JP2020019898A - Production fluid treatment system and production fluid treatment method - Google Patents

Abstract

To provide a production fluid treatment system and a production fluid treatment method which efficiently remove a sulfur-containing compound in a production fluid and downsize a production fluid treatment facility.SOLUTION: A production fluid treatment system 1 of the present invention comprises: a first mixing device 10 which obtains a first mixed fluid by mixing an oil-soluble sulfur compound-fixing agent and a production fluid containing hydrocarbon gas, crude oil and a sulfur-containing compound; and a gas separator which separates a gas phase component containing the hydrocarbon gas from the first mixed fluid. The first mixing device 10 comprises a storage part 15 for storing the first mixed fluid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a production fluid treatment system and a production fluid treatment method.

  Production fluids produced from oil wells contain various hydrocarbons, moisture, sulfur-containing compounds such as hydrogen sulfide and mercaptan. In oil plants, hydrocarbon gas and moisture are separated from these production fluids, and crude oil is shipped using pipelines or other transportation means.

The hydrocarbon gas separated from the production fluid is commercialized as petroleum gas after removing sulfur-containing compounds. Petroleum gas is usually shipped in a separate pipeline from crude oil due to its density differences.
The concentration of sulfur-containing compounds in products is limited due to their toxicity, odor, corrosiveness to metals, and the like. The concentration of the sulfur-containing compound in the product is set to about several ppm for petroleum gas and about 100 ppm for crude oil.

  As a method for removing the sulfur-containing compound, absorption treatment with an amine (amine absorption method) is widely known. However, the amine absorption method requires a regeneration step of heating and regenerating an absorbing solution that has absorbed carbon dioxide and hydrogen sulfide contained together with the hydrocarbon gas. In addition, a step of separating and removing hydrogen sulfide generated in the regeneration step is required. For this reason, the scale of the plant increases, and it is not profitable in terms of processing costs and the like.

  In order to solve such a problem, for example, Patent Documents 1 and 2 propose a technique in which a composition containing a dialdehyde having 6 to 16 carbon atoms is added to a hydrocarbon such as crude oil to remove a sulfur-containing compound. . According to the techniques of Patent Documents 1 and 2, it is attempted to efficiently remove a sulfur-containing compound contained in a hydrocarbon.

WO 2015/141535 International Publication No. WO 2016/121747

However, mercaptans are less reactive than hydrogen sulfide and have longer reaction times than hydrogen sulfide. For this reason, the techniques of Patent Documents 1 and 2 cannot efficiently remove mercaptan.
In addition, when removing sulfur-containing compounds from hydrocarbon gas, the treatment is carried out in a large volume gas state, so large equipment is required for the treatment of hydrocarbon gas. Was difficult to process.

  Therefore, an object of the present invention is to provide a production fluid treatment system and a production fluid treatment method capable of more efficiently removing a sulfur-containing compound contained in a production fluid and reducing the size of a production fluid treatment facility.

The present invention has the following aspects.
[1] A first mixing device that obtains a first mixed fluid by mixing an oil-soluble sulfur compound fixing agent with a production fluid containing hydrocarbon gas, crude oil, and a sulfur-containing compound; A gas separation device that separates a gaseous phase component containing hydrogen gas, wherein the first mixing device includes a storage unit that stores the first mixed fluid.
[2] The production fluid treatment system according to [1], further comprising an adsorption device that contacts an oil solution containing a new oil-soluble sulfur compound fixing agent with the gas phase component, at a stage subsequent to the gas separation device. .
[3] An oil separation device that separates an oil phase component containing the crude oil from the first mixed fluid, and the oil solution that is in contact with the gas phase component is mixed with the oil phase component at a stage subsequent to the adsorption device. The production fluid treatment system according to [2], further comprising: a second mixing device.
[4] The production fluid processing system according to [2], further comprising a third mixing device that mixes the production fluid with the oil solution that has come into contact with the gas phase component, in a stage preceding the gas separation device.
[5] The production fluid treatment system according to any one of [1] to [4], further including a decompression device that decompresses the first mixed fluid before the gas separation device.

Further, the present invention has the following aspects.
[6] a first mixing step of mixing a production fluid containing a hydrocarbon gas, crude oil and a sulfur-containing compound with an oil-soluble sulfur compound fixing agent to obtain a first mixed fluid; A gas separation step of separating a gaseous phase component containing hydrogen gas, wherein the first mixing step includes a storage operation of storing the first mixed fluid.
[7] The method for treating a production fluid according to [6], wherein the oil-soluble sulfur compound fixing agent contains an oil-soluble compound having an aldehyde group.
[8] The production according to [6] or [7], further comprising, after the gas separation step, an adsorption step of bringing the oil solution containing a new oil-soluble sulfur compound fixing agent into contact with the gas phase component. Fluid treatment method.
[9] After the oil separation step of separating the oil phase component containing the crude oil from the first mixed fluid, and after the adsorption step, mixing the oil solution in contact with the gas phase component with the oil phase component The method for treating a production fluid according to [8], further comprising: two mixing steps.
[10] The method for treating a production fluid according to [8], further comprising, before the gas separation step, a third mixing step of mixing the oil solution in contact with the gas phase component with the production fluid.
[11] The method for treating a production fluid according to any one of [6] to [10], further comprising a pressure reducing step of reducing the pressure of the first mixed fluid before the gas separation step.

  According to the production fluid treatment system and the production fluid treatment method of the present invention, the sulfur-containing compound contained in the production fluid can be more efficiently removed, and the production fluid treatment facility can be downsized.

It is a system diagram showing the composition of the production fluid processing system concerning a first embodiment of the present invention. It is a system diagram showing composition of a production fluid processing system concerning a second embodiment of the present invention. It is a system diagram showing the composition of the production fluid processing system concerning a third embodiment of the present invention.

The production fluid treatment system of the present invention includes a first mixing device and a gas separation device.
The production fluid treatment system of the present invention removes a sulfur compound from a production fluid in the vicinity of a well in an oil / gas field, and mixes the treated sulfur compound with the produced crude oil so that the oil field associated gas or crude oil can be removed. Is easily transported to petroleum refining facilities and LNG plants.
The method for treating a production fluid according to the present invention includes a first mixing step and a gas separation step.
The method for treating a production fluid according to the present invention is particularly suitable as a production method for commercializing oil field accompanying gas in small and medium-sized oil fields as natural gas and petroleum gas.

  As used herein, the "production fluid treatment facility" to which the production fluid treatment system of the present invention is applied is a production fluid treatment facility having a daily production of crude oil or condensate oil of less than 5000 barrels (about 795 kL). preferable. Condensate oil is a hydrocarbon mainly containing an alkane having 5 to 10 carbon atoms. More preferably, less than 4000 barrels (about 636 kL), more preferably less than 3000 barrels (about 477 kL) of crude oil or condensate oil is produced per day. The lower limit of the production amount of crude oil or condensate oil per day is not particularly limited, but is preferably, for example, 100 barrels (about 15.9 kL) or more. In addition, the daily production fluid output at the wellhead is preferably less than 30,000 barrels (4770 kL).

The production fluid in this specification is a fluid produced from the wellhead of a well such as an oil well or a gas well. Particularly when the well is an oil well, the production fluid is a mixture mainly composed of liquid hydrocarbon, gaseous hydrocarbon gas and water under an environment of normal temperature and normal pressure. The production fluid contains gaseous components such as nitrogen gas, sulfur-containing compounds such as hydrogen sulfide, and carbon dioxide, and is transported by a liquid phase from the bottom of a production well. The substance may be contained in a small amount. The production fluid is generally in a liquid phase at the bottom of an oil well, but when the pressure decreases near the ground, the dissolved gas phase component is separated and becomes a gas-liquid mixed phase fluid. In addition, the liquid phase component, when allowed to stand, usually separates into an oil phase mainly composed of hydrocarbons and an aqueous phase mainly composed of water. Each of the oil phase and the aqueous phase contains a small amount of water or oil in an emulsion state. The production fluid is usually separated from the production fluid by a separator to separate water and gas components by specific gravity, and the remaining oil phase is shipped as crude oil. For this reason, the production fluid and the crude oil produced from the oil and gas well are substances that are clearly different in terms of physical properties, composition, and economic value.
The hydrocarbon gas in the present specification is a hydrocarbon that is a gas under an environment of normal temperature and normal pressure, and mainly contains an alkane having 4 or less carbon atoms. Hydrocarbon gas is obtained by removing sulfur-containing compounds, water vapor, nitrogen gas, and the like from gas phase components (also referred to as oil field accompanying gas) separated by a separator, and utilizing the difference in boiling points to obtain condensate oil, petroleum gas, It is supplied to the market as natural gas. In addition, in this specification, "normal temperature" means 15 degreeC-40 degreeC. “Normal pressure” refers to a pressure when neither reduced pressure nor increased pressure is applied, and for example, 900 to 1100 hPa.

  The sulfur-containing compound refers to hydrogen sulfide, a compound containing a thiol group, or a mixture thereof. Here, examples of the compound containing a thiol group include a sulfur-containing compound represented by the chemical formula “R-SH” and classified as a mercaptan. Here, R is an alkyl group, an aryl group, an aralkyl group, or the like.

The sulfur compound fixing agent reacts with the sulfur-containing compound contained in the production fluid to form an oil-soluble compound, and can keep the sulfur-containing compound in the liquid phase of the first mixed fluid even at 70 ° C. and 1 atmosphere. A composition that can be made. The sulfur compound fixing agent is an oil-soluble organic compound that is liquid under an environment of normal temperature and normal pressure.
The first mixed fluid is a mixed fluid of the production fluid and the sulfur compound fixing agent.
Examples of the sulfur compound fixing agent include a fixing agent which is stably present even when reacted with the sulfur-containing compound and does not decompose with the sulfur-containing compound due to a reverse reaction. As the sulfur compound fixing agent, an oil-soluble compound having excellent reactivity with a sulfur-containing compound and excellent stability and having at least one aldehyde group bonded to a hydrocarbon group having 4 or more carbon atoms is preferable. Examples of the oil-soluble sulfur compound fixing agent include 3-methyl-2-butenal, 1,9-nonandial, 2-methyl-1,8-octanedial and the like. As the oil-soluble sulfur compound fixing agent, 3-methyl-2-butenal is preferable because of its excellent reactivity with the sulfur-containing compound.
From the viewpoint of adjusting the fluidity, these sulfur compound fixing agents are preferably diluted with kerosene, naphtha, condensate oil, crude oil or the like and used as an oil solution. Examples of the oil solution include a liquid obtained by diluting a mixed liquid obtained by diluting a sulfur compound fixing agent and naphtha at a mass ratio of 1: 3 to 3: 1 with a crude oil having a mass of 2 to 20 times the mass of the mixed liquid. As the oil solution, for example, a liquid obtained by diluting a mixed liquid obtained by diluting a sulfur compound fixing agent and naphtha at a mass ratio of 1: 1 with crude oil having a mass 10 times the mixed liquid is particularly preferable.
In this specification, the term “oil-soluble” refers to a compound which does not phase-separate by mixing the compound and kerosene in a volume ratio of 2: 8 to 8: 2 with kerosene No. 1 specified in JIS K2203: 2009. Means the properties of

The gas phase component in this specification includes a hydrocarbon gas. The gas phase component further includes carbon dioxide gas, hydrogen sulfide, water vapor, mercaptans, and the like.
The oil phase component in this specification includes crude oil. The oil phase component further includes a condensate oil, a sulfur-containing compound, an inorganic metal compound, an organometallic compound, and the like.
The liquid phase component in the present specification comprises an oil phase component and an aqueous phase component. The aqueous phase component contains water-soluble mercaptans such as methyl mercaptan and ethyl mercaptan in addition to water.

[First embodiment]
Hereinafter, a production fluid treatment system according to a first embodiment of the present invention and a production fluid treatment method using this system will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios and the like of the respective components are not necessarily the same as the actual ones. Absent.

<Production fluid processing system>
FIG. 1 is a system diagram showing the configuration of the production fluid processing system according to the first embodiment of the present invention. As shown in FIG. 1, the production fluid treatment system 1 includes a first mixing device 10, a separation device 20, an adsorption device 30, a second mixing device 40, a decompression device 50, a stirring and mixing device 80, a crude oil A tank 60 and pipes L1 to L15 are provided.

The first mixing device 10 is connected to the production well PW by a pipe L1. The pipe L1 is provided with a choke valve CV. A separation device 20 is provided downstream of the first mixing device 10, and the first mixing device 10 and the separation device 20 are connected by a pipe L3. The pressure reducing device 50 is provided in the pipe L3. That is, the decompression device 50 is located before the separation device 20. The pipe L3 is connected to the pipe L4 at a branch 102. The pipe L4 is connected to the adding unit 70.
An adsorbing device 30 is provided downstream of the separating device 20, and the separating device 20 and the adsorbing device 30 are connected by a pipe L7. A crude oil tank 60 is provided downstream of the separation device 20. The separation device 20 and the crude oil tank 60 are connected by a pipe L6. The pipe L6 is provided with a stirring and mixing device 80. The pipe L6 is connected to the pipe L8 at a branch 103. The pipe L8 is connected to the addition unit 71. The pipe L5 is connected to the separation device 20. The second mixing device 40 is provided downstream of the crude oil tank 60, and the crude oil tank 60 and the second mixing device 40 are connected by a pipe L9. A pipe L10 is connected to the second mixing device 40.
The suction device 30 is connected to a pipe L11 and a pipe L12. The adsorption device 30 and the second mixing device 40 are connected by a pipe L12. The pipe L13 is connected to the pipe L12 at a branch 105. The pipe L13 is connected to the suction device 30. The pipe L14 is connected to the pipe L13 at a branch 106. The pipe L14 is connected to the adding section 72.

The production well PW is not particularly limited, and examples thereof include an oil well in which oil can be pumped and extracted from the ground, and a gas well in which natural gas can be pumped and extracted from the ground.
A known choke valve can be used as the choke valve CV, and may be a manual choke valve or an automatic choke valve. From the viewpoint of easily adjusting the pressure of the production fluid, the choke valve CV is preferably an automatic choke valve.

(First mixing device)
The first mixing device 10 is a device for mixing a production fluid with an oil-soluble sulfur compound fixing agent to obtain a first mixed fluid.
The first mixing device 10 includes an addition unit 13, a stirring and mixing unit 14, a storage unit 15, a pipe L1, a pipe L2, and a pipe L15. The pipe L1 is connected to the storage unit 15. The stirring and mixing unit 14 is provided in the pipe L1. The pipe L1 is connected to the pipe L2 at a branch 101. The pipe L2 is connected to the addition unit 13. The pipe L15 is connected to the storage unit 15.
The addition unit 13 may be any unit that can add an oil-soluble sulfur compound fixing agent (first sulfur compound fixing agent) to the production fluid, and examples thereof include a high-pressure liquid pump such as a gear pump.
The stirring and mixing unit 14 is not particularly limited, and includes, for example, an in-line type mixing device such as a static mixer.
The storage section 15 only needs to be able to temporarily store the first mixed fluid, and examples thereof include a storage tank, a buffer tank, a pressure-resistant tank, and a long pipe for ensuring a storage time.

The pipe L1 is not particularly limited, and examples thereof include a metal pipe, a resin pipe, and a pipe using a composite material in which carbon fiber is mixed into a resin. The pipe L1 is preferably made of carbon steel or chromium-based stainless steel. In a cold region, it is preferable that the pipe L1 be covered with a non-combustible heat insulating material such as glass wool to keep the temperature of the product fluid in a cold region.
The material of the pipe L2 may be the same as or different from the material of the pipe L1. Hereinafter, the same applies to the types and materials of piping in this specification.

(Separation device)
The separation device 20 of the present embodiment is a device that separates a gaseous phase component containing a hydrocarbon gas and an oil phase component containing a crude oil from a first mixed fluid. That is, the separation device 20 also functions as a gas separation device that separates a gas phase component containing a hydrocarbon gas from the first mixed fluid and an oil separation device that separates an oil phase component containing crude oil from the first mixed fluid.
The separator 20 is not particularly limited, and includes, for example, a separator that can separate the first mixed fluid into a liquid phase component and a gas phase component by specific gravity.
The separation device 20 is not limited to the present embodiment, and may be a separation device having each of a gas separation device and an oil separation device. Examples of the oil separation device include a separator capable of separating a liquid phase component into an aqueous phase component and an oil phase component.
From the viewpoint of reducing the size of the production fluid treatment system 1, it is preferable that one gas separation device and one oil separation device also serve as one separation device 20.

(Suction device)
The adsorption device 30 is a device for bringing an oil solution containing a new oil-soluble sulfur compound fixing agent (second sulfur compound fixing agent) into contact with the gas phase component separated by the separation device 20. The oil solution that has been brought into contact with the gas phase component by the adsorption device 30 is referred to as a contact oil solution.
The adsorption device 30 includes, for example, a reactor such as an absorption tower, and an introduction portion 73 inside the reactor. The introduction part 73 is connected to the pipe L13. Examples of the introduction unit 73 include a known shower head and a dispersion plate.
The adsorption device 30 is a device that sprays an oil solution from the introduction portion 73 into the inside of the reactor and brings the oil solution into contact with a gas phase component. That is, the adsorption device 30 is brought into contact with a gaseous component such as a hydrocarbon gas mainly composed of methane, carbon dioxide, hydrogen sulfide, and water vapor, and an oil solution obtained by dissolving the second sulfur compound fixing agent in a solvent. , An absorption tower that absorbs hydrogen sulfide.
The adsorption device 30 is not limited to a device for spraying an oil solution, and may be a device for bubbling a gas phase component to an oil solution stored at the bottom of the absorption tower, or an absorption tower filled with a packing material. Good.

(Second mixing device)
The second mixing device 40 is a device that mixes the contact oil solution with the oil phase component separated by the separation device 20.
As the second mixing device 40, for example, an in-line type mixing device such as a static mixer or the like can be used.

(Decompression device)
The decompression device 50 is a device that decompresses the first mixed fluid.
In the first mixing device 10, the first mixed fluid moves in the pipe L3 in a pressurized state (for example, 1 MPa) from the viewpoint of the size of the equipment and the removal efficiency of the sulfur-containing compound. The first mixed fluid is supplied to the separation device 20 in a state where the pressure is reduced to about normal pressure (less than 0.3 MPa) in order to increase the separation efficiency of the gas phase component and the liquid phase component in the separation device 20. Is preferred. For this reason, it is preferable that the production fluid treatment system 1 includes a decompression device 50 that decompresses the first mixed fluid before the separation device 20.
The depressurizing device 50 only needs to be able to reduce the pressure of the first mixed fluid in the pipe L3, and examples thereof include a known depressurizing valve, an on-off valve, and a pipe whose inner diameter and length are adjusted.
Note that the first mixed fluid receives a pressure loss when moving in the pipe L3. When the first mixed fluid is reduced in pressure to about normal pressure due to pressure loss, the pressure reducing device 50 may be omitted.

(Crude oil tank)
The crude oil tank 60 is a tank for temporarily storing the oil phase component separated by the separation device 20.
Examples of the crude oil tank 60 include a built-in tank capable of temporarily storing an oil phase component, a movable tank loaded vehicle, and the like.

The addition unit 70 is a device that can add an emulsion breaker (oil-water separating agent) to the first mixed fluid. Examples of the adding section 70 include a high-pressure liquid sending pump such as a gear pump similar to the adding section 13.
The addition unit 71 is a device that can add an oil-soluble sulfur compound fixing agent to the oil phase component separated by the separation device 20. Examples of the adding unit 71 include a high-pressure liquid sending pump such as a gear pump similar to the adding unit 13.
The addition unit 72 is a device that can add an oil solution containing an oil-soluble sulfur compound fixing agent to the adsorption device 30. Examples of the adding unit 72 include a high-pressure liquid sending pump such as a gear pump similar to the adding unit 13.
These additional portions may be the same or different.

The stirring and mixing device 80 is not particularly limited, and is similar to the stirring and mixing unit 14. Examples of the stirring and mixing device 80 include an in-line type mixing device such as a static mixer. The stirring and mixing device 80 may be the same as or different from the stirring and mixing unit 14.
The pump 81 is not particularly limited, and includes a known high-pressure liquid pump.

<Processing method of production fluid>
Next, a method of processing a production fluid using the production fluid treatment system 1 will be described.
The method for treating a production fluid according to the present embodiment includes a first mixing step, a decompression step, a gas separation step, an oil separation step, an adsorption step, and a second mixing step.
The first mixing step is a step of mixing a production fluid containing hydrocarbon gas, crude oil, and a sulfur-containing compound with an oil-soluble sulfur compound fixing agent to obtain a first mixed fluid.
The method for treating a production fluid of the present embodiment can fix the sulfur-containing compound in the production fluid to the sulfur compound fixing agent by having the first mixing step.

In the present embodiment, the production fluid mined from the production well PW is decompressed in the process of ascending in the well and is converted into a two-phase fluid of a gaseous gas (gas phase component) and a liquid phase component in the production well PW Moves in the pipe L1 by the pressure of. Liquid phase components include water, liquid hydrocarbons, and gas compositions dissolved therein.
The pressure of the production fluid in the pipe L1 (the pressure of the production fluid in the pipe refers to the difference from the atmospheric pressure (0.1013 MPa); the same applies hereinafter) is preferably, for example, 0.1 to 10 MPa, and 0.3. -5.5 MPa is more preferable. The pressure of the production fluid in the pipe L1 is usually set within the above numerical range.

The production fluid further moves in the pipe L1 by opening the choke valve CV, merges with the first sulfur compound fixing agent supplied from the addition section 13 via the pipe L2 at the branch 101, and mixes with the stirring and mixing section. The mixture is dispersed at 14 and becomes a first mixed fluid (first mixing step).
The sulfur compound fixing agent (first sulfur compound fixing agent) added to the production fluid in the first mixing step has a thiol group such as mercaptan in the production fluid even if the reaction time is disadvantageous in terms of the reaction time. Sulfur compound fixing agents, such as 3-methyl-2-butenal, which are highly reactive with organic sulfur compounds are preferred. The addition amount of the first sulfur compound fixing agent is preferably 1 to 10 times, more preferably 1.2 to 3 times, the number of moles of hydrogen sulfide and mercaptan contained in the production fluid in terms of aldehyde groups. Further, when the first sulfur compound fixing agent is 3-methyl-2-butenal, the amount of the first sulfur compound fixing agent is 1 to 1 in mass ratio to the mass of sulfur atoms contained in the production fluid. 10 times is preferable, and 1.5 to 3 times is more preferable.
The first mixed fluid is supplied to the storage unit 15 and is temporarily stored (a storage operation). The storage section 15 of the present embodiment is a pressure-resistant tank having a cylindrical body portion and a dome-shaped top that covers the body portion in order to obtain pressure resistance. The first mixed fluid is introduced into the tank (body portion) through the pipe L1 in the tangential direction of the cylindrical wall near the bottom of the body portion, and is discharged from the top to the outside of the storage unit 15 by the pipe L3. Further, a discharge pipe L15 is provided at the bottom of the storage section 15, and when the oil phase and the aqueous phase are separated in the storage section 15, the collected aqueous phase portion is stored in the storage section via the pipe L15. 15 is discharged outside.

The sulfur-containing compound in the first mixed fluid reacts with the sulfur compound fixing agent and dissolves in the oil phase component of the first mixed fluid as an oil-soluble and non-volatile compound. Therefore, the sulfur-containing compound contained in the gas phase component and the water phase component of the first mixed fluid can be removed.
Note that in this specification, a non-volatile compound refers to a compound that does not vaporize or hardly vaporizes at room temperature.
The time during which the first mixed fluid stays in the storage section 15 (residence time) is preferably longer from the viewpoint of ensuring the time for the sulfur-containing compound to react with the sulfur compound fixing agent. In the tank-shaped storage section 15 of the present embodiment, since the flow rate of the first mixed fluid inside the storage section 15 is low, the gas phase-liquid phase separation, and the oil phase-water phase in the liquid phase Separation easily occurs. Therefore, for example, when the sulfur compound fixing agent is 3-methyl-2-butenal and the temperature of the first mixed fluid is 30 ° C., the residence time is preferably 0.5 to 3 hours, and is preferably 0.7 to 2 hours. Is more preferable, and 1 to 1.5 hours is still more preferable. When the residence time is equal to or longer than the lower limit, the concentration of the sulfur-containing compound contained in the gas phase and the aqueous phase of the first mixed fluid is more easily reduced. When the residence time is less than or equal to the upper limit, the production fluid can be more efficiently processed.
The temperature in the storage section 15 is preferably a temperature at which the viscosity of the first mixed fluid in the storage section 15 is 10 to 10000 Pa · s. The temperature in the storage unit 15 is preferably 30 to 80 ° C., for example, when the present invention is applied to an oil well that produces heavy oil.

The first mixed fluid is a viscous fluid in which an oil phase, an aqueous phase, and a gas phase are mixed, and rises inside the tank-shaped storage unit 15. At this time, a part of the gas component inside the storage unit 15 moves to the gas phase due to the head difference.
The first mixed fluid obtained in the first mixing step is supplied to the separation device 20 via the pipe L3. When the first mixed fluid is a gas-liquid two-phase fluid, the pipe L3 is provided with an ascending gradient of 0 to 1.5% toward the separation device 20 in order to prevent the formation of a trap. Preferably, they are connected.

The first mixed fluid is supplied to the pipe L3 in a pressurized state (pressure obtained by subtracting the water head in the storage unit 15 from the pressure of L1) and moves in the pipe L3. The separation device 20 is preferably formed of a two- or three-stage separator (Gas-Oil-Separator). In order to stably separate the gas phase component and the liquid phase component in the separation device 20, it is preferable that the first mixed fluid is supplied to the separation device 20 in a state where the pressure is reduced to less than 3 MPa. For this reason, it is preferable that the processing method of the production fluid of the present embodiment includes a decompression step of decompressing the first mixed fluid before the gas separation step.
The pressure of the first mixed fluid in the decompression step is, for example, preferably from 0.3 to 1.5 MPa, and more preferably from 0.7 to 1.0 MPa. When the pressure of the first mixed fluid is within the above numerical range, the separation efficiency of the gas phase component and the liquid phase component in the separation device 20 is more easily increased.
When the first mixed fluid is depressurized to about normal pressure due to pressure loss, the depressurizing step may be omitted.

The production fluid contains 10 to 95% by mass of water with respect to the total mass of the production fluid together with the hydrocarbon (crude oil component). Part of the water is in the form of a crude oil component and an emulsion (emulsion). For this reason, it is preferable to add an emulsion breaker (oil-water separating agent) to the first mixed fluid that has exited the storage unit 15 from the viewpoint of oil-water separation.
Examples of the emulsion breaker include a nonionic surfactant containing divalent or trivalent metal ions such as potassium aluminum sulfate dodecahydrate (potassium alum), a nonionic surfactant containing polyethylene oxide and nonylphenol, and an anionic surfactant containing a formalin condensate. Surfactants and the like.

The emulsion breaker is supplied from the addition unit 70 via the pipe L4, merges with the first mixed fluid at the branch 102, and is mixed.
The input amount of the emulsion breaker can be adjusted according to the water content of the production fluid, and for example, is preferably 0.5 to 10 g per 1 L of the first mixed fluid.
The first mixed fluid mixed with the emulsion breaker is decompressed by the decompression device 50 and supplied to the separation device 20.

The emulsion breaker may be charged before or immediately after the addition of the sulfur compound fixing agent. However, it is preferable that the emulsion breaker is charged after a certain period of time from the addition of the sulfur compound fixing agent to the production fluid. By introducing an emulsion breaker after the reaction between the sulfur-containing compound and the sulfur compound fixing agent has progressed, the transfer of the sulfur-containing compound into the aqueous phase as a water-soluble mercaptan such as methanethiol or ethanethiol is suppressed. Because it is easy.
In the present embodiment, the first mixed fluid is temporarily stored in the tank-shaped storage unit 15. For this reason, the flow rate of the first mixed fluid in the storage unit 15 is low, and oil-water separation in the storage unit 15 is likely to occur excessively. Also from the viewpoint of preventing excessive oil-water separation in the storage unit 15, it is preferable that the emulsion breaker is charged after the first mixed fluid has left the storage unit 15.

The first mixed fluid supplied to the separation device 20 is separated into a gas phase component and a liquid phase component by specific gravity (gas separation step).
The temperature in the separation device 20 in the gas separation step is, for example, preferably from 10 to 80 ° C, and more preferably from 30 to 60 ° C.
For example, the pressure at the inlet of the separation device 20 in the gas separation step is preferably 0.05 to 3 MPa higher than atmospheric pressure, and more preferably 0.1 to 3 MPa higher than atmospheric pressure. When the pressure at the inlet of the separation device 20 is equal to or higher than the lower limit, gas separation of the first mixed fluid can be suppressed, and more sulfur-containing compounds can be collected by the sulfur compound fixing agent in the liquid phase of the first mixed fluid. In addition, the concentration of the sulfur-containing compound in the gas phase component separated in the gas separation step is easily reduced. When the pressure at the inlet of the separation device 20 is equal to or less than the upper limit, when the separation device 20 forms a Gas-Oil-Separator, the gas component is prevented from being rapidly separated from the liquid phase in the Gas-Oil-Separator. And facilitates gas-liquid separation. For this reason, when the pressure of the production fluid in the vicinity of the choke valve CV is lower than 0.3 MPa in an oil well having a low wellhead (outlet of the production well PW) pressure, for example, a multiphase flow pump or the like is provided between the wellhead and the choke valve CV. Is preferably provided.
The gas phase component separated in the gas separation step contains a hydrocarbon gas. The gas phase component is supplied to the adsorption device 30 via the pipe L7.

The liquid phase component in the first mixed fluid separated in the gas separation step is separated into an aqueous phase component and an oil phase component by specific gravity (oil separation step).
The aqueous phase component separated in the oil separation step is discharged out of the system via the pipe L5. The water phase component discharged out of the system is so-called oil field accompanying water. After removing dissolved heavy metal ions, organic substances, etc., the oil field accompanying water is re-injected underground or discharged into the environment.
When a large amount of iron ions are contained in the production fluid, a large amount of iron sulfide easily precipitates in the oil field accompanying water. For this reason, when refilling the oilfield accompanying water into the underground, it is necessary to remove the water by specific gravity separation and filtration from the viewpoint of preventing clogging of the permeable layer.
The present embodiment has a feature that by using the first sulfur compound fixing agent, iron sulfide such as iron sulfide is not discharged into the production fluid. For this reason, it is not necessary to remove iron sulfide by specific gravity separation and filtration.
The oil phase component separated in the oil separation step contains crude oil. The oil phase component is supplied to the crude oil tank 60 via the pipe L6.

The gas separation step and the oil separation step may be performed separately or simultaneously. In the present embodiment, the gas separation device and the oil separation device are shared by one separation device 20, and the gas separation process and the oil separation process are performed simultaneously. That is, in the present embodiment, the first mixed fluid supplied to the separation device 20 is separated into three phases of a gas phase component, an aqueous phase component, and an oil phase component by specific gravity.
From the viewpoint of reducing the size of the production fluid treatment system 1 and improving the treatment efficiency of the production fluid, the gas separation step and the oil separation step are preferably performed simultaneously. For example, by applying a Gas-Oil-Separator to the separation device 20, the gas separation step and the oil separation step are performed simultaneously.

The gas phase components separated by the separation device 20 include hydrocarbon gases such as methane, ethane, propane, and butane, hydrocarbons having 5 or more carbon atoms, vapors such as metallic mercury and water, and sulfur-containing compounds such as hydrogen sulfide. And The sulfur-containing compound contained in the gas phase component may be dissolved in the aqueous phase component, or may have already been transferred from the liquid phase to the gas phase component in the process up to the gas separation step. Examples include hydrogen sulfide that could not be removed.
The gas phase component separated by the separation device 20 is supplied to the adsorption device 30 via the pipe L7 after removing the contained metallic mercury, moisture, and the like as necessary.

  In the adsorption device 30, an oil solution containing a new oil-soluble sulfur compound fixing agent (second sulfur compound fixing agent) is introduced from the addition unit 72 through the pipe L14, the branch 106, and the pipe L13 from the introduction unit 73. Is done. The oil solution containing the second sulfur compound fixing agent is introduced after being diluted with 1 to 10 times by mass conversion naphtha in order to reduce the viscosity and increase the contact area with the gas phase component. As a result, the oil solution comes into contact with the gas phase component (adsorption step), and the sulfur-containing compound in the gas phase component is adsorbed by the sulfur compound fixing agent in the oil solution and stored at the bottom of the adsorption device 30. . The oil solution (contact oil solution) on which the sulfur-containing compound has been adsorbed is circulated by the pump 81 together with the newly added oil solution. The contact oil solution overflowing in this process is supplied to the second mixing device 40 via the branch 105 and the pipe L12 in a state where the sulfur-containing compound is fixed in the liquid.

The amount of the oil solution containing the second sulfur compound fixing agent in the adsorption step is, for example, 2 to 5 times the number of moles of aldehyde groups in terms of the number of moles of hydrogen sulfide contained in the gas phase component per hour. Preferably, 3 to 5 times the number of moles is more preferable.
The temperature in the adsorption device 30 in the adsorption step is, for example, preferably from 10 to 150 ° C, more preferably from 20 to 130 ° C, and still more preferably from 30 to 95 ° C. When the temperature in the adsorption device 30 is equal to or higher than the lower limit, the sulfur-containing compound is easily adsorbed by the second sulfur compound fixing agent. When the temperature in the adsorption device 30 is equal to or lower than the above upper limit, the decomposition of the second sulfur compound fixed by adsorbing the sulfur-containing compound is easily suppressed, and the evaporation of the naphtha component into the gas phase component can be suppressed.
In addition, the second sulfur compound fixing agent may be the same as or different from the first sulfur compound fixing agent. As the second sulfur compound fixing agent, 1,9-nonandial, 2-methyl-1,8-octanediene, which has a higher reaction rate than 3-methyl-2-butenal, from the viewpoint of reducing the size of the adsorption device 30. Earl is preferred.

  If the pressure in the adsorption device 30 in the adsorption step is increased, the size of the adsorption device 30 can be reduced, but equipment costs such as pressure resistance and pressure boosting equipment are required. For this reason, the pressure in the adsorption device 30 in the adsorption step is preferably from 0 to 10 MPa, more preferably from 0.1 to 0.5 MPa.

The gas phase component containing the hydrocarbon gas from which the sulfur-containing compound has been removed in the adsorption step is shipped via the pipe L11 as a refined oil field accompanying gas. Oil field accompanying gas shipped via the pipe L11 is finally separated into natural gas, liquefied petroleum gas, condensate oil, etc. by boiling point after removing carbon dioxide, residual hydrogen sulfide, water vapor, mercury, etc. Be commercialized.
The concentration of hydrogen sulfide in the oil field accompanying gas to be shipped depends on the specifications of the pipeline used for shipping. For example, 10,000 ppm (ppm is the ratio of the volume of hydrogen sulfide gas to the volume of the oil field accompanying gas to be shipped. In this paragraph, the same applies hereinafter.) Is preferably at most 3000 ppm, more preferably at most 1,000 ppm.
Note that the concentration of hydrogen sulfide in the oil field accompanying gas to be shipped is set to prevent corrosion of shipping facilities such as pipelines due to hydrogen sulfide, and depends on the specifications and standards of the shipping facility and the destination LNG plant. Different concentrations.
The hydrogen sulfide content is most preferably 0 ppm. However, if the concentration is less than the upper limit, corrosion of shipping facilities such as pipelines can be prevented. It may be more than 0 ppm.
As described above, from the viewpoint of reducing the concentration of hydrogen sulfide in the oil field accompanying gas to be shipped, the treatment method of the production fluid preferably has an adsorption step after the gas separation step.

The oil phase component separated in the oil separation step is supplied to the crude oil tank 60 via the pipe L6. In order to more reliably fix unreacted sulfur-containing compounds in the crude oil, the oil-phase components separated by the separator 20 are added to the sulfur compound fixing agent (third) from the addition unit 71 via the pipe L8 and the branch 103. Sulfur compound fixing agent) may be further added.
The addition amount of the third sulfur compound fixing agent is the same as the addition amount of the first sulfur compound fixing agent.
The third sulfur compound fixing agent may be the same as or different from the first sulfur compound fixing agent.
The oil phase component to which the third sulfur compound fixing agent has been added is dispersed by the stirring and mixing device 80 and supplied to the crude oil tank 60.

  The oil phase component supplied to the crude oil tank 60 is temporarily stored in the crude oil tank 60. By temporarily storing the oil phase component in the crude oil tank 60, the reaction between the sulfur-containing compound in the oil phase component and the sulfur compound fixing agent can be further advanced.

After being temporarily stored in the crude oil tank 60, the oil phase component is supplied to the second mixing device 40 via the pipe L9. In the second mixing device 40, the second sulfur compound fixing agent that is in contact with the gas phase component in the adsorption device 30, absorbs hydrogen sulfide in the gas phase, and is fixed is mixed as an oil solution (contact oil solution). (Second mixing step). As a result, the second sulfur compound fixing agent is oil-soluble even after reacting with hydrogen sulfide, and is uniformly mixed with the oil phase component to form a second mixed fluid. The second mixed fluid is discharged via the pipe L10. The discharged second mixed fluid is subjected to desulfurization treatment in a larger-scale petroleum refining plant via transportation means such as a pipeline or a tank lorry.
The contact oil solution in the second mixing step contains an unreacted second sulfur compound fixing agent. Therefore, even in the transportation process after the pipe L10, the hydrogen sulfide remaining in the second mixed fluid can be absorbed and fixed. The addition amount of the contact oil solution in the second mixing step may be about 0.03 to 0.3 times the addition amount of the first sulfur compound fixing agent in the first mixing step.

The concentration of the volatile sulfur-containing compound that has not reacted with the sulfur compound fixing agent in the second mixed fluid is 1000 ppm (ppm is the ratio of the volume of the volatile sulfur-containing compound to the volume of the second mixed fluid. In this paragraph, the same applies hereinafter.) Or less, preferably 500 ppm or less, more preferably 100 ppm or less.
When the concentration of the volatile sulfur-containing compound that has not reacted with the sulfur compound fixing agent in the second mixed fluid is equal to or less than the upper limit, corrosion of a pipeline or the like is easily suppressed. For this reason, it is preferable that the method for treating the production fluid further includes a second mixing step.

The production fluid processing system 1 of the present embodiment includes a first mixing device 10. According to the first mixing device 10, the sulfur-containing compound contained in the production fluid can be fixed to the sulfur compound fixing agent and dissolved in the crude oil contained in the production fluid. Therefore, it is easy to remove the sulfur-containing compound contained in the gas phase component of the production fluid.
The first mixing device 10 includes a storage unit 15. In the storage unit 15, the first mixed fluid is temporarily stored, and the reaction between the sulfur-containing compound and the sulfur compound fixing agent is promoted. For this reason, it is easy to remove more sulfur-containing compounds contained in the gas phase component.
In the storage unit 15, the flow rate of the first mixed fluid is slow, and a heavy aqueous phase component easily accumulates at the bottom of the storage unit 15. For this reason, the production fluid treatment system 1 of the present embodiment is particularly suitable when the water content of the production fluid is less than 20% by mass based on the total mass of the production fluid.
The production fluid processing system 1 includes a separation device 20. According to the separation device 20, a gas phase component having a reduced concentration of the sulfur-containing compound can be separated from the first mixed fluid. Therefore, the equipment for removing the sulfur-containing compound from the gas phase component can be downsized.
The production fluid processing system 1 includes an adsorption device 30. According to the adsorption device 30, the sulfur-containing compound remaining in the gas phase component can be more reliably removed. For this reason, an oil field accompanying gas with a reduced hydrogen sulfide concentration can be obtained.
The production fluid processing system 1 includes a second mixing device 40. According to the second mixing device 40, crude oil containing more sulfur-containing compounds can be obtained. Therefore, the sulfur-containing compound can be treated more efficiently.
The production fluid processing system 1 includes a decompression device 50. According to the decompression device 50, the gas phase components in the separation device 20 can be separated more efficiently. For this reason, more oil field accompanying gas is easily obtained.

[Second embodiment]
Next, a production fluid treatment system according to a second embodiment of the present invention and a production fluid treatment method using this system will be described. Hereinafter, FIG. 2 will be described focusing on parts different from the first embodiment described above. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

<Production fluid processing system>
FIG. 2 is a system diagram showing the configuration of the production fluid processing system according to the second embodiment of the present invention. As shown in FIG. 2, the production fluid treatment system 2 includes a first mixing device 210, a separation device 220, an adsorption device 230, a stirring and mixing device 280, a crude oil tank 260, a third mixing device 290, L5, piping L7, piping L11, and piping L21 to L33 are provided.

The first mixing device 210 is connected to the production well PW via a pipe L21 and a pipe L22. The piping L22 is provided with a choke valve CV. A separation device 220 is provided downstream of the first mixing device 210, and the first mixing device 210 and the separation device 220 are connected by a pipe L24.
An adsorbing device 230 is provided downstream of the separating device 220, and the separating device 220 and the adsorbing device 230 are connected by a pipe L7. A stirring and mixing device 280 is provided downstream of the separation device 220, and the separation device 220 and the stirring and mixing device 280 are connected by a pipe L25. The pipe L25 is connected to the pipe L26 at a branch 203. The pipe L26 is connected to the addition unit 271. A crude oil tank 260 is provided downstream of the stirring and mixing device 280, and the stirring and mixing device 280 and the crude oil tank 260 are connected by a pipe L27. The pipe L27 is connected to the pipe L29 at a branch 204. The pipe L29 is connected to the third mixing device 290. The pipe L29 is provided with a pump 282. A pipe L28 is connected to the crude oil tank 260. The pipe L5 is connected to the separation device 220.
The pipe L11 and the pipe L30 are connected to the suction device 230. The pipe L30 is connected to the adding section 272. A third mixing device 290 is provided downstream of the adsorption device 230, and the adsorption device 230 and the third mixing device 290 are connected by a pipe L31. The pipe L31 is provided with a pump 283.
The pipe L33 is connected to the third mixing device 290. The pipe L33 is connected to the pipe L22 at a branch 201.

(First mixing device)
The first mixing device 210 of the present embodiment includes an addition unit 213, an addition unit 270, a stirring and mixing unit 214, a storage unit 215, a pipe L21, a pipe L22, and a pipe L23.
The addition unit 213 is connected to the production well PW by a pipe L21. The pipe L22 is connected to the pipe L23 at a branch 202. The pipe L23 is connected to the addition unit 270. The pipe L22 is provided with a stirring and mixing unit 214. The pipe L22 is connected to the storage unit 215.

The addition unit 213 is similar to the addition unit 13 in the first embodiment described above. The pipe L21 is connected to the production well PW, and the sulfur compound fixing agent injected from the addition unit 213 is added to the production fluid in the vicinity of the reservoir deep in the production well PW.
The addition unit 270 is the same as the addition unit 70 in the first embodiment described above. According to the addition unit 270, an emulsion breaker can be supplied to the production fluid.
The stirring and mixing unit 214 is the same as the stirring and mixing unit 14 in the first embodiment described above.

The storage part 215 is configured such that the pipe extends in one of the horizontal directions, then the pipe is folded to extend to the other in the horizontal direction, and further, the pipe is folded to extend in one of the horizontal directions, and this is repeated. Equipped with piping. That is, the storage part 215 is provided so that the pipes meander in the horizontal direction. The length of the pipe in the storage part 215 is, for example, preferably 100 to 3000 m, and more preferably 500 to 2000 m. When the length of the pipe in the storage unit 215 is equal to or greater than the above lower limit, it is easy to secure time during which the sulfur-containing compound reacts with the sulfur compound fixing agent. When the length of the pipe in the storage unit 215 is equal to or less than the upper limit, the production fluid processing system 2 is easily reduced in size. In the storage unit 215, when the pipe is provided so as to meander in the vertical direction, the first mixed fluid moves vertically up and down in the pipe. In this case, due to the head difference in the pipe, the vaporized gas phase component stays in the vicinity of the upper part of the turned pipe, causing a trap to prevent the transport of the first mixed fluid. For this reason, it is preferable that the storage part 215 is provided so as to meander in the horizontal direction.
The inner diameter of the pipe in the storage part 215 is, for example, preferably 2 to 20 inches (5 to 50 cm), and more preferably 5 to 10 inches (12.5 to 25 cm). When the inner diameter of the pipe in the storage unit 215 is equal to or larger than the lower limit, pressure loss due to the flow of the first mixed fluid in the storage unit 215 is easily suppressed, and gas-liquid separation is remarkable in the storage unit 215. It is easy to suppress becoming. Therefore, it is easy to suppress an increase in the volume of the first mixed fluid, and it is easy to reduce the size of the storage unit 215. When the inner diameter of the pipe in the storage unit 215 is equal to or less than the upper limit, a decrease in the flow velocity of the first mixed fluid is easily suppressed, and the dispersion of the gas phase component in the first mixed fluid is easily improved. For this reason, the sulfur-containing compound such as hydrogen sulfide in the gas phase and the sulfur compound fixing agent easily react sufficiently.
As the piping inside the storage part 215 of the present embodiment, for example, a 500 m long pipe that is meandering in the horizontal direction and is kept warm by a heat insulating material and 500 mm long by an insulating material and 8 inches (20 cm) in inner diameter is used. A pipe connected to a pipe having an inner diameter of 4 inches (10 cm) is preferable.

The separation device 220 is the same as the separation device 20 in the first embodiment described above.
The suction device 230 is the same as the suction device 30 in the first embodiment described above.
The crude oil tank 260 is the same as the crude oil tank 60 in the first embodiment described above.

(Third mixing device)
The third mixing device 290 includes an addition unit 274, a stirring and mixing unit 284, a pipe L29, a pipe L31, a pipe L32, and a pipe L33.
The addition section 274 is connected to the pipe L32. The pipe L32 is connected to the pipe L29 at a branch 206. The pipe L31 is connected to the pipe L29 at a branch 205. The pipe L29 is connected to the stirring and mixing unit 284. The pipe L33 is connected to the stirring and mixing section 284. The pipe L33 is connected to the pipe L22 at a branch 201.

The third mixing device 290 is a device for mixing an oil solution containing an oil-soluble sulfur compound fixed in contact with a gas phase component (contact oil solution) with a production fluid.
Since the production fluid treatment system 2 of the present embodiment includes the third mixing device 290, the sulfur-containing compound can be more reliably dissolved in the oil phase component.
The addition unit 274 is similar to the addition unit 13 in the above-described first embodiment.
The stirring and mixing unit 284 is the same as the stirring and mixing unit 14 in the first embodiment described above.
As the third mixing device 290, a mixing device similar to the second mixing device 40 in the above-described first embodiment can be used. As the third mixing device 290, for example, an in-line type mixing device such as a static mixer or the like can be mentioned.

The addition unit 271 is the same as the addition unit 71 in the first embodiment described above.
The addition section 272 is similar to the addition section 72 in the first embodiment described above.
The introduction unit 273 is the same as the introduction unit 73 in the first embodiment described above.
The stirring and mixing device 280 is the same as the stirring and mixing device 80 in the first embodiment described above.
The pump 282 is similar to the pump 81 in the first embodiment described above.
The pump 283 is the same as the pump 81 in the first embodiment described above.

<Processing method of production fluid>
Next, a method for processing a production fluid using the production fluid treatment system 2 will be described.
The production fluid processing method of the present embodiment includes a first mixing step, a gas separation step, an oil separation step, an adsorption step, and a third mixing step.

In the present embodiment, an oil-soluble sulfur compound fixing agent (first sulfur compound fixing agent) is introduced into the production well PW from the addition unit 213 via the pipe L21.
The addition amount of the first sulfur compound fixing agent is preferably 1 to 10 times, more preferably 1.2 to 3 times, the number of moles of hydrogen sulfide and mercaptan contained in the production fluid in terms of aldehyde groups. Further, when the first sulfur compound fixing agent is 3-methyl-2-butenal, the amount of the first sulfur compound fixing agent is 1 to 1 in mass ratio to the mass of sulfur atoms contained in the production fluid. 10 times is preferable, and 1.5 to 3 times is more preferable.
The pressure of the first sulfur compound fixing agent in the pipe L21 is preferably a pressure capable of injecting the added amount of the sulfur compound fixing agent against the pressure at the bottom of the production well PW, and usually the pressure at the choke valve CV. Is set in the range of 105 to 200%.

  The production fluid rises in the production well PW while mixing the first sulfur compound fixed, and the flow rate is adjusted by the choke valve CV provided at the wellhead to be supplied to the pipe L22.

An emulsion breaker is supplied to the production fluid from the addition unit 270 via a pipe L23, and merges at a branch 202. The production fluid into which the emulsion breaker has been introduced is dispersed in the stirring and mixing unit 214 to obtain a first mixed fluid (first mixing step).
The input amount of the emulsion breaker can be adjusted according to the water content of the production fluid, and for example, is preferably 0.5 to 10 g per 1 L of the first mixed fluid.
The production fluid is supplied to the storage unit 215, and the reaction between the sulfur-containing compound and the sulfur compound fixing agent further proceeds in the storage unit 215 (storage operation).

Since the storage section 215 of the present embodiment is formed of a pipe material, the flow velocity of the fluid is larger than that of the tank-shaped storage section 15. For this reason, even if oil-water separation progresses, the water phase and the oil phase having a small specific gravity difference are uniformly transported in the piping of the storage unit 215. Therefore, by supplying and dispersing the emulsion breaker in advance, it becomes possible to supply the first mixed fluid, in which the oil-water separation in the fluid has sufficiently proceeded in the storage unit 215, to the separation device 220.
In the first mixing device 210, the reaction between the sulfur-containing compound and the sulfur compound fixing agent proceeds during the time when the production fluid moves in the well. For this reason, it is possible to shorten the length of the pipe of the storage unit 215, or to omit the storage unit 215.
The production fluid treatment system 2 of the present embodiment is suitable for a production fluid treatment facility in which the daily production amount of crude oil or condensate oil at the wellhead is 2500 to 5000 barrels (about 397.5 to 795 kL).

The first mixed fluid in the storage unit 215 is supplied to the separation device 220 via the pipe L24. Like the pipe L3 of the first embodiment, the pipe L24 is preferably connected with a rising gradient of 0 to 1.5% toward the separation device 220 in order to prevent trap formation.
The gas separation step is the same as in the above-described first embodiment. The gas phase component separated by the separation device 220 is supplied to the adsorption device 230 via the pipe L7.
In the adsorption device 230, an oil solution obtained by diluting the second sulfur compound fixing agent with kerosene or other liquid hydrocarbon in an amount of 2 to 20 times in terms of mass is sprayed from the addition unit 272 via the pipe L30 into the introduction unit 273. Introduced by As a result, the oil solution containing the second sulfur compound fixing agent comes into contact with the gas phase component (adsorption step), and the sulfur compound in the gas phase component is adsorbed by the sulfur compound fixing agent in the oil solution, It is stored at the bottom of the adsorption device 230.
The oil solution to which the sulfur-containing compound has been adsorbed (contact oil solution) is pressurized by the pump 283 in a state where the sulfur-containing compound is fixed in the liquid, and is supplied to the third mixing device 290 via the pipe L31.

The addition amount of the second sulfur compound fixing agent in the adsorption step is the same as the addition amount of the second sulfur compound fixing agent in the adsorption step of the first embodiment described above.
In the present embodiment, since the second sulfur compound fixing agent comes into contact with the gas phase component in the form of a mist, it is possible to efficiently absorb hydrogen sulfide in the gas phase component. Since kerosene is used as a diluent for diluting the second sulfur compound fixing agent, the temperature in the adsorption device 230 in the adsorption process is lower than the temperature in the adsorption device 30 in the adsorption process of the above-described first embodiment. Is preferred. The temperature in the adsorption device 230 in the adsorption step is, for example, preferably from 10 to 60 ° C, more preferably from 10 to 40 ° C.
In order to collect the sprayed oil solution, a cyclone or another oil solution collection device (not shown) may be installed in L11.
In addition, as a diluent, low-viscosity liquid hydrocarbons available in a production fluid treatment facility, such as naphtha and condensate oil, may be used in addition to kerosene. The temperature in the adsorption device 230 can be adjusted according to the boiling point of the diluent.
The pressure in the adsorption device 230 in the adsorption process is the same as the pressure in the adsorption device 30 in the adsorption process of the first embodiment described above.

The oil separation step is the same as in the first embodiment described above. The oil phase component separated by the separation device 220 is supplied to the crude oil tank 60 via a pipe L25, a stirring and mixing device 280, and a pipe L27.
A part of the oil phase component that has flowed through the stirring and mixing device 280 branches off at the branch 204 and flows through the pipe L30, and is then pressurized by the pump 282 and supplied to the third mixing device 290.
The remainder of the oil phase component flowing through the stirring and mixing device 280 is supplied to the crude oil tank 260. The oil phase component supplied to the crude oil tank 260 is temporarily stored and then discharged via the pipe L28. The discharged oil phase component is subjected to desulfurization treatment in a larger-scale petroleum refining plant via transportation means such as a pipeline or a tank lorry.
Further, the aqueous phase component separated by the separation device 220 is discharged out of the system via the pipe L5 as oilfield accompanying water, and can be treated in the same manner as the oilfield accompanying water of the first embodiment.

In the present embodiment, the contact oil solution flowing through the pipe L31 and the oil phase component flowing through the pipe L29 merge at the branch 205. A third sulfur compound fixing agent is further supplied to the contact oil solution joined at the branch 205 from the addition unit 274 via the pipe L32 as necessary. The addition unit 274 is provided to stabilize the fixation of the sulfur-containing compound at an early stage such as at the time of startup. Except during startup, for example, when the supply of the first sulfur compound fixing agent in the addition unit 213 is stopped due to a sudden change in conditions in a well, or as a modification of the present embodiment, the addition unit 213 and the pipe L21 In the case where the first sulfur compound fixing agent is not provided, the first sulfur compound fixing agent may be supplied from the addition section 274 to the production fluid.
The contact oil solution is dispersed in the stirring and mixing section 284. The contact oil solution flowing through the stirring and mixing section 284 is mixed with the production fluid flowing through the pipe L22 via the pipe L33 and the branch 201 (third mixing step). In the third mixing step, the crude oil component fractionated in the branch 204 is mixed with the contact oil solution flowing through the pipe L31 and the first sulfur compound fixing agent introduced from the addition section 274, and the mixture is stirred. After adjusting the viscosity to the same as the liquid phase portion of the production fluid at 284, it may be mixed with the production fluid.
As for the contact oil solution in the third mixing step, it is preferable to mix the entire amount generated by the adsorption device 230 with the production fluid unless there is a special situation such as at the time of startup.

The production fluid processing system 2 of the present embodiment includes a first mixing device 210. According to the first mixing device 210, since the sulfur compound fixing agent is added to the production fluid in the production well PW in advance, it is easy to secure the reaction time between the sulfur-containing compound and the sulfur compound fixing agent in the production fluid.
The first mixing device 210 includes a storage unit 215. Since the storage unit 215 includes a long pipe, it is easy to secure a reaction time between the sulfur-containing compound and the sulfur compound fixing agent. For this reason, it is easy to remove more sulfur-containing compounds contained in the gas phase component.
Since the storage part 215 includes a long pipe, the first mixed fluid flowing through the pipe in the storage part 215 is susceptible to pressure loss. As a result, the first mixed fluid in the storage unit 215 is easily reduced in pressure to about normal pressure. For this reason, in the production fluid treatment system 2 of the present embodiment, the decompression device can be omitted, and the production fluid treatment facility can be easily reduced in size.
In the storage unit 215, the flow velocity of the fluid is large, and it is difficult for the aqueous phase component to accumulate in the storage unit 215. For this reason, the production fluid treatment system 2 of the present embodiment is particularly suitable when the water content of the production fluid is 20% by mass or more based on the total mass of the production fluid.
The production fluid treatment system 2 includes a third mixing device 290 that inputs the contact oil solution in which the sulfur-containing compound is fixed by the adsorption device 230 to the production fluid. In the adsorption device 230, it is necessary to add an excessive amount of the third sulfur compound fixing agent to the hydrogen sulfide in the gas phase, but according to the third mixing device 290, the unreacted third sulfur compound fixing agent is fixed. Since the agent is also supplied to the production fluid, the sulfur compound fixing agent can be effectively used in the entire production fluid treatment system 2. For this reason, it is possible to reduce the amount of the first sulfur compound fixing agent added.

[Third embodiment]
Next, a production fluid treatment system according to a third embodiment of the present invention and a production fluid treatment method using this system will be described. Hereinafter, FIG. 3 will be described focusing on portions different from the above-described first embodiment and second embodiment. The same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

<Production fluid processing system>
FIG. 3 is a system diagram showing a configuration of the production fluid processing system according to the third embodiment of the present invention. As shown in FIG. 3, the production fluid processing system 3 includes a first mixing device 310, a separation device 320, an adsorption device 330, a stirring and mixing device 380, a crude oil tank 360, a third mixing device 390, L5, piping L7, piping L11, and piping L41 to L53 are provided.

The first mixing device 310 is connected to the production well PW by a pipe L41. The pipe L41 is provided with a choke valve CV. A separation device 320 is provided downstream of the first mixing device 310, and the first mixing device 310 and the separation device 320 are connected by a pipe L43.
An adsorbing device 330 is provided downstream of the separating device 320, and the separating device 320 and the adsorbing device 330 are connected by a pipe L7. A stirring and mixing device 380 is provided downstream of the separation device 320, and the separation device 320 and the stirring and mixing device 380 are connected by a pipe L44. The pipe L44 is connected to the pipe L45 at a branch 303. The pipe L45 is connected to the addition unit 371. A crude oil tank 360 is provided downstream of the stirring and mixing device 380, and the stirring and mixing device 380 and the crude oil tank 360 are connected by a pipe L46. The pipe L46 is connected to the pipe L48 at a branch 304. The pipe L48 is connected to the third mixing device 390. The pipe L48 is provided with a pump 382. A pipe L47 is connected to the crude oil tank 360. The pipe L5 is connected to the separation device 320.
The pipe L11 and the pipe L49 are connected to the suction device 330. The pipe L49 is provided with a pump 381. The pipe L49 is connected to the pipe L51 at a branch 307. The pipe L49 is connected to the pipe L50 at a branch 308. The pipe L50 is connected to the adding section 372. A third mixing device 390 is provided downstream of the adsorption device 330, and a pipe L51 is connected to the third mixing device 390. The pipe L51 is provided with a pump 383.
The pipe L53 is connected to the third mixing device 390. The pipe L53 is connected to the pipe L41 at a branch 302.

(First mixing device)
The first mixing device 310 of the present embodiment includes an addition unit 313, a stirring and mixing unit 314, a storage unit 315, a pipe L41, and a pipe L42.
The pipe L41 is provided with a stirring and mixing unit 314. The pipe L41 is connected to the pipe L42 at a branch 301. The pipe L42 is connected to the addition unit 313. The pipe L41 is connected to the pipe L53 at a branch 302. The pipe L41 is connected to the storage unit 315.

The addition unit 313 is the same as the addition unit 13 in the first embodiment described above.
The stirring and mixing unit 314 is the same as the stirring and mixing unit 14 in the first embodiment described above.

The storage section 315 is provided such that the zigzag pipe extends vertically upward (upward).
The length of the pipe in the storage part 315 is the same as the length of the pipe in the storage part 215 in the above-described second embodiment.
The inside diameter of the pipe in the storage section 315 is the same as the inside diameter of the pipe in the storage section 215 in the second embodiment described above.
As the piping inside the storage unit 315, for example, a 500-m long pipe with an inner diameter of 8 inches (20 cm) kept warm by a heat insulating material, and a 500-m long, 4-inch (10 cm) inner diameter pipe kept warm by a heat insulating material. Connected tubing is preferred.

The separation device 320 is the same as the separation device 20 in the first embodiment described above.
The suction device 330 is the same as the suction device 30 in the first embodiment described above.
The crude oil tank 360 is similar to the crude oil tank 60 in the first embodiment described above.
The third mixing device 390 is the same as the third mixing device 290 in the second embodiment described above.
The addition unit 374 is the same as the addition unit 13 in the first embodiment described above.
The stirring and mixing unit 384 is the same as the stirring and mixing unit 14 in the first embodiment described above.

The addition unit 371 is the same as the addition unit 71 in the first embodiment described above.
The addition section 372 is the same as the addition section 72 in the first embodiment described above.
The introduction unit 373 is the same as the introduction unit 73 in the first embodiment described above.
The stirring and mixing device 380 is the same as the stirring and mixing device 80 in the first embodiment described above.
The pump 381 is similar to the pump 81 in the first embodiment described above.
The pump 382 is the same as the pump 81 in the first embodiment described above.
The pump 383 is similar to the pump 81 in the first embodiment described above.

<Processing method of production fluid>
Next, a method of processing a production fluid using the production fluid treatment system 3 will be described.
The production fluid processing method of the present embodiment includes a first mixing step, a gas separation step, an oil separation step, an adsorption step, and a third mixing step.

The storage part 315 is provided such that a zigzag pipe extending obliquely upward with a gradient of 0.01 to 2% extends upward (upward) in the vertical direction. The production fluid becomes the first mixed fluid by adding the emulsion breaker and the sulfur compound fixing agent in the branches 301 and 302 and dispersing them in the stirring and mixing unit 314 (first mixing step). The first mixed fluid contains bubbles of the gas phase component separated from the liquid phase by reducing the pressure, and the bubbles rise along the gradient, so that the liquid phase component also moves in the piping of the storage unit 315 together with the bubbles. Further, since the first mixed fluid of the present embodiment moves in the vertical direction, the gas phase separation due to the head difference is more easily promoted than the first mixed fluid of the second embodiment. In addition, the vertical movement of the first mixed fluid is performed by flowing in a thin pipe extending obliquely upward in a zigzag manner. For this reason, in the storage part 315, the gas phase-liquid phase and the oil phase-water phase in the liquid phase are easily transported more uniformly than in the first embodiment. As described above, in the present embodiment, it is easy to suppress clogging of the pipe in the storage unit 315 due to the first mixed fluid. In particular, even when the pressure at the wellhead is less than 0.5 MPa, it is possible to stably supply the first mixed fluid to the separation device 320 without installing a pressure increasing device such as a pump (storage operation).
The production fluid treatment system 3 of the present embodiment is suitable for a production fluid treatment facility in which the daily output of crude oil or condensate oil at the wellhead is 2500 to 5000 barrels (about 397.5 to 795 kL).

  Other aspects of the method for processing a production fluid according to the present embodiment are the same as those for the method for processing a production fluid according to the above-described second embodiment, and a description thereof will be omitted.

The production fluid processing system 3 of the present embodiment includes a first mixing device 310. The first mixing device 310 includes a storage unit 315.
In the storage section 315, the flow velocity of the fluid is large, and the internal piping is provided such that a zigzag-shaped piping extends upward. For this reason, it is difficult for the aqueous phase component to accumulate in the storage unit 315. For this reason, the production fluid treatment system 2 of the present embodiment is particularly suitable when the water content of the production fluid is 20% by mass or more based on the total mass of the production fluid.
The production fluid processing system 3 includes a third mixing device 390. According to the third mixing device 390, the sulfur compound fixing agent having an adsorption ability can be reused. Therefore, the sulfur-containing compound can be treated more efficiently.
The second sulfur compound fixing agent has a low viscosity because it performs a gas-liquid reaction in the absorption tower of the adsorption device 330. The low viscosity oil solution is difficult to mix with the oil phase component of the first mixed fluid. Therefore, in the third mixing device 390, a part of the oil phase component separated by the separation device 320 and the low-viscosity contact oil solution are mixed to improve the viscosity of the contact oil solution. By increasing the viscosity of the contact oil solution, the contact oil solution and the first mixed fluid can be more easily mixed.
Crude oil or heavy oil prepared in advance can also be used as the oil phase component to be mixed with the contact oil solution.
When the production fluid contains iron sulfide, the concentration of iron sulfide in the oil field accompanying water can be reduced by applying the production fluid treatment method of the present embodiment. For this reason, it becomes easier to reuse the oil field accompanying water.
According to the present embodiment, since the zigzag pipe is provided in the storage section 315 so as to extend upward, the movement of the bubbles in the first mixed fluid promotes the flow of the first mixed fluid. For this reason, even if the separation of the oil and water proceeds in the first mixed fluid, the first mixed fluid does not easily stay inside the storage unit 315. As a result, the production fluid treatment system 3 can be stably operated with a wide oil-water ratio even if the emulsion breaker is put in front of the storage unit 315.

As described above, according to the production fluid treatment system of the present invention, the sulfur-containing compound can be efficiently removed from the gas phase component of the production fluid. As a result, high quality natural gas or oil gas can be obtained. In addition, in the production fluid treatment system of the present invention, since the oil-soluble sulfur compound fixing agent is used, the contact oil solution in contact with the sulfur-containing compound is also oil-soluble, and the contact oil solution is mixed with the first mixed fluid. By doing so, the sulfur-containing compound in the production fluid can be dissolved in the oil phase component.
According to the production fluid treatment system of the present invention, mercaptans, which are more difficult to treat than hydrogen sulfide, can also be treated.
Further, according to the production fluid treatment system of the present invention, since the concentration of the sulfur-containing compound in the separated gas phase component can be reduced, the equipment for removing the sulfur-containing compound from the gas phase component can be downsized.

[Other Embodiments]
Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and includes a design and the like within a range not departing from the gist of the present invention.
For example, the above-described production fluid treatment system 1 has one separation device, but the separation device may be two of a gas separation device and an oil separation device, or may be three or more separation devices. When the number of separation devices increases, the scale of the plant increases, and therefore, the number of separation devices is preferably one.
In the above-described embodiment, the production fluid treatment system including the adsorption device has been described. However, when the concentration of the sulfur-containing compound in the gas phase component is equal to or lower than a set value (for example, 1000 ppm), the adsorption device may be omitted. .
In the embodiment described above, the production fluid processing system having one crude oil tank has been described. However, the number of crude oil tanks may be two, or three or more. When the number of the crude oil tanks is two or more, the reaction between the sulfur-containing compound and the sulfur compound fixing agent contained in the crude oil can proceed more reliably.
The storage unit 15 of the first embodiment described above can be replaced with the storage unit 215 of the second embodiment described above.
The storage unit 15 of the first embodiment described above can be replaced with the storage unit 315 of the third embodiment described above.
The storage unit 215 of the above-described second embodiment can be replaced with the storage unit 315 of the above-described third embodiment.
As the storage section 315, a spiral pipe may be used instead of the zigzag pipe.

By using the production fluid treatment system and the production fluid treatment method of the present invention, a sulfur-containing compound contained in a gas phase component of a production fluid can be removed, and a refined petroleum gas can be produced. Further, high-value-added crude oil can be obtained without discharging a large amount of waste. Furthermore, as compared with the case where hydrogen sulfide is removed by the amine absorption method, a regeneration process is not required, the scale of the plant can be reduced, and the sulfur-containing compound can be efficiently treated. In addition, even in a small-scale oil and gas field, removal of sulfur-containing compounds at a production site becomes easy, and energy saving can be achieved.
In addition, the oil field accompanying water generated by the production fluid treatment system and the production fluid treatment method of the present invention has little precipitation of insoluble iron sulfide, and therefore is less likely to be clogged by underground injection when re-injected underground. For this reason, water is injected into the oil phase to recover the remaining hydrocarbons in the oil phase in waterflooding methods, as well as secondary and higher-order recovery in which carbon dioxide and surfactants are injected together with water. The production fluid treatment system and production fluid treatment method of the present invention are particularly suitable.

1, 2, 3 Production fluid treatment system 10, 210, 310 First mixing device 20, 220, 320 Separation device 30, 230, 330 Adsorption device 40 Second mixing device 50 Decompression device 60, 260, 360 Crude oil tank 290, 390 Third mixing device 13, 70, 71, 72, 213, 270, 271, 272, 274, 313, 371, 372, 374 Addition unit 14, 214, 284, 314, 384 Stirring mixing unit 15, 215, 315 Storage unit 73, 273, 373 Introducing section 80, 280, 380 Stirring / mixing apparatus 81, 282, 283, 381, 382, 383 Pump 101 to 106, 201 to 206, 301 to 308 Branch L1 to L15, L21 to L33, L41 to L53 Piping PW Production well CV Choke valve

Claims (7)

A first mixing device that obtains a first mixed fluid by mixing an oil-soluble sulfur compound fixing agent with a production fluid containing hydrocarbon gas, crude oil, and a sulfur-containing compound,
A gas separation device that separates a gas phase component containing the hydrocarbon gas from the first mixed fluid,
With
The production fluid processing system, wherein the first mixing device includes a storage unit that stores the first mixed fluid.   2. The production fluid treatment system according to claim 1, further comprising an adsorption device that contacts an oil solution containing a new oil-soluble sulfur compound fixing agent with the gas phase component, at a stage subsequent to the gas separation device. 3.   An oil separation device that separates an oil phase component containing the crude oil from the first mixed fluid, and a second mixing step that mixes the oil solution in contact with the gas phase component with the oil phase component at a stage subsequent to the adsorption device. The production fluid treatment system of claim 2, further comprising: an apparatus.   3. The production fluid treatment system according to claim 2, further comprising a third mixing device that mixes the production fluid with the oil solution that has come into contact with the gas phase component, before the gas separation device. 4.   The production fluid treatment system according to any one of claims 1 to 4, further comprising a decompression device that decompresses the first mixed fluid before the gas separation device. A first mixing step of obtaining a first mixed fluid by mixing an oil-soluble sulfur compound fixing agent with a production fluid containing hydrocarbon gas, crude oil, and a sulfur-containing compound,
A gas separation step of separating a gas phase component containing the hydrocarbon gas from the first mixed fluid,
Has,
The first mixing step is a method of processing a production fluid having a storage operation of storing the first mixed fluid.   The method for treating a production fluid according to claim 6, wherein the oil-soluble sulfur compound fixing agent contains an oil-soluble compound having an aldehyde group.

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