Valve system

Abstract

A valve system for use in a wellbore includes a side pocket mandrel and one or more well tools, where the side pocket mandrel includes an elongated body section provided with a connector at its ends, the elongated body section being provided with a substantially fully open main bore for alignment with the well tubing and an offset side pocket bore. At least one through opening is provided in the side pocket mandrel, leading into the side pocket bore, and at least one through opening is provided in the internal wall, leading into the main bore, where the at least two openings are in fluid communication through the side pocket bore, in which side pocket bore at least two valves are arranged in series to form a double fluid barrier between the main bore and an outside of the pocket mandrel, the at least two valves being independently retrievable through at least one installation opening arranged in the internal wall of the side pocket mandrel.

Claims

1. A valve system for use in a wellbore, comprising a side pocket mandrel where the side pocket mandrel comprises an elongated body section, the elongated body section comprising: a main bore for alignment and fluid communication with a production tubing of the wellbore; a laterally offset side pocket bore, the laterally offset side pocket bore being provided with first and second landing receptacles arranged inside the laterally offset side pocket bore; a first valve arranged in the first landing receptacle; and a second valve arranged in the second landing receptacle, the first and second valves being in fluid communication with each other and being arranged in series to form a double fluid barrier between the main bore and an outside of the side pocket mandrel, the first and second valves being independently retrievable through the main bore and the production tubing, and each of the first and second valves being capable of preventing a fluid medium from flowing through the respective valve; wherein each of the first and second valves has an open position and a closed position while the respective valve is mounted in the elongated body section.

2. The valve system according to claim 1, wherein the first valve comprises an inlet for receiving a fluid from an annulus of the wellbore.

3. The valve system according to claim 2, wherein the first valve is arranged to open at a limit value set by pressure settings of the first valve to allow a fluid from the annulus to flow through the first valve, and in that the second valve is arranged to open at a limit value set by pressure settings of the second valve to allow the fluid from the first valve to flow through the second valve and into the main bore.

4. The valve system according to claim 3, wherein said valves are arranged to open or close at the same pressure.

5. The valve system according to claim 3, wherein said valves are arranged to open or close at different pressures.

6. The valve system according to claim 5, wherein said valves are gas lift valves.

7. The valve system according to claim 3, wherein the limit value set by the pressure settings of the second valve is the same as or lower than the limit value set by the pressure settings of the first valve.

8. The valve system according to claim 1, wherein said valves are chosen from a group consisting of flow control devices, gas lift devices, and chemical injection devices.

9. A wellbore for the extraction of hydrocarbons from a hydrocarbon bearing earth formation, wherein it comprises a valve systems according to claim 1.

10. A method of operating a wellbore, comprising the steps of: placing at least one side pocket mandrel along a production tubing of the wellbore, wherein the side pocket mandrel comprises an elongated body section which comprises: a main bore for alignment and fluid communication with the production tubing of the wellbore; a laterally offset side pocket bore, the laterally offset side pocket bore being provided with first and second landing receptacles arranged inside the laterally offset side pocket bore; a first valve arranged in the first landing receptacle; and a second valve arranged in the second landing receptacle, wherein the first and second valves are in fluid communication with each other and are arranged in series to form a double fluid barrier between the main bore and an outside of the side pocket mandrel, and wherein the first and second valves are independently retrievable through the main bore and the production tubing, and each of the first and second valves is capable of preventing a fluid medium from flowing through the respective valve, and if one of said first valve and second valve needs to be maintained, replaced or adjusted, retrieving the valve in need of maintenance, replacement or adjustment through the well tubing, leaving the remaining valve in the side pocket mandrel, wherein each of the first and second valves has an open position and a closed position while the respective valve is mounted in the elongated body section.

11. The method according to claim 10, wherein said outside of the side pocket mandrel comprises an annulus formed between the production tubing and a casing of the wellbore, and wherein the valve remaining in the side pocket mandrel is arranged to prevent production fluid from within the production tubing from flowing out of the production tubing, through the side pocket mandrel and into the annulus.

12. A valve system for use in a wellbore, comprising a side pocket mandrel where the side pocket mandrel comprises an elongated body section, the elongated body section comprising: a main bore for alignment and fluid communication with a production tubing of the wellbore; a first valve and a landing receptacle for the first valve; a second valve and a landing receptacle for the second valve, the first and second valves being in fluid communication with each other and being arranged in series to form a double fluid barrier between the main bore and an outside of the side pocket mandrel, the first and second valves being independently retrievable through the main bore and the production tubing, and each of the first and second valves being capable of preventing a fluid medium from flowing through the respective valve, wherein each of the first and second valves is independently retrievable with the other of the first and second valves being maintained in the elongated body section.

13. The valve system according to claim 12, wherein each of the first and second valves has an open position and a closed position while the respective valve is mounted in the elongated body section.

14. The valve system according to claim 12, wherein the first valve comprises an inlet for receiving a fluid from an annulus of the wellbore.

15. The valve system according to claim 14, wherein the first valve is arranged to open at a limit value set by pressure settings of the first valve to allow a fluid from the annulus to flow through the first valve, and in that the second valve is arranged to open at a limit value set by pressure settings of the second valve to allow the fluid from the first valve to flow through the second valve and into the main bore.

16. The valve system according to claim 15, wherein the first and second valves are arranged to open or close at the same pressure.

17. The valve system according to claim 15, wherein the first and second valves are arranged to open or close at different pressures.

18. The valve system according to claim 15, wherein the limit value set by the pressure settings of the second valve is the same as or lower than the limit value set by the pressure settings of the first valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features of the present invention, as well as the invention itself, will be best understood from the attached drawings, considered with the following description, to which similar reference numerals refer to similar parts, and in which:

(2) FIG. 1 is a schematic view of an oil and/or gas well,

(3) FIG. 2 shows a valve system according to a preferred embodiment of the present invention, and

(4) FIG. 3 shows an enlarged cross section view of a mandrel of the valve system according to FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) While the invention is subject to various modifications and alternative forms, specific embodiments have been shown by way of examples in the drawings and will be described in detail herein. The drawings are not necessarily in scale and the proportions of certain parts have been exaggerated to better illustrate particular details of the present invention.

(6) Referring now to FIG. 1, an embodiment of the present invention is shown, where a floating structure 1 or a sea- or land-based structure (not shown) is connected to an oil and/or gas well 2 by a production tubing 3. The floating structure 1 and the sea- or land-based structure can be production and/or storing facilities. In this embodiment the valve system according to the present invention is used as an artificial lift system.

(7) In order to enhance the production of the oil and/or gas well 2, a pressurized fluid medium is injected into the annular space (annulus) 4 between a casing 5 of the oil and/or gas well 2 and the production tubing 3. Along the production tubing 3 is/are arranged a plurality of side pocket mandrels 6, where the side-pocket mandrels 6 are connected to tubular elements of the production tubing 3 in appropriate ways.

(8) FIG. 2 shows the valve system according to the present invention, where the valve system comprises a side pocket mandrel 6, in which at least two valves 100, 101 in form of gas lift valves (see also FIG. 3) are arranged. Each and one of the valves 100, 101 forms a fluid barrier in the side pocket mandrel 6. The valves 100, 101 are designed to open at a given differential pressure between two fluids ortwo positions in the well, for instance across the valve 100, 101 or in two different positions arranged relatively above each other in the well, where this differential pressure may vary between the different valves 100, 101. In addition, if the pressurized fluid in the annular space 4 reaches a certain limit value, then the valves 100, 101 will open and the pressurized fluid will be allowed to flow through the valves 100, 101 and into the production tubing 3.

(9) The fluid medium can be gas, liquid, processed well fluid or even a part of the well fluid from the reservoir and can be taken at a position in the vicinity of the side pocket mandrel 6 (that is from the well) or added from the floating installation 1 (or othersea or land based structures, not shown) away from the side pocket mandrel 6.

(10) How many side pocket mandrels 6 should be placed along the production tubing 3 and which features they should possess will depend on the needs of the field or each specific well.

(11) FIG. 3 shows an enlarged cross section view (indicated with B in FIG. 2) of the side pocket mandrel 6 of the valve system, where it can be seen that the side pocket mandrel 6 comprises an elongated tubular body section 7 that is provided with connecting means 8 (just indicated) at both of its ends. The connecting means 8 is a threaded portion on the inside (or outside) of the tubular body section 7, such that the tubular body section 7 can be connected to a well tubing, such as a production tubing 3. The tubular body section 7 is provided with a through substantially fully open main bore 9 and a laterally offset side pocket bore 10. When the side pocket mandrel 6 is connected to the production tubing 3 the main bore 9 will be aligned with a bore of the production tubing 3.

(12) The tubular body section 7 will then have two flowing paths, as the substantially fully open main bore 9 is separated from a laterally offset side pocket bore 10 by an internal wall 11 (see also FIG. 3).

(13) The laterally offset side pocket bore 10 is shaped to accommodate at least two fluid barrier elements, for instance in form of gas lift valves 100, 101, and/or other equipment or tools (not shown). The expression fluid barrier should be understood as an element that will prevent a fluid medium from flowing over the element in at least one direction: This will provide a double barrier inside the side pocket mandrel 6. If for instance one of the valves 100, 101 in the laterally offset side pocket bore 10 due to different reasons has to be maintained, replaced or adjusted, a kick over tool may be run down the production tubing 3 in order to retrieve the valve 100, 101. At least one installation opening (not shown) is then arranged in the internal wall 11 of the side pocket mandrel 6. When the valve 100, 101 is removed by the kick over tool, the other remaining valve 100, 101 in the side pocket mandrel 6 will prevent production fluid within the production tubing 3 from flowing out of the production tubing 3, through the side pocket mandrel 6 and into the annular space 4 between the production tubing 3 and the casing 5 of the well.

(14) The laterally offset side pocket bore 10 is on its inside provided with at least two landing receptacles 15 for the valves 100, 101 and/or other equipment, such that the valves 100, 101 and/or equipment (not shown) can be fixed in the landing receptacles 15. The landing receptacles 15 are provided with at least one set of packing elements 14. When the valves 100, 101 and/or other equipment are introduced into the landing receptacles 15, the valves 100, 101 and/or other equipment will be maintained under pressure, due to: the compression created by the packing elements 14. This will also provide the necessary seals between the valves 100, 101 and/or other equipment and the landing receptacles 15.

(15) The side pocket mandrel 6 of the valve system is designed in a manner such that the valves 100, 101 and/or other equipment may be replaced when necessary without having to pull out the tubing. This replacement may be accomplished by means of an operation in which special tools (not shown) are lowered through the interior of the production tubing 3. The special tools are attached to a fine steel cable or to a wire line. The special tools may for instance be kick over tools or the like.

(16) Furthermore, the side pocket mandrel 6 is provided with at least one through opening (inlet) 12 (just indicated), where the at least one through opening 12 is provided in the laterally offset side pocket bore 10, This will provide a communication between an outer and inner side of the laterally offset side pocket bore 10. Similarly, at least one opening (outlet) 13 (just indicated) to the substantially fully open main bore 9 in the laterally offset side pocket bore 10 (will be the inlet to the substantially fully open main bore 9) is provided in the internal wall 11 that is dividing the substantially fully open main bore 9 and the laterally offset side pocket bore 10. This will provide a communication between the outside and the inside of the side pocket mandrel 6.

(17) In the figure the at least one opening 12 is arranged in a vicinity of an inlet (not shown) of the valve 100 in the laterally offset side pocket bore 10, such that when a fluid from the annulus enters the laterally offset side pocket bore 10, the fluid medium will be guided into an inlet of the first valve 100. This first valve 100 will then be considered to be the primary fluid barrier in the side pocket mandrel 6. When the fluid reaches a limit valve (set by the pressure settings of the valve), the valve 100 will open and allow the fluid medium to flow through the valve 100. The fluid medium will then reach the second valve 101 arranged in the laterally offset side pocket bore 10, where this valve 101 is considered to be the secondary fluid barrier in the side pocket mandrel 6. This second valve 101 may have the same pressure settings as the first valve 100, but preferably the second valve 101 will have a lower pressure limit value. The valve 101 will therefore open and allow the fluid to flow through the valve 101 and into the substantially fully open main bore 9 of the tubular body section 7, through the at least one opening (outlet) 13 of the laterally offset side pocket bore 10.

(18) Furthermore, at least one replaceable sleeve (not shown) is arranged on the outside or inside of the main bore 9 or the offset side pocket bore 10, where the at least one sleeve through the adjustment can control the opening of the openings 12, 13. The at least one sleeve may be arranged to rotate around the bore 9, 10 or to slide in a longitudinal direction of the bore 9, 10.