KR19990077020A - Method and apparatus for flowing marine petroleum products using primary gas separation - Google Patents

Abstract

The present invention relates to a method and apparatus for flowing marine products of hydrocarbon mixtures containing high concentration gases. The primary separation vessel 52 is used and the product is converted to this vessel. This vessel 52 is designed to allow for primary separation of the gas flowing through the specified line 56 to the collection center 63. Within the primary separation vessel 52 there is a U-shaped pipe 53 and its arm is connected to two flow lines 57 and 58 extending to the collection center. The mechanical interface 70 driven by the high pressure gas periodically moves along these lines 56, 57, 58 and carries a large amount of liquid phase accumulated in the lines to the collection center 63 to the interface. If a liquid phase passes into the gas flow line 56, the mechanical interface 70 can pass along this line to remove the large amount of liquid accumulated in this line.

Description

Method and apparatus for flowing offshore petroleum products using primary gas separation

Increasing oil exploration in deeper territorial waters requires skilled practitioners in the field to develop new technologies to increase hydrocarbon production from offshore oil wells. It can be seen that the hydrocarbon mixture starting from the oil well can vary substantially with respect to the amount of phase, which is generally water, oil and gas.

Once the step of obtaining a large amount of hydrocarbon mixture from the well has been completed, the mixture should be discharged to a collection center with primary treatment facilities. The location of the collection center may be an offshore platform, vessel or land collection station. The mixture is discharged to the collection center via a pipeline which may be rigid or flexible or a combination of the two.

The reservoir pressure itself is simply the energy used to flow the hydrocarbon mixture along the pipe into the collection center. However, this arrangement has several disadvantages due to the formation of a column containing a significant amount of fluid, as the accumulation of fluid in the riser pipes increases the hydrostatic pressure at the well well or manifold. This pressure increase is undesirable because it prevents the flow of hydrocarbon mixture from reaching the collection center. There may also be extreme situations where the storage pressure simply cannot maintain flow to the collection center.

When the hydrocarbon mixture contains a large amount of gas, a number of factors can cause severe interruptions, which fluctuate significantly at the pressure level of the fluid flow. The basic condition of severe interruption is the formation of a liquid seal in the flow line that promotes gas separation to the upper part of the pipe. Finally, when a large amount of separation gas passes in a constant fashion along the ridges of the pipes extending from the seabed to the collection center (referred to by those skilled in the art as "risers"), a significant increase in pressure occurs in this ridge line. This sudden increase in pressure is not only undesirable for the device, but also harmful.

GB-A-2282399 proposes the use of a second riser line connected to the flow line at a point located at a specific distance from the junction between the lower flow line and the main line. This second riser line is connected to the main riser at a point located at the junction between the main riser and the lower guide line.

The function of the secondary riser is to lower the gas pressure in the flow of the hydrocarbon mixture occurring upstream from the point where the lower flow line joins the main riser, and to inject the gas downstream from the junction point. The control valve is fitted at the second riser controlled by a sensor installed proximate the connection between the flow line and the second riser to control the flow of gas injected into the riser. In this way, the effects of severe interruptions can be reduced or avoided because of sudden changes in pressure when the gas flows into the collection center when the gas is injected into the main riser in a controlled manner. Because there is no.

This technique significantly contributes to the control of severe interruptions in multiphase flows. However, the formation of a column with a significant amount of fluid in the riser pipe may continue to cause an undesirable increase in pressure at the offshore oil well or manifold and reduce on discharge.

The present invention relates to a method and apparatus for flowing a hydrocarbon mixture containing a high concentration of gas to the ground. The present invention can be applied to a single offshore oil well or offshore manifold that receives emissions from various wells for continuous collection.

1 schematically illustrates the application of a conventional method; And

2 schematically illustrates the application of the method and apparatus according to the invention in which a primary gas separation vessel is used.

It is an object of the present invention to overcome the above mentioned problems and thus propose an apparatus and method for completely or almost completely flowing a hydrocarbon mixture produced to a collection center.

The present invention relates to a method and apparatus for producing petroleum in a controlled manner to avoid accumulation of large amounts of gaseous and liquid phases in a production line.

Accordingly, a first aspect of the present invention provides an apparatus for collecting marine petroleum products from an oil well or oil well manifold to a collection center along one or more flow lines using primary gas separation. The use of a primary separation vessel designed to receive emissions of hydrocarbon mixtures from the well wells / manifolds; There is a U-shaped pipe in the primary separation vessel, the curved portion of which is connected to a short length pipe having a check valve at its lower end; Two arms of the U-shaped pipe are connected to two flow lines extending from the primary separation vessel to the collection center; The primary separation vessel is designed such that primary separation of the gas contained in the hydrocarbon mixture occurs in the vessel to separate the gas into the upper portion of the vessel; A gas discharge line is connected to an upper portion of the primary separation vessel to discharge the separated gas to the collection center; The apparatus is characterized in that the mechanical interface is periodically passed through the assembly formed by the U-shaped pipe in the flow line and the primary separation vessel to facilitate the flow of the hydrocarbon mixture accumulated in the pipe to the collection center. It is done.

A second aspect of the present invention provides a method for collecting offshore petroleum products using primary gas separation, which method

Inserting a mechanical interface into the launch device when the amount of hydrocarbon mixture accumulated in the flow line from the well or well well manifold reaches a desired level;

Then opening a gas transfer valve to discharge pressurized gas from the tank into the launch device;

The mechanical pressure is driven by gas pressure to move along the one of the flow lines and in the one flow line, through the first valve near the primary separation vessel, the length in the primary separation vessel is U-shaped. After passing along the shaped pipe, it begins to return to the collection center along the other flow line, so that the check valve of the short pipe connected in the flow line at the point in the primary separation vessel causes the pressurized gas to Removing a large amount of hydrocarbon mixture accumulated in the flow line and the U-shaped pipe into the tank while preventing passage into the primary separation vessel;

Removing almost all of the bulk hydrocarbon mixture accumulated in the flow line with the surge tank when the mechanical interface reaches the receiving device; And

Close the gas transfer valve and depressurize the flow line and the U-shaped pipe to allow the mechanical interface to move along the line when a large amount of the mixture accumulated in the line reaches the desired level and depressurize these lines Opening said second valve in said collection center to fill with said hydrocarbon mixture.

The average pressure at the well well or manifold is kept low and the occurrence of severe interruptions is prevented, and the adverse effects of high pressure in the flow line on the flow of hydrocarbon mixture to the well well or manifold are also prevented.

The product is conveyed to a primary separation vessel located at the point close to the well well or manifold. This vessel allows the effect on the primary separation of the gases present in the hydrocarbon mixture produced. The upper portion of the vessel is connected to a gas discharge line extending to the collection center. It is preferred that gas flow through this line.

In the primary separation vessel there is a U-shaped pipe and the curved portion of the pipe is connected to a short length pipe with a bottom valve designed to collect liquid phase from the produced hydrocarbon mixture collected at the bottom of the vessel.

The two branches of the U-shaped pipe are connected to two flow lines appearing from within the primary separation vessel and extending to the collection center. Periodically the mechanical interface is passed through a circuit formed by a flow line and a U-shaped pipe in length and driven by gas at high pressure. The mechanical interface removes almost all of the large amount of fluid accumulated in the line.

If a flow of liquid occurs in the gas discharge line, the operation is carried out using a shutoff valve present in the line to pass a mechanical interface through the gas discharge line to remove the liquid accumulated in the line to the collection center.

The features of the present invention will be better understood from the detailed description which follows by way of illustration only with reference to the drawings mentioned below, which form an integral part of this description.

1 is a diagram schematically illustrating an embodiment of a conventional apparatus as disclosed in the above-mentioned GB-A-2282399.

At a certain point C there is a lower flow line 1 connected to the main riser 2. The second riser 3 is connected to the lower flow line 1 at point B and to the main riser 2 at point A. The pressure sensor 14 installed in the lower flow line 1 proximate the intersection point B with the riser 1 controls the control valve 4 fitted to the second riser 3.

When the pressure at the intersection point (B) reaches a higher level than the pressure sensor 14 is set, the control valve (4) is operated in such a way that it maintains a controlled flow of gas between the point (A) and the point (B). Will work. When pressure sensor 14 detects an increase or decrease in pressure near point B, control valve 4 opens or closes proportionally to allow a controlled flow of gas between these two points A and B. To minimize or eliminate the effects of severe enforcement.

As mentioned above, this technique meant significant advances in the field of controlling severe interruptions, but the problem of back pressure exerted by the accumulation of fluid in the flow lines above the well wells or manifolds continued to exist.

2 illustrates an embodiment of the present invention that provides a solution to the two above mentioned problems. There may be a well 50 or a manifold, and for simplicity there is a unit 50 which will be referred to herein as an well well / manifold. Line 51 derives the hydrocarbon mixture produced from the well jetting basin / manifold 50 into a primary separation vessel 52 having a U-shaped pipe 53 therein.

The lower part of the U-shaped pipe 53 is connected to the short length pipe 54 having a check valve 55 at its end. This short pipe 54 collects fluid (generally liquid) that collects at the bottom of the primary separation vessel 52 and transfers the fluid into a pipe 53 that is U-shaped in length.

The two branches of the U-shaped pipes connect with the flow lines 57 and 58 to extend out of the primary separation vessel 52 and in this case to the collection center located on the platform 63.

The primary separation vessel 52 is designed in such a way that the primary separation of the gas contained in the hydrocarbon mixture occurs in the vessel and the gas separates into the upper portion of the primary separation vessel 52. The upper portion of the vessel is connected to the gas discharge line 56, through which the separated gas flows into the vessel 90 located in the collection center as shown in FIG. The shutoff valve 61 may be close to the point at which the gas discharge line 56 is connected to the vessel 90.

The hydrocarbon mixture produced in this example flows into the surge tank 68 installed above the platform 63 is only proposed for illustration. However, the collection center may be replaced by a container or a land collection station.

The external source of pressurized gas illustrated in FIG. 2 by the tank 66 located on the platform 63 supplies the gas used to drive the mechanical interface 70 along the line 58/57 or 56/57. do.

Launcher 64 located on platform 63 operates to launch mechanical interface 70 into lines 58 and 56. The gas transfer valve 65 controls the supply of gas from the tank 66 to the launch device 64. The receiving device 67 located on the platform 63 operates to receive the mechanical interface 70 after the mechanical interface 70 has been passed along the line 58/57 or 56/57. The gas discharge or pressure reducing shutoff valve 69 depressurizes the line set 58/57 or 56/57.

A through-flow shut-off valve 62 is provided to the flow line 58 proximate to the junction between the flow line and one of the arms of the U-shaped pipe 53 coming out of the primary separation vessel 52. Is installed. This valve is generally left open and passes the hydrocarbon mixture into flow line 58.

The short U-shaped pipe 20, located close to the primary separation vessel 52, serves as a connection line connected to the gas discharge line 56 to the flow line 57, and the flow-through shutoff valve 60 ). There is a check valve 59 at the gas discharge line 56 proximate to the junction point 25 between the gas discharge line 56 and the U-shaped connecting line. A perfusion valve is a valve that allows a mechanical interface to pass through the valve along a fluid passage.

When the amount of hydrocarbon mixture accumulated in lines 57, 58 reaches the desired level, the process of the process according to the invention is started as follows:

The mechanical interface 70 is inserted into the launch device 64. Thereafter, the gas transfer shutoff valve 65 is opened to discharge the pressurized gas from the tank 66 to the launch device 64.

Driven by this gas, the mechanical interface 70 moves along the flow line 58 and passes through the cut-off valve 62 and the pipe 53 having a U-shaped length in the primary separation vessel 52. Thereafter, the return to the platform 63 is started along the flow line 57, so that the length of the U-shaped pipe 53 and the large amount of hydrocarbon mixture accumulated in the flow lines 58 and 57 are removed. . The check valve 55 on the short length pipe 54 prevents pressurized gas from passing into the interior of the primary separation vessel 52.

When the mechanical interface 70 reaches the receiver 67, much of the hydrocarbon mixture accumulated in the flow line will be removed to the surge tank 68.

Thereafter, the gas transfer valve 65 is closed, and then the pressure reducing valve 69 is opened to depressurize the flow lines 57 and 58 and the U-shaped pipe 53 to fill these lines with the hydrocarbon mixture. The mechanical interface 70 can thus move back along them when a large amount of accumulated mixture is sufficient.

A situation arises where the liquid phase passes into the gas discharge line 56 as a result of the accumulation of liquid caused by a reduction in the separation efficiency in the primary separation vessel 52 or for other reasons. This accumulation of liquid is undesirable because the gas separated in the primary separation vessel prevents the general flow into the tank 90 located on the platform 63. This liquid must then be removed from the line 56 and this is done by passing through a mechanical interface 70 driven by pressurized gas.

The launch of the mechanical interface 70 into the gas discharge line 56 is initiated by opening the check valve 60 and closing the shutoff valves 62, 61. Then, the mechanical interface 70 is located in the launch device 64, and the gas transfer valve 65 is opened to allow gas to pass from the tank 66 to the launch device 64, so that the gas discharge line 56 Drive the mechanical interface 70. High pressure gas will not flow into tank 90 when check valve 61 is closed.

Driven by the gas, the mechanical interface 70 moves along the gas discharge line 56 and passes through the pipe 20, which is U-shaped in length at the point of intersection 25. The check valve 59 prevents gas from passing into the primary separation vessel 52.

When the shutoff valve 60 is opened, the mechanical interface 70 continues to move through the intersection point 26 in the pipe 20 having a U-shape length and return to the platform 63 along the flow line 57. To start.

When the mechanical interface 70 reaches the receiver 67, almost the liquid phase of the hydrocarbon mixture accumulated in the gas discharge line 56 may be transferred into the surge tank 68 together with the hydrocarbon mixture accumulated in the flow line 57. will be. Thereafter, the gas transfer valve 65 is closed and the pressure reducing valve 69 is opened to depressurize the lines 56 and 57.

Finally, the shutoff valves 62 and 61 are opened and the shutoff valve 60 is closed to restore normal operation.

It is pointed out that it is important that the above mentioned process of opening and closing the valve is preferably remotely controlled from the position located in the collection center 63. The valve control line is not shown merely to simplify the drawing. The demand device 67 points out that the mechanical interface 70 does not block the flow of fluid to the surge tank 68 and has an internal mechanism that can be removed from the inside. Launcher 64 has an internal actuation mechanism that can select which line 56 or 58 to launch the mechanical interface 70. The mechanism of the receiving device 67 and the mechanism of the launching device 64 are not described in detail in the above description if they are known to those skilled in the art without forming an essential part of the present invention.

Launcher 64 and receiver 67 may be connected into a single unit having an internal mechanism such that the necessary operation of launching and receiving a mechanical interface can be performed for ease of operation. This possibility is not shown in FIG. 2 because it is known to those skilled in the art and does not form part of the present invention.

Claims (5)

An apparatus for collecting offshore oil products from an oil well 50 or an oil well manifold to a collection center 63 using primary gas separation, the apparatus comprising: Consisting of the use of a primary separation vessel 52 designed to receive the emissions of hydrocarbon mixtures arising from the manifold 50; In the primary separation vessel 52 there is a U-shaped pipe 53, the curved portion of which is connected to a short pipe 54 having a check valve 55 at its lower end; Two arms of the U-shaped pipe (53) are connected to two flow lines (57, 58) extending out of the primary separation vessel (52) and into the collection center (63); The primary separation vessel (52) is designed such that primary separation of the gas contained in the hydrocarbon mixture occurs in the vessel to separate gas into the upper portion of the vessel (52); A gas discharge line 56 is connected to an upper portion of the primary separation vessel 52 to discharge the separated gas to the collection center 63; The apparatus comprises a U-shaped pipe 53 in length in the flow lines 57 and 58 and in the primary separation vessel to facilitate the flow of the hydrocarbon mixture accumulated in the pipes 57 and 58 to the collection center 63. Wherein the mechanical interface (70) is periodically passed through the assembly formed by the device. 2. The set or gas discharge of claim 1, wherein the line 57 is connected to a gas discharge line 56 in one of the flow lines 57, 58 and further comprises the two flow lines 57, 58. A U-shaped length also having valves 20, 62, 69 which cause the operation to be carried out to control the movement of the mechanical interface along any one of the set consisting of line 56 and said one flow line 57. And a pipe (20) that is shaped. The gas separated by the mechanical interface launch device 64, the mechanical interface receiving device 67, and the primary separation vessel 52, according to claim 1 or 2, which is carried by the source 66 of the high pressure gas. And a surge tank (68) for receiving a fluid adapted to flow by movement of the mechanical interface (70) in the receiving vessel (90) and in the flow line (56, 57, 58). A method of collecting marine petroleum products using primary gas separation, the method comprising Inserting the mechanical interface 70 into the launcher 64 when a large amount of hydrocarbon mixture accumulated in the flow line 57, 58 from the oil well 50 or the oil well manifold reaches a desired level; Then opening a gas transfer valve (65) to discharge pressurized gas from the tank (66) into the launch device (64); The gas pressure drives the mechanical interface 70 to move along the one flow line 58 and in the one flow line 58, the first valve 62 near the primary separation vessel 52. Pass through) through the U-shaped pipe 53 in the primary separation vessel 52 and then return to the collection center 63 along the other flow line 57, so that The check valve 55 of the short pipe 54 connected in the flow lines 57 and 58 at the point in the primary separation vessel 52 allows pressurized gas to pass into the primary separation vessel 52. Removing a large amount of hydrocarbon mixture accumulated in the flow line (58, 57) and the length of the U-shaped pipe (53) into the tank (90) while preventing it from being prevented; Removing almost all of the large amount of hydrocarbon mixture accumulated in the flow line (57, 58) with the surge tank (68) when the mechanical interface (70) reaches the receiving device (67); And Close the gas transfer valve 65 and allow flow lines 57, 58 and length to allow the mechanical interface 70 to move along the line when the amount of mixture accumulated in the line reaches a desired level. Opening the second valve (69) in the collection center to depressurize the pipe (53) having a U-shape and to fill these lines with the hydrocarbon mixture. 5. A liquid phase according to claim 4, wherein the liquid phase passes from the primary separation vessel (52) into the gas discharge line (56) and then the mechanical interface (70) near the vessel (52) and the oil well (50) or Open the third valve 60 in the connecting line 20 between the gas discharge line 56 and the other flow line 57 at the manifold and at the inlet to the tank 90 at the collection center After closing the 62 and the fourth valve 61 and positioning the mechanical interface 70 to the launch device 64, the fourth valve 61 prevents the high pressure gas from passing into the tank 90. Launching a mechanical interface (70) into the gas discharge line by opening a gas transfer valve (65) to allow gas to pass from the gas tank (66) to the launch device (64) while being closed so as to be closed; By acting on the mechanical interface 70 by means of gas, the check valve 59 stops the passage of gas into the primary separation vessel 52, along the gas discharge line 56, the connection line 20. Moving into; When the third valve 60 is opened, the mechanical interface 70 continues to move along the connecting line 20 and begins returning to the collection center 63 via the other flow line 57. ; When the mechanical interface 70 reaches the receiver 67, almost all of the liquid phase of the hydrocarbon mixture accumulated in the gas discharge line 56 is accumulated in the other flow line 57 into the surge tank 68. Closing the gas transfer valve (65) and opening the second valve (69) after being moved with a hydrocarbon mixture to depressurize the lines; And Finally opening the first and fourth valves (62, 61) and closing the third valve (60) to restore normal operation.