on the ground, and the precision instruments at the bottom of the well cannot be protected, the present invention proposes a drilling fluid waste heat utilization system and method based on the drilling site.

[0006] In a first aspect, an embodiment of the present invention provides a drilling fluid waste heat utilization system based on a drilling well site, which is arranged at the outlet of a drilling well, and includes a drilling fluid waste heat utilization device and a drilling fluid waste heat utilization power generation device;

[0007] The drilling fluid waste heat utilization device comprises a heat dissipation circulation tank, a circulation tank group and a drilling fluid working medium pump which are connected in sequence; the heat dissipation circulation tank is used to perform heat exchange between the circulating working medium and the drilling fluid flowing out from the drilling fluid surface outlet of the drilling well site, and utilize the waste heat of the drilling fluid to convert the circulating working medium from liquid to gas; the circulation tank group is used to store and filter impurities of the drilling fluid after being cooled by the heat dissipation circulation tank; the drilling fluid working medium pump is used to pump the drilling fluid in the circulation tank group into the drilling well through the drilling fluid surface inlet of the drilling well site for continuous circulation;

[0008] The drilling fluid waste heat utilization power generation device includes a heat dissipation circulation tank shared with the drilling fluid waste heat utilization device, and also includes a turbine, a generator, a condenser, a condensate reservoir and a working fluid liquid pump. The turbine is used to utilize the gaseous circulating working fluid output by the heat dissipation circulation tank to perform mechanical expansion work to drive the generator to generate electricity; the condenser is used to cool the circulating working fluid discharged by the turbine to condense it into liquid circulating working fluid, and store it in the condensate reservoir; the working fluid liquid pump is used to pump the liquid circulating working fluid stored in the condensate reservoir into the heat dissipation circulation tank for continued circulation.

[0009] In some implementations, the heat dissipation circulation tank includes:

[0010] A flow channel, used for guiding the drilling fluid flowing through the drilling fluid surface outlet to the heat dissipation circulation tank;

[0011] A heat exchanger is arranged in the flow channel, and the heat exchanger contacts and exchanges heat with the drilling fluid in the heat dissipation circulation tank;

[0012] A working fluid liquid inlet, for the inflow of liquid circulating working fluid;

[0013] Working fluid liquid outlet, used for outputting gaseous circulating working fluid;

[0014] The drilling fluid outlet is connected to the inlet of the circulation tank group and is used to input the drilling fluid cooled by the heat dissipation circulation tank into the circulation tank group.

[0015] In some implementations, the heat dissipation circulation tank further includes a drilling fluid mixer, and the drilling fluid mixer is used to stir the drilling fluid in the heat dissipation circulation tank.

[0016] In some implementations, the heat exchanger includes heat exchange tubes or heat exchange fins.

[0017] In some implementations, a first coupling, a gearbox, and a second coupling are sequentially provided between the turbine and the generator; the first output end of the turbine is connected to the first coupling; the first coupling is also connected to the input shaft of the gearbox; the output shaft of the gearbox is connected to the second coupling; and the second coupling is connected to the generator.

[0018] In some implementations, the circulating working fluid includes carbon dioxide, or liquid air, or liquid nitrogen.

[0019] In some implementations, the pipeline for conveying the circulating working medium in the drilling fluid waste heat utilization power generation device adopts a cryogenic pipe, and a throttle valve is provided on the cryogenic pipe;

[0020] The working fluid liquid pump adopts a supercritical gas turbine;

[0021] The heat dissipation circulation tank and the condensate reservoir are both provided with a pressure vessel and a protection device, and the protection device includes a pressure limiting valve or a safety valve.

[0022] In a second aspect, an embodiment of the present invention provides a method for utilizing waste heat of drilling fluid based on the above-mentioned waste heat utilization system of drilling fluid based on a drilling well site, comprising:

[0023] The drilling fluid flowing through the drilling fluid surface outlet of the drilling well site enters the heat dissipation circulation tank and dissipates heat to the liquid circulating medium. The cooled drilling fluid enters the circulating tank group for storage and impurity filtration. Then, the drilling fluid working medium pump pumps the drilling fluid in the circulating tank group into the well through the drilling fluid surface outlet of the drilling well site for continued circulation.

[0024] The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat dissipation circulation tank by absorbing the heat emitted by the drilling fluid in the heat dissipation circulation tank; the gaseous circulating working fluid enters the turbine to undergo mechanical expansion and perform work, thereby driving the generator to generate electricity; after performing work, the circulating working fluid discharged from the turbine is cooled and condensed into a liquid circulating working fluid in the condenser and stored in the condensate reservoir, and then the working fluid liquid pump pumps the liquid circulating working fluid in the condensate reservoir into the heat dissipation circulation tank for continued circulation.

[0025] In a third aspect, an embodiment of the present invention provides a drilling fluid waste heat utilization device, comprising:

[0026] The heat dissipation circulation tank is used to perform heat exchange between the drilling fluid flowing out of the drilling fluid surface outlet of the drilling well site and the circulating working medium, and utilizes the waste heat of the drilling fluid to convert the circulating working medium from liquid to gas;

[0027] A circulation tank group, used for storing and filtering impurities of the drilling fluid after being cooled by the heat dissipation circulation tank;

[0028] The drilling fluid working medium pump is used to pump the drilling fluid in the circulation tank group into the well through the drilling fluid ground inlet for continuous circulation.

[0029] In a fourth aspect, an embodiment of the present invention provides a drilling fluid waste heat utilization power generation device, comprising:

[0030] The heat dissipation circulation tank is used to perform heat exchange between the drilling fluid flowing out of the ground outlet of the drilling fluid and the circulating working medium, and utilize the waste heat of the drilling fluid to convert the circulating working medium from liquid to gas;

[0031] A turbine and a generator, wherein the turbine is used to utilize the gaseous circulating medium outputted from the heat dissipation circulation tank to mechanically expand and perform work to drive the generator to generate electricity;

[0032] A condenser, used for cooling the circulating working fluid discharged from the turbine and condensing it into liquid circulating working fluid;

[0033] A condensate reservoir, used for storing the liquid circulating medium condensed by the condenser;

[0034] The working fluid liquid pump is used to pump the liquid circulating working fluid stored in the condensate reservoir into the heat dissipation circulation tank.

[0035] One or more embodiments of the present invention bring at least the following beneficial effects:

[0036] The present invention can increase the heat dissipation area of ​​the heat dissipation circulation tank by improving the structure of the heat dissipation circulation tank, thereby improving the heat dissipation efficiency of the drilling fluid and reducing the circulation temperature of the drilling fluid, thereby solving the problem that the drilling fluid is not sufficiently cooled on the ground due to the short contact time of the heat exchanger with the drilling fluid due to space limitations in the drilling well site, and is unable to protect the precision instruments at the bottom of the well, as well as the problem of difficulty in utilizing the waste heat of the drilling fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 A schematic diagram of a drilling fluid waste heat utilization system based on a drilling well site provided by an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of a heat dissipation circulation tank provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] 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.

[0041] Embodiment 1

[0042] This embodiment provides a drilling fluid waste heat utilization system based on a drilling well site, which is arranged at the outlet of the drilling well. Figure 1 As shown, the system includes a drilling fluid waste heat utilization device and a drilling fluid waste heat utilization power generation device.

[0043] The drilling fluid waste heat utilization device includes a heat dissipation circulation tank 1, a circulation tank group 2 and a drilling fluid working medium pump 3 which are connected in sequence. The heat dissipation circulation tank 1 is used to perform heat exchange between the circulating working medium and the drilling fluid flowing out from the drilling fluid surface outlet of the drilling well site, and the circulating working medium is converted from liquid to gaseous state by using the waste heat of the drilling fluid. The circulation tank group 2 is used to store and filter impurities of the drilling fluid after cooling by the heat dissipation circulation tank 1. The drilling fluid working medium pump 3 is used to pump the drilling fluid in the circulation tank group 2 into the well through the drilling fluid surface inlet of the drilling well site for continued circulation. Specifically, the drilling fluid working medium pump 3 pumps the drilling fluid in the circulation tank group 2 into the well, so that the liquid level of the drilling fluid in the circulation tank group 2 is reduced, and the drilling fluid after cooling in the heat dissipation circulation tank 1 can automatically enter the circulation tank group 2. The circulation tank group 2 includes at least three circulation tanks connected in sequence. The heat dissipation circulation tank 1 and the circulation tank are both connected to drilling fluid equipment such as a degasser, a desilter, a desander, an all-in-one machine, etc.

[0044] The drilling fluid waste heat utilization power generation device includes a heat dissipation circulation tank 1 shared with the drilling fluid waste heat utilization device, and also includes a turbine 4, a generator 8, a condenser 9, a condensate reservoir 10 and a working fluid liquid pump 11. The turbine 4 is used to utilize the gaseous circulating working fluid output from the heat dissipation circulation tank 1 to perform mechanical expansion work to drive the generator 8 to generate electricity. The condenser 9 is used to cool and condense the circulating working fluid discharged from the turbine 4 into a liquid circulating working fluid, and store it in the condensate reservoir 10. The working fluid liquid pump 11 is used to pump the liquid circulating working fluid stored in the condensate reservoir 10 into the heat dissipation circulation tank 1 for continued circulation.

[0045] Preferably, the heat dissipation circulation tank 1 is the main equipment for heat exchange between drilling fluid and circulating medium, and is the first circulation tank that the drilling fluid enters after the rock cuttings are separated by the vibrating screen. Figure 2 As shown, the heat dissipation circulation tank 1 includes a tank body, a flow channel 12, a heat exchanger 14, a working fluid liquid inlet 13, a working fluid liquid outlet 18, a drilling fluid mixer 16 and a drilling fluid outlet 19. The flow channel 12 is used to guide the drilling fluid flowing through the drilling fluid ground outlet to the heat dissipation circulation tank 1. Specifically, after the drilling fluid flows out from the drilling fluid ground outlet, the coarse solid phase is separated by a vibrating screen and then guided to the heat dissipation circulation tank 1 through the flow channel 12. The heat exchanger 14 is arranged in the flow channel 12, and is used for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1, so as to increase the heat exchange area of ​​the entire heat dissipation circulation tank 1. Furthermore, the heat exchanger 14 is close to the inner wall 15 of the tank body, which is convenient for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1. The radiator 14 includes a heat exchange tube or a heat exchange plate. And according to the shape and size of the heat dissipation circulation tank 1, the number and shape of the radiator 14 can be changed, and the material used by the radiator 14 can be changed according to the physical properties of the circulating working fluid, such as the heat exchanger 14 using heat exchange tubes or heat exchange plates made of ultra-low temperature heat exchange working fluid. The working fluid liquid inlet 13 is used to flow in liquid circulating working fluid, and the working fluid liquid outlet 18 is used to output gaseous circulating working fluid. Specifically, the working fluid liquid inlet 13 is connected to the working fluid liquid pump 11, and the liquid circulating working fluid is pumped into the heat dissipation circulation tank 1 by the working fluid liquid pump 11, and exchanges heat with the high-temperature drilling fluid through the heat exchanger 14, thereby being converted into a gaseous circulating working fluid, and then enters the turbine 4 through the working fluid liquid outlet 18 to perform mechanical expansion and work.

[0046] Preferably, the heat dissipation circulation tank 1 further comprises a drilling fluid mixer 16. The drilling fluid mixer 16 is used to stir the drilling fluid in the heat dissipation circulation tank 1, so that the temperature of the drilling fluid near the inner wall 15 of the heat dissipation circulation tank 1 can be kept consistent with that of the heat dissipation circulation tank 1, thereby increasing the heat exchange efficiency.

[0047] Preferably, since the temperature of the drilling fluid after vibration screening is lower than the temperature of the drilling fluid at the drilling fluid outlet, the efficiency of using the Organic Rankine Cycle (ORC) is low, and a circulating working fluid with a lower boiling point needs to be selected. For example, the circulating working fluid can use a circulating working fluid with an ORC Rankine cycle boiling point of 0 to 40°C, which can achieve drilling fluid power generation at about 60 to 70°C; the circulating working fluid can also use a circulating working fluid with a lower boiling point, such as carbon dioxide or liquefied air or liquefied nitrogen, with a boiling point as low as -196°C, which can achieve heat source power generation above 10°C, and the working fluid liquid pump 11 needs to be replaced with a supercritical gas turbine with a low-temperature working fluid. Other equipment also needs to be modified accordingly. For example, the heat dissipation circulation tank 1 and the condensate reservoir 10 are provided with pressure vessels and protection equipment for storing low-temperature working fluids with high-efficiency thermal insulation. The protection equipment includes a pressure limiting valve or a safety valve. The pipeline for conveying the circulating working fluid in the drilling fluid waste heat utilization power generation device adopts a low-temperature pipe, and a throttle valve is provided on the low-temperature pipe.

[0048] The system provided in this embodiment can increase the 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 temperature is 180℃, the surface outlet temperature is 90℃, and the drilling fluid waste heat utilization system based on the drilling well site is adopted. The electricity bill of a well can be saved by 90,720 yuan per day. If the drilling time from directional drilling is 50 days, the drilling time with rotary steering drilling is 40 days, and the drilling fluid waste heat utilization system based on the drilling well site is adopted, 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 10% power conversion efficiency, the generated electricity is 4.032×105kWh. The current national implementation is the peak electricity fee difference. According to 0.6 yuan / kWh, the electricity fee is saved by 241,920 yuan. According to 1kWh=860kCal, 1kg standard coal heat=7000kCal, converted to 1kWh of electricity=860 / 7000=0.1229kg standard coal heat, then generating one kilowatt-hour of electricity is equivalent to consuming 323g standard coal. Further calculation based on the "carbon (C)" emission coefficient of "carbon dioxide (CO2)" produced 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 per kilowatt-hour of electricity generated are 793.5141g CO2. The carbon emissions of each extended displacement well or horizontal well are reduced by 480.076t.

[0049] 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.

[0050] The system provided in this embodiment can reduce construction costs. Unlike the commonly used low-temperature waste heat power generation system that can be used at a water temperature of about 80°C, the value of the drilling fluid waste heat utilization technology based on the drilling well site is mainly to save the daily cost of cooling the drilling fluid. The daily cost of cooling the drilling fluid is about 200,000 for 15 days, and the drilling fluid waste heat utilization technology based on the drilling well site can realize the power generation of the device, reduce carbon emissions and significantly reduce construction costs.

[0051] In summary, the system provided in this embodiment can reduce carbon emissions through waste heat power generation, reduce economic losses caused by failure of high-end instruments such as rotary guides, improve drilling construction efficiency, and reduce construction costs.

[0052] Embodiment 2

[0053] This embodiment provides a method for utilizing waste heat of drilling fluid based on the drilling fluid waste heat utilization system based on a drilling well site according to the first embodiment, comprising:

[0054] The drilling fluid flowing through the drilling fluid ground outlet of the drilling well site enters the heat dissipation circulation tank 1 and dissipates heat to the liquid circulating working medium. The cooled drilling fluid enters the circulation tank group 2 for storage and impurity filtration, and then the drilling fluid working medium pump 3 pumps the drilling fluid in the circulation tank group 2 into the well through the drilling fluid ground outlet of the drilling well site for continued circulation.

[0055] The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat dissipation circulation tank 1 by absorbing the heat emitted by the drilling fluid in the heat dissipation circulation tank 1; the gaseous circulating working fluid enters the turbine 4 to undergo mechanical expansion and perform work, thereby driving the generator 8 to generate electricity; after performing work, the circulating working fluid discharged from the turbine 4 is cooled and condensed into a liquid circulating working fluid in the condenser 9, and is stored in the condensate reservoir 10, and then the working fluid liquid pump 11 pumps the liquid circulating working fluid in the condensate reservoir 10 into the heat dissipation circulation tank 1 for continued circulation.

[0056] The method provided by the present invention 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 circulation 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.

[0057] Embodiment 3

[0058] This embodiment provides a drilling fluid waste heat utilization device, including a heat dissipation circulation tank 1, a circulation tank group 2 and a drilling fluid working medium pump 3 connected in sequence. The heat dissipation circulation tank 1 is used to perform heat exchange between the circulating working medium and the drilling fluid flowing out from the drilling fluid surface outlet of the drilling well site, and the circulating working medium is converted from liquid to gaseous state by using the waste heat of the drilling fluid. The circulation tank group 2 is used to store and filter impurities from the drilling fluid after cooling by the heat dissipation circulation tank 1. The drilling fluid working medium pump 3 is used to pump the drilling fluid in the circulation tank group 2 into the well through the drilling fluid surface inlet of the drilling well site for continued circulation. Specifically, the drilling fluid working medium pump 3 pumps the drilling fluid in the circulation tank group 2 into the well, so that the liquid level of the drilling fluid in the circulation tank group 2 is lowered, and the drilling fluid in the heat dissipation circulation tank 1 after cooling can automatically enter the circulation tank group 2. The circulation tank group 2 includes at least three circulation tanks connected in sequence. The heat dissipation circulation tank 1 and the circulation tank are both connected to drilling fluid equipment such as a degasser, a desilter, a desander, an all-in-one machine, etc.

[0059] Preferably, the heat dissipation circulation tank 1 is the main equipment for heat exchange between drilling fluid and circulating medium, and is the first circulation tank that the drilling fluid enters after the rock cuttings are separated by the vibrating screen. Figure 2 As shown, the heat dissipation circulation tank 1 includes a tank body, a flow channel 12, a heat exchanger 14, a working fluid liquid inlet 13, a working fluid liquid outlet 18, a drilling fluid mixer 16 and a drilling fluid outlet 19. The flow channel 12 is used to guide the drilling fluid flowing through the drilling fluid ground outlet to the heat dissipation circulation tank 1. Specifically, after the drilling fluid flows out from the drilling fluid ground outlet, the coarse solid phase is separated by a vibrating screen and then guided to the heat dissipation circulation tank 1 through the flow channel 12. The heat exchanger 14 is arranged in the flow channel 12, and is used for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1, so as to increase the heat exchange area of ​​the entire heat dissipation circulation tank 1. Furthermore, the heat exchanger 14 is close to the inner wall 15 of the tank body, which is convenient for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1. The radiator 14 includes a heat exchange tube or a heat exchange plate. And according to the shape and size of the heat dissipation circulation tank 1, the number and shape of the radiator 14 can be changed, and the material used by the radiator 14 can be changed according to the physical properties of the circulating medium, such as the heat exchanger 14 using a heat exchange tube or heat exchange plate made of ultra-low temperature heat exchange medium. The working medium liquid inlet 13 is used to flow in the liquid circulating medium, and the working medium liquid outlet 18 is used to output the gaseous circulating medium.

[0060] Preferably, the heat dissipation circulation tank 1 further comprises a drilling fluid mixer 16. The drilling fluid mixer 16 is used to stir the drilling fluid in the heat dissipation circulation tank 1, so that the temperature of the drilling fluid near the inner wall 15 of the heat dissipation circulation tank 1 can be kept consistent with that of the heat dissipation circulation tank 1, thereby increasing the heat exchange efficiency.

[0061] The drilling fluid waste heat utilization device provided in this embodiment improves the structure of the heat dissipation circulation tank 1 to increase the heat dissipation area, thereby solving the problem that the heat exchanger is in short contact with the drilling fluid due to space limitations in the drilling well site, resulting in insufficient cooling of the drilling fluid on the ground and failure to protect precision instruments at the bottom of the well.

[0062] Embodiment 4

[0063] This embodiment provides a drilling fluid waste heat utilization power generation device, including a heat dissipation circulation tank 1, a turbine 4, a generator 8, a condenser 9, a condensate reservoir 10 and a working fluid liquid pump 11. The heat dissipation circulation tank 1 is used to perform heat exchange between the circulating working fluid and the drilling fluid flowing out of the drilling fluid surface outlet of the drilling well site, and use the waste heat of the drilling fluid to convert the circulating working fluid from a liquid state to a gaseous state. The heat dissipation circulation tank 1 is connected to drilling fluid equipment such as a degasser, a desilter, a desander, and an all-in-one machine. The turbine 4 is used to use the gaseous circulating working fluid output by the heat dissipation circulation tank 1 to perform mechanical expansion work to drive the generator 8 to generate electricity. The condenser 9 is used to cool and condense the circulating working fluid discharged by the turbine 4 into a liquid circulating working fluid, and store it in the condensate reservoir 10. The working fluid liquid pump 11 is used to pump the liquid circulating working fluid stored in the condensate reservoir 10 into the heat dissipation circulation tank 1 for continued circulation.

[0064] Preferably, the heat dissipation circulation tank 1 is the main equipment for heat exchange between drilling fluid and circulating medium, and is the first circulation tank that the drilling fluid enters after the rock cuttings are separated by the vibrating screen. Figure 2As shown, the heat dissipation circulation tank 1 includes a tank body, a flow channel 12, a heat exchanger 14, a working fluid liquid inlet 13, a working fluid liquid outlet 18, a drilling fluid mixer 16 and a drilling fluid outlet 19. The flow channel 12 is used to guide the drilling fluid flowing through the drilling fluid ground outlet to the heat dissipation circulation tank 1. Specifically, after the drilling fluid flows out from the drilling fluid ground outlet, the coarse solid phase is separated by a vibrating screen and then guided to the heat dissipation circulation tank 1 through the flow channel 12. The heat exchanger 14 is arranged in the flow channel 12, and is used for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1, so as to increase the heat exchange area of ​​the entire heat dissipation circulation tank 1. Furthermore, the heat exchanger 14 is close to the inner wall 15 of the tank body, which is convenient for contact heat exchange with the drilling fluid in the heat dissipation circulation tank 1. The radiator 14 includes a heat exchange tube or a heat exchange plate. And according to the shape and size of the heat dissipation circulation tank 1, the number and shape of the radiator 14 can be changed, and the material used by the radiator 14 can be changed according to the physical properties of the circulating working fluid, such as the heat exchanger 14 using heat exchange tubes or heat exchange plates made of ultra-low temperature heat exchange working fluid. The working fluid liquid inlet 13 is used to flow in liquid circulating working fluid, and the working fluid liquid outlet 18 is used to output gaseous circulating working fluid. Specifically, the working fluid liquid inlet 13 is connected to the working fluid liquid pump 11, and the liquid circulating working fluid is pumped into the heat dissipation circulation tank 1 by the working fluid liquid pump 11, and exchanges heat with the high-temperature drilling fluid through the heat exchanger 14, thereby being converted into a gaseous circulating working fluid, and then enters the turbine 4 through the working fluid liquid outlet 18 to perform mechanical expansion and work.

[0065] Preferably, the heat dissipation circulation tank 1 further comprises a drilling fluid mixer 16. The drilling fluid mixer 16 is used to stir the drilling fluid in the heat dissipation circulation tank 1, so that the temperature of the drilling fluid near the inner wall 15 of the heat dissipation circulation tank 1 can be kept consistent with that of the heat dissipation circulation tank 1, thereby increasing the heat exchange efficiency.

[0066] Preferably, since the temperature of the drilling fluid after vibration screening is lower than the temperature of the drilling fluid at the drilling fluid outlet, the efficiency of using an organic Rankine cycle (ORC) is low, and a circulating working fluid with a lower boiling point needs to be selected. For example, the circulating working fluid can use the circulating working fluid with an ORC Rankine cycle boiling point of 0 to 40°C, which can achieve drilling fluid power generation at about 60 to 70°C; the circulating working fluid can also use a circulating working fluid with a lower boiling point, such as carbon dioxide or liquefied air or liquefied nitrogen, with a working fluid boiling point as low as -196°C, which can achieve heat source power generation above 10°C. At the same time, the working fluid liquid pump 11 needs to be replaced with a supercritical gas turbine for low-temperature working fluid, and other equipment must also be modified accordingly. For example, the heat dissipation circulation tank 1 and the condensate reservoir 10 are provided with a pressure vessel and protection equipment for storing low-temperature working fluid with high-efficiency thermal insulation, the protection equipment includes a pressure limiting valve or a safety valve, and the pipeline used for conveying the circulating working fluid in the drilling fluid waste heat utilization power generation device adopts a low-temperature pipe, and a throttle valve is provided on the low-temperature pipe.

[0067] The drilling fluid waste heat power generation device provided in this embodiment improves the structure of the heat dissipation circulation tank 1, increases the heat dissipation area, reduces the circulation temperature of the drilling fluid, and solves the problem of difficulty in utilizing the waste heat of the drilling fluid.

[0068] 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.

[0069] 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.

[0070] 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 utilization system based on a drilling well site, It is characterized in that It is arranged at the well exit, and includes a drilling fluid waste heat utilization device and a drilling fluid waste heat utilization power generation device; The drilling fluid waste heat utilization device comprises a heat dissipation circulation tank (1), a circulation tank group (2) and a drilling fluid working medium pump (3) which are connected in sequence; the heat dissipation circulation tank (1) is used to perform heat exchange between the circulating working medium and the drilling fluid flowing out from the drilling fluid surface outlet of the drilling well site, and utilize the waste heat of the drilling fluid to convert the circulating working medium from a liquid state to a gas state; the circulation tank group (2) is used to store and filter impurities from the drilling fluid after being cooled by the heat dissipation circulation tank (1); the drilling fluid working medium pump (3) is used to pump the drilling fluid in the circulation tank group (2) into the drilling well through the drilling fluid surface inlet of the drilling well site for continued circulation; The drilling fluid waste heat utilization power generation device comprises a heat dissipation circulation tank (1) shared with the drilling fluid waste heat utilization device, and also comprises a turbine (4), a generator (8), a condenser (9), a condensate reservoir (10) and a working fluid liquid pump (11). The turbine (4) is used to utilize the gaseous circulating working fluid output by the heat dissipation circulation tank (1) to perform mechanical expansion work to drive the generator (8) to generate electricity; the condenser (9) is used to cool the circulating working fluid discharged by the turbine (4) to condense it into liquid circulating working fluid and store it in the condensate reservoir (10); the working fluid liquid pump (11) is used to pump the liquid circulating working fluid stored in the condensate reservoir (10) into the heat dissipation circulation tank (1) for continued circulation.

2. The drilling fluid waste heat utilization system based on a drilling well site according to claim 1, It is characterized in that The heat dissipation circulation tank (1) comprises: A flow channel (12) for guiding the drilling fluid flowing through the drilling fluid surface outlet into the heat dissipation circulation tank (1); A heat exchanger (14) is arranged in the flow channel (12), and the heat exchanger (14) performs contact heat exchange with the drilling fluid in the heat dissipation circulation tank (1); A working fluid liquid inlet (13) for the inflow of liquid circulating working fluid; A working fluid liquid outlet (18) for outputting gaseous circulating working fluid; The drilling fluid outlet (19) is connected to the inlet of the circulation tank group (2) and is used to input the drilling fluid cooled by the heat dissipation circulation tank (1) into the circulation tank group (2).

3. The drilling fluid waste heat utilization system based on the drilling well site according to claim 2, It is characterized in that The heat dissipation circulation tank (1) further comprises a drilling fluid mixer (16), wherein the drilling fluid mixer (16) is used to stir the drilling fluid in the heat dissipation circulation tank (1).

4. The drilling fluid waste heat utilization system based on a drilling well site according to claim 2, It is characterized in that The heat exchanger (14) comprises heat exchange tubes or heat exchange fins.

5. The drilling fluid waste heat utilization system based on a drilling well site according to claim 1, It is characterized in that A first coupling (5), a gear box (6) and a second coupling (7) are arranged in sequence between the turbine (4) and the generator (8); the first output end of the turbine (4) is connected to the first coupling (5); the first coupling (5) is also connected to the input shaft of the gear box (6); the output shaft of the gear box (6) is connected to the second coupling (7); and the second coupling (7) is connected to the generator (8).

6. The drilling fluid waste heat utilization system based on a drilling well site according to claim 1, It is characterized in that The circulating working fluid includes a working fluid with a boiling point of 0 to 30° C. for the ORC Rankine cycle, or carbon dioxide, or liquid air, or liquid nitrogen.

7. The drilling fluid waste heat utilization system based on a drilling well site according to claim 6, It is characterized in that The pipeline used for conveying the circulating working medium in the drilling fluid waste heat utilization power generation device adopts a low-temperature pipe, and a throttle valve is arranged on the low-temperature pipe; The working fluid pump (11) adopts a supercritical gas turbine; The heat dissipation circulation tank (1) and the condensate reservoir (10) are both provided with a pressure container and a protective device, wherein the protective device comprises a pressure limiting valve or a safety valve.

8. A method for utilizing waste heat of drilling fluid based on the waste heat utilization system of drilling fluid at a drilling well site according to any one of claims 1 to 7, It is characterized in that include: The drilling fluid flowing through the drilling fluid surface outlet of the drilling well site enters the heat dissipation circulation tank (1) and dissipates heat to the liquid circulating medium. The cooled drilling fluid enters the circulating tank group (2) for storage and impurity filtration. Then, the drilling fluid working medium pump (3) pumps the drilling fluid in the circulating tank group (2) into the well through the drilling fluid surface outlet of the drilling well site for continued circulation. The liquid circulating working fluid is converted into a gaseous circulating working fluid in the heat dissipation circulation tank (1) by absorbing the heat dissipated by the drilling fluid in the heat dissipation circulation tank (1); the gaseous circulating working fluid enters the turbine (4) to undergo mechanical expansion and perform work, thereby driving the generator (8) to generate electricity; after performing work, the circulating working fluid discharged from the turbine (4) is cooled and condensed into a liquid circulating working fluid in the condenser (9), and stored in the condensate reservoir (10); then the working fluid liquid pump (11) pumps the liquid circulating working fluid in the condensate reservoir (10) into the heat dissipation circulation tank (1) for continued circulation.

9. A drilling fluid waste heat utilization device, It is characterized in that include: The heat dissipation circulation tank (1) is used to perform heat exchange between the drilling fluid flowing out of the drilling fluid surface outlet of the drilling well site and the circulating working medium, and utilize the waste heat of the drilling fluid to convert the circulating working medium from liquid to gas; A circulation tank group (2) is used to store and filter impurities from the drilling fluid after being cooled by the heat dissipation circulation tank (1); The drilling fluid working medium pump (3) is used to pump the drilling fluid in the circulation tank group (2) into the well through the drilling fluid surface inlet for continued circulation.

10. A drilling fluid waste heat power generation device, It is characterized in that include: The heat dissipation circulation tank (1) is used to perform heat exchange between the drilling fluid flowing out of the drilling fluid surface outlet and the circulating working medium, and utilize the waste heat of the drilling fluid to convert the circulating working medium from liquid to gas; a turbine (4) and a generator (8), wherein the turbine (4) is used to utilize the gaseous circulating working fluid outputted from the heat dissipation circulation tank (1) to perform mechanical expansion and work so as to drive the generator (8) to generate electricity; A condenser (9) for cooling the circulating working fluid discharged from the turbine to condense the circulating working fluid into liquid state; A condensate reservoir (10) for storing the liquid circulating medium condensed by the condenser (9); A working fluid liquid pump (11) is used to pump the liquid circulating working fluid stored in the condensate reservoir (10) into the heat dissipation circulation tank (1).

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