A shallow-water landing string

Abstract

The present invention relates to a shallow water landing string, comprising a ground test tree, a blowout preventer nipple, a quick connector, a gate valve, a plurality of oil pipes, a shear blowout preventer valve, and an oil pipe hanging and running tool; the bottom of the ground test tree is detachably connected to the blowout preventer nipple, the bottom end of the blowout preventer nipple is detachably plug-connected to the quick connector, the bottom end of the quick connector is detachably connected to the gate valve, the bottom end of the gate valve is detachably connected to one of the oil pipes, a plurality of the oil pipes are detachably connected to each other, the bottom end of the oil pipe is detachably connected to the top end of the shear blowout preventer valve, and the bottom end of the shear blowout preventer valve is detachably connected to the oil pipe hanging and running tool. The shallow water landing string uses a deepwater string for shallow waters, so that direct production can be achieved at the bottom of the well during shallow water operations without the need for platforms and other facilities, ensuring the normal development of marine oil operations while ensuring a clear waterway.

Description

Technical Field

[0001] The invention relates to a shallow water landing pipe string, belonging to the field of petroleum exploration equipment. Background Art

[0002] When the upper completion string is lowered during the well completion operation on a semi-submersible platform, an underwater wellhead landing string is required. The landing string must have a maximum outer diameter sufficient to smoothly pass through the riser and blowout preventer assembly of the target operating platform, and a minimum inner diameter sufficient to allow the tubing hanger plug and wireline tool to be lowered. The string must be capable of installing and recovering the tubing hanger, starting the pump in the production well, providing a blowout prevention channel for well cleaning and flowback, and providing a well control barrier for the emergency tubing well.

[0003] Since shallow sea areas involve the issue of occupying waterways, the shallow sea area exploitation model generally adopts the form of offshore oil production modules, that is, a permanent oil production platform is established above the sea surface. Once the oil production platform is established, commercial transport ships will not be able to pass nearby. At present, some oil reservoirs in Bohai are within the waterway range, so they cannot be mined according to the previous model. However, there is no problem of waterway occupation in the deepwater oil production and completion process.

[0004] Currently, landing strings are primarily used in deepwater subsea completion operations. However, for shallow-water completions, deepwater strings are too complex and require an underwater string release function for emergency situations. Shallow-water completions are performed using jack-up platforms, and the subsea wellhead equipment cannot be released in an emergency. Therefore, landing strings do not require an emergency release function. Therefore, deepwater landing strings are not universal and require targeted string structure design to meet the needs of shallow-water offshore completions. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a shallow water landing string, which enables direct production at the bottom of the well during shallow water operations without the need for platforms and other facilities, ensuring the normal development of marine oil work while ensuring that the waterway is unobstructed.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] An embodiment of the present invention provides a shallow water landing string, comprising a surface test tree, a blowout preventer nipple, a quick connector, a gate valve, a plurality of oil pipes, a shear blowout preventer valve, and an oil pipe hanging and running tool;

[0008] The bottom of the ground test tree is detachably connected to the blowout preventer pup joint, the bottom end of the blowout preventer pup joint is detachably plug-connected to the quick connector, the bottom end of the quick connector is detachably connected to the gate valve, the bottom end of the gate valve is detachably connected to the oil pipe, the bottom end of the oil pipe is detachably connected to the top end of the shear blowout preventer valve, the bottom end of the shear blowout preventer valve is detachably connected to the tubing hanger running tool, and the tubing hanger running tool is detachably connected to the tubing hanger.

[0009] The shallow water landing string includes at least one pressure-bearing short joint, the top and / or bottom end of the pressure-bearing short joint is detachably connected to the oil pipe, and a plurality of hydraulic channels are opened in the side wall of the pressure-bearing short joint, and the top and bottom ends of the hydraulic channels are connected to the hydraulic pipeline.

[0010] The shear blowout preventer is a ball valve, which has an open well state and a closed well state. When the ball valve is in the open well state, the ball valve provides a channel for the downhole tool string and well fluid to pass through. When the ball valve is in the closed well state, the ball valve has the function of cutting the rope used to lower the tool string.

[0011] The surface test tree includes a wax cleaning valve, a lower main valve, a well-killing wing valve and a production wing valve. When the wax cleaning valve and the well-killing wing valve are closed, the lower main valve and the production wing valve are opened to complete the cleaning or injection operation; when the wax cleaning valve and the lower main valve are closed, the production wing valve and the well-killing wing valve are opened to complete the process pressure test operation; when the well-killing wing valve is closed, the wax cleaning valve, the lower main valve and the production wing valve are opened to complete the artificial lift operation.

[0012] The quick connector includes an upper connector, a lower connector, a connecting sleeve and a fixing pin. The bottom of the upper connector and the top of the lower connector are connected by the connecting sleeve, and the connecting parts of the connecting sleeve, the upper connector and the lower connector are fastened by the fixing pin.

[0013] The present invention has the following advantages due to the adoption of the above technical solution:

[0014] The overall tubing string adopts structures such as a tubing hanger, a tubing hanger running tool, a blowout preventer valve, and a pressure-bearing short joint. These structures are all tubing string structures for deep water use. Therefore, the present invention simplifies the deepwater tubing string while retaining some necessary functions for shallow water use. On the one hand, it solves the problem of channel occupation, and on the other hand, it can also meet the needs of shallow water oil production and completion.

[0015] The underwater tree part of the deepwater pipe string is omitted, and a blowout preventer valve and a pressure-bearing short joint are used to ensure that the pipe string can be released in an emergency during the test.

[0016] The upper test tree adopts a small-sized test tree, which saves manpower, material resources and time during testing operations, improves safety during operations and reduces risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those skilled in the art. The accompanying drawings are only used to illustrate the preferred embodiment and are not to be considered as limitations of the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components.

[0018] In the attached figure:

[0019] Figure 1 This is a blast diagram of an embodiment of a shallow water landing string;

[0020] Figure 2 It is a structural diagram of an embodiment of a ground test tree;

[0021] Figure 3 It is a structural schematic diagram of an embodiment of a quick connector;

[0022] Figure 4 It is a structural schematic diagram of an embodiment of a pressure-bearing nipple;

[0023] Figure 5 1. It is a structural diagram of an embodiment of a shear blowout preventer valve;

[0024] The symbols in the accompanying drawings represent the following:

[0025] 1-Surface Christmas tree, 2-Blowout preventer nipple, 3-Quick connector, 4-Gate valve, 5-Tubing, 6-Pressure-bearing nipple, 7-Shear blowout preventer valve, 8-Tubing hook-running tool, 9-Hydraulic channel, 11-Wax cleaning valve, 12-Production wing valve, 13-Lower main valve, 14-Well killing wing valve. DETAILED DESCRIPTION

[0026] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0027] The present invention provides a shallow water landing string, comprising a surface test tree, a blowout preventer nipple, a quick connector, a gate valve, a plurality of oil pipes, a shear blowout preventer valve, and a tubing hanger delivery tool. The bottom of the surface test tree is detachably connected to the blowout preventer nipple, the bottom end of the blowout preventer nipple is detachably plug-connected to the quick connector, the bottom end of the quick connector is detachably connected to the gate valve, the bottom end of the gate valve is detachably connected to one of the oil pipes, a plurality of the oil pipes are detachably connected to each other, the bottom end of the oil pipe is detachably connected to the top end of the shear blowout preventer valve, the bottom end of the shear blowout preventer valve is detachably connected to the tubing hanger delivery tool, and the tubing hanger delivery tool is detachably connected to the tubing hanger. The shallow water landing string uses a deepwater string for shallow waters, enabling direct bottom-hole production during shallow water operations without the need for platforms or other facilities. This ensures the normal development of offshore oil operations while ensuring a clear waterway.

[0028] Example 1

[0029] like Figures 1 to 5 As shown, an embodiment of the present invention provides a shallow water landing string, comprising a surface test tree 1, a blowout preventer sub 2, a quick connector 3, a gate valve 4, a plurality of oil pipes 5, a shear blowout preventer valve 7, and a tubing hanger running tool 8. The bottom of the surface test tree 1 is detachably connected to the blowout preventer sub 2, the bottom end of the blowout preventer sub 2 is detachably plug-connected to the quick connector 3, the bottom end of the quick connector 3 is detachably connected to the gate valve 4, the bottom end of the gate valve 4 is detachably connected to the tubing 5, the plurality of tubings 5 are detachably connected to each other, the bottom end of the tubing 5 is detachably connected to the top end of the shear blowout preventer valve 7, the bottom end of the shear blowout preventer valve 7 is detachably connected to the tubing hanger running tool 8, and the tubing hanger running tool 8 is detachably connected to the tubing hanger.

[0030] The tubing hanger delivery tool 8 at the bottom of the shallow water landing string is connected to the tubing hanger, and the bottom end of the tubing hanger is connected to the completion tool string. During use, the shallow water landing string, together with the tubing hanger and the completion tool string, is lowered to the bottom of the well by increasing the number of sections of tubing 5. When the tubing hanger reaches the designated position in the adoption tree, it stops being lowered. The tubing hanger is located at the corresponding position on the adoption tree, and the completion operation is completed through the shallow water landing string. During the completion process, the tool is pre-set into the blowout preventer nipple 2 by quickly disassembling or connecting the blowout preventer nipple 2 and the quick connector 3, and then the quick connector 3 is docked and connected before the tool is lowered. After the completion operation is completed, the tubing hanger delivery tool 8 is disconnected from the tubing hanger, the shallow water landing string is removed from the bottom of the well, and oil production begins.

[0031] The surface test tree 1 is a conventional, small-scale wellhead fluid control device consisting of a paraffin cleaning valve 11, a lower main valve 13, a kill wing valve 14, and a production wing valve 12. It can coordinate pressure testing, blowout, squeeze injection, and artificial lift operations according to on-site process requirements. For example, closing the paraffin cleaning valve 11 and the kill wing valve 14 and opening the lower main valve 13 and the production wing valve 12 allows for blowout; closing the paraffin cleaning valve 11 and the production wing valve 12 and opening the lower main valve 13 and the kill wing valve 14 allows for squeeze injection; closing the paraffin cleaning valve 11 and the lower main valve 13 and opening the production wing valve 12 and the kill wing valve 14 allows for process pressure testing; and closing the kill wing valve 14 and opening the paraffin cleaning valve 11, the lower main valve 14, and the production wing valve 12 allows for artificial lift. The surface test tree 1 serves as a control unit for high-pressure wellhead fluids, providing a safety barrier.

[0032] The bottom of the ground test tree 1 is detachably connected to the blowout preventer sub 2, and the bottom end of the blowout preventer sub 2 is detachably plugged into the quick connector 3. The ground test tree 1 is a small-sized test tree 1 with a relatively small inner diameter. If the outer diameter of the tool being lowered exceeds the inner diameter of the ground test tree 1, the quick connector 3 must be removed, the tool pre-placed in the blowout preventer sub 2, and then the quick connector 3 must be docked before the tool can be lowered.

[0033] For tools with an outer diameter exceeding the inner diameter of the surface test tree 1, in order to facilitate repeated placement from the top of the blowout preventer sub 2 to the bottom of the well, the blowout preventer sub 2 and the quick connector 3 need to be connected or disconnected repeatedly. To facilitate the rapid connection and disconnection of the quick connector 3 and the blowout preventer sub 2, a detachable plug-in connection is adopted between the blowout preventer sub 2 and the quick connector 3. Compared with the rotational connection method, the detachable plug-in connection can prevent hydraulic lines and the like from being twisted off during the disassembly process.

[0034] The quick connector 3 includes an upper connector, a lower connector, a connecting sleeve, and a set pin. The bottom of the upper connector is connected to the top of the lower connector via the connecting sleeve, and the connecting sleeve, the upper connector, and the lower connector are fastened by the set pin. The upper connector is plug-in connected to the bottom of the blowout preventer sub 2, and the lower connector is plug-in connected to the gate valve 4.

[0035] The inner diameter of the blowout preventer sub 2 can be adjusted according to actual operational needs, ensuring that large-scale wireline tool strings can be raised above the gate valve 4 for on-site tool string replacement. A quick connector 3 allows for rapid disconnection and connection between the blowout preventer sub 2 and the gate valve 4. During on-site operations, the blowout preventer sub 2 and the upper connector of the quick connector 3 are pre-connected. The gate valve 4 shown is a manual gate valve.

[0036] The gate valve 4 is a blowout prevention device on the upper part of the platform. The internal isolation of the pipe string is achieved by opening and closing the gate valve 4 to release the upper pressure. The gate valve 4 is pre-connected with the lower joint of the quick connector 3.

[0037] By sequentially connecting the oil pipes 5 at the rod roots, the shallow water landing string, the oil pipe hanger connected to the bottom of the shallow water landing string, and the tool string connected to the bottom of the oil pipe hanger can be placed into the bottom of the well.

[0038] The shear blowout preventer 7 is a core emergency shut-in device for shallow-water tubing. It can shut down the well in emergency well control situations and features an upper pump-through function, providing a positive extrusion well fluid channel. The shear blowout preventer 7 is preferably a ball valve, capable of both open and shut-in states. In the open state, it provides a channel for the downhole tool string and well fluid to pass through. In the shut-in state, it cuts the rope used to lower the tool string.

[0039] The bottom end of the tubing hanger running tool 8 is detachably connected to the tubing hanger, and the bottom end of the tubing hanger is detachably connected to the downhole tool string. When the shallow water landing string lowers the tubing hanger into the designated position in the Christmas tree, the tubing hanger is clamped in the designated position of the Christmas tree, and the underground tool string is suspended on the tubing hanger, which serves as a load-bearing component.

[0040] Furthermore, in order to transmit the surface hydraulic pressure to below the pressure-bearing nipple 6, chemicals can also be injected through the hole below the pressure-bearing nipple 6. The shallow water landing string also includes at least one pressure-bearing nipple 6. The top and bottom ends of the pressure-bearing nipple 6 are detachably connected to different oil pipes 5 through joints. Several hydraulic channels 10 are opened in the side wall of the pressure-bearing nipple 6. The top and bottom ends of the hydraulic channels 10 are connected to the hydraulic pipeline. The hydraulic pipeline is located outside the shallow water landing string. The hydraulic pipeline is connected through the hydraulic channel 10 at the position of the pressure-bearing nipple 6. The pressure-bearing nipple 6 is a necessary equipment of the landing string system. It can achieve annulus isolation in conjunction with the shear blowout preventer 7 and the gate valve 4. Therefore, compared with the hydraulic pipeline being an integral pipeline, the present invention disconnects the hydraulic pipeline 10 at the pressure-bearing nipple 6 and connects it through the hydraulic channel 10, so that the annulus can be sealed when the shear blowout preventer 7 and the gate valve 4 are closed while ensuring the pressure transmission capacity of the hydraulic channel.

[0041] Specifically, 26 hydraulic channels 10 are opened on the inner side wall of the pressure-bearing nipple 6. The hydraulic channels 10 can be used to provide channel connections for different liquids, including the oil pipe hanging tool control pipeline, the blowout preventer valve control pipeline, the chemical injection pipeline, etc. The outer diameter of the pressure-bearing nipple is consistent with the seal size of the blowout preventer gate.

[0042] The shallow water landing string provided by the present invention uses a deep water string for shallow seas, so that direct production at the well bottom can be achieved during shallow sea operations without the need for platforms and other facilities. While ensuring that the waterway is unobstructed, the normal development of marine oil work is guaranteed.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A shallow water landing string, characterized in that: Includes a surface test tree, blowout preventer nipple, quick connector, gate valve, several oil pipes, shear blowout preventer valve and oil pipe hanging and running tool; The bottom of the ground test tree is detachably connected to the blowout preventer sub, the bottom end of the blowout preventer sub is detachably plug-connected to the quick connector, the bottom end of the quick connector is detachably connected to the gate valve, the bottom end of the gate valve is detachably connected to the oil pipe, the bottom end of the oil pipe is detachably connected to the top end of the shear blowout preventer valve, the bottom end of the shear blowout preventer valve is detachably connected to the tubing hanger delivery tool, and the tubing hanger delivery tool is detachably connected to the tubing hanger; It comprises at least one pressure-bearing nipple, the top and / or bottom of which are detachably connected to the oil pipe. A plurality of hydraulic channels are opened in the side wall of the pressure-bearing nipple, and the top and bottom of the hydraulic channels are both connected to the hydraulic pipeline.

2. The shallow water landing string according to claim 1, characterized in that: The shear blowout preventer is a ball valve, which has an open well state and a closed well state. When the ball valve is in the open well state, the ball valve provides a channel for the downhole tool string and well fluid to pass through. When the ball valve is in the closed well state, the ball valve has the function of cutting the rope used to lower the tool string.

3. The shallow water landing string according to claim 1, characterized in that: The surface test tree includes a wax cleaning valve, a lower main valve, a well-killing wing valve and a production wing valve. When the wax cleaning valve and the well-killing wing valve are closed, the lower main valve and the production wing valve are opened to complete the cleaning or injection operation; when the wax cleaning valve and the lower main valve are closed, the production wing valve and the well-killing wing valve are opened to complete the process pressure test operation; when the well-killing wing valve is closed, the wax cleaning valve, the lower main valve and the production wing valve are opened to complete the artificial lift operation.

4. The shallow water landing string according to claim 1, characterized in that: The quick connector includes an upper connector, a lower connector, a connecting sleeve and a fixing pin. The bottom of the upper connector and the top of the lower connector are connected by the connecting sleeve, and the connecting parts of the connecting sleeve, the upper connector and the lower connector are fastened by the fixing pin.

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