A drilling circulating fluid temperature regulation system, method and application

Abstract

This invention discloses a drilling circulating fluid temperature control system, method, and application. The system is connected to the wellbore and includes a mud pit, an ambient temperature storage tank, a cryogenic storage tank, a cooling device, a mixing valve, a buffer tank, a first throttle valve, and a second throttle valve. The mud pit is connected to the wellbore annulus, allowing drilling circulating fluid from the annulus to flow into the mud pit. The mud pit is connected to both the ambient temperature and cryogenic storage tanks. The cooling device is positioned between the mud pit and the cryogenic storage tank. The ambient temperature and cryogenic storage tanks are connected to the buffer tank via mixing valves. The mixing valves are adapted to mix the drilling circulating fluid flowing from the ambient temperature and cryogenic storage tanks. The buffer tank is connected to the drill string within the wellbore. The first throttle valve is positioned between the ambient temperature storage tank and the mixing valve. The second throttle valve is positioned between the cryogenic storage tank and the mixing valve. This system can quickly obtain drilling circulating fluid at the target temperature, significantly shortening the response time for drilling circulating fluid temperature control.

Description

Technical Field

[0001] This invention relates to the field of drilling engineering technology, and in particular to a drilling circulating fluid temperature control system, method and application. Background Technology

[0002] Drilling deep wells, ultra-deep wells, and hydrated reservoir sections in terrestrial permafrost zones presents corresponding safety, environmental, and geological risks. In particular, ultra-deep well sections and hydrated reservoir sections in terrestrial permafrost zones have complex geological conditions and extremely high engineering and technical requirements for drilling. Ensuring wellbore safety and wellbore stability during drilling is a major challenge.

[0003] During drilling, the rotation of the drill bit cutting through the formation and the flow of fluid within the wellbore both generate significant heat, leading to an increase in wellbore temperature. This elevated temperature can easily cause dangerous downhole accidents, such as wellbore instability and blowouts. Therefore, timely temperature control is crucial for wellbore safety. Cooling the wellbore can be achieved by reducing the temperature of the drilling circulating fluid. Conventional methods for cooling drilling circulating fluid involve real-time temperature control of the returning fluid at the wellhead using cooling equipment, which has certain limitations. Summary of the Invention

[0004] To enrich the types of drilling circulating fluid cooling systems, increase the selection space of drilling circulating fluid cooling methods, and improve the efficiency of wellbore temperature control, this invention proposes a drilling circulating fluid temperature control system, method, and application.

[0005] In a first aspect, embodiments of the present invention provide a drilling circulating fluid temperature control system connected to the wellbore, including a mud pit, a normal temperature storage tank, a low temperature storage tank, a cooling device, a mixing valve, a buffer tank, a first throttle valve, and a second throttle valve;

[0006] The mud pit is connected to the wellbore annulus so that the drilling circulating fluid in the wellbore annulus can enter the mud pit;

[0007] The mud tank is connected to the ambient temperature storage tank and the cryogenic storage tank respectively; the cooling device is installed between the mud tank and the cryogenic storage tank;

[0008] The ambient temperature storage tank and the cryogenic storage tank are respectively connected to the buffer tank via the mixing valve; the mixing valve is adapted to mix the drilling circulation fluid flowing out of the ambient temperature storage tank with the drilling circulation fluid flowing out of the cryogenic storage tank;

[0009] The buffer tank is connected to the drill string inside the wellbore and is suitable for storing drilling circulating fluid at the target temperature flowing out from the mixing valve;

[0010] The first throttle valve is disposed between the ambient temperature storage tank and the mixing valve, and is suitable for adjusting the flow rate of drilling circulating fluid between the ambient temperature storage tank and the mixing valve;

[0011] The second throttle valve is located between the cryogenic storage tank and the mixing valve, and is suitable for adjusting the flow rate of the drilling circulating fluid between the cryogenic storage tank and the mixing valve.

[0012] In one or more alternative embodiments, the cooling device includes a refrigerator, a coolant tank, and a heat exchanger connected in sequence;

[0013] The refrigerator is adapted to circulate and cool the coolant in the coolant tank, and the coolant in the coolant tank can flow through the heat exchanger and return to the coolant tank;

[0014] The heat exchanger is connected to the mud pit and the cryogenic storage tank respectively, so that the drilling circulating fluid in the mud pit flows through the heat exchanger and then into the cryogenic storage tank for storage.

[0015] In one or more alternative embodiments, the drilling circulating fluid temperature control system further includes a first shut-off valve, a second shut-off valve, a third shut-off valve, a fourth shut-off valve, and a fifth shut-off valve;

[0016] The first shut-off valve is located between the ambient temperature storage tank and the drill string;

[0017] The second shut-off valve is located between the ambient temperature storage tank and the mixing valve;

[0018] The third shut-off valve is located between the mud pit and the cryogenic storage tank;

[0019] The fourth shut-off valve is located between the cryogenic storage tank and the mixing valve;

[0020] The fifth shut-off valve is located between the buffer tank and the drill string.

[0021] In one or more alternative embodiments, the ambient temperature storage tank is equipped with a first thermometer;

[0022] And / or, the cryogenic storage tank is equipped with a second thermometer;

[0023] And / or, the buffer tank is equipped with a third thermometer;

[0024] And / or, the outlet of the mixing valve is provided with a fourth thermometer.

[0025] In one or more alternative embodiments, a first flow meter is provided between the ambient temperature storage tank and the mixing valve;

[0026] A second flow meter is installed between the cryogenic storage tank and the mixing valve.

[0027] In one or more alternative embodiments, the ambient temperature storage tank is connected to the drill string.

[0028] In a second aspect, embodiments of the present invention provide a method for controlling the temperature of drilling circulating fluid, using the drilling circulating fluid temperature control system described in the first aspect, comprising:

[0029] Obtain a pre-set first preset temperature, which is the inlet temperature of the drilling circulating fluid required for drilling operations;

[0030] Determine whether the temperature of the drilling circulating fluid in the ambient temperature storage tank is lower than the first preset temperature;

[0031] If so, the drilling circulating fluid in the ambient temperature storage tank is introduced into the drill string;

[0032] If not, determine whether the temperature of the drilling circulating fluid in the cryogenic storage tank is lower than the first preset temperature;

[0033] If so, the drilling circulating fluid in the cryogenic storage tank and the drilling circulating fluid in the ambient temperature storage tank are introduced into the mixing valve, and after being mixed by the mixing valve, they are introduced into the buffer tank;

[0034] If not, the drilling circulating fluid that is about to enter the cryogenic storage tank is cooled by a cooling device, and the cooled drilling circulating fluid in the cryogenic storage tank and the drilling circulating fluid in the normal temperature storage tank are introduced into the mixing valve, mixed by the mixing valve and then introduced into the buffer tank.

[0035] Adjust the opening of the first throttle valve and the second throttle valve so that the temperature of the drilling circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank are both equal to the first preset temperature.

[0036] The drilling circulating fluid in the buffer tank is introduced into the drill string.

[0037] In one or more alternative embodiments, before adjusting the opening of the first throttle valve and the second throttle valve to make the temperature of the circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank both equal to the first preset temperature, the method further includes:

[0038] Calculate the mixing ratio of drilling circulation fluid flowing out of the cryogenic storage tank and drilling circulation fluid flowing out of the ambient temperature storage tank;

[0039] The opening adjustment values ​​of the first and second throttle valves are determined based on the mixing ratio of the drilling circulation fluid flowing out of the cryogenic storage tank and the drilling circulation fluid flowing out of the ambient temperature storage tank.

[0040] In one or more optional embodiments, calculating the mixing ratio of drilling circulation fluid flowing out of the cryogenic storage tank and drilling circulation fluid flowing out of the ambient temperature storage tank includes:

[0041] Based on the temperatures of the drilling circulating fluid flowing out of the ambient temperature tank, the cryogenic temperature tank, and the mixing valve, the mixing ratio of the drilling circulating fluid flowing out of the cryogenic tank and the ambient temperature tank is calculated using the following formula 1:

[0042]

[0043] In the formula, T H Q represents the temperature of the drilling circulating fluid flowing out of the ambient temperature storage tank. vH T is the volumetric flow rate of the drilling circulating fluid flowing out of the ambient temperature storage tank. L Q represents the temperature of the drilling circulating fluid flowing out of the cryogenic storage tank. vL T represents the volumetric flow rate of the drilling circulating fluid exiting the cryogenic storage tank. mix The temperature of the drilling circulating fluid flowing out of the mixing valve.

[0044] In one or more alternative embodiments, adjusting the opening of the first throttle valve and the second throttle valve so that the temperature of the drilling circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank are both equal to a first preset temperature includes:

[0045] Determine whether the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature;

[0046] If so, then the opening of the first throttle valve and the second throttle valve will not be adjusted;

[0047] If not, determine whether the temperature of the drilling circulating fluid in the buffer tank is greater than the first preset temperature;

[0048] If so, increase the opening of the second throttle valve, and / or decrease the opening of the first throttle valve until the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature;

[0049] If not, increase the opening of the first throttle valve and / or decrease the opening of the second throttle valve until the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature.

[0050] In one or more alternative embodiments, after increasing the opening of the second throttle valve and / or decreasing the opening of the first throttle valve until the temperature of the drilling circulating fluid in the buffer tank equals a first preset temperature, the method further includes:

[0051] Decrease the opening of the second throttle valve, and / or increase the opening of the first throttle valve until the temperature of the drilling circulating fluid at the outlet of the mixing valve is equal to the first preset temperature.

[0052] In one or more alternative embodiments, after increasing the opening of the first throttle valve and / or decreasing the opening of the second throttle valve until the temperature of the drilling circulating fluid in the buffer tank equals a first preset temperature, the method further includes:

[0053] Decrease the opening of the first throttle valve and / or increase the opening of the second throttle valve until the temperature of the drilling circulating fluid at the outlet of the mixing valve is equal to the first preset temperature.

[0054] Thirdly, embodiments of the present invention provide an application of the drilling circulating fluid temperature control system described in the first aspect in drilling circulating fluid temperature control.

[0055] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0056] The drilling circulating fluid temperature control system provided in this invention mixes the drilling circulating fluid flowing from the ambient temperature storage tank and the drilling circulating fluid flowing from the cryogenic storage tank using a mixing valve to obtain a mixed drilling circulating fluid. A first throttle valve and a second throttle valve are used to regulate the temperature of the mixed drilling circulating fluid in the buffer tank, thereby quickly obtaining the drilling circulating fluid at the target temperature and storing it in the buffer tank, improving the accuracy of temperature control. By connecting the buffer tank to the wellbore, the drilling circulating fluid at the target temperature in the buffer tank can be directly introduced into the wellbore without waiting for the drilling circulating fluid returning from the wellbore annulus to cool down, significantly shortening the response time of drilling circulating fluid temperature control and achieving rapid temperature adjustment. The temperature-controlled drilling circulating fluid is directly sent into the wellbore, effectively ensuring wellbore stability.

[0057] The drilling circulating fluid temperature control system provided in this invention uses five main devices arranged around the wellbore: a mud pit, a normal temperature storage tank, a cooling device, a cryogenic storage tank, and a buffer tank. The connection between these five main devices is simple and clear, making the entire drilling circulating fluid temperature control system simple in structure, easy to implement and apply. Furthermore, it reduces the overall cost of the drilling circulating fluid temperature control system, improves economic efficiency, and facilitates its widespread promotion and application.

[0058] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0059] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0060] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0061] Figure 1 This is a schematic diagram of the drilling circulating fluid temperature control system provided in an embodiment of the present invention;

[0062] Figure 2 This is a schematic diagram illustrating the cooling principle of the cooling device provided in this embodiment of the invention;

[0063] Figure 3 This is a schematic flowchart of the drilling circulating fluid temperature control method provided in an embodiment of the present invention;

[0064] Figure 4 This is a schematic flowchart illustrating the adjustment process of the first and second throttle valves in the drilling circulating fluid temperature control method provided in this embodiment of the invention.

[0065] Figure 5 This is a schematic diagram of the switching logic of the shut-off valve in the drilling circulating fluid temperature control method provided in this embodiment of the invention.

[0066] In the picture:

[0067] 10 represents the wellbore, 101 represents the wellbore annulus, and 102 represents the drill string;

[0068] 1 is a mud pit, 2 is an ambient temperature storage tank, and 3 is a cryogenic storage tank;

[0069] 401 is the coolant tank, 402 is the refrigerator, and 403 is the heat exchanger;

[0070] 5 is the mixing valve, and 6 is the buffer tank;

[0071] 701 is the first throttle valve, 702 is the second throttle valve, 703 is the third throttle valve, 704 is the fourth throttle valve, 705 is the fifth throttle valve, and 706 is the sixth throttle valve;

[0072] 801 is the first shut-off valve, 802 is the second shut-off valve, 803 is the third shut-off valve, 804 is the fourth shut-off valve, 805 is the fifth shut-off valve, and 806 is the sixth shut-off valve.

[0073] 901 is the first thermometer, 902 is the second thermometer, 903 is the third thermometer, 904 is the fourth thermometer, 905 is the fifth thermometer, 906 is the sixth thermometer, 907 is the seventh thermometer, 908 is the eighth thermometer, 909 is the ninth thermometer, and 910 is the tenth thermometer.

[0074] 1001 is the first flow meter, 1002 is the second flow meter, 1003 is the third flow meter, 1004 is the fourth flow meter, 1005 is the fifth flow meter, 1006 is the sixth flow meter, 1007 is the seventh flow meter, and 1008 is the eighth flow meter;

[0075] 1101 is the first pressure monitor, 1102 is the second pressure monitor, and 1103 is the third pressure monitor;

[0076] 1201 is the first transfer pump, 1202 is the second transfer pump, 1203 is the third transfer pump, 1204 is the fourth transfer pump, 1205 is the fifth transfer pump, 1206 is the sixth transfer pump, 1207 is the seventh transfer pump, and 1208 is the eighth transfer pump. Detailed Implementation

[0077] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0078] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] The inventors discovered that conventional drilling circulating fluid cooling methods involve using cooling equipment to instantly regulate the temperature of the returning drilling circulating fluid at the wellhead. However, due to limitations of the cooling equipment, rapid cooling of the drilling circulating fluid is not possible. The drilling circulating fluid must wait at the wellhead for its temperature to drop to the target temperature, which takes a long time. Furthermore, after the cooled drilling circulating fluid is reintroduced into the well, it still takes some time to circulate and flow to the target well section for wellbore temperature regulation. The total time spent on wellhead cooling and circulation within the wellbore is too long, which delays the progress of wellbore temperature regulation and misses the opportune moment for wellbore temperature regulation, thereby leading to uncontrollable complex risks downhole.

[0081] Based on this, embodiments of the present invention provide a drilling circulating fluid temperature control system, method, and application, which will be described in detail below through specific embodiments.

[0082] Example 1

[0083] This invention provides a drilling circulating fluid temperature control system, referring to... Figure 1 As shown, it includes a buffer tank 6, a mud pit 1, a normal temperature storage tank 2, a low temperature storage tank 3, a cooling device, a mixing valve 5, a first throttle valve 701, and a second throttle valve 702;

[0084] The mud pit 1 is connected to the wellbore annulus 101 so that the drilling circulating fluid of the wellbore annulus 101 can enter the mud pit 1;

[0085] The mud tank 1 is connected to the ambient temperature storage tank 2 and the cryogenic storage tank 3 respectively; the cooling device is installed between the mud tank 1 and the cryogenic storage tank 3.

[0086] The ambient temperature storage tank 2 and the cryogenic storage tank 3 are respectively connected to the buffer tank 6 via the mixing valve 5; the mixing valve 5 is suitable for mixing the drilling circulating fluid flowing out of the ambient temperature storage tank 2 with the drilling circulating fluid flowing out of the cryogenic storage tank 3;

[0087] The buffer tank 6 is connected to the drill string 102 inside the wellbore 10 and is suitable for storing drilling circulating fluid at the target temperature flowing out from the mixing valve 5;

[0088] The first throttle valve 701 is located between the ambient temperature storage tank 2 and the mixing valve 5, and is suitable for regulating the flow rate of the drilling circulating fluid between the ambient temperature storage tank 2 and the mixing valve 5;

[0089] The second throttle valve 702 is located between the cryogenic storage tank 3 and the mixing valve 5, and is suitable for regulating the flow rate of the drilling circulating fluid between the cryogenic storage tank 3 and the mixing valve 5.

[0090] In this embodiment of the invention, reference is made to Figure 1As shown, the ambient temperature storage tank 2 is connected to the drill string 102, and the drilling circulating fluid in the ambient temperature storage tank 2 can be directly introduced into the drill string 102. During drilling operations, the drilling circulating fluid returning from the wellbore annulus 101 first enters the mud pit 1, where it undergoes a certain degree of sedimentation and natural cooling. After sedimentation and natural cooling to near ambient temperature, the drilling circulating fluid is introduced into the ambient temperature storage tank 2, and / or, after being cooled by a cooling device, it is introduced into the cryogenic storage tank 3. The inlet temperature of the drilling circulating fluid required for drilling operations is set as a first preset temperature. When the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is not higher than the first preset temperature, the drilling circulating fluid in the ambient temperature storage tank 2 can be directly introduced into the drill string 102. When the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is higher than the first preset temperature, the drilling circulating fluid in the low temperature storage tank 3 and the drilling circulating fluid in the ambient temperature storage tank 2 are introduced into the mixing valve 5. After being mixed by the mixing valve 5, the fluid is introduced into the buffer tank 6. The temperature of the drilling circulating fluid in the buffer tank 6 is adjusted to be equal to the first preset temperature by the first throttle valve 701 and the second throttle valve 702. Then, the drilling circulating fluid in the buffer tank 6 can be sent into the drill string 102 to participate in the drilling operation.

[0091] In this embodiment of the invention, the drilling circulating fluid circulates within the wellbore annulus, the drilling circulating fluid temperature control system, and the drill string. When wellbore temperature control is required, only the opening of the first throttle valve 701 and the second throttle valve 702 needs to be adjusted to ensure that the temperature of the drilling circulating fluid in the buffer tank 6 equals a first preset temperature. Then, the drilling circulating fluid in the buffer tank 6 is directly fed into the drill string, allowing for timely wellbore temperature control. Compared to immediate cooling of the returning drilling circulating fluid at the wellhead using cooling equipment, the drilling circulating fluid temperature control system provided in this embodiment eliminates the need to wait for the drilling circulating fluid to cool at the wellhead, significantly reducing the time required for temperature control and enabling rapid adjustment of the drilling circulating fluid temperature. This avoids delays in wellbore temperature control and effectively ensures wellbore stability.

[0092] In one specific embodiment, reference is made to Figure 1 As shown, the cooling device includes a refrigerator 402, a coolant tank 401, and a heat exchanger 403 connected in sequence. (Ref.) Figure 1 and 2As shown, the working principle of the cooling device is as follows: the cooler 402 circulates and cools the coolant in the coolant tank 401. When the temperature of the coolant in the coolant tank 401 is too high, the coolant circulates between the cooler 402 and the coolant tank 401. After being cooled in the cooler 402, it returns to the coolant tank 401 to keep the coolant in the coolant tank 401 at a relatively low temperature. The coolant tank 401 is connected to the refrigerant inlet and refrigerant outlet of the heat exchanger 403. The mud tank 1 is connected to the heat medium inlet of the heat exchanger 403, and the cryogenic storage tank 3 is connected to the heat medium outlet of the heat exchanger 403. The drilling circulating fluid in the mud tank 1 flows through the heat exchanger 403, and the coolant in the coolant tank 401 flows through the heat exchanger 403. After cooling the drilling circulating fluid flowing through the heat exchanger 403, it returns to the coolant tank 401. The cooled drilling circulating fluid enters the cryogenic storage tank 3 for storage.

[0093] In one specific embodiment, in order to successfully exchange heat and cool the drilling circulating fluid flowing through heat exchanger 403, the selected coolant should have the characteristics of low freezing point, high fluidity, and high specific heat capacity, and should at least meet the cooling requirement of -20°C. In this embodiment, a low-freezing-point coolant prepared with ethylene glycol is selected. This coolant has characteristics such as high boiling point, low foaming tendency, good viscosity-temperature performance, corrosion resistance, and scale prevention, which meet the heat exchange and cooling requirements of the drilling circulating fluid. Obviously, the coolant includes, but is not limited to, a low-freezing-point coolant prepared with ethylene glycol, and can be selected according to actual needs, as long as it can meet the heat exchange and cooling requirements of the drilling circulating fluid. Further details will not be elaborated here.

[0094] In this embodiment of the invention, based on the characteristics and heat exchange requirements of the drilling circulating fluid, the internal piping of the heat exchanger 403 must be able to adapt to the flow characteristics of the drilling circulating fluid to achieve rapid cooling. For example, a wound tube heat exchanger 403 can be used to cool the drilling circulating fluid. The wound tube heat exchanger 403 has advantages such as a wide applicable temperature range, good thermal shock resistance, self-elimination of thermal stress, high efficiency, and high compactness, and is suitable for heat exchange with fluids experiencing thermal shock and large temperature differences. When it is necessary to cool the wound tube heat exchanger 403 flowing through it, the appropriate coolant discharge rate should be adjusted according to the operating standards of the heat exchanger 403 and the required temperature reduction of the drilling circulating fluid, ensuring that the drilling circulating fluid reaches a suitable temperature after passing through the heat exchanger 403.

[0095] In one specific embodiment, reference is made to Figure 1As shown, the drilling circulating fluid temperature control system also includes a first shut-off valve 801, a second shut-off valve 802, a third shut-off valve 803, a fourth shut-off valve 804, and a fifth shut-off valve 805. The first shut-off valve 801 is located between the ambient temperature storage tank 2 and the drill string 102, and is used to control the flow of fluid between them. The second shut-off valve 802 is located between the ambient temperature storage tank 2 and the mixing valve 5, and is used to control the flow of fluid between them. The third shut-off valve 803 is located between the mud pit 1 and the cryogenic storage tank 3, and is used to control the flow of fluid between them. The fourth shut-off valve 804 is located between the cryogenic storage tank 3 and the mixing valve 5, and is used to control the flow of fluid between them. The fifth shut-off valve 805 is located between the buffer tank 6 and the drill string 102, and is used to control the flow of fluid between them. The first shut-off valve 801, the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 work together to achieve rapid and precise control of the drilling circulating fluid temperature, and to ensure that the controlled drilling circulating fluid smoothly enters the wellbore 10, ensuring a relatively stable temperature in the wellbore 10. For example, when the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 cannot meet the requirements of drilling operations, the first shut-off valve 801 is closed, while the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 are opened, so that the drilling circulating fluid in the ambient temperature storage tank 2 mixes with the drilling circulating fluid in the cryogenic storage tank 3 and reaches a first preset temperature before being introduced into the drill string 102.

[0096] In this embodiment of the invention, the first shut-off valve 801 and the second shut-off valve 802 cannot be opened at the same time, nor can they be closed at the same time. Furthermore, when the second shut-off valve 802 is opened, the third shut-off valve 803 should be opened at the same time; however, when the third shut-off valve 803 is opened, the fourth shut-off valve 804 can be closed.

[0097] In one specific embodiment, reference is made to Figure 1 As shown, the drilling circulating fluid temperature control system may also include a sixth shut-off valve 806, which is located between the wellbore annulus 101 and the mud pit 1, and is used to control the flow of fluid between the wellbore annulus 101 and the mud pit 1.

[0098] In this embodiment of the invention, the first shut-off valve 801, the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, the fifth shut-off valve 805, and the sixth shut-off valve 806 are connected to an external electric control device, enabling automatic adjustment via the electric control device. Simultaneously, a manual control module is retained, and the manual control module has a higher priority than the automatic adjustment of the electric control device. In case of emergency, the electric adjustment can be cut off via the manual control module, switching to manual control of the shut-off valves to ensure operational safety. The configuration of the electric control device and the manual control module can be found in the detailed description of existing technologies, and will not be repeated here.

[0099] In one specific embodiment, reference is made to Figure 1 As shown, the ambient temperature storage tank 2 is equipped with a first thermometer 901; the cryogenic storage tank 3 is equipped with a second thermometer 902; the buffer tank 6 is equipped with a third thermometer 903; the outlet of the mixing valve 5 is equipped with a fourth thermometer 904; the mud tank 1 is equipped with a fifth thermometer 905; the coolant tank 401 is equipped with a sixth thermometer 906; the heat medium inlet of the heat exchanger 403 is equipped with a seventh thermometer 907; the heat medium outlet of the heat exchanger 403 is equipped with an eighth thermometer 908; the refrigerant inlet of the heat exchanger 403 is equipped with a ninth thermometer 909; and the refrigerant outlet of the heat exchanger 403 is equipped with a tenth thermometer 910. The aforementioned first thermometer 901, second thermometer 902, third thermometer 903, fourth thermometer 904, fifth thermometer 905, seventh thermometer 907, and eighth thermometer 908 are used to measure the temperature of the drilling circulating fluid at the corresponding locations. The sixth thermometer 906, the ninth thermometer 909, and the tenth thermometer 910 are used to measure the temperature of the coolant at the corresponding locations.

[0100] In one specific embodiment, reference is made to Figure 1 As shown, a first flow meter 1001 is installed between the ambient temperature storage tank 2 and the mixing valve 5; a second flow meter 1002 is installed between the cryogenic storage tank 3 and the mixing valve 5; a third flow meter 1003 is installed between the mud tank 1 and the ambient temperature storage tank 2; a fourth flow meter 1004 is installed between the ambient temperature storage tank 2 and the drill string 102; a fifth flow meter 1005 is installed between the mud tank 1 and the heat exchanger 403; a sixth flow meter 1006 is installed between the heat exchanger 403 and the cryogenic storage tank 3; a seventh flow meter 1007 is installed between the coolant tank 401 and the heat exchanger 403; and an eighth flow meter 1008 is installed between the coolant tank 401 and the refrigerator 402. The aforementioned first flow meter 1001, second flow meter 1002, third flow meter 1003, fourth flow meter 1004, fifth flow meter 1005, and sixth flow meter 1006 are used to detect the flow rate of the drilling circulating fluid at the corresponding locations. The seventh flow meter 1007 and the eighth flow meter 1008 are used to detect the flow rate of coolant at the corresponding locations.

[0101] In one specific embodiment, reference is made to Figure 1 As shown, the drilling circulating fluid temperature control system also includes a first pressure monitor 1101, a second pressure monitor 1102, and a third pressure monitor 1103. The first pressure monitor 1101 is installed in the ambient temperature storage tank 2 and is used to monitor the pressure inside the ambient temperature storage tank 2; the second pressure monitor 1102 is installed in the cryogenic storage tank 3 and is used to monitor the pressure inside the cryogenic storage tank 3; the third pressure monitor 1103 is installed in the buffer tank 6 and is used to monitor the pressure inside the buffer tank 6.

[0102] In one specific embodiment, reference is made to Figure 1 As shown, the first throttle valve 701 is simultaneously located between the ambient temperature storage tank 2, the mixing valve 5, and the drill string 102. When the first shut-off valve 801 is open and the second shut-off valve 802 is closed, the first throttle valve 701 is suitable for regulating the flow rate of the drilling circulating fluid between the ambient temperature storage tank 2 and the drill string 102; when the first shut-off valve 801 is closed and the second shut-off valve 802 is open, the first throttle valve 701 is suitable for regulating the flow rate of the drilling circulating fluid between the ambient temperature storage tank 2 and the mixing valve 5. A third throttle valve 703 is located between the mud tank 1 and the ambient temperature storage tank 2; a fourth throttle valve 704 is located between the mud tank 1 and the cryogenic storage tank 3; a fifth throttle valve 705 is located between the coolant tank 401 and the refrigerator 402; and a sixth throttle valve 706 is located between the coolant tank 401 and the cold source inlet of the heat exchanger 403. The third throttle valve 703 and the fourth throttle valve 704 are used to regulate the flow rate of the drilling circulating fluid at the corresponding locations. The fifth throttle valve 705 and the sixth throttle valve 706 are used to adjust the flow rate of the coolant at the corresponding positions; by adjusting the flow rate of the coolant from the coolant tank 401 to the refrigerator 402, the cooling rate of the coolant in the coolant tank 401 can be adjusted; by adjusting the flow rate of the coolant from the coolant tank 401 to the heat exchanger 403, the cooling rate of the drilling circulating fluid flowing through the heat exchanger 403 can be adjusted.

[0103] In one specific embodiment, reference is made to Figure 1As shown, the drilling circulating fluid temperature control system also includes a first delivery pump 1201, a second delivery pump 1202, a third delivery pump 1203, a fourth delivery pump 1204, a fifth delivery pump 1205, a sixth delivery pump 1206, a seventh delivery pump 1207, and an eighth delivery pump 1208. The first transfer pump 1201 is located between the wellbore annulus 101 and the mud tank 1, and is adapted to pump the drilling circulating fluid returning from the wellbore annulus 101 into the mud tank 1; the second transfer pump 1202 is located between the mud tank 1 and the ambient temperature storage tank 2, and is adapted to pump the drilling circulating fluid in the mud tank 1 into the ambient temperature storage tank 2; the third transfer pump 1203 is located between the ambient temperature storage tank 2 and the drill string 102 and the mixing valve 5, and is adapted to pump the drilling circulating fluid in the ambient temperature storage tank 2 into the drill string 102 or the mixing valve 5; the fourth transfer pump 1204 is located between the mud tank 1 and the heat exchanger 403, and is adapted to pump the drilling circulating fluid in the mud tank 1 into the heat exchanger 403 for cooling, and after cooling, the drilling circulating fluid is pumped to the cryogenic storage tank. Tank 3; the fifth transfer pump 1205 is located between the cryogenic storage tank 3 and the mixing valve 5, and is suitable for pumping the drilling circulating fluid in the cryogenic storage tank 3 into the mixing valve 5; the sixth transfer pump 1206 is located between the buffer tank 6 and the drill string 102, and is suitable for pumping the drilling circulating fluid in the buffer tank 6 into the drill string 102; the seventh transfer pump 1207 is located between the coolant tank 401 and the refrigerator 402, and is suitable for pumping the coolant in the coolant tank 401 into the refrigerator 402 for cooling; the eighth transfer pump 1208 is located between the coolant tank 401 and the heat exchanger 403, and is suitable for pumping the coolant in the coolant tank 401 into the heat exchanger 403 to exchange heat with the drilling circulating fluid flowing through the heat exchanger 403.

[0104] In this embodiment of the invention, the first delivery pump 1201, the second delivery pump 1202, the third delivery pump 1203, the fourth delivery pump 1204, the fifth delivery pump 1205, the sixth delivery pump 1206, the seventh delivery pump 1207 and the eighth delivery pump 1208 are all positive displacement pumps, which only allow the fluid to flow in one direction, avoid fluid backflow, and thus prevent the system from malfunctioning.

[0105] This invention provides a drilling circulating fluid temperature control system. The system uses a mixing valve 5 to mix the drilling circulating fluid flowing from the ambient temperature storage tank 2 and the cryogenic storage tank 3, resulting in a mixed drilling circulating fluid. A first throttle valve 701 and a second throttle valve 702 are used to regulate the temperature of the mixed drilling circulating fluid in the buffer tank 6. This allows the drilling circulating fluid to be rapidly cooled to a suitable temperature at the wellhead, improving the speed and accuracy of temperature control. By connecting the buffer tank 6 to the wellbore, the drilling circulating fluid at the target temperature in the buffer tank 6 can be directly introduced into the wellbore without waiting for the circulating fluid returning from the wellbore annulus to cool down. This significantly shortens the response time for drilling circulating fluid temperature control, enabling rapid temperature adjustment. The temperature-controlled drilling circulating fluid is directly fed into the wellbore, effectively ensuring wellbore stability and guaranteeing the safe exploration and development of deep wells, ultra-deep wells, and hydrate reservoirs in permafrost zones.

[0106] The drilling circulating fluid temperature control system provided in this invention comprises five main devices arranged around the wellbore: a mud pit 1, a normal temperature storage tank 2, a cooling device, a cryogenic storage tank 3, and a buffer tank 6. The connection between these five main devices is simple and clear, making the structure of the entire drilling circulating fluid temperature control system simple, easy to implement and apply. Furthermore, it reduces the overall cost of the drilling circulating fluid temperature control system, improves economic efficiency, and facilitates its widespread promotion and application.

[0107] Example 2

[0108] Based on the same inventive concept, this invention also provides a method for controlling the temperature of drilling circulating fluid, using the drilling circulating fluid temperature control system of Embodiment 1, with reference to... Figure 3 As shown, it includes:

[0109] S101: Obtain a preset first temperature, which is the inlet temperature of the drilling circulating fluid required for drilling operations;

[0110] S102: Determine whether the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is lower than the first preset temperature; if yes, proceed to step S103; if no, proceed to step S104.

[0111] S103: Pass the drilling circulating fluid in the ambient temperature storage tank 2 into the drill string;

[0112] S104: Determine whether the temperature of the drilling circulating fluid in the cryogenic storage tank 3 is lower than the first preset temperature; if yes, proceed to step S105; if no, proceed to step S106.

[0113] S105: The drilling circulating fluid in the low-temperature storage tank 3 and the drilling circulating fluid in the normal temperature storage tank 2 are introduced into the mixing valve 5, and after being mixed by the mixing valve 5, they are introduced into the buffer tank 6.

[0114] S106: The drilling circulating fluid that is about to enter the cryogenic storage tank 3 is cooled by the cooling device. The cooled drilling circulating fluid in the cryogenic storage tank 3 and the drilling circulating fluid in the normal temperature storage tank 2 are introduced into the mixing valve 5. After being mixed by the mixing valve 5, they are introduced into the buffer tank 6.

[0115] S107: Adjust the opening of the first throttle valve 701 and the second throttle valve 702 so that the temperature of the drilling circulating fluid at the outlet of the mixing valve 5 and the temperature of the drilling circulating fluid in the buffer tank 6 are both equal to the first preset temperature.

[0116] S108: Pass the drilling circulating fluid in the buffer tank 6 into the drill string.

[0117] In this embodiment of the invention, the first preset temperature can be determined based on the actual well depth, formation characteristics, etc. Taking the temperature regulation of the drilling circulating fluid in the drilling process of natural gas hydrate drilling as an example, when the temperature of the drilling circulating fluid at the actual drill string inlet is higher than the first preset temperature, it will cause the wellbore temperature at the reservoir location to rise, triggering the decomposition of hydrates in the already unstable solid phase of the reservoir, generating a large amount of gas in the reservoir, causing accidents such as formation slippage and blowouts. When the temperature of the drilling circulating fluid at the actual drill string inlet is lower than the first preset temperature, it will cause the overall temperature of the entire wellbore section to decrease, making it easier for gas components in the annulus fluid to generate hydrates in the annulus, thereby clogging the wellbore and causing accidents such as annulus flow obstruction and wellbore instability. It can be seen that both excessively high and excessively low temperatures of the drilling circulating fluid at the actual drill string inlet will affect the wellbore safety during drilling operations. Therefore, the first preset temperature needs to be reasonably determined based on the actual well depth, formation characteristics, etc.

[0118] In this embodiment, the specific process of cooling the drilling circulating fluid that is about to enter the cryogenic storage tank 3 using a cooling device may include:

[0119] In this embodiment of the invention, the coolant in the coolant tank 401 is pumped into the refrigerator 402. After the coolant is cooled to a second preset temperature, it returns to the coolant tank 401. The coolant circulates between the coolant tank 401 and the refrigerator 402 to maintain the low temperature of the coolant in the coolant tank 401. At the same time, the low-temperature coolant in the coolant tank 401 is pumped into the heat exchanger 403. The coolant exchanges heat with the drilling circulating fluid that is about to enter the low-temperature storage tank 3 in the heat exchanger 403, thereby reducing the temperature of the drilling circulating fluid that is about to enter the low-temperature storage tank 3 to a third preset temperature. The coolant that has been heated by the heat exchange returns to the coolant tank 401. When cooling the drilling circulating fluid pumped from mud pit 1 to cryogenic storage tank 3, the opening of the throttle valve on the connection circuit between coolant tank 401 and heat exchanger 403 is adjusted according to the operating standards of heat exchanger 403 and the required temperature reduction of the drilling circulating fluid. This adjusts the appropriate coolant discharge rate through heat exchanger 403, ensuring that the ambient temperature drilling circulating fluid is reduced to a suitable temperature after passing through heat exchanger 403. The temperature of the drilling circulating fluid in cryogenic storage tank 3 is denoted as T. L The temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is T. N Let the first preset temperature be denoted as T. pi The temperature drop of the drilling circulating fluid is denoted as ΔT, and the temperature after cooling is T. L T should be satisfied pi -ΔT <T L ≤T pi ΔT should be reasonably determined based on the actual drilling conditions.

[0120] In this embodiment of the invention, if the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is lower than the first preset temperature, the drilling circulating fluid in the ambient temperature storage tank 2 is directly introduced into the drill string. At this time, the first shut-off valve 801 is open, and the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 are all closed. If the temperature of the drilling circulating fluid in the ambient temperature storage tank 2 is not lower than the first preset temperature but not lower than the first preset temperature, it is necessary to mix the drilling circulating fluid flowing out of the ambient temperature storage tank 2 and the drilling circulating fluid flowing out of the cryogenic storage tank 3. At this time, the first shut-off valve 801 is closed, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 are open, and the second shut-off valve 802 is either open or closed.

[0121] In one specific embodiment, before adjusting the opening degrees of the first throttle valve 701 and the second throttle valve 702 to ensure that the temperature of the drilling circulating fluid at the outlet of the mixing valve 5 and the temperature of the drilling circulating fluid in the buffer tank 6 are both equal to the first preset temperature, it is necessary to calculate the mixing ratio of the drilling circulating fluid flowing out of the cryogenic storage tank 3 and the drilling circulating fluid flowing out of the ambient temperature storage tank 2. Based on the mixing ratio of the drilling circulating fluid flowing out of the cryogenic storage tank 3 and the drilling circulating fluid flowing out of the ambient temperature storage tank 2, the adjustment size of the opening degrees of the first throttle valve 701 and the second throttle valve 702 is determined. This allows for adjusting the mixing ratio of the ambient temperature drilling circulating fluid flowing out of the ambient temperature storage tank 2 and the cryogenic drilling circulating fluid flowing out of the cryogenic storage tank 3 according to the required fluid temperature in the buffer tank 6, until the temperature of the mixed drilling circulating fluid equals the first preset temperature. The specific calculation process for the mixing ratio of the ambient temperature drilling circulating fluid and the cryogenic drilling circulating fluid flowing out of the cryogenic storage tank 3 is as follows:

[0122] The temperature T of the ambient temperature drilling circulating fluid (drilling circulating fluid in ambient temperature storage tank 2) is known. H Volumetric flow rate Q of circulating fluid in ambient temperature drilling vH The temperature T of the cryogenic drilling circulating fluid (drilling circulating fluid in cryogenic storage tank 3) L Volumetric flow rate Q of cryogenic drilling circulating fluid vL The temperature T of the mixed drilling circulation fluid (the drilling circulation fluid flowing out of mixing valve 5) mix And the pipe cross-sectional area A, and the specific heat capacity C of the mixed drilling circulating fluid. m and density ρ m All are known. Let ΔT be... H and ΔT L Let be the temperature changes after mixing the ambient temperature drilling circulating fluid and the cryogenic drilling circulating fluid, respectively. Then:

[0123]

[0124] When fluid flows in a pipe, there are density formulas and volumetric flow rates Q. v Calculation formula and mass flow rate Q m The calculation formulas, when combined, yield:

[0125]

[0126] In the formula: v (m / s) is the fluid velocity in the pipe, m (kg) is the mass of the fluid flowing through the pipe, and ρ is the density;

[0127] According to Formula 2, we can obtain:

[0128]

[0129] According to the law of conservation of energy, combined with Equation 1, we can obtain:

[0130] C m ×m H (T H -T mix ) = C m ×m L (T mix -T L ), formula 4;

[0131] Where: m H (kg) represents the mass of the ambient temperature drilling circulating fluid flowing through the pipeline between ambient temperature storage tank 2 and mixing valve 5; m L (kg) represents the mass of cryogenic drilling circulating fluid in the pipeline between cryogenic storage tank 3 and mixing valve 5;

[0132] According to Formula 4, we can obtain:

[0133]

[0134] Combining equations 3 and 5, we can obtain:

[0135]

[0136] In the formula: Q vH (m 3 / s) is the volumetric flow rate of the ambient temperature drilling circulation in the pipeline between ambient temperature storage tank 2 and mixing valve 5; Q vL (m 3 / s) is the volumetric flow rate of the ambient temperature drilling circulation in the pipeline between the ambient temperature storage tank 2 and the mixing valve 5.

[0137] If the required temperature of the drilling circulation fluid in buffer tank 6 (i.e., the temperature T of the mixed drilling circulation fluid) is determined... mix The volumetric flow rate of the ambient temperature drilling circulation in the pipeline between the ambient temperature storage tank 2 and the mixing valve 5 can be calculated according to Formula 6. The ratio of the volumetric flow rate of the ambient temperature drilling circulation in the pipeline between the ambient temperature storage tank 2 and the mixing valve 5 can then be adjusted according to the calculated ratio until the temperature of the drilling circulation fluid in the buffer pipe reaches the target temperature.

[0138] In this embodiment of the invention, the temperature of the drilling circulating fluid in the buffer tank 6 is denoted as T. in Let the first preset temperature be denoted as T. pi The temperature of the drilling circulating fluid at the outlet of mixing valve 5 is denoted as T. mix The opening degrees of the first throttle valve 701 and the second throttle valve 702 are adjusted so that the temperature of the drilling circulating fluid at the outlet of the mixing valve 5 and the temperature of the drilling circulating fluid in the buffer tank 6 are both equal to the first preset temperature, as per the reference. Figure 4 As shown, the specific steps may include:

[0139] S1071: Determine T in Is it equal to T? pi If yes, proceed to step S1072; otherwise, proceed to step S1073.

[0140] S1072: Then the opening of the first throttle valve 701 and the second throttle valve 702 will not be adjusted;

[0141] S1073: Determine T in Is it greater than T? pi If yes, proceed to step S1074; otherwise, proceed to step S1075.

[0142] S1074: Increase the opening of the second throttle valve 702, and / or decrease the opening of the first throttle valve 701, and adjust T pi and T in The size relationship is continuously judged until T. pi =T in ;

[0143] S1075: Increase the opening of the first throttle valve 701, and / or decrease the opening of the second throttle valve 702, and adjust T... pi and T in The size relationship is continuously judged until T. pi =T in .

[0144] In this embodiment of the invention, if T in greater than T pi By increasing the opening of the second throttle valve 702 and / or decreasing the opening of the first throttle valve 701, and affecting T... pi and T in The size relationship is continuously judged until T. pi =T in Afterwards, it is necessary to appropriately reduce the opening of the second throttle valve 702, and / or appropriately increase the opening of the first throttle valve 701, and adjust T accordingly. pi T in and T mix The size relationship is continuously judged until T. pi =T in =T mix In T pi =T in Previously, if T in greater than T pi The temperature T of the mixed drilling circulating fluid flowing into buffer tank 6 mix It must be lower than T in Only then can T be gradually reduced in Therefore, in T pi =Tin Afterwards, the temperature T of the mixed drilling circulating fluid must be appropriately increased. mix To ensure T in =T pi =T mix Thus ensuring T in No more because of T mix And change.

[0145] In this embodiment of the invention, if T in less than T pi By increasing the opening of the first throttle valve 701 and / or decreasing the opening of the second throttle valve 702, and affecting T... pi and T in The size relationship is continuously judged until T. pi =T in Afterwards, it is necessary to appropriately reduce the opening of the first throttle valve 701 and / or appropriately increase the opening of the second throttle valve 702, and adjust T accordingly. pi T in and T mix The size relationship is continuously judged until T. pi =T in =T mix In T pi =T in Previously, if T in less than T pi The temperature T of the mixed drilling circulating fluid flowing into buffer tank 6 mix It must be higher than T in Only then can T gradually increase in Therefore, in T pi =T in Afterwards, the temperature T of the mixed drilling circulating fluid must be appropriately reduced. mix To ensure T in =T pi =T mix Thus ensuring T in No more because of T mix And change.

[0146] In one specific embodiment, reference is made to Figure 1 and Figure 5 As shown, in the drilling circulating fluid temperature control method, the switching logic of the first shut-off valve 801, the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 is as follows:

[0147] When the drilling circulating fluid returning from the wellbore annulus does not require cooling treatment, the first shut-off valve 801 opens, and the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804 and the fifth shut-off valve 805 close.

[0148] When the drilling circulating fluid returning from the wellbore annulus needs to be cooled, there are two scenarios: If it is necessary to mix the normal temperature drilling circulating fluid and the cryogenic drilling circulating fluid, then the first shut-off valve 801 is closed, and the second shut-off valve 802, the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 are open; if only the cryogenic circulating fluid is needed, then the first shut-off valve 801 and the second shut-off valve 802 are closed, and the third shut-off valve 803, the fourth shut-off valve 804, and the fifth shut-off valve 805 are closed.

[0149] The drilling circulating fluid temperature control method provided in this invention achieves a gradient reduction in the drilling circulating fluid temperature by mixing ambient temperature drilling circulating fluid and low temperature drilling circulating fluid. The drilling circulating fluid does not need to undergo continuous temperature changes, but the temperature of the drilling circulating fluid is rapidly reduced to the target temperature through mixing, thereby significantly reducing the time required for cooling the drilling circulating fluid.

[0150] The drilling circulating fluid temperature control method provided in this invention can quickly adopt corresponding strategies based on the drilling circulating fluid inlet temperature required for drilling operations, rapidly adjust the temperature of the drilling circulating fluid during the drilling process, and directly pump the drilling circulating fluid at the appropriate temperature into the wellbore. This reduces the time spent on drilling circulating fluid temperature control before well entry, enables timely control of the wellbore temperature, ensures wellbore stability, prevents the occurrence of complex downhole risks, and thus ensures the safety of drilling operations.

[0151] Example 3

[0152] Based on the same inventive concept, this invention also provides an application of a drilling circulating fluid temperature control system in drilling circulating fluid temperature control.

[0153] In this embodiment of the invention, the application of the drilling circulating fluid temperature control system in drilling circulating fluid temperature control can refer to the process of using the drilling circulating fluid temperature control system to achieve drilling circulating fluid temperature control in the above embodiment one. The repeated parts will not be described again here.

[0154] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A drilling circulating fluid temperature regulation system in connection with a wellbore, characterized by, It includes mud pits, ambient temperature storage tanks, cryogenic storage tanks, cooling devices, mixing valves, buffer tanks, first throttle valves, and second throttle valves; The mud pit is connected to the wellbore annulus so that the drilling circulating fluid in the wellbore annulus can enter the mud pit; The mud tank is connected to the ambient temperature storage tank and the cryogenic storage tank respectively; the cooling device is installed between the mud tank and the cryogenic storage tank; The ambient temperature storage tank and the cryogenic storage tank are respectively connected to the buffer tank via the mixing valve; the mixing valve is adapted to mix the drilling circulation fluid flowing out of the ambient temperature storage tank with the drilling circulation fluid flowing out of the cryogenic storage tank; The buffer tank is connected to the drill string inside the wellbore and is suitable for storing drilling circulating fluid at the target temperature flowing out from the mixing valve; The first throttle valve is disposed between the ambient temperature storage tank and the mixing valve, and is suitable for adjusting the flow rate of drilling circulating fluid between the ambient temperature storage tank and the mixing valve; The second throttle valve is disposed between the cryogenic storage tank and the mixing valve, and is suitable for adjusting the flow rate of the drilling circulating fluid between the cryogenic storage tank and the mixing valve; The first throttle valve and the second throttle valve can adjust the mixing ratio of the ambient temperature drilling circulation fluid flowing out of the ambient temperature storage tank and the low temperature drilling circulation fluid flowing out of the low temperature storage tank until the temperature of the mixed drilling circulation fluid reaches the target temperature.

2. The drilling circulating fluid temperature regulation system of claim 1, wherein, The cooling device includes a refrigerator, a coolant tank, and a heat exchanger connected in sequence. The refrigerator is adapted to circulate and cool the coolant in the coolant tank, and the coolant in the coolant tank can flow through the heat exchanger and return to the coolant tank; The heat exchanger is connected to the mud pit and the cryogenic storage tank respectively, so that the drilling circulating fluid in the mud pit flows through the heat exchanger and then into the cryogenic storage tank for storage.

3. The drilling circulating fluid temperature regulation system of claim 1, wherein, It also includes a first shut-off valve, a second shut-off valve, a third shut-off valve, a fourth shut-off valve, and a fifth shut-off valve; The first shut-off valve is located between the ambient temperature storage tank and the drill string; The second shut-off valve is located between the ambient temperature storage tank and the mixing valve; The third shut-off valve is located between the mud pit and the cryogenic storage tank; The fourth shut-off valve is located between the cryogenic storage tank and the mixing valve; The fifth shut-off valve is located between the buffer tank and the drill string.

4. The drilling circulating fluid temperature regulation system of claim 1, wherein, The ambient temperature storage tank is equipped with a first thermometer; And / or, the cryogenic storage tank is equipped with a second thermometer; And / or, the buffer tank is equipped with a third thermometer; And / or, the outlet of the mixing valve is provided with a fourth thermometer.

5. The drilling circulating fluid temperature regulation system of claim 1, wherein, A first flow meter is installed between the ambient temperature storage tank and the mixing valve; A second flow meter is installed between the cryogenic storage tank and the mixing valve.

6. The drilling circulating fluid temperature regulation system of any of claims 1-5, wherein, The ambient temperature storage tank is connected to the drill string.

7. A method of temperature regulation of a drilling circulating fluid using the temperature regulation system of any one of claims 1 to 6, characterized in that, include: Obtain a pre-set first preset temperature, which is the inlet temperature of the drilling circulating fluid required for drilling operations; Determine whether the temperature of the drilling circulating fluid in the ambient temperature storage tank is lower than the first preset temperature; If so, the drilling circulating fluid in the ambient temperature storage tank is introduced into the drill string; If not, determine whether the temperature of the drilling circulating fluid in the cryogenic storage tank is lower than the first preset temperature; If so, the drilling circulating fluid in the cryogenic storage tank and the drilling circulating fluid in the ambient temperature storage tank are introduced into the mixing valve, and after being mixed by the mixing valve, they are introduced into the buffer tank; If not, the drilling circulating fluid that is about to enter the cryogenic storage tank is cooled by a cooling device, and the cooled drilling circulating fluid in the cryogenic storage tank and the drilling circulating fluid in the normal temperature storage tank are introduced into the mixing valve, mixed by the mixing valve and then introduced into the buffer tank. Adjust the opening of the first throttle valve and the second throttle valve so that the temperature of the drilling circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank are both equal to the first preset temperature. The drilling circulating fluid in the buffer tank is introduced into the drill string.

8. The method of temperature regulation of a drilling circulating fluid of claim 7, wherein, Before adjusting the opening of the first and second throttle valves to ensure that the temperature of the circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank are both equal to the first preset temperature, the process also includes: Calculate the mixing ratio of drilling circulation fluid flowing out of the cryogenic storage tank and drilling circulation fluid flowing out of the ambient temperature storage tank; The opening adjustment values ​​of the first and second throttle valves are determined based on the mixing ratio of the drilling circulation fluid flowing out of the cryogenic storage tank and the drilling circulation fluid flowing out of the ambient temperature storage tank.

9. The method of temperature regulation of a drilling circulating fluid of claim 8, wherein, The calculation of the mixing ratio of drilling circulation fluid flowing out of the cryogenic storage tank and drilling circulation fluid flowing out of the ambient temperature storage tank includes: Based on the temperatures of the drilling circulation fluid flowing out of the ambient temperature tank, the cryogenic temperature tank, and the mixing valve, the mixing ratio of the drilling circulation fluid flowing out of the cryogenic tank and the ambient temperature tank is calculated using the following formula 1: , Equation 1 where T H is the temperature of the drilling circulating fluid flowing from the ambient temperature storage tank, Q vH is the volumetric flow rate of the drilling circulating fluid flowing from the ambient temperature storage tank, T L is the temperature of the drilling circulating fluid flowing from the low temperature storage tank, Q vL is the volumetric flow rate of the drilling circulating fluid flowing from the low temperature storage tank, T mix is the temperature of the drilling circulating fluid flowing from the mixing valve.

10. The method of temperature regulation of a drilling circulating fluid of claim 7, wherein, Adjusting the opening of the first and second throttle valves so that the temperature of the drilling circulating fluid at the outlet of the mixing valve and the temperature of the drilling circulating fluid in the buffer tank are both equal to the first preset temperature includes: Determine whether the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature; If so, then the opening of the first throttle valve and the second throttle valve will not be adjusted; If not, determine whether the temperature of the drilling circulating fluid in the buffer tank is greater than the first preset temperature; If so, increase the opening of the second throttle valve, and / or decrease the opening of the first throttle valve until the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature; If not, increase the opening of the first throttle valve and / or decrease the opening of the second throttle valve until the temperature of the drilling circulating fluid in the buffer tank is equal to the first preset temperature.

11. The method of temperature regulation of a drilling circulating fluid of claim 10, wherein, After increasing the opening of the second throttle valve and / or decreasing the opening of the first throttle valve until the temperature of the drilling circulating fluid in the buffer tank equals the first preset temperature, the method further includes: Decrease the opening of the second throttle valve, and / or increase the opening of the first throttle valve until the temperature of the drilling circulating fluid at the outlet of the mixing valve is equal to the first preset temperature.

12. The method of temperature regulation of a drilling circulating fluid of claim 10, wherein, After increasing the opening of the first throttle valve and / or decreasing the opening of the second throttle valve until the temperature of the drilling circulating fluid in the buffer tank equals the first preset temperature, the method further includes: reducing the opening of the first choke valve and / or increasing the opening of the second choke valve until the temperature of the drilling circulating fluid at the outlet of the mixing valve equals a first predetermined temperature.

13. Use of the drilling circulating fluid temperature regulating system according to any one of claims 1-6 for regulating the temperature of a drilling circulating fluid.

Images