An unmanned treatment system and treatment method for removing acid gases from oil fields

Abstract

The present application relates to a kind of unmanned processing system and processing method for removing oilfield acid gas, system includes oil-gas gathering and transportation processing unit;Oil-gas gathering and transportation processing unit includes oil nozzle, multi-way valve and separator in turn in series, separator is connected with export pump and flare knockout drum by pipeline respectively, export pump is connected with submarine pipeline, flare knockout drum is connected with flare by gas pipeline, oil nozzle is connected with the outlet of oil well stream pipeline.Oil-gas gathering and transportation processing unit carries out gas-liquid separation to oilfield produced fluid, removes acid gas in oilfield produced fluid, avoids the corrosion risk of acid medium in oilfield produced fluid to submarine pipeline and the pipeline and equipment of downstream central platform, reduces the frequency of anticorrosion operation and maintenance of unmanned platform pipeline equipment and submarine pipeline, such as corrosion coupon detection, sea pipe through ball, reduces the operation of system on site by offshore platform personnel, reduces labor cost, improves the reliability of oilfield acid gas treatment.

Description

Technical Field

[0001] This invention relates to the field of offshore oilfield development and research technology, and in particular to an unmanned processing system and method for removing acidic gases from oilfields. Background Technology

[0002] Offshore oilfield production involves a large workload of on-site operations. Oil and gas gathering and transportation, well metering, depressurization and degassing, pressurization and external transportation, reagent injection, and subsea pipeline preheating and replacement all require the participation and support of multiple personnel to ensure the safety, efficiency, and stability of oilfield production. However, offshore oilfield development personnel face high operating costs, heavy burdens in transporting living supplies, and significant impacts from extreme weather events such as typhoons and cold waves. Therefore, reduced-staff or even unmanned operations are a crucial direction for cost reduction in offshore oilfield development.

[0003] The development and processing system of an oilfield is determined by the properties of the oil and gas. Offshore oilfields with associated gas containing high levels of CO2 and H2S must separate, degas, and pressurize the gas for external transport to reduce the corrosion of subsea pipelines by acidic media and prevent the subsea pipelines from prematurely consuming their corrosion reserves, which could lead to production safety and environmental risks.

[0004] In existing technologies, systems for removing acidic gases from oilfields require separators, external pumps, flare heads and ignition devices, chemical tanks and injection pumps. The process is complex, and the workload for equipment operation and maintenance and chemical filling is large. Furthermore, it is limited by the requirements of separator liquid level, process pressure, operation of moving equipment, stability of flare combustion, and chemical replenishment. The process involves a high degree of human involvement, resulting in high labor costs. On-site operations by personnel on offshore platforms are greatly affected by extreme weather, leading to low reliability in the treatment of acidic gases from oilfields. Summary of the Invention

[0005] To address one or more of the aforementioned problems, the present invention aims to provide an unmanned processing system and method for removing acidic gases from oil fields. This reduces the need for on-site personnel to operate the system on offshore platforms, lowers labor costs, improves the reliability of acidic gas treatment, and enables unmanned operation of the processing system on offshore platforms.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An unmanned processing system for removing acidic gases from oil fields includes:

[0008] An oil and gas gathering and processing unit includes an oil nozzle, a multi-way valve, and a separator connected in series. The separator is connected to an external pump and a flare distribution tank, respectively. The external pump is connected to a subsea pipeline, the flare distribution tank is connected to a flare, and the oil nozzle is connected to an oil well logistics pipeline.

[0009] The multi-way valve, the separator, the external pump, and the flare separator are remotely controlled via external equipment.

[0010] Preferably, it further includes:

[0011] The drug injection unit includes an umbilical cable, which includes multiple drug injection lines. These multiple drug injection lines are respectively connected to the pipeline at the nozzle, the pipeline between the multi-way valve and the separator, and the pipeline at the outlet of the seawater submersible pump; the umbilical cable is connected to an external drug supply device.

[0012] Preferably, it further includes:

[0013] The subsea pipeline preheating and replacement unit includes a submersible seawater pump, which is connected to the input ends of the multi-way valve and the external pump via pipelines. A first subsea pipeline replacement switch valve is provided on the pipeline between the submersible seawater pump and the multi-way valve. A second subsea pipeline replacement switch valve is provided on the pipeline between the input ends of the submersible seawater pump and the external pump. A subsea pipeline preheating heater is connected in parallel to the second subsea pipeline replacement switch valve. Subsea pipeline preheating switch valves are provided at both ends of the subsea pipeline preheating heater.

[0014] Preferably, a first emergency shut-off valve is provided on the pipeline between the multi-way valve and the separator.

[0015] Preferably, a separator pressure regulating valve is provided in the pipeline between the separator and the flare separator tank.

[0016] Preferably, the separator is equipped with a remote pressure monitoring sensor, and the pressure monitoring sensor is connected to the pressure regulating valve of the separator via a cable.

[0017] Preferably, the separator is connected to a remote liquid level monitoring sensor, and the remote liquid level monitoring sensor is connected to the external pump via a cable and an external pump frequency converter is connected; the output end of the external pump is connected to the separator via a pipeline, and an external pump reflux regulating valve is provided on the pipeline, and the external pump reflux regulating valve is connected to the remote liquid level monitoring sensor via a cable.

[0018] Preferably, the injection pipeline connected to the nozzle in the umbilical cable is equipped with a corrosion inhibitor control valve; the injection pipeline connected to the multi-way valve and the separator in the umbilical cable is equipped with a demulsifier control valve; and the injection pipeline connected to the outlet of the submersible seawater pump in the umbilical cable is equipped with a subsea pipeline corrosion inhibitor control valve.

[0019] A flash evaporation method for removing acidic gases from oil fields. This method is based on any one of the unmanned processing systems described above for removing acidic gases from oil fields, and includes the following steps:

[0020] After the produced fluid from the oilfield is collected on the offshore platform, it is introduced into the separator through the nozzle and the multi-way valve in sequence. The separator flash-evaporates hydrocarbons and acidic gases and liquids by reducing the pressure.

[0021] The generated gas is sent to a flare separator for washing, and the washed gas is then burned and discharged into the flare.

[0022] The generated liquid is then pumped into the subsea pipeline via an external pump.

[0023] Preferably, in the step of collecting the produced fluid from the oilfield on the offshore platform and introducing it into the separator through the nozzle and multi-way valve in sequence, the corrosion inhibitor and demulsifier are injected into the nozzle and the pipeline at the input end of the separator through the injection pipeline in the umbilical cable.

[0024] The present invention has the following advantages due to the adoption of the above technical solutions:

[0025] 1. The unmanned processing system for removing acidic gases from oilfields provided by this invention involves an oil and gas gathering and processing unit that performs gas-liquid separation on the produced fluid from the oilfield to remove acidic gases. This avoids the risk of corrosion of subsea pipelines and downstream central platform pipelines and equipment by acidic media in the produced fluid, reduces the frequency of corrosion prevention operations and maintenance on unmanned platform pipelines and equipment and subsea pipelines, such as corrosion detection and pipeline balling. It also reduces the number of personnel on the offshore platform operating the system on-site, lowers labor costs, and improves the reliability of acidic gas treatment in oilfields.

[0026] 2. The unmanned processing system for removing acidic gases from oil fields provided by the present invention automatically ensures the stability of the separator liquid level through the frequency converter of the external pump and the return regulating valve of the external pump, and automatically ensures the stability of the process pressure through the separator pressure regulating valve, thus ensuring the stability of the unmanned platform liquid separation processing.

[0027] 3. The unmanned processing system for removing acidic gases from oilfields provided by this invention includes a multi-way valve, an automatically starting external pump and a seawater submersible pump, a plasma torch, an umbilical cable, and an emergency shut-off valve / switching valve / regulating valve. It can be remotely controlled and operated, and automatically realizes ignition after torch extinguishing, and regulation of separator liquid level and pressure. This minimizes the on-site workload of personnel in oilfield development, such as manpower to operate equipment, valves, replenish chemicals, and ignite torches, thereby reducing the labor costs of oilfield development.

[0028] 4. The method for removing acidic gases from oil fields provided by the present invention separates the acidic gases through a separator and discharges them through combustion in a flare, thereby reducing the risk of corrosion of subsea pipelines and pipelines and equipment on downstream central platforms by acidic media. Attached Figure Description

[0029] Figure 1This is a schematic diagram of the connection structure of an unmanned processing system for removing acidic gases from oil fields, provided in an embodiment of the present invention.

[0030] Figure 2 This is a flowchart of the steps of the method for removing acidic gases from oil fields provided in this embodiment of the present invention.

[0031] Marked in the attached diagram:

[0032] 1 is the nozzle, 2 is the multi-way valve, 3 is the separator, 4 is the external pump, 5 is the flare separator tank, 6 is the flare, 7 is the seawater submersible pump, 8 is the first subsea pipeline replacement switch valve, 9 is the second subsea pipeline replacement switch valve, 10 is the subsea pipeline preheater, 11 is the subsea pipeline preheating switch valve, 12 is the umbilical cable, 13 is the multiphase flow meter, 14 is the first emergency shut-off valve, 15 is the separator pressure regulating valve, 16 is the remote pressure monitoring sensor, 17 is the remote liquid level monitoring sensor, 18 is the external pump frequency converter, 19 is the external pump reflux regulating valve, 20 is the corrosion inhibitor control valve, 21 is the demulsifier control valve, 22 is the subsea pipeline corrosion inhibitor compound control valve, 23 is the second emergency shut-off valve, and 24 is the third emergency shut-off valve. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] In the description of this invention, it should be noted that arrows represent the direction of liquid or gas flow, and terms such as "up," "down," "front," and "back" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" 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.

[0036] This invention provides an unmanned treatment system and method for removing acidic gases from oil fields. By using remotely controllable multi-way valves, external pumps, seawater submersible pumps, umbilical cables, switching valves, and automatically controlled flares, it reduces on-site personnel operation on offshore platforms, ensures the safety of personnel in offshore oil field development, reduces labor costs, improves the reliability of acidic gas treatment in oil fields, and realizes unmanned operation of the treatment system on offshore platforms.

[0037] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0038] Example 1

[0039] Reference Figure 1 As shown, the unmanned processing system for removing acidic gases from oil fields provided in this embodiment includes an oil and gas gathering and processing unit.

[0040] The oil and gas gathering and processing unit includes an oil nozzle 1, a multi-way valve 2, and a separator 3 connected in series. The separator 3 is connected to the external pump 4 and the flare distribution tank 5 via pipelines. The external pump 4 is connected to the subsea pipeline. The flare distribution tank 5 and the flare 6 are connected via a gas pipeline. The oil nozzle 1 is connected to the outlet of the oil well logistics pipeline. The multi-way valve 2, the separator 3, the external pump 4, and the flare distribution tank 5 are remotely controlled by external equipment.

[0041] In practical applications, the function of the oil and gas gathering and processing unit is to realize unmanned processing of oil and gas gathering and transportation, low-pressure separation and degassing, associated gas flare discharge, and liquid pressurization and external transportation; the multi-way valve 2 has multiple inlets and outlets, which can be connected to different pipelines respectively. For example, the oil nozzle 1 and the seawater submersible pump 7 are connected to different inlets of the multi-way valve 2 through their respective pipelines; the multi-way valve 2 is a remotely controllable valve; the separator 3 is a low-pressure separator that can flash-evaporate acidic gases such as CO2 and H2S at an operating pressure of 200 kPaA. The separated acidic gases enter the flare separator tank 5 for washing, and the washed gas enters the flare 6 for combustion and discharge, which reduces corrosion to downstream facilities; the flare 6 is a plasma flare, equipped with flame monitoring instruments, and the flare 6 can be automatically controlled to open and close; the external equipment is a remote controller.

[0042] The unmanned processing system for removing acidic gases from oil fields in this embodiment can be remotely controlled by a remote controller. The multi-way valve 2, separator 3, external pump 4, and liquid separator 5 can be operated on-site on the offshore platform without the need for personnel. This enables unmanned processing of acidic gases from oil fields on the offshore platform.

[0043] In this embodiment, the processing system further includes a subsea pipeline preheating and replacement unit and a reagent injection unit;

[0044] The subsea pipeline preheating and replacement unit includes a submersible seawater pump 7, which is connected to the input ends of a multi-way valve 2 and an external pump 4 via pipelines. A first subsea pipeline replacement switch valve 8 is provided on the pipeline between the submersible seawater pump 7 and the multi-way valve 2. A second subsea pipeline replacement switch valve 9 is provided on the pipeline between the input ends of the submersible seawater pump 7 and the external pump 4. A subsea pipeline preheating heater 10 is connected in parallel to the second subsea pipeline replacement switch valve 9. Subsea pipeline preheating switch valves 11 are provided at both ends of the subsea pipeline preheating heater 10.

[0045] The drug injection unit includes an umbilical cable 12, which includes multiple drug injection lines. These multiple drug injection lines are respectively connected to the pipeline at the nozzle 1, the pipeline between the multi-way valve 2 and the separator 3, and the pipeline at the outlet of the seawater submersible pump 7. The umbilical cable 12 is connected to an external drug supply device.

[0046] In practical applications, the function of the subsea pipeline preheating and replacement unit is to realize on-site operation of subsea pipeline preheating during the oilfield commissioning phase and remote operation of subsea pipeline replacement during the oilfield emergency shutdown phase. This ensures that the subsea pipeline has a sufficiently high temperature during the commissioning phase and that crude oil is emptied during the shutdown phase, avoiding the risk of subsea pipeline condensation. In the subsea pipeline preheating and replacement unit, the seawater is raised to the height of the offshore platform using the submersible seawater pump 7, maintaining an operating pressure of 600 kPa on the lower deck. The seawater enters the subsea pipeline preheating heater 10 and is heated to 60°C to meet the subsea pipeline preheating requirements. The pressure is then boosted to 1500 kPa by the external pump 4 to preheat the subsea pipeline. Finally, the seawater is treated by the water treatment system of the downstream central treatment platform through the subsea pipeline and then reinjected into the formation or discharged.

[0047] The function of the chemical injection unit is to inject corrosion inhibitors, demulsifiers, and subsea pipeline corrosion inhibitors into the pipeline at the nozzle 1 of the oil and gas gathering and processing unit and the outlet of the seawater submersible pump 7 of the subsea pipeline preheating and replacement unit, respectively, to improve the demulsification efficiency of the oilfield produced fluid treatment and alleviate the corrosion of the block's upper facilities and subsea pipelines by the oilfield produced fluid and seawater during the production stage and the subsea pipeline preheating and replacement stage. The umbilical cable 12 is connected to the downstream central processing platform, which is the chemical supply device. The multiple chemical injection pipelines in the umbilical cable 12 are connected to the nozzle 1 of the oil and gas gathering and processing unit, the pipeline, and the outlet of the seawater submersible pump 7 of the subsea pipeline preheating and replacement unit, respectively.

[0048] In this embodiment, a multiphase flow meter 13 is provided between the multi-way valve 2 and the separator 3.

[0049] In practical applications, the oilfield produced fluid is collected and distributed in the multi-way valve 2 through the nozzle 1. The multi-way valve 2 periodically introduces the produced fluid from the production well into the multiphase flow meter 13 for measurement.

[0050] In this embodiment, a first emergency shut-off valve 14 is provided on the pipeline between the multi-way valve 2 and the separator 3.

[0051] In practical applications, when the separator 3 and its downstream components malfunction, the pipeline can be shut off by the first emergency shut-off valve 14 to prevent the produced fluid from flowing into the separator 3; after the malfunction is resolved, the first emergency shut-off valve 14 can be reopened to resume the processing of the subsequent produced fluid.

[0052] In this embodiment, a second emergency shut-off valve 23 is provided on the pipeline between the separator 3 and the output pump 4, and a third emergency shut-off valve 24 is provided on the pipeline at the output end of the infusion pump, so that the corresponding pipeline can be shut off in case of emergency.

[0053] In this embodiment, a separator pressure regulating valve 15 is provided in the pipeline between the separator 3 and the flare separator tank 5.

[0054] In practical applications, adjusting the separator pressure regulating valve 15 can regulate the gas pressure entering the flare separator tank 5.

[0055] In this embodiment, the separator 3 is equipped with a remote pressure monitoring sensor 16, and the pressure monitoring sensor 16 is connected to the separator pressure regulating valve 15 via a cable.

[0056] In specific applications, the remote pressure monitoring sensor 16 can monitor the gas pressure inside the separator 3. The separator pressure regulating valve 15 adjusts its valve opening size according to the gas pressure inside the separator 3 monitored by the remote pressure monitoring sensor 16 to maintain a stable gas pressure output. The gas separated by the separator 3 enters the flare separator tank 5 through the separator pressure regulating valve 15, and after being washed by the flare separator tank 5, it enters the flare 6 for combustion and discharge.

[0057] In this embodiment, the separator 3 is connected to a remote liquid level monitoring sensor 17, and the remote liquid level monitoring sensor 17 is connected to the external pump 4 via a cable via an external pump frequency converter 18; the output end of the external pump 4 is connected to the separator 3 via a pipeline, and an external pump reflux regulating valve 19 is provided on the pipeline, and the external pump reflux regulating valve 19 is connected to the remote liquid level monitoring sensor 17 via a cable.

[0058] In practical applications, after the separator 3 establishes pressure and liquid level, the separated liquid enters the external pump 4 for pressurization, which is increased to the set external pressure, for example, up to about 2600 kPaA. At the same time, the remote liquid level monitoring sensor 17, the external pump frequency converter 18, and the external pump reflux regulating valve 19 are activated. The remote liquid level monitoring sensor 17 monitors the liquid level of the separator 3 in real time and automatically adjusts the frequency of the external pump frequency converter 18 and the opening of the external pump reflux regulating valve 19 to maintain the stability of the liquid level in the separator 3.

[0059] In this embodiment, a corrosion inhibitor control valve 20 is provided on the injection pipeline connected to the nozzle 1 in the umbilical cable 12; a demulsifier control valve 21 is provided on the injection pipeline connected to the multi-way valve 2 and the separator 3 in the umbilical cable 12; and a subsea pipeline corrosion inhibitor control valve 22 is provided on the injection pipeline connected to the outlet of the seawater submersible pump 7 in the umbilical cable 12.

[0060] In specific applications, the umbilical cable 12 is controlled to inject the corresponding agents into the oil and gas gathering and processing unit and the subsea pipeline preheating and replacement unit by means of corrosion inhibitor control valve 20, demulsifier control valve 21 and subsea pipeline corrosion inhibitor composite agent control valve 22.

[0061] In this embodiment, the equipment and valves in the systems such as the multi-way valve 2, separator 3, external pump 4, seawater submersible pump 7, first emergency shut-off valve 14, second emergency shut-off valve 23, third emergency shut-off valve 24, first subsea pipeline replacement switch valve 8, second subsea pipeline replacement switch valve 9, separator pressure regulating valve, and external pump reflux regulating valve 19 can all be connected to a remote controller located in the central control room via cables. The operation of each valve and equipment can be controlled through the remote controller. Therefore, unmanned on-site removal of acidic gases from oilfields can be achieved on the offshore platform.

[0062] This embodiment describes an unmanned processing system for removing acidic gases from oilfields. During the oilfield commissioning phase, a living support vessel is deployed on the platform to allow for manned operation. Subsea pipeline preheating can be achieved through on-site personnel. Seawater is pressurized and heated before entering the subsea pipeline, increasing its temperature. On-site operations include starting the submersible seawater pump 7, the subsea pipeline preheater 10, and the external pump 4; opening the subsea pipeline preheating switch valve 11 and the third emergency shut-off valve 24 at the subsea pipeline inlet; and simultaneously opening the subsea pipeline corrosion inhibitor control valve 22, injecting the corrosion inhibitor into the seawater via the umbilical cable 12. The submersible seawater pump 7 lifts the seawater to the platform, maintaining an operating pressure of 600 kPa on the lower deck. The seawater then enters the subsea pipeline preheater 10, heating it to 60°C to meet the preheating requirements. The external pump 4 then further pressurizes the seawater to 1500 kPa for subsea pipeline preheating. After treatment by the water treatment system on the downstream central processing platform, the seawater is either reinjected into the formation or discharged.

[0063] During the oilfield production phase, the offshore platform is unmanned. Oil and gas gathering and transportation, gas-liquid separation, flare discharge, pressurized external transportation, and reagent injection must be operated remotely. All equipment and valves are controlled by remote controllers, which are connected to the control equipment and valves on site via instrumentation cables. The first emergency shut-off valve 14, the second emergency shut-off valve 23, the third emergency shut-off valve 24, the multi-way valve 2, and the multiphase flow meter 13 are remotely opened. After the liquid level and pressure are established in the separator 3, the external transportation pump 4, the external transportation pump frequency converter 18, the external transportation pump reflux regulating valve 19, the separator pressure regulating valve 15, and the flare 6 are remotely opened, connecting the oil and gas gathering and transportation process.

[0064] Oilfield produced fluid is collected and distributed in multi-way valve 2 via nozzle 1. Multi-way valve 2 periodically introduces produced fluid from production wells into multiphase flow meter 13 for metering. The produced fluid enters separator 3 for low-pressure separation, where acidic gases such as CO2 and H2S are flashed out at an operating pressure of 200 kPa, mitigating corrosion to downstream facilities. After the separator 3 establishes pressure and level, the separated liquid enters external pump 4 and is pressurized to the external transmission pressure, up to approximately 2600 kPa. Simultaneously, the remote level monitoring sensor 17, external pump frequency converter 18, and external pump reflux regulator are activated. When valve 19 is activated, the liquid level of separator 3 is monitored in real time, and the frequency of external pump inverter 18 and the opening of external pump return regulating valve 19 are automatically adjusted to maintain the stability of liquid level in separator 3. The separated gas enters flare separator tank 5 through separator pressure regulating valve 15, and the scrubbing gas enters flare 6 for combustion and discharge. At the same time, umbilical cable 12 is activated, and corrosion inhibitor control valve 20 and demulsifier control valve 21 are opened to inject corrosion inhibitor and demulsifier into the pipeline at the oil nozzle and the pipeline at the input end of separator 3 to ensure the efficiency and stability of oil and gas gathering and transportation process.

[0065] During the emergency shutdown of the oilfield, the platform is unmanned. It is crucial to remotely replace the crude oil in the upper and subsea pipelines as quickly as possible to ensure there is no risk of pipe clogging during the oilfield shutdown. First, all equipment in the emergency shutdown oil and gas gathering and processing unit, including multi-way valve 2, multiphase flow meter 13, external pump 4, and the first, second, and third emergency shut-off valves, must be shut down or switched on / off. Then, the seawater submersible pump 7 and external pump 4 must be remotely started, and the first and second subsea pipeline replacement valves 8 and 9, as well as the first, second, and third emergency shut-off valves, must be opened. Simultaneously, the subsea pipeline corrosion inhibitor control valve 22 must be opened, and the subsea pipeline corrosion inhibitor must be injected into the seawater through the umbilical cable 12. Seawater is pumped to the platform using submersible pump 12 to maintain an operating pressure of 600 kPa on the lower deck. The seawater is mixed with a corrosion inhibitor from the umbilical cable and introduced into the multi-way valve 2 through the first submersible pipeline replacement valve 8. This replaces the crude oil in the upper pipeline of the platform into the separator 3, and then the pressure is boosted to the external pressure, which is up to approximately 2600 kPa, by the external pump 4 before being transported to the downstream central processing platform. After the replacement of the upper pipeline of the platform is completed, the first submersible pipeline replacement valve 8 is closed, while the second submersible pipeline replacement valve 9 remains open. The seawater is then directly introduced into the external pump 4 for pressurization and transported to the downstream central processing platform. The seawater enters the water treatment system of the central processing platform for treatment before being reinjected into the formation or discharged.

[0066] Example 2

[0067] Reference Figure 2 As shown, the method for removing acidic gases from oil fields provided in this embodiment is based on the unmanned processing system for removing acidic gases from oil fields in Embodiment 1, and includes the following steps:

[0068] S01, the produced fluid from the oilfield is collected on the offshore platform and then introduced into the separator 3 through the nozzle 1 and the multi-way valve 2 in sequence. The separator 3 flash-evaporates hydrocarbons and acidic gases and liquids by reducing the pressure.

[0069] S02, the generated gas is sent to the flare separator 5 for washing, and the washed gas enters the flare 6 for combustion and discharge;

[0070] S03, the generated liquid is transported into the subsea pipeline via external pump 4.

[0071] The subsea pipeline connects to the central processing platform, where the liquid is centrally processed into qualified crude oil.

[0072] The multi-way valve 2, separator 3, external pump 4, and flare separator 5 can be remotely controlled, eliminating the need for on-site personnel on the offshore platform and enabling unmanned removal of acidic gases from oilfields on the offshore platform.

[0073] In this embodiment, the separator 3 flash-evaporates hydrocarbons and acidic gases, including CO2 and H2S, by reducing pressure. When the associated gas containing CO2 is emitted by the combustion of the flare 6, if the flare is extinguished due to excessive wind speed or short-term low calorific value of the associated gas, it can be detected immediately by the matching flame monitoring instrument. The flare 6 can be ignited immediately to ensure the stability of the flare combustion emission, avoid the risk of backfire, and ensure the safety of production.

[0074] In this embodiment, during the step of separating hydrocarbons and acidic gases and liquids by reducing pressure and flashing out in separator 3, after separator 3 establishes pressure and liquid level, the separated liquid enters external pump 4 and is pressurized to the external pressure, which is up to about 2600 kPa. At the same time, remote liquid level monitoring sensor 17, external pump frequency converter 18 and external pump reflux regulating valve 19 are activated to monitor the liquid level of separator 3 in real time and automatically adjust the frequency of external pump frequency converter 18 and the opening of external pump reflux regulating valve 19 to maintain the liquid level of separator 3 stable. The separated gas enters flare separator tank 5 through separator pressure regulating valve 15, and the scrubbing gas enters flare 6 for combustion and discharge.

[0075] In this embodiment, after the produced fluid from the oilfield is collected on the offshore platform, it is sequentially introduced into the separator 3 through the nozzle 1 and the multi-way valve 2. Corrosion inhibitors and demulsifiers are injected into the nozzle 1 and the pipeline at the input end of the separator 3 through the injection pipeline in the umbilical cable 12.

[0076] In this embodiment, the unmanned processing system for removing acidic gases from oil fields operates during the oil field commissioning phase. Operators start the seawater submersible pump 7, the subsea pipeline preheater 10, and the external pump 4, open the subsea pipeline preheating switch valve 11 and the third emergency shut-off valve 24 at the subsea pipeline inlet, and open the preheating process of the subsea pipeline. At the same time, the subsea pipeline corrosion inhibitor control valve 22 is opened, and the subsea pipeline corrosion inhibitor is injected into the seawater through the umbilical cable 12.

[0077] In this embodiment, during the oilfield production stage, the first emergency shut-off valve 14 is remotely opened, the multi-way valve 2 and the multiphase flow meter 13 are started, and after the liquid level and pressure are established in the separator 3, the external pump 4, the external pump frequency converter 18, the external pump reflux regulating valve 19, the separator pressure regulating valve 15 and the flare 6 are started, realizing unmanned oil and gas gathering and transportation, well metering, gas-liquid separation, pressurized external transportation, flare combustion and emission and other oilfield production operations.

[0078] In this embodiment, during the emergency shutdown phase of the oilfield, the submersible seawater pump 7 and the external pump 4 are remotely started, and the first subsea pipeline replacement switch valve 8, the second subsea pipeline replacement switch valve 9, the first emergency shut-off valve 14, the second emergency shut-off valve 23, and the third emergency shut-off valve 24 are opened. At the same time, the pipeline corrosion inhibitor control valve 22 is opened, and the subsea pipeline corrosion inhibitor is injected into the seawater through the umbilical cable 12, realizing the replacement of the subsea pipeline in an unmanned manner.

[0079] In this embodiment, chemical agents are drawn from the downstream central processing platform via the umbilical cable 12 and controlled by the corrosion inhibitor control valve 20, the demulsifier control valve 21, and the subsea pipeline corrosion inhibitor composite agent control valve 22 to inject corrosion inhibitors, demulsifiers, and subsea pipeline preheating and replacement units.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An unmanned processing system for removing acidic gases from oil fields, characterized in that, include: The oil and gas gathering and processing unit includes an oil nozzle, a multi-way valve, and a separator connected in series. The separator is connected to an external pump and a flare distribution tank, respectively. The external pump is connected to a subsea pipeline, the flare distribution tank is connected to a flare, and the oil nozzle is connected to an oil well logistics pipeline. The subsea pipeline connects to a central processing platform to centrally process the liquid into qualified crude oil. Oilfield produced fluid is collected and distributed through the multi-way valve via the oil nozzle. The produced fluid enters the separator to separate and flash out acidic gases. The separated acidic gases enter the flare distribution tank for washing, and the washed gas enters the flare for combustion and emission. After the separator establishes pressure and liquid level, the separated liquid enters the external pump to be pressurized to the external pressure and is transported to the downstream central processing platform. The seawater enters the water treatment system of the central processing platform through the subsea pipeline, is treated, and then reinjected into the formation or discharged. The subsea pipeline preheating and replacement unit includes a submersible seawater pump, which is connected to the input ends of the multi-way valve and the external pump via pipelines. A first subsea pipeline replacement switch valve is provided on the pipeline between the submersible seawater pump and the multi-way valve. A second subsea pipeline replacement switch valve is provided on the pipeline between the input ends of the submersible seawater pump and the external pump. A subsea pipeline preheating heater is connected in parallel to the second subsea pipeline replacement switch valve. Subsea pipeline preheating switch valves are provided at both ends of the subsea pipeline preheating heater. The drug injection unit includes an umbilical cable, which includes multiple drug injection lines. These multiple drug injection lines are respectively connected to the pipeline at the nozzle, the pipeline between the multi-way valve and the separator, and the pipeline at the outlet of the seawater submersible pump; the umbilical cable is connected to an external drug supply device. The nozzle and the submersible seawater pump are connected to different inlets of the multi-way valve via their respective pipelines; the multi-way valve is a remotely controllable valve. The umbilical cable is connected to the downstream central processing platform, which is a drug supply device. The multiple drug injection pipelines in the umbilical cable are respectively connected to the oil nozzle of the oil and gas gathering and processing unit, the pipeline, and the seawater submersible pump outlet of the subsea pipeline preheating and replacement unit. The multi-way valve, the separator, the external pump, and the flare separator are remotely controlled via external equipment.

2. The unmanned processing system for removing acidic gases from oil fields according to claim 1, characterized in that, A first emergency shut-off valve is provided on the pipeline between the multi-way valve and the separator.

3. The unmanned processing system for removing acidic gases from oil fields according to claim 1, characterized in that, The pipeline between the separator and the flare separator tank is equipped with a separator pressure regulating valve.

4. The unmanned processing system for removing acidic gases from oil fields according to claim 3, characterized in that, The separator is equipped with a remote pressure monitoring sensor, which is connected to the pressure regulating valve of the separator via a cable.

5. The unmanned processing system for removing acidic gases from oil fields according to claim 1, characterized in that, The separator is connected to a remote liquid level monitoring sensor, and the remote liquid level monitoring sensor is connected to the external pump via a cable and an external pump frequency converter; the output end of the external pump is connected to the separator via a pipeline, and an external pump reflux regulating valve is provided on the pipeline, and the external pump reflux regulating valve is connected to the remote liquid level monitoring sensor via a cable.

6. The unmanned processing system for removing acidic gases from oil fields according to claim 1, characterized in that, The injection pipeline connected to the nozzle in the umbilical cable is equipped with a corrosion inhibitor control valve; the injection pipeline connected to the multi-way valve and the separator in the umbilical cable is equipped with a demulsifier control valve; the injection pipeline connected to the outlet of the submersible seawater pump in the umbilical cable is equipped with a subsea pipeline corrosion inhibitor control valve.

7. A method for flash evaporation to remove acidic gases from oilfields, characterized in that, This method is based on an unmanned processing system for removing acidic gases from oil fields as described in any one of claims 1 to 6, and includes the following steps: After the produced fluid from the oilfield is collected on the offshore platform, it is introduced into the separator through the nozzle and the multi-way valve in sequence. The separator flash-evaporates hydrocarbons and acidic gases and liquids by reducing the pressure. The generated gas is sent to a flare separator for washing, and the washed gas is then burned and discharged into the flare. The generated liquid is then pumped into the subsea pipeline via an external pump.

8. The method for flash evaporation to remove acidic gases from oilfields according to claim 7, characterized in that, In the process of collecting the produced fluid from the oilfield on the offshore platform and then introducing it into the separator through the nozzle and multi-way valve, corrosion inhibitors and demulsifiers are injected into the nozzle and the separator input pipe through the injection pipeline in the umbilical cable.

Images