A hot water circulating device for fracturing an oil and water well

Abstract

The utility model discloses a hot water circulating device for oil-water well fracturing, including steam injection boiler, and is linked with heat exchanger, heat exchanger is linked with steam injection boiler, water pump and import valve group respectively, water pump is linked with export valve group in one end, and is linked with heat exchanger in the other end, import valve group is linked with heat exchanger in one end, and is linked with liquid storage tank group in the other end, liquid storage tank group is linked with import valve group in one end, and is linked with export valve group in the other end, export valve group is linked with liquid storage tank group in one end, and is linked with water pump in one way in the other end, and is linked with thousand type fracturing car group suction end in another way, the utility model has the beneficial effects that structure and operation are simple, and the performance is reliable, and process pressure, temperature and performance are stable, and the maximum amount of one cycle heating is 800 square, can satisfy one conventional fracturing construction demand, can guarantee that fracturing fluid temperature in well is above 60 degrees, effectively reduces the cold injury of low temperature fracturing fluid to formation, protects oil reservoir to the maximum extent, improves oil-water well fracturing effect.

Description

Technical Field

[0001] This utility model relates to the field of oil production engineering technology, specifically to a hot water circulation device for fracturing oil and water wells. Background Technology

[0002] In oil extraction, oil-water wells are an important method for enhancing oil and gas production. Conventional oil well fracturing fluids are typically room-temperature liquids around 20 degrees Celsius. However, a certain oil reservoir is a high-pour-point heavy oil reservoir, with crude oil having a pour point of only around 40 degrees Celsius. High-pour-point heavy oil is a crucial resource for global economic development. According to 2019 statistics, the world's proven heavy oil reserves are approximately 815 billion tons, accounting for 70% of global remaining oil reserves. my country's high-pour-point heavy oil resources are approximately 19.87 billion tons. High-pour-point heavy oil is characterized by a high pour point, high viscosity, and poor fluidity. Some blocks of high-pour-point heavy oil also contain high levels of wax and asphalt resin.

[0003] The introduction of large quantities of ambient or cryogenic fracturing fluid into the formation can lower the reservoir temperature, causing high-pour-point heavy oil to precipitate wax and solidify under these conditions, blocking oil flow channels and significantly increasing crude oil viscosity. This reduces formation permeability and hinders subsequent oil extraction, especially in winter when temperatures drop below -20°C. Large quantities of cryogenic fracturing fluid entering the oil layer require over 24 hours to reach formation temperature (approximately 60°C), during which time the cryogenic fluid continuously causes cold damage to the high-pour-point crude oil. In severe cases, this can lead to the precipitation of asphaltenes and waxes from the crude oil, forming irreversible organic blockages and causing reservoir cold damage, resulting in unsatisfactory development outcomes. Therefore, high-temperature fracturing fluids are necessary. Currently, due to limitations in insulation conditions during transportation and cost factors, heating the working fluid is not only a complex process but also consumes a large amount of energy, increasing development costs. Large-scale transportation of hot fracturing fluid is also impossible, especially during volumetric fracturing, where it is difficult to heat thousands of cubic meters of fracturing fluid in a short period. There is an urgent need for a high-performance hot water circulation device for oil and water well fracturing, which can achieve on-site liquid circulation heating to meet the requirements for high-temperature fracturing fluid preparation.

[0004] Existing technology discloses an automatic water-filling thermal storage electric boiler device (disclosure number CN218210109U). This automatic water-filling thermal storage electric boiler uses multiple electric heating components evenly distributed vertically within the boiler's heating tank to simultaneously heat different sections of water, thus improving hydrothermal efficiency. However, this technical solution does not consider achieving a circulating heating temperature of 85 degrees Celsius within a short time, which cannot meet the construction requirements of oil and water well fracturing sites. To address these technical needs, this paper studies a hot water circulation device for oil and water well fracturing to effectively solve the high-temperature fracturing fluid preparation requirements of fracturing wells in high-viscosity oil reservoirs. Utility Model Content

[0005] The purpose of this invention is to provide a hot water circulation device for oil and water well fracturing, which circulates and heats liquids at the fracturing site to meet the requirements for low-cost and high-efficiency high-temperature fracturing fluid preparation.

[0006] The hot water circulation device for fracturing oil and water wells described in this utility model includes: A steam injection boiler, connected to a heat exchanger, is used to generate high-temperature softened water, which is then depressurized and sent to the heat exchanger. The heat exchanger is connected to the steam injection boiler, water pump and inlet valve group respectively, and is used to exchange heat between the high temperature softened water generated by the steam injection boiler and the low temperature fracturing fluid sent by the water pump. The water pump has one end connected to the water supply system to inject the required cryogenic fracturing fluid into the storage tank group, and the other end connected to the outlet valve group and the other end connected to the heat exchanger to send the cryogenic fracturing fluid from the outlet valve group into the heat exchanger and provide circulation power. The imported valve assembly is connected to the heat exchanger at one end and to the storage tank assembly at the other end. It is used to send the high-temperature fracturing fluid after heat exchange in the heat exchanger into the storage tank assembly. The storage tank group is connected to the inlet valve group at one end and the outlet valve group at the other end, and is used to store fracturing fluid that requires circulating heat exchange. The outlet valve assembly is connected to the storage tank assembly at one end and to a water pump at the other end. One end is used to send the low-temperature fracturing fluid from the storage tank assembly into the water pump. The other end is connected to the suction end of the fracturing truck assembly, which is used to pump the high-temperature fracturing fluid that meets the construction requirements into the formation through the fracturing truck assembly to complete the fracturing operation.

[0007] Preferably, the water pump is connected to the outer tube of the heat exchanger, and the steam injection boiler is connected to the inner tube of the heat exchanger.

[0008] Preferably, a liquid level float is installed on the liquid storage tank assembly, and a temperature monitoring instrument is installed on the outlet valve assembly.

[0009] Preferably, the steam injection boiler has a pressure of 15-30 MPa, a temperature of 300-450 degrees Celsius, a flow rate of 7-11 T / H, and a burner power of 20-30 MMBTU.

[0010] Preferably, the steam injection boiler is a subcritical pressure boiler. The fuel required for heating is diesel oil. It also has a small footprint and is easy to transport.

[0011] Preferably, the water pump is specifically two or more multi-stage centrifugal pumps. Based on the structural characteristics of existing steam injection boilers, multi-stage centrifugal pumps are selected as the inlet water pumps.

[0012] Preferably, each centrifugal pump has a pressure of 0.2-2 MPa and a water flow rate of 30-100 m³. 3 / H.

[0013] Preferably, the liquid storage tank assembly includes two or more liquid storage tanks. The standard volume of the liquid storage tank is 100 cubic meters. If the liquid storage tanks are too large, they are difficult to move; if they are too small, too many are required, resulting in a large footprint.

[0014] The working principle of a hot water circulation system for oil and water well fracturing: After the storage tank assembly is placed at the fracturing well site, the inlet valve assembly, outlet valve assembly, and pipeline are connected to its lower part. A steam injection boiler and heat exchanger are installed according to the actual site conditions. A level float is installed on the storage tank assembly, and a temperature monitoring instrument is installed on the outlet valve assembly. Before heating, 800 cubic meters of low-temperature fracturing fluid are injected into the storage tank assembly. Softened water is added to the steam injection boiler. The steam injection boiler is started, and the softened water in the boiler is heated to 370 degrees Celsius using diesel combustion, forming high-temperature softened water. The storage tank assembly is connected to the outer tube of the heat exchanger for external circulation via the outlet valve assembly, water pump, and pipeline. The steam injection boiler is connected to the inner tube of the heat exchanger for internal circulation. The outlet valve assembly is opened, allowing the low-temperature fracturing fluid in the storage tank assembly to flow into the outer tube of the heat exchanger. The low-temperature fracturing fluid and high-temperature softened water exchange heat through the outer and inner tubes of the heat exchanger, achieving the purpose of raising the temperature of the low-temperature fracturing fluid. The fracturing fluid, pumped back to the storage tank by the water pump through the inlet valve assembly, is heated to increase its temperature. Ground operators monitor the fluid level in the storage tank using a float valve to prevent overflow, and monitor the temperature rise using a temperature monitoring instrument on the outlet valve assembly. Circulation and heating cease only when the required site temperature is met. The heated, high-temperature fracturing fluid is pre-stored in the storage tank assembly. When needed, it is fed into the suction end of the fracturing truck through the outlet valve assembly and then pumped into the formation to complete the fracturing operation. After fracturing is completed, all equipment is dismantled.

[0015] The beneficial effects of this utility model are as follows: 1. It has a simple and unique structure, and its working principle meets the requirements of the oil well field process. It is easy to operate and has reliable performance.

[0016] 2. The process pressure, temperature, and performance are stable, which helps eliminate potential safety hazards on site. It effectively meets the actual needs of on-site operators.

[0017] 3. At the fracturing well site, the low-temperature fracturing fluid is circulated and heated from 20 degrees to 85 degrees. The maximum heating capacity for one cycle is 800 cubic meters, which can meet the needs of a conventional fracturing operation.

[0018] 4. It can ensure that the temperature of the fracturing fluid entering the well is above 60 degrees Celsius, effectively reducing the cold damage of low-temperature fracturing fluid to the formation, maximizing the protection of the oil reservoir, and improving the fracturing effect of oil and water wells. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a hot water circulation device for fracturing oil and water wells.

[0020] In the diagram: 1. Steam injection boiler; 2. Water pump; 3. Heat exchanger; 4. Inlet valve assembly; 5. Liquid storage tank assembly; 6. Outlet valve assembly. Detailed Implementation

[0021] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this utility model or its application or use. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] Example 1: Based on the analysis of historical fracturing effects and the current fracturing status of a certain block, the fracturing fluid volume is determined to be between 600-1000 cubic meters. Taking the average value, this example requires heating capacity for at least 800 cubic meters of fracturing fluid. Considering both fracturing needs and heat loss, this process requires heating and on-site construction to be completed on the same day. On-site construction time generally takes 4 hours, therefore, the maximum heating time is calculated as 12 hours, with the temperature rising from 20 degrees Celsius to 85 degrees Celsius, a temperature difference of 65 degrees Celsius. The total heat required is 2 × 10⁻⁶. 8 1,000 joules.

[0025] like Figure 1 As shown, this embodiment provides a hot water circulation device for fracturing oil and water wells, including: Steam injection boiler 1 is connected to heat exchanger 3 to generate high-temperature softened water, which is then depressurized and sent into heat exchanger 3. The heat exchanger is connected to the steam injection boiler 1, the water pump 2 and the inlet valve group 4 respectively, and is used to exchange heat between the high temperature softened water generated by the steam injection boiler 1 and the low temperature fracturing fluid sent by the water pump 2. Pump 2 has one end connected to the water supply system to inject 800 cubic meters of cryogenic fracturing fluid into the storage tank group 5, and the other end connected to the outlet valve group 6 and the other end connected to the heat exchanger 3 to send the cryogenic fracturing fluid from the outlet valve group 6 into the heat exchanger 3 and provide circulation power. The inlet valve group 4 is connected to the heat exchanger 3 at one end and to the liquid storage tank group 5 at the other end. It is used to send the high-temperature fracturing fluid after heat exchange in the heat exchanger 3 into the liquid storage tank group 5. Storage tank group 5 is connected at one end to inlet valve group 4 and at the other end to outlet valve group 6, and is used to store fracturing fluid that requires circulating heat exchange. The outlet valve assembly 6 is connected at one end to the storage tank assembly 5 and at the other end to the water pump 2. It is used to send the low-temperature fracturing fluid in the storage tank assembly 5 into the water pump 2. The other end is connected to the suction end of the fracturing truck assembly, which is used to pump the high-temperature fracturing fluid that meets the construction requirements into the formation through the fracturing truck assembly to complete the fracturing operation.

[0026] The water pump 2 is connected to the outer tube of the heat exchanger 3, and the steam injection boiler 1 is connected to the inner tube of the heat exchanger 3.

[0027] A liquid level float is installed on the liquid storage tank group 5, and a temperature monitoring instrument is installed on the outlet valve group 6.

[0028] The steam injection boiler 1 is a YZG9.2-21-D type, with a pressure of 21 MPa, a temperature of 370 degrees Celsius, a flow rate of 9.2 T / H, and a burner power of 25 MMBTU. The steam injection boiler 1 can provide a total heat of 2.4 × 10⁻⁶ liters per second in 12 hours. 8 kilojoules, greater than the total heat required on site 2×10 8 The steam injection boiler 1 has a capacity of kilojoules, thus meeting the requirements for on-site construction.

[0029] The steam injection boiler 1 is a subcritical pressure boiler. It requires diesel fuel for heating and is small in size and easy to transport.

[0030] Pump 2 is a multi-stage centrifugal pump with a pressure of 0.5 MPa and a flow rate of 50 cubic meters per hour. Heating 800 cubic meters of fracturing fluid from 20 degrees Celsius to 85 degrees Celsius requires three cycles of heating. An additional pump is needed for preheating and also serves as a backup. Therefore, four centrifugal pumps are required to meet the actual needs. Usage: One pump is used for preheating, and four pumps are used for circulating heating.

[0031] The liquid storage tank group 5 includes 12 liquid storage tanks. The standard volume of each liquid storage tank is 100 cubic meters. If the liquid storage tanks are too large, they are difficult to move; if they are too small, too many are needed, and they occupy too much land.

[0032] Example 2: Working principle of hot water circulation device for oil and water well fracturing: After the storage tank group 5 is placed at the fracturing well site, the inlet valve group 4, outlet valve group 6 and pipeline are connected to its lower part. The steam injection boiler 1 and heat exchanger 3 are installed according to the actual site conditions. A liquid level float is installed on the storage tank group 5, and a temperature monitoring instrument is installed on the outlet valve group 6. Before heating, 800 cubic meters of cryogenic fracturing fluid are injected into the storage tank group 5 via water pump 2. Softened water is added to the steam injection boiler 1, and the steam injection boiler 1 is started to heat the softened water in the steam injection boiler 1 to 370 degrees Celsius through diesel combustion, forming high-temperature softened water. The storage tank group 5 is connected to the outer tube of the heat exchanger 3 for external circulation via pipelines, outlet valve group 6, and water pump 2. The steam injection boiler 1 is connected to the inner tube of the heat exchanger 3 for internal circulation. The outlet valve group 6 is opened to allow the cryogenic fracturing fluid in the storage tank group 5 to flow into the outer tube of the heat exchanger 3. The cryogenic fracturing fluid and the high-temperature softened water exchange heat through the outer and inner tubes of the heat exchanger 3, thereby raising the temperature of the cryogenic fracturing fluid. The purpose of raising the temperature is to pump the heated fracturing fluid back to the storage tank group 5 through the inlet valve group 4 under the action of water pump 2, thereby achieving the goal of increasing the temperature. Ground operators observe the fluid level in the storage tank group 5 through a level float installed on it to prevent overflow, and monitor the temperature rise of the fracturing fluid through a temperature monitoring instrument installed on the outlet valve group 6. The circulation heating stops only when the required site temperature is met. The heated, high-temperature fracturing fluid, meeting the construction requirements, is pre-stored in the storage tank group 5. When needed, it is fed into the suction end of the fracturing truck through the outlet valve group 6, and then pumped into the formation by the fracturing truck to complete the fracturing operation. After the fracturing operation is completed, all equipment is dismantled.

[0033] This invention relates to a hot water circulation device for oil and water well fracturing. It circulates and heats the fracturing fluid at the fracturing well site, raising it from approximately 20 degrees Celsius to approximately 85 degrees Celsius. A single circulation can heat up to 800 cubic meters of fracturing fluid, sufficient for a typical fracturing operation. The fracturing fluid, heated by this device, is pumped into the formation via a fracturing truck. Its temperature remains above 55 degrees Celsius, exceeding the 40-degree Celsius pour point of most high-viscosity oils. Therefore, it avoids relying on formation temperature for heat exchange, preventing a rapid drop in oil layer temperature and the resulting wax solidification that could block oil flow. This effectively prevents cold damage to the formation from the incoming low-temperature fracturing fluid, maximizing reservoir protection and improving the fracturing effect of oil and water wells.

Claims

1. A hot water circulation device for fracturing oil and water wells, characterized in that: include: Steam injection boiler (1) is connected to heat exchanger (3); The heat exchanger (3) is connected to the steam injection boiler (1), the water pump (2) and the inlet valve group (4) respectively; The water pump (2) has one end connected to the water supply system, the other end connected to the outlet valve group (6), and the other end connected to the heat exchanger (3); The inlet valve assembly (4) is connected at one end to the heat exchanger (3) and at the other end to the liquid storage tank assembly (5); The liquid storage tank group (5) is connected at one end to the inlet valve group (4) and at the other end to the outlet valve group (6); The outlet valve assembly (6) is connected at one end to the liquid storage tank assembly (5), and at the other end, one path is connected to the water pump (2), and the other path is connected to the suction end of the fracturing truck assembly.

2. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: The water pump (2) is connected to the outer tube of the heat exchanger (3), and the steam injection boiler (1) is connected to the inner tube of the heat exchanger (3).

3. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: A liquid level float is installed on the liquid storage tank group (5).

4. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: Temperature monitoring instruments are installed on the outlet valve assembly (6).

5. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: The steam injection boiler (1) is a subcritical pressure boiler. The pressure of the steam injection boiler (1) is 15-30 MPa, the burner power is 20-30 MMBTU, the temperature of the steam injection boiler (1) is 300-450 degrees, and the flow rate of the steam injection boiler (1) is 7-11 T / H.

6. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: The liquid storage tank group (5) includes two or more liquid storage tanks.

7. The hot water circulation device for fracturing oil and water wells according to claim 1, characterized in that: The water pump (2) is specifically two or more multi-stage centrifugal pumps.

8. The hot water circulation device for fracturing oil and water wells according to claim 6, characterized in that: The standard volume of the storage tank is 100 cubic meters.

9. The hot water circulation device for fracturing oil and water wells according to claim 7, characterized in that: The pressure of each centrifugal pump is 0.2-2 MPa.

10. The hot water circulation device for fracturing oil and water wells according to claim 9, characterized in that: The water volume of each centrifugal pump is 30-100m³. 3 / H.

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