An electric submersible pump production test riser system for a subsea tree head

Abstract

The application discloses an underwater Christmas tree top submersible pump production test riser system, which comprises an underwater Christmas tree device, a production and test riser and a submersible pump device; the underwater Christmas tree device is installed above an underwater wellhead device; the production and test riser comprises an outer drill rod, a water casing and an inner oil pipe; the lower end of the water casing is installed on the top of the underwater Christmas tree through a release device; the inner oil pipe is arranged inside the outer drill rod and the water casing; and the lower end of the inner oil pipe suspends the submersible pump device. The submersible pump is installed inside the water casing on the top of the underwater Christmas tree, and high-voltage power cables can be directly provided from an installation operation platform to the submersible pump, so that the submersible pump can be immediately started and oil well testing can be timely performed, valuable oil reservoir measured information can be obtained as early as possible, the risk caused by oil reservoir uncertainty can be reduced as much as possible, and the whole oilfield efficient development scheme can be further formulated or optimized according to the information, and the technical scheme uncertainty can be reduced.

Description

Technical Field

[0001] This invention relates to an electric submersible pump production and testing riser system at the top of an underwater oil production tree, belonging to the field of underwater oil and gas extraction technology. Background Technology

[0002] Submersible electric submersible pumps (ESPs) are typically installed at the bottom of the tubing string inside the well, below the mudline. Current technology lacks the capability to directly supply high-voltage power cables from the installation platform to the ESP inside the well. This is because current technology uses a hydraulically controlled installation string (HMS) to lower the tubing string in one go, with the tubing hanger at the top and the ESP at the bottom. After lowering, the HMS hanger is secured to the submersible Christmas tree using HMS tools, and the entire tubing string is then suspended by the hanger. Due to the limited cross-sectional dimensions of the HMS, only a few small hydraulic channels can be provided internally, making it impossible to provide additional channels for large high-voltage power cables. This prevents the immediate activation of the ESP for timely well testing. Consequently, well testing often requires waiting several months to lay a long-distance high-voltage power cable for the ESP before it can be activated to deliver oil to the production platform for testing, resulting in excessively long testing cycles.

[0003] On the other hand, the average service life of an ESP (Electric Submersible Pump) is about 3 to 4 years. Since the ESP is installed inside the wellbore below the mudline, if it fails and needs replacement, a major well workover operation requires re-operating the deepwater drilling platform to retrieve the tubing string and the entire tubing string. The comprehensive daily cost of a deepwater drilling platform is approximately US$1 million, depending on the water depth. A major well workover operation to replace an ESP takes 7 to 15 days and costs approximately US$7 to 15 million. Therefore, the cost of retrieving the tubing string to replace the ESP inside the wellbore is extremely high, which will seriously affect the economics of deepwater oil and gas field development. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides an electric submersible pump (ESP) production test riser system at the top of an underwater production tree, which aims to achieve independent, separate installation and retrieval of the ESP and tubing by installing the ESP inside the test and production riser at the top of the underwater production tree.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a production and testing riser system for an electric submersible pump at the top of an underwater production tree, comprising an underwater production tree device, a production and testing riser, and an electric submersible pump device; wherein, the underwater production tree device is installed above an underwater wellhead device, and the underwater production tree device includes an underwater production tree, a tubing head, and a tubing hanger; the underwater production tree is installed above the underwater wellhead device via the tubing head, and the tubing hanger is installed inside the tubing head; the production and testing riser includes an outer drill pipe, an underwater casing, and an inner tubing, the upper end of the outer drill pipe is connected to the installation platform, the lower end of the outer drill pipe is connected to the upper end of the underwater casing, the outer drill pipe is used to isolate seawater, and to lower the underwater casing to the top of the underwater production tree; The lower end of the underwater casing is installed on top of the subsea production tree via the release device, which is configured to provide a release function between the underwater casing and the subsea production tree. The inner tubing is located inside the outer drill pipe and the underwater casing. The upper end of the inner tubing is connected to the installation platform, and the lower end of the inner tubing suspends the electric submersible pump unit. The tubing hanger, the subsea production tree, and the release device form a coaxially arranged production channel and annular channel. The electric submersible pump unit includes an electric submersible pump assembly, a motor protector, a motor, and a high-voltage power cable. The electric submersible pump assembly, the motor protector, and the motor are suspended from top to bottom at the lower end of the inner tubing. The high-voltage power cable is located on the outer wall of the inner tubing, is lowered into the system together with the inner tubing, and is connected to the motor.

[0006] Preferably, in the electric submersible pump production test riser system, the subsea tree device further includes a control cable and an annular hose. The control cable is used to connect the subsea tree and release device to the installation platform, and the annular hose is used to connect the tubing hanger, the subsea tree and release device, and the annular channel to the installation platform.

[0007] Preferably, the electric submersible pump production test riser system includes a main production valve and a production suction valve located in the production channel of the subsea tree, and an annular main valve and an annular suction valve located in the annular channel of the subsea tree.

[0008] Preferably, the electric submersible pump production test riser system includes a retention valve in the production channel of the release device and an annular inlet valve in the annular channel of the release device.

[0009] Preferably, the electric submersible pump production test riser system includes an annular isolation valve located in the annular channel at the oil pipe head.

[0010] Preferably, the electric submersible pump production test riser system includes a blowout preventer valve installed inside the inner oil pipe.

[0011] Preferably, in the electric submersible pump production and testing riser system, the upper end of the outer drill rod is connected to the installation platform via a rotating ring and an upper flexible joint, and the lower end of the underwater casing is connected to the release device via a lower flexible joint.

[0012] Preferably, in the electric submersible pump production test riser system, the outer drill pipe is also connected to the installation platform via a tensioning and heave compensation system and a tension rope to ensure that the outer drill pipe and the inner tubing are in a vertical and static state.

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

[0014] 1. This invention installs an electric submersible pump inside the underwater casing at the top of the underwater production tree. A high-voltage power cable can be directly supplied to the electric submersible pump from the installation platform. It has the function of immediately starting the electric submersible pump to conduct oil well testing in a timely manner. It can obtain valuable reservoir measurement information as early as possible, so as to minimize the risks caused by reservoir uncertainty. Based on this, it can further formulate or optimize an efficient development plan for the entire oilfield, which is conducive to reducing the uncertainty of technical solutions.

[0015] 2. When the electric submersible pump fails, the present invention can directly remove the electric submersible pump from the top of the wellhead, which has the advantage of quickly replacing the failed electric submersible pump and can save up to 50%-70% of the operating costs, thus having good economic benefits. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. As shown in the figures:

[0017] Figure 1 This is a schematic diagram of the structure of an electric submersible pump production testing riser system provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the tubing head of the present invention after it has been installed in the underwater wellhead device;

[0019] Figure 3 This is a schematic diagram of the oil pipe hanger of the present invention installed inside the oil pipe head;

[0020] Figure 4 This is a schematic diagram showing the underwater production tree of the present invention after it has been installed on top of the tubing head;

[0021] Figure 5 This is a schematic diagram showing the underwater casing and outer drill pipe of the present invention after they have been installed to the top of the underwater production tree;

[0022] Figure 6This is a schematic diagram of the electric submersible pump device of the present invention installed in the underwater casing. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the system or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., used to define components are merely for the convenience of distinguishing the aforementioned components. Unless otherwise stated, these terms have no special meaning and should not be construed as indicating or implying relative importance.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The subsea production tree top electric submersible pump (ESP) production and testing riser system provided by this invention includes a subsea production tree assembly, a production and testing riser, and an ESP assembly. The subsea production tree assembly is installed above the subsea wellhead assembly. The production and testing riser includes an outer drill pipe, a subsea casing, and an inner tubing. The lower end of the subsea casing is installed at the top of the subsea production tree via a release device. The inner tubing is located inside the outer drill pipe and the subsea casing, and the lower end of the inner tubing suspends the ESP assembly. This invention installs the ESP inside the subsea casing at the top of the subsea production tree, allowing direct high-voltage power cable supply to the ESP from the installation platform. It enables immediate activation of the ESP for timely well testing, allowing for the acquisition of valuable reservoir measurement information as early as possible. This minimizes the risks associated with reservoir uncertainties and facilitates the development or optimization of efficient development plans for the entire oilfield, thus reducing the uncertainty of technical solutions.

[0027] The electric submersible pump production test riser system at the top of the submersible production tree provided in this embodiment of the invention will now be described in detail with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the electric submersible pump production and testing riser system at the top of the underwater production tree provided by the present invention includes an underwater production tree device 1, a production and testing riser 2, and an electric submersible pump device 3.

[0029] The subsea wellhead device is installed above the subsea wellhead device 4. The subsea wellhead device includes a subsea wellhead 101, a tubing head 102, and a tubing hanger 103. The subsea wellhead 101 is installed above the subsea wellhead device 4 via the tubing head 102, and the tubing hanger 103 is installed inside the tubing head 102.

[0030] The production and testing riser 2 includes an outer drill pipe 201, an underwater casing 202, and an inner tubing 203. The upper end of the outer drill pipe 201 is connected to the installation platform 5, and the lower end of the outer drill pipe 201 is connected to the upper end of the underwater casing 202. The outer drill pipe 201 is used to isolate seawater and lower the underwater casing 202 to the top of the subsea tree 101. The lower end of the underwater casing 102 is installed on the top of the subsea tree 101 through a release device 6. The release device 6 is configured to provide a release function between the underwater casing 202 and the subsea tree 101 to avoid damage to the production and testing riser 2 when the installation platform 5 accidentally deviates from the predetermined center position to a large angle. The inner tubing 203 is located inside the outer drill pipe 201 and the underwater casing 202. The upper end of the inner tubing 203 is connected to the installation platform 5, and the lower end of the inner tubing 203 suspends the electric submersible pump device 3. The tubing hanger 103, the subsea production tree 101, and the release device 6 have a coaxially arranged production channel a and annular channel b inside.

[0031] The electric submersible pump (ESP) unit 3 includes an ESP assembly 301, a motor protector 302, a motor 303, and a high-voltage power cable 304. The ESP assembly 301, motor protector 302, and motor 303 are suspended from top to bottom at the lower end of the inner tubing 203. The high-voltage power cable 304 is installed on the outer wall of the inner tubing 203, lowered along with the inner tubing 203, and connected to the motor 303. This configuration enables the ESP production test riser system to immediately start the ESP unit 3 for well testing. Oil flows through the ESP unit 3 and is lifted to the inner tubing 203 and the installation platform 5 for production testing and processing. When the ESP unit 3 fails and needs replacement, the inner tubing 203 can be pulled out for quick replacement of the ESP unit 3.

[0032] In the above embodiments, preferably, the subsea production tree device 1 further includes a control cable 104 and annular hose 105. The control cable 104 is used to connect the subsea production tree 101 and the release device 6 to the installation platform 5 to control the valves of the subsea production tree 101 and the valves and release functions of the release device 6. The annular hose 105 is used to connect the tubing hanger 103, the annular channel b of the subsea production tree 101 and the release device 6 to the installation platform 5 to provide functions such as circulation and pressure testing.

[0033] In the above embodiments, preferably, a production main valve F1 and a production suction valve F2 are installed in the production channel a of the subsea tree 101, and an annular main valve F3 and an annular suction valve F4 are installed in the annular channel b of the subsea tree 101. Through these arrangements, the production main valve F1 and the production suction valve F2 form two safety barriers in the production channel a of the subsea tree 101, and the annular main valve F3 and the annular suction valve F4 form two safety barriers in the annular channel b of the subsea tree 101.

[0034] In the above embodiments, preferably, a retention valve F5 is provided in the production channel a of the release device 6, and an annular inlet valve F6 is provided in the annular channel b of the release device 6. Through this arrangement, the retention valve F5 can be used to isolate crude oil inside the riser during the release of production and testing risers, preventing crude oil leakage into the ocean and environmental pollution; the annular inlet valve F6 closes when there is no operational need, providing a safety barrier within the annular channel b of the release device 6, and opens when circulation and pressure testing are required, allowing oil to flow through the annular hose 105 into the annular channel b.

[0035] In the above embodiments, preferably, an annular isolation valve F7 is provided in the annular channel b located in the tubing head 102. With this configuration, the annular isolation valve F7 closes to provide a safety barrier within the annular channel b of the tubing head 102 when there is no operational need, and opens to allow oil to flow through the annular hose 105 into the annular channel b when circulation and pressure testing are required.

[0036] In the above embodiments, preferably, a blowout preventer valve F8 is installed inside the inner tubing 203. With this configuration, after the ESP assembly 301, motor protector 302, and motor 303 are installed, the lower part of the inner tubing 203 is isolated by closing the blowout preventer valve F8. This allows for pressure testing of the testing equipment connected to the inner tubing 203 on the installation platform 5. If the test is successful, the conditions are met for starting the ESP assembly 3 to conduct well testing.

[0037] In the above embodiment, preferably, the upper end of the outer drill pipe 201 is connected to the installation platform 5 via a rotating ring 7 and an upper flexible joint 8, and the lower end of the underwater casing 202 is connected to the release device 6 via a lower flexible joint 9. This arrangement allows for a certain deflection angle between the outer drill pipe 201 and the underwater casing 202 and the installation platform 5 and the release device 6.

[0038] In the above embodiments, preferably, the outer drill pipe 201 is also connected to the installation platform 5 through the tensioning and heave compensation system 10 and the tension rope 11 to ensure that the outer drill pipe 201 and the inner tubing 203 are in a vertical and static state.

[0039] The specific installation process of the electric submersible pump production test riser system at the top of the underwater production tree provided by this invention is as follows:

[0040] S100. Lower the tubing head 102 to the top of the submersible wellhead device 4 (e.g., ...). Figure 2 (as shown);

[0041] S200. Lower the oil pipe hanger 103 into the inside of the oil pipe head 102 (e.g., ... Figure 3 (as shown);

[0042] S300. Lower the submersible wellhead 101 to the top of the tubing head 102 (e.g., Figure 4 (as shown);

[0043] S400. The following components are sequentially lowered: release device 6, lower flexible joint 9, underwater casing 202, outer drill pipe 201, tensioning and heave compensation system 10, tension rope 11, swivel ring 7, and upper flexible joint 8. The tensioning and heave compensation system 10 keeps the outer drill pipe 201 and underwater casing 202 in a vertical, stationary state. After all components are in place, the control cable 104 is lowered to point I and connected to the subsea Christmas tree 101. Additionally, the annular hose 105 is lowered to point II and connected to the release device 6, providing functions such as circulation and pressure testing (e.g., ...). Figure 5 (as shown);

[0044] S500. The motor 303, motor protector 302, ESP assembly 301, and inner tubing 203 are sequentially installed inside the outer drill pipe 201 and underwater casing 202. After all components are in place, the high-voltage power cable 304 is lowered and connected to the motor 303, thus enabling immediate startup of the ESP assembly 3 for well production testing (e.g., ...). Figure 6 (As shown).

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A riser system for production testing of an electric submersible pump at the top of an underwater production tree, characterized in that, This includes subsea wellhead equipment, production and testing risers, and electric submersible pump equipment; The subsea wellhead device is installed above the subsea wellhead device. The subsea wellhead device includes a subsea wellhead, a tubing head, and a tubing hanger. The subsea wellhead is installed above the subsea wellhead device via the tubing head, and the tubing hanger is installed inside the tubing head. The production and testing riser includes an outer drill pipe, an underwater casing, and an inner tubing. The upper end of the outer drill pipe is connected to the installation platform, and the lower end of the outer drill pipe is connected to the upper end of the underwater casing. The outer drill pipe is used to isolate seawater and lower the underwater casing to the top of the subsea production tree. The lower end of the underwater casing is installed at the top of the subsea production tree via a release device, which is configured to provide a release function between the underwater casing and the subsea production tree. The inner tubing is located inside the outer drill pipe and the underwater casing. The upper end of the inner tubing is connected to the installation platform, and the lower end of the inner tubing suspends the electric submersible pump device. The tubing hanger, the subsea production tree, and the release device form a coaxially arranged production channel and annular channel. The electric submersible pump device includes an electric submersible pump assembly, a motor protector, a motor, and a high-voltage power cable. The electric submersible pump assembly, the motor protector, and the motor are suspended from top to bottom at the lower end of the inner tubing. The high-voltage power cable is located on the outer wall of the inner tubing, and is lowered into the inner tubing together with it and connected to the motor. The subsea wellhead assembly also includes a control cable and annular hose. The control cable is used to connect the subsea wellhead and release device to the installation platform, and the annular hose is used to connect the tubing hanger, the subsea wellhead and release device's annular channel to the installation platform.

2. The electric submersible pump production and testing riser system according to claim 1, characterized in that, A main production valve and a production suction valve are installed in the production channel located in the subsea tree, and an annular main valve and an annular suction valve are installed in the annular channel located in the subsea tree.

3. The electric submersible pump production testing riser system according to claim 1, characterized in that, A retention valve is installed in the production channel of the release device, and an annular inlet valve is installed in the annular channel of the release device.

4. The electric submersible pump production testing riser system according to claim 1, characterized in that, An annular isolation valve is installed in the annular channel located at the oil pipe head.

5. The electric submersible pump production testing riser system according to claim 1, characterized in that, A blowout preventer is installed inside the inner oil pipe.

6. The electric submersible pump production testing riser system according to any one of claims 1 to 5, characterized in that, The upper end of the outer drill pipe is connected to the installation platform in sequence via a rotating ring and an upper flexible joint, and the lower end of the underwater casing is connected to the release device via a lower flexible joint.

7. The electric submersible pump production testing riser system according to any one of claims 1 to 5, characterized in that, The outer drill pipe is also connected to the installation platform via a tensioning and heave compensation system and a tension rope to ensure that the outer drill pipe and the inner tubing are in a vertical and static state.

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