Oil wellhead gas-liquid sampling device

Abstract

This invention relates to the field of oil well fluid sampling technology, specifically an oil wellhead gas-liquid sampling device comprising an inlet pipe and a hollow separation tank. The invention features a reasonable and compact structure, is convenient to use, and simple to operate. During sampling, the separation tank depressurizes and separates the gas-liquid mixture. The separated water-vapor mixture is transported to a gas sample filtration assembly through a gas sample collection pipe. After filtering out the moisture in the water-vapor mixture, a dry and accurate gas sample is collected through a U-shaped outlet pipe. Similarly, the separated oil-liquid mixture flushes the liquid sample collection pipe, resulting in a clean and accurate liquid sample. When not sampling, the gas-liquid mixture flows out of the separation tank and back into the main pipeline through the outlet pipe, significantly reducing the generation of dead oil within the sampling device. The collected dead oil can also be poured back into the separation tank through a dead oil treatment assembly when not sampling, flowing back into the main pipeline along with the gas-liquid mixture entering the separation tank, effectively preventing the waste of petroleum resources and environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of oil well fluid sampling technology, and is a gas-liquid sampling device for oil wellheads. Background Technology

[0002] Currently, oil wells need to be sampled regularly during oil extraction. The following problems exist during oil well sampling: Dead oil inside the casing must be drained before sampling; the crude oil in the container is difficult to handle, and leaving the container in the open causes environmental pollution; each sampling session releases at least three liters of crude oil from a single well, resulting in at least fifteen liters released per month, and a large amount of crude oil being released nationwide annually. According to specific environmental protection requirements, the crude oil released during sampling cannot be arbitrarily disposed of or buried, nor can it be recycled, resulting in a huge waste of resources; oil splatter often occurs during oil well sampling, increasing the workload of on-site operators, increasing safety risks, toxic gases harming the health of operators, and also causing surface pollution.

[0003] Furthermore, with the advancement of carbon capture, utilization and storage (CCUS) technology, new requirements have been placed on wellhead sampling operations in oil wells. In addition to taking liquid samples from the wellhead in the conventional way to test indicators such as water content, it is also necessary to take gas samples from the wellhead to test carbon dioxide content.

[0004] Existing wellhead sampling devices have the following shortcomings in actual use: when sampling gas, there is no dedicated sampling port, oil is easily splashed, and sampling is difficult; the sampling port is relatively far from the location of the flowing oil well produced fluid, and there is a large amount of dead oil, which makes the sampling accuracy low; during liquid sampling, the released dead oil will cause resource waste, and if not handled in time, it will easily pollute the environment. Summary of the Invention

[0005] This invention provides a gas-liquid sampling device for oil wellheads, which overcomes the shortcomings of the prior art. It can effectively solve the problems of sampling difficulties and low accuracy of existing wellhead sampling devices, as well as the problem of oil sample splashing during the sampling process.

[0006] The technical solution of the present invention is achieved through the following measures: a gas-liquid sampling device for oil wellheads, comprising an inlet pipe and a hollow separation tank, an inlet port on the upper left side of the separation tank, an inlet pipe fixedly installed inside the inlet port, an outlet port on the right side of the separation tank corresponding to the position above the inlet pipe, a gas sample collection pipe fixedly installed inside the outlet port, and a gas sampling control valve on the gas sample collection pipe; an outlet port in the middle of the lower end of the separation tank, a three-way connector fixedly installed inside the outlet port, a liquid sample collection pipe fixedly installed on the lower connector of the three-way connector, a liquid sample collection control valve on the liquid sample collection pipe, and an outlet pipe fixedly installed on the left connector of the three-way connector.

[0007] The following are further optimizations and / or improvements to the above-mentioned technical solution:

[0008] The upper end of the aforementioned separator may be equipped with a dead oil treatment component that connects the inside and outside of the separator. The dead oil treatment component may include a central guide pipe, an oil inlet funnel, and a dead oil treatment control valve. The upper end of the separator is equipped with an oil inlet, and a central guide pipe connected to the liquid inlet pipe on the lower left side is fixedly installed inside the oil inlet. An oil inlet funnel is provided at the upper end of the central guide pipe, and a dead oil treatment control valve is provided on the central guide pipe at the position corresponding to the position between the oil inlet funnel and the separator.

[0009] The aforementioned dead oil treatment component may also include a flared mouth, a filter screen, and an oil baffle plate. A flared mouth with a shape that is smaller at the top and larger at the bottom is fixedly installed at the lower end of the central guide pipe. A filter screen is fixedly installed on the inner side of the lower part of the flared mouth. An oil baffle plate is fixedly installed on the outer side of the central guide pipe at the position corresponding to the position between the liquid inlet and the air outlet.

[0010] The other end of the gas sample collection tube can be equipped with a gas sample filtration assembly. The gas sample filtration assembly may include a filter element, a bent tube, a U-shaped gas outlet tube, a drain tube, a drain valve, a sealing cap, and an upward-opening filter canister. A sealing cap is detachably installed on the outer side of the upper end of the filter canister. A filter element capable of removing moisture from the gas sample is provided on the inner side of the middle part of the filter canister. The filter element has a first through hole, a second through hole, and a third through hole from left to right. An air inlet that runs through the inside and outside is provided on the upper left part of the filter canister. A bent tube located in the first through hole on the lower right is fixedly installed in the air inlet. The left end of the bent tube is fixedly installed together with the other end of the gas sample collection tube. A fourth through hole that runs through the inside and outside is provided on the sealing cap corresponding to the position of the third through hole. A U-shaped gas outlet tube located in the second and third through holes respectively is provided in the fourth through hole. An internal and external drain outlet that runs through the inside and outside is provided on the lower middle part of the filter canister. A drain tube is fixedly installed in the drain outlet, and a drain valve is provided on the drain tube.

[0011] The above may also include an inlet control valve and an outlet control valve, with an inlet control valve installed on the inlet pipe and an outlet control valve installed on the outlet pipe.

[0012] The above may also include a plug, a T-shaped tee, and an inlet guide tube. The right connector of the T-shaped tee is screwed with a plug having an axial channel. The inlet guide tube, with its left end located in the left connector of the T-shaped tee, is sealed inside the plug. The right end of the inlet guide tube is detachably installed together with the left end of the inlet pipe. A wrench groove is provided on the outer side of the right end of the plug. The lower connector of the T-shaped tee is fixedly installed together with one end of the outlet pipe.

[0013] This invention features a reasonable and compact structure, is convenient to use, and is simple and easy to operate. During sampling, the gas-liquid mixture is depressurized and separated by a separator. The separated water-vapor mixture is then transported to a gas sample filtration assembly through a gas sample collection tube. After filtering out the moisture in the water-vapor mixture, a dry and accurate gas sample can be collected through a U-shaped outlet pipe. The separated oil-liquid mixture cleans the liquid sample collection tube, allowing for the collection of a clean and accurate liquid sample. When not sampling, the gas-liquid mixture flows out of the separator and back into the main pipeline through the liquid outlet pipe, greatly reducing the amount of dead oil generated in the sampling device. The collected dead oil can also be poured back into the separator through a dead oil treatment assembly when not sampling, flowing back into the main pipeline along with the gas-liquid mixture entering the separator, effectively avoiding waste of petroleum resources and environmental pollution. Attached Figure Description

[0014] Appendix Figure 1 This is a schematic diagram of the main view partial cross-sectional structure of Embodiments 1-6 of the present invention.

[0015] The codes in the attached diagram are as follows: 1 is the inlet pipe, 2 is the separator, 3 is the gas sample collection pipe, 4 is the gas sampling control valve, 5 is the tee connector, 6 is the liquid sample collection pipe, 7 is the liquid sample collection control valve, 8 is the outlet pipe, 9 is the central guide pipe, 10 is the oil inlet funnel, 11 is the dead oil treatment control valve, 12 is the bell mouth, 13 is the filter screen, 14 is the oil baffle, 15 is the filter element, 16 is the bend, 17 is the U-shaped gas outlet pipe, 18 is the drain pipe, 19 is the drain valve, 20 is the sealing cap, 21 is the filter tank, 22 is the inlet control valve, 23 is the outlet control valve, 24 is the plug, 25 is the T-type tee, 26 is the inlet guide pipe, and 27 is the wellhead nozzle sleeve. Detailed Implementation

[0016] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0017] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0018] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0019] Example 1: As shown in the attached document Figure 1 As shown, the wellhead gas-liquid sampling device includes an inlet pipe 1 and a hollow separation tank 2. The upper left side of the separation tank 2 has an inlet port, and the inlet pipe 1 is fixedly installed inside the inlet port. The right side of the separation tank 2, corresponding to the position above the inlet pipe 1, has an outlet port, and a gas sample collection pipe 3 is fixedly installed inside the outlet port. A gas sampling control valve 4 is installed on the gas sample collection pipe 3. The lower middle part of the separation tank 2 has an outlet port, and a three-way connector 5 is fixedly installed inside the outlet port. A liquid sample collection pipe 6 is fixedly installed on the lower connector of the three-way connector 5. A liquid sample collection control valve 7 is installed on the liquid sample collection pipe 6. An outlet pipe 8 is fixedly installed on the left connector of the three-way connector 5.

[0020] During operation, the gas-liquid mixture to be sampled is depressurized and separated in the separator 2. When sampling is required, the gas-liquid mixture sample enters the separator 2 through the inlet pipe 1, where it is depressurized and separated into oil and gas. The separated oil-liquid mixture flows back into the main pipeline through the outlet pipe 8. At this time, if the liquid sample collection container is connected to the liquid sample collection pipe 6 and the liquid sample collection control valve 7 is opened, the liquid sample can flow into the liquid sample collection container through the liquid sample collection pipe 6. After reaching the sampling volume, the liquid sample collection control valve 7 is closed. The separated gas, being lighter, floats to the top of the separator 2. After connecting the gas sample collection container to the gas sample collection pipe 3 and opening the gas sampling control valve 4, the gas sample can flow into the gas sample collection container through the gas sample collection pipe 3. After reaching the sampling volume, the gas sampling control valve 4 is closed. The above sampling process is simple and easy to operate, with separate sampling of gas and liquid, resulting in high sample accuracy. In addition, the gas separated by the separator 2 is more completely separated and has a relatively low pressure, effectively avoiding oil splashing when collecting gas samples.

[0021] Depending on the requirements, both the liquid sampling control valve 7 and the gas sampling control valve 4 can be implemented using existing known technologies such as gate valves, ball valves, or butterfly valves. The inlet pipe 1 can be directly connected to the main pipeline or connected to the well nozzle sleeve and the main oil pipeline via a tee fitting. In this way, when not sampling, the liquid in the separation tank 2, the inlet pipe 1, and the outlet pipe 8 can be flushed by the gas-liquid mixture, so that the liquid in the device is always in a flowing state, thereby effectively avoiding the presence of stagnant oil in the separation tank 2 and the pipeline, which would affect the quality of liquid sampling. In addition, to avoid the presence of a small amount of stagnant oil in the liquid sampling pipe 6, the liquid sampling control valve 7 can be opened before sampling to flush away the stagnant oil remaining in the liquid sampling pipe 6 with the oil-liquid mixture before sampling, thereby improving the quality of oil sampling.

[0022] The above-mentioned wellhead gas-liquid sampling device can be further optimized and / or improved according to actual needs:

[0023] Example 2: As shown in the attached document Figure 1As shown, the upper end of the separator 2 is provided with a dead oil treatment component that connects the inside and outside of the separator 2. The dead oil treatment component includes a central guide pipe 9, an oil inlet funnel 10, and a dead oil treatment control valve 11. The upper end of the separator 2 is provided with an oil inlet. The lower left side of the central guide pipe 9, which is connected to the liquid inlet pipe 1, is fixedly installed inside the oil inlet. The upper end of the central guide pipe 9 is provided with an oil inlet funnel 10. The dead oil treatment control valve 11 is provided on the central guide pipe 9 at the position between the oil inlet funnel 10 and the separator 2.

[0024] During use, the dead oil mixture used to flush out the stagnant oil accumulated in the liquid sample collection tube 6 can be poured back into the separator 2 through the oil inlet funnel 10 and the central guide pipe 9 when not sampling. This mixture flows back to the main pipeline along with the liquid mixture in the separator 2, thus avoiding waste of petroleum resources and environmental pollution. Depending on the requirements, the oil inlet funnel 10 and the central guide pipe 9 can be connected by detachable installation methods such as screws, clips, or set screws, or by fixed installation methods such as welding or riveting. To reduce the formation of dead oil in the separator 2 wall, the lower end of the central guide pipe 9 is located at the bottom of the separator 2.

[0025] Example 3: As shown in the attached document Figure 1 As shown, the dead oil treatment assembly also includes a flared mouth 12, a filter screen 13, and an oil baffle 14. A flared mouth 12 with a shape that is smaller at the top and larger at the bottom is fixedly installed at the lower end of the central guide pipe 9. A filter screen 13 is fixedly installed on the inner side of the lower part of the flared mouth 12. An oil baffle 14 is fixedly installed on the outer side of the central guide pipe 9 corresponding to the position between the liquid inlet and the air outlet.

[0026] During use, the central guide pipe 9 and the flared mouth 12 can effectively prevent the gas-liquid mixture from spraying and spreading to the inner wall of the right side of the separator 2, and also facilitate the direct impact of the gas-liquid mixture on the bottom of the separator 2, thus accelerating gas-liquid separation. The filter screen 13 can filter out particulate impurities in the dead oil, preventing impurities from entering the separator 2. When the separated gas floats up and comes into contact with the oil baffle 14, it will change the direction of gas flow, causing the gas to flow along the lower side of the oil baffle 14 to the gap between the oil baffle 14 and the separator 2. The oil baffle 14 will gradually adsorb the tiny droplets and impurities in the gas, and cause them to gather together to form droplets, which will then fall back into the oil-liquid mixture at the bottom of the separator pipe and flow out of the separator 2, thereby improving the accuracy and purity of the gas sample.

[0027] Example 4: As shown in the appendix Figure 1As shown, a gas sample collection tube 3 has a gas sample filtration assembly installed at the other end. The gas sample filtration assembly includes a filter element 15, a bend 16, a U-shaped gas outlet tube 17, a drain tube 18, a drain valve 19, a sealing cap 20, and an upward-opening filter canister 21. The sealing cap 20 is detachably installed on the outer side of the upper end of the filter canister 21. The filter element 15, which can remove moisture from the gas sample, is located on the inner side of the middle part of the filter canister 21. The filter element 15 has a first through hole, a second through hole, and a third through hole from left to right. The upper left part of the filter canister 21 has a... An air inlet with internal and external penetration is provided. A bent pipe 16 located in the first through hole at the lower right is fixedly installed inside the air inlet. The left end of the bent pipe 16 is fixedly installed together with the other end of the gas sample collection tube 3. A fourth through hole is provided on the sealing cap 20 corresponding to the third through hole. A U-shaped air outlet pipe 17 located in the second and third through holes at the lower part of the fourth through hole is provided. A drain outlet with internal and external penetration is provided in the middle of the lower end of the filter tank 21. A drain pipe 18 is fixedly installed inside the drain outlet. A drain valve 19 is provided on the drain pipe 18.

[0028] During use, the separated gas sample flows through the bend 16 to the bottom of the filter tank 21 and gradually rises. As the rising gas sample passes through the filter element 15, moisture is filtered out, resulting in a relatively dry gas sample. The dried gas sample flows into the gas sample collection container from the U-shaped outlet pipe 17. The water accumulated in the filter tank 21 can be periodically drained out of the filter tank 21 through the drain pipe 18 by opening the drain valve 19. Depending on the requirements, the gas sample filtration assembly can effectively improve the dryness and accuracy of the gas sample, resulting in a higher quality gas sample. The bend 16 can be implemented using existing technologies such as semi-circular bends or right-angle bends, or it can be implemented using a straight pipe with an elbow. For easy replacement, the filter element 15 and the filter tank 21 can be connected by existing technologies such as plug-in, snap-fit, or interference fit. The filter element 15 can be implemented using existing technologies such as a highly polar water-absorbing material that does not chemically react with the gas sample, or it can be implemented using existing technologies such as a semi-permeable membrane that only allows gas to pass through and not water vapor.

[0029] Example 5: As shown in the attached document Figure 1 As shown, it also includes an inlet control valve 22 and an outlet control valve 23. The inlet pipe 1 is equipped with an inlet control valve 22, and the outlet pipe 8 is equipped with an outlet control valve 23.

[0030] With this configuration, the inlet control valve 22 can control the inflow rate of the gas-liquid mixture, and the outlet control valve 23 can be adjusted to make it easier to adjust the sampling flow rate in the liquid sample collection tube 6. In addition, after both are closed, it is easier to clean the impurities and inner wall deposits in the separation tank 2 without affecting the main pipeline, so as to improve the sampling accuracy.

[0031] Example 6: As attached Figure 1As shown, it also includes a plug 24, a T-shaped tee 25, and an inlet guide tube 26. The right connector of the T-shaped tee 25 is screwed with a plug 24 having an axial channel. The inlet guide tube 26, with its left end located in the left connector of the T-shaped tee 25, is sealed inside the plug 24. The right end of the inlet guide tube 26 is detachably installed together with the left end of the inlet pipe 1. A wrench groove is provided on the outer side of the right end of the plug 24. The lower connector of the T-shaped tee 25 is fixedly installed together with one end of the outlet pipe 8.

[0032] During use, first connect the left connector of the T-type tee 25 to the wellhead nozzle sleeve 27, and then connect the lower connector of the T-type tee 25 to the main pipeline. This allows the inlet guide pipe 26 to be suspended in the middle of the wellhead fluid flow, so as to avoid impurities such as wax on the inner wall of the pipeline from affecting the sampling results. Depending on the requirements, the shape of the wrench groove can be matched with the opening shape of the open wrench or adjustable wrench.

[0033] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A gas-liquid sampling device for oil wellheads, characterized in that, The separator includes an inlet pipe and a hollow separator. An inlet is located on the upper left side of the separator, with an inlet pipe fixedly installed inside. A gas outlet is located on the right side of the separator, above the inlet pipe, with a gas sampling tube fixedly installed inside. The gas sampling tube is equipped with a gas sampling control valve. An outlet is located in the middle of the lower end of the separator, with a three-way connector fixedly installed inside. A liquid sampling tube is fixedly installed on the lower connector of the three-way connector, with a liquid sampling control valve on the liquid sampling tube. An outlet pipe is fixedly installed on the left connector of the three-way connector. A dead oil connection is located at the top of the separator, linking the inside and outside of the separator. The dead oil treatment assembly includes a central guide pipe, an oil inlet funnel, and a dead oil treatment control valve. The upper end of the separator tank has an oil inlet, inside which a central guide pipe connected to the liquid inlet pipe on the lower left side is fixedly installed. An oil inlet funnel is located at the upper end of the central guide pipe, and a dead oil treatment control valve is installed on the central guide pipe corresponding to the position between the oil inlet funnel and the separator tank. A gas sample collection pipe has a gas sample filtration assembly installed at the other end. The gas sample filtration assembly includes a filter element, a bend, a U-shaped gas outlet pipe, a liquid drain pipe, a liquid drain valve, a sealing cap, and an upward-opening filter tank. A sealing cap is detachably installed on the outer side of the upper end of the filter tank. The filter canister has a filter element inside the middle section to remove moisture from the gas sample. From left to right, the filter element has a first through hole, a second through hole, and a third through hole. The upper left part of the filter canister has an inlet that runs through both the inside and outside. A bent tube located in the lower right section of the first through hole is fixedly installed inside the inlet. The left end of the bent tube is fixedly installed to the other end of the gas sample collection tube. A fourth through hole is located on the sealing cap corresponding to the third through hole. A U-shaped outlet tube located in the lower part of the fourth through hole is located in the second and third through holes respectively. A drain outlet running through both the inside and outside is located at the lower center of the filter canister for draining liquid. A drain pipe is fixedly installed inside the inlet, and a drain valve is provided on the drain pipe. It also includes an inlet control valve and an outlet control valve. The inlet pipe is equipped with an inlet control valve, and the outlet pipe is equipped with an outlet control valve. The dead oil treatment component also includes a flared mouth and an oil baffle. A flared mouth with a shape that is smaller at the top and larger at the bottom is fixedly installed at the lower end of the central guide pipe. An oil baffle is fixedly installed on the outside of the central guide pipe at the position between the liquid inlet and the air outlet. It also includes a T-type tee and an inlet guide pipe. The right end of the inlet guide pipe is detachably installed together with the left end of the liquid inlet pipe. The lower connector of the T-type tee is fixedly installed together with one end of the outlet pipe.

2. The wellhead gas-liquid sampling device according to claim 1, characterized in that, A filter screen is fixedly installed on the inner side of the lower part of the flared mouth.

3. The wellhead gas-liquid sampling device according to claim 1 or 2, characterized in that, The right connector of the T-type tee is screwed with a plug with an axial channel. The inside of the plug is sealed with an inlet guide tube located at the left end of the left connector of the T-type tee. A wrench groove is provided on the outside of the right end of the plug.

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