Comprehensive utilization system for oilfield associated gas

Abstract

The utility model discloses a comprehensive utilization system for oilfield associated gas. The comprehensive utilization system comprises an associated gas pretreatment device, a gas generator set, a heat exchanger, a cyclone mixer, a multi-stage centrifugal compressor and a distribution valve group which are sequentially communicated through a process pipeline, the power output end of the gas generator set is connected with the input end of the power distribution module, the power distribution module is provided with two output ends, the first output end is connected with the multi-stage centrifugal compressor, and the second output end is connected with well site electric equipment; and an outlet of the multi-stage centrifugal compressor is connected with the gas injection well through the distribution valve group. The oil field associated gas comprehensive utilization system provided by the utility model can realize gradient utilization of associated gas energy and recycling of tail gas, utilizes the associated gas to generate power and increase the yield of the tail gas, and reduces the gas injection cost of oil field yield increase.

Description

Technical Field

[0001] This utility model relates to an oilfield associated gas comprehensive utilization system, belonging to the field of oilfield production enhancement technology. Background Technology

[0002] Oilfield enhancement technologies are a core component of improving oil recovery (EOR). Traditional gas injection enhancement technologies mainly include carbon dioxide flooding, nitrogen flooding, and natural gas reinjection. Existing gas injection enhancement technologies have the following problems:

[0003] Relying on external gas sources (such as liquid CO2 transportation) is costly and carries supply chain risks; conventional natural gas reinjection requires the construction of dedicated compression stations, with equipment investment accounting for more than 40% of the increased production cost.

[0004] Associated gas is generated during oil extraction. Traditional methods for treating associated gas mainly involve flaring and combustion (flare gas) or simple power generation. However, existing associated gas power generation technologies have the following problems:

[0005] Associated gas utilization is low, and the temperature of the exhaust gas from associated gas power generation is generally higher than 300℃, which leads to thermal pollution when directly emitted; residual nitrogen, carbon dioxide and other components in the exhaust gas are not utilized as resources.

[0006] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Utility Model Content

[0007] This invention addresses the shortcomings of the prior art by providing an oilfield associated gas comprehensive utilization system that enables the cascade utilization of associated gas energy and the resource recovery of tail gas, utilizes associated gas to generate electricity and increase production, and reduces the gas injection cost for increasing oilfield production.

[0008] To solve the above technical problems, the present invention adopts the following technical solution:

[0009] The associated gas utilization system in the oilfield includes an associated gas pretreatment unit, a gas generator set, a heat exchanger, a cyclone mixer, a multi-stage centrifugal compressor, and a distribution valve group, which are connected sequentially through process pipelines. The power output terminal of the gas generator set is connected to the input terminal of the power distribution module. The power distribution module has two output terminals: the first output terminal is connected to the multi-stage centrifugal compressor, and the second output terminal is connected to the well site electrical equipment. The outlet of the multi-stage centrifugal compressor is connected to the gas injection well via the distribution valve group.

[0010] Furthermore, the inlet of the associated gas pretreatment device is connected to the associated gas inlet pipe.

[0011] Furthermore, the heat exchanger includes a shell, inside which there is a tail gas flow chamber and a heating chamber, the end of which is connected to a hot water outlet pipe.

[0012] Furthermore, the heating chamber is located above the exhaust gas flow chamber, and several heat pipes are installed inside the exhaust gas flow chamber and the heating chamber. Multiple fins for heat absorption are installed below the main body of the heat pipes.

[0013] Furthermore, the side of the cyclone mixer is connected to the output water pipeline and the nano-additive injection unit.

[0014] Furthermore, the gas-liquid ratio in the cyclone mixer is 1:3 to 1:5.

[0015] Furthermore, the outlet pressure of the multi-stage centrifugal compressor is 15-25 MPa.

[0016] Furthermore, an optical fiber sensor electrically connected to the distribution valve group is installed inside the gas injection well.

[0017] Compared with the prior art, the present invention, by adopting the above technical solution, has the following advantages:

[0018] Associated gas is desulfurized and dehydrated before entering the gas generator set to generate electricity. The electricity is distributed to the multi-stage centrifugal compressor and well site electrical equipment via the distribution module. Waste heat is recovered by the heat exchanger and used to heat the crude oil at the wellhead. The cooled tail gas enters the cyclone mixer and forms a stable foam fluid with the produced water and nano-additives. The fluid is pressurized by the multi-stage centrifugal compressor to reach a supercritical state and is injected into the target oil layer through the distribution valve group.

[0019] This invention enables the cascade utilization of associated gas energy and the resource recovery of exhaust gas, increasing production by utilizing the exhaust gas from associated gas power generation and reducing gas injection costs; it also achieves triple utilization of associated gas power generation, waste heat, and exhaust gas, significantly improving the overall energy efficiency of the system.

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the heat exchanger.

[0023] In the diagram, 1-Associated gas pretreatment device, 2-Gas generator set, 3-Heat exchanger, 31-Tail gas flow chamber, 32-Heating chamber, 33-Heat pipe, 4-Swirl mixer, 5-Multi-stage centrifugal compressor, 6-Distribution valve group, 7-Injection well, 8-Associated gas inlet pipe, 9-Power distribution module, 10-Well site electrical equipment, 11-Hot water outlet pipe, 12-Producted water pipeline, 13-Nano additive injection unit, 14-Fiber optic sensor. Detailed Implementation

[0024] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described with reference to the accompanying drawings.

[0025] like Figure 1 and Figure 2 As shown in the figure, this utility model provides an oilfield associated gas comprehensive utilization system, including an associated gas pretreatment device 1, a gas generator set 2, a heat exchanger 3, a cyclone mixer 4, a multi-stage centrifugal compressor 5, and a distribution valve group 6, which are connected in sequence through process pipelines.

[0026] The inlet of the associated gas pretreatment unit 1 is connected to the associated gas inlet pipe 8. The associated gas from the oilfield enters the associated gas pretreatment unit 1 through the associated gas inlet pipe 8 for desulfurization and dehydration treatment, and then is fed into the gas generator set 2 for power generation to improve power generation efficiency.

[0027] The power output terminal of the gas generator set 2 is connected to the input terminal of the power distribution module 9. The power distribution module 9 has two output terminals. The first output terminal is connected to the multi-stage centrifugal compressor 5 to supply power to the multi-stage centrifugal compressor 5. The second output terminal is connected to the well site electrical equipment 10 for oilfield production.

[0028] The heat exchanger 3 includes a shell, inside which there is a tail gas flow chamber 31 and a heating chamber 32, and the end of the heating chamber 32 is connected to the hot water outlet pipe 11.

[0029] The heating chamber 32 is located above the exhaust gas flow chamber 31. Several heat pipes 33 are installed inside the exhaust gas flow chamber 31 and the heating chamber 32. Multiple fins for heat absorption are installed below the main body of the heat pipes 33. The heat pipes 33 are used to transfer heat from the exhaust gas flow chamber 31 to the water flow in the heating chamber 32. The heated water is then output through the hot water outlet pipe 11 and used to heat the crude oil at the wellhead.

[0030] The side of the cyclone mixer 4 is connected to the output water pipeline 12 and the nano-additive injection unit 13. The cyclone mixer 4 forms a gas-liquid two-phase flow with the cooled exhaust gas, output water and nano-additive, with a gas-liquid ratio of 1:3 to 1:5. The nano-additive is a fluorocarbon surfactant.

[0031] The outlet of the multi-stage centrifugal compressor 5 is connected to the injection well 7 via a distribution valve group 6. The multi-stage centrifugal compressor 5 pressurizes the mixture to a supercritical state and injects it into the target oil layer. The outlet pressure of the multi-stage centrifugal compressor 5 is 15-25 MPa.

[0032] The gas injection well 7 is equipped with a fiber optic sensor 14 that is electrically connected to the distribution valve group 6. Based on the pressure data fed back by the downhole fiber optic sensor 14, the distribution valve group 6 controls the gas injection rate within the range of 50-200 m³ / h.

[0033] The specific working principle of this utility model is as follows:

[0034] Associated gas, after desulfurization and dehydration, enters the gas generator set 2 to generate electricity. The electricity is distributed to the multi-stage centrifugal compressor 5 and the well site electrical equipment 10 via the power distribution module 9. The waste heat is recovered by the heat exchanger 3 and used to heat the crude oil at the wellhead. The cooled tail gas enters the cyclone mixer 4 and forms a stable foam fluid with the produced water and nano-additives. The fluid is pressurized by the multi-stage centrifugal compressor 5 to reach the supercritical CO2 state, and the supercritical fluid is injected into the target oil layer through the distribution valve group 6. The distribution valve group 6 controls the gas injection rate within the range of 50-200 m³ / h based on the pressure data fed back by the downhole fiber optic sensor 14.

[0035] The above description provides examples of the preferred embodiments of this utility model. Any aspects not detailed herein are common knowledge to those skilled in the art. The scope of protection of this utility model is determined by the claims. Any equivalent modifications based on the technical teachings of this utility model are also within the scope of protection of this utility model.

Claims

1. An oilfield associated gas comprehensive utilization system, characterized in that: The system includes a gas pretreatment device (1), a gas generator set (2), a heat exchanger (3), a cyclone mixer (4), a multi-stage centrifugal compressor (5), and a distribution valve group (6) connected sequentially through process pipelines. The power output end of the gas generator set (2) is connected to the input end of the power distribution module (9). The power distribution module (9) has two output ends. The first output end is connected to the multi-stage centrifugal compressor (5), and the second output end is connected to the well site electrical equipment (10). The outlet of the multi-stage centrifugal compressor (5) is connected to the gas injection well (7) through the distribution valve group (6).

2. The oilfield associated gas comprehensive utilization system of claim 1, wherein: The inlet of the associated gas pretreatment device (1) is connected to the associated gas inlet pipe (8).

3. The oilfield associated gas comprehensive utilization system of claim 1, wherein: The heat exchanger (3) includes a shell, inside which there is a tail gas flow chamber (31) and a heating chamber (32), and the end of the heating chamber (32) is connected to the hot water outlet pipe (11).

4. The oilfield associated gas utilization system of claim 3, wherein: The heating chamber (32) is located above the exhaust gas flow chamber (31). Several heat pipes (33) are installed inside the exhaust gas flow chamber (31) and the heating chamber (32). Multiple fins for heat absorption are installed below the main body of the heat pipes (33).

5. The oilfield associated gas utilization system of claim 1, wherein: The side of the cyclone mixer (4) is connected to the output water line (12) and the nano-additive injection unit (13).

6. The oilfield associated gas utilization system of claim 5, wherein: The gas-liquid ratio in the cyclone mixer (4) is 1:3 to 1:

5.

7. The oilfield associated gas utilization system of claim 1, wherein: The outlet pressure of the multi-stage centrifugal compressor (5) is 15-25 MPa.

8. The oilfield associated gas utilization system of claim 1, wherein: The gas injection well (7) is equipped with an optical fiber sensor (14) that is electrically connected to the distribution valve group (6).

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