Subsea pipeline end manifold (PLEM) system for oil production choke and methods for commissioning a choke module of the PLEM system

Abstract

The present invention relates to a subsea pipeline end manifold (PLEM) system for oil production choke, composed of a gas-lift / service header and branch, a production header and branch, at least two choke modules, valves, single-phase and multiphase meters, and MQC interfaces. In addition, it includes a method for commissioning a choke module, which involves steps such as injecting and circulating diesel and water, as well as removing and commissioning the choke module. A method for commissioning via ROV is also disclosed, which reduces the need to circulate large volumes of water and diesel by performing the circulation with a flow of MEG.

Description

Subsea Pipeline End Manifold Manifold (PLEM) System for Oil Production Choke and Commissioning Methods for the PLEM System Choke Module. Field of the Invention

[0001] The present invention falls within the technical field of oil and gas production and transportation, especially in offshore exploration operations.

[0002] More specifically, the invention focuses primarily on a system of subsea equipment used in the oil and gas industry. This system features changes aimed at improving the efficiency, safety, and economy of subsea production operations through strategies such as optimizing equipment architecture, flow control, and well monitoring. BACKGROUND OF THE INVENTION

[0003] The Subsea Pipeline End Manifold (PLEM) plays a crucial role in deep-sea oil exploration, a complex activity involving the drilling of subsea wells and the extraction of the oil found. This subsea equipment acts as a central piece by connecting different oil production pipelines into a single flow line.

[0004] Without PLEM, subsea oil exploration operations would be significantly more expensive. It allows for the interconnection of production pipelines, facilitating the transport of oil and gas to the surface or to other subsea facilities. Furthermore, PLEM offers operational flexibility, enabling the connection and disconnection of pipelines as needed, whether for maintenance, inspection, or operational adjustments.

[0005] The importance of PLEM (Planned Subsea Oil Mill) in subsea oil exploration is undeniable, as it helps optimize operational efficiency and ensure the safety of operations. Its presence enables the integrated functioning of the entire subsea system, from production to the transport of extracted oil, contributing significantly to the success of seabed exploration operations.

[0006] Current systems generally have four lines leading to the power plant: • oil production line (OP); • gas-lift or service line (SV); • in addition to the control umbilical and at least two choke modules.

[0007] This type of architecture offers good flexibility for conducting tests, verifying what is produced and what is injected into each well. However, this type of system does not allow commissioning for the replacement of a choke module without interrupting production in all wells connected to it.

[0008] Thus, the technical problem solved by the present invention consists of providing systems that, when commissioning one of its modules, do not interrupt the overall production of the wells connected to it, in addition to providing access, via MQC, for depressurization and MEG injection operations via ROV.

[0009] There are no prior art documents that address alternatives aimed at: the possibility of commissioning one of the choke modules of a subsea pipeline end manifold without the need to interrupt production from other wells. SUMMARY OF THE INVENTION

[0010] The present invention discloses a subsea pipeline end manifold (PLEM) system for oil production choke comprising: • an oil production header and branches; • a gas-lift header and branches; • resident valves and MQC accesses; • at least two choke modules, containing single-phase and multi-phase valves, sensors, and meters.

[0011] Furthermore, the present invention also relates to a method for commissioning a choke module, which involves the following steps: diesel injection and initial circulation, secondary diesel circulation, water and MEG injection and circulation, and removal and commissioning of the choke module.

[0012] It also concerns a commissioning method using ROVs, which mitigates the need to circulate large volumes of water and diesel, and is carried out via circulation with MEG flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will now be described with reference to typical embodiments thereof and with reference to the accompanying drawings, in which:

[0014] Figure 1 is a representation of the state-of-the-art subsea pipeline end manifold (PLEM) choke system.

[0015] Figure 2 is a representation of the choke pipe end manifold (PLEM) subsea system according to the present invention.

[0016] Figure 3 is a representation of the valve state, in production mode, of the subsea pipeline end manifold (PLEM) choke system according to the present invention.

[0017] Figure 4 is a representation of the completed step 1 of the choke module commissioning via service line according to the present invention.

[0018] Figure 5 is a representation of the completed step 2 of the choke module commissioning via service line according to the present invention.

[0019] Figure 6 is a representation of the completed step 3 of the choke module commissioning via service line according to the present invention.

[0020] Figure 7 is a representation of the ROV-based choke module commissioning procedure according to the present invention. DETAILED DESCRIPTION OF THE INVENTION SYSTEM ARCHITECTURE

[0021] The present invention proposes a subsea pipeline end manifold (PLEM) choke system for oil production. This type of architecture, shown in Figure 2, when compared with the architecture of the prior art equipment shown in Figure 1, presents several advantages: • It has resident valve pairs at the well module inlets with Multiple Quick Connector (MQC) interfaces for ROV access, so that these valve pairs allow one of the PLEM Choke Modules to be commissioned for replacement without necessarily stopping production from the other well. • These same MQC access points allow for valve leak testing, local depressurization, and MEG injection.

[0022] Figure 3 shows the state of the valves when the two wells connected to the PLEM of the present invention are producing normally. Only the choke module connected to well 2 is piggable (accepts the use of PIGs) and the two closed valves in the choke module connected to well 2 are part of the pigging circuit (VH-SV2; VH-PO2) (circuit through which the PIG passes). The gas lift is distributed to the two wells by the service line (SV) while the production trunkline (PO) groups the production of the two wells.

[0023] The system of the present invention is composed of the following structures: • A header and oil production branches; • A header and gas lift and / or service branches; • At least two choke modules, containing single-phase and multi-phase meters, chokes, and pressure and temperature sensors.

[0024] To achieve the proposed technical effect, the system features pairs of valves located at the well module inlets with MQC interfaces for ROV access. In addition, the system includes valves VR-SV1, VR-SV2, VR-SV3, VR-SV4, VR-PO1, VR-PO2, VR-PO3, and VR-PO4 (to isolate the gas lift and production lines of each choke module), valves VH-SV1 and VH-PO1 (to align the system for chokes and meters), and VH-SV2 and VH-PO2 (to allow pig passage). COMMISSIONING METHOD FOR PLEM SYSTEM CHOKE MODULE

[0025] Initially, consider a scenario in which, during normal equipment production, one of the Multiphase Meters (MPFM) in the choke module stops operating, making it necessary to replace it.

[0026] Figures 4 to 6 show the valve states and flows considered for carrying out the commissioning steps through the service line, enabling the recovery of the choke module that receives production from well 2 without having to stop production from well 1.

[0027] For this commissioning, it is necessary to interrupt the gas lift injection through the service trunkline, with well 1 connected to the PLEM producing by flow. The commissioning procedure is presented in the following steps, taking as a starting point the normal production situation of the two wells connected to the PLEM: Step a) – Diesel Injection and First Circulation I. via UEP, close valves M1 and M2 of ANM 2, interrupting production from this well; II. via UEP, close valve W2 of ANM 2, interrupting the possibility of fluid circulation through this ANM; III. via UEP, close valve M2 in ANM 1, preventing gas lift injection into well 1; IV. interrupt the gas lift flow through the SV trunkline and via UEP inject diesel through this trunkline; V. via UEP, open valve XO in ANM 1; VI. Diesel fuel circulates through the choke module connected to Well 1, passing through the W2 – XO – W1 circuit at ANM 1 and returning through the production line, along with the production from Well 1; VII. via UEP, close valves W2 and XO of ANM 1, where valve W1 remains open so that well 1 continues producing by flow; VIII. via UEP, open valve PXO of ANM 1, allowing diesel cleaning of this section of ANM 1, where diesel circulates through this section and continues through the production line, being carried by the production of well 1; IX. via UEP, close valve PXO of ANM 1; and X. End of Stage 1, as per Figure 4. Stage b) – Second Diesel Circulation XI. via UEP, open valves W2 and XO of ANM 2, initiating diesel cleaning of the choke module and ANM 2; XII. Circulate diesel fuel through the W2 – XO – W1 circuit of ANM 2, returning through the choke module production line, passing through valves VR-PO4, VR-PO3, VH-PO1, VR-PO2 and VR-PO1, returning through the PLEM production header along with the production from well 1; XIII. via UEP, close valves W2, XO and W1 of ANM 2; XIV. via UEP, open valve PXO of ANM 2, allowing the cleaning of this section of ANM 2; and XV.via UEP, open valves VH-SV2 and VH-PO2 of the choke module connected to well 2, allowing diesel circulation for cleaning all sections of the choke module of well 2 that is being commissioned for replacement; XVI. End of Step b), as per Figure 5. Step c) – Water Injection and Circulation and MEG XVII. inject water through the SV trunkline, circulate water through the choke module connected to ANM 2, with circulation of this water through the GL line to ANM 2; XVIII. Circulate water through ANM 2, entering ANM 2 through the GL line, passing through the PXO valve and returning through the production line to the production header, cleaning all sections of the choke module and being carried along with the production from well 1; XIX. Via UEP, close valves VH-SV2 and VH-PO2 in the choke module connected to well 2; XX. Via ROV, close valves VR-SV1, VR-SV2 and VR-PO2; XXI. Via ROV, inject MEG through the MQC access between valves VR-PO1 and VR-PO2 at the entrance of the choke module of well 2, with the objective of inhibiting the formation of hydrates in the production header of the PLEM-Choke, in the section where there will be direct contact between the fluid produced by well 1 and the standing water in the header, during the period of replacement of the choke module of well 2; XXII. via ROV, close the VR-PO1 valve at the choke module inlet of well 2, after injecting an appropriate volume of MEG; XXIII.After closing the resident valves (VR-SV1, VRSV2, VR-PO1, VR-PO2) at the choke module inlet of well 2, perform a leak test on them using an ROV via MQC interfaces positioned between valves VR-SV1 / VR-SV2 and VR-PO1 / VR-PO2; XXIV. If the results of these tests are positive, the choke module connected to well 2 is filled with water and ready to be recovered. XXV. End of step c), as per Figure 6. ROV COMMISSIONING METHOD.

[0028] A more advantageous commissioning alternative than the one presented in this section is to commission This operation involves using the resident valve pairs positioned between the choke modules and the MCVs for commissioning, with MEG injection and circulation via ROV through the MQC accesses between the resident valve pairs at the choke module inlets, as shown in Figure 7, without involving diesel and water circulation operations via UEP.

Claims

CLAIMS 1. SUBSEAS PIPELINE END MANIFOLD SYSTEM (PLEM) FOR OIL PRODUCTION CHOKE characterized in that it comprises: - production header and branches; - gas lift / service header and branches; - at least two choke modules, containing single-phase and multi-phase meters, chokes, and pressure and temperature sensors.

2. System according to claim 1, characterized in that it has at least two choke modules.

3. System according to claim 1, characterized in that the service header and branch (SV) comprise: a VR-SV1 valve; a VR-SV2 valve; a VR-SV3 valve; a VR-SV4 valve; a single-phase meter (SPFM); a VH-SV1 valve; a VH-SV2 valve; a choke; and at least two pairs of pressure and temperature transducers.

4. System according to claim 1, characterized in that the oil production (PO) trunkline comprises: a VR-PO1 valve; a VR-PO2 valve; a VR-PO3 valve; a VR-PO4 valve; a VH-PO1 valve; a VH-PO2 valve; a multiphase meter (MPFM); choke; at least three pairs of pressure and temperature transducers.

5. System, according to any one of claims 1 to 5, characterized in that the VR type valves are actuatable by an ROV.

6. COMMISSIONING METHOD, VIA UEP, OF PLEM SYSTEM CHOKE MODULE, as defined in any one of claims 1 to 6, characterized in that it comprises the following steps: a) diesel injection and first circulation; b) second diesel circulation; c) water and MEG injection and circulation; d) removal and commissioning of the choke module. 7.Method, according to claim 7, characterized in that step a) comprises: • via UEP, closing valves M1 and M2 of ANM 2, interrupting production from that well; • via UEP, closing valve W2 of ANM 2, interrupting the possibility of fluid circulation through that ANM; • via UEP, closing valve M2 in ANM 1, preventing gas lift injection into well 1; • interrupting the gas lift flow through the SV trunkline and via UEP injecting diesel through that trunkline; • via UEP, open valve XO on ANM 1; • circulate diesel through the choke module connected to Well 1, passing through the W2 – XO – W1 circuit on ANM 1 and returning through the production line, along with the production from well 1; • via UEP, close valves W2 and XO on ANM 1, where valve W1 remains open so that well 1 continues producing by flow; • via UEP, open valve PXO on ANM 1, allowing diesel to be used to clean this section of ANM 1, where the diesel circulates through this section and continues through the production line, being carried by the production from well 1; and • via UEP, close valve PXO on ANM 1. 8.Method, according to claim 7, characterized in that step b) comprises: • via UEP, opening valves W2 and XO of ANM 2, initiating diesel cleaning of the choke module and ANM 2; • circulating diesel through the W2 – XO – W1 circuit of ANM 2, returning through the production line of the choke module, passing through valves VR-PO4, VR-PO3, VH-PO1, VR-PO2 and VR-PO1, returning through the production header of the PLEM together with the production from well 1; • via UEP, closing valves W2, XO and W1 of ANM 2; • via UEP, opening valve PXO of ANM 2, allowing cleaning of this section of ANM 2; and • via UEP, opening valves VH-SV2 and VH-PO2 of the choke module connected to well 2, allowing circulation.

9. Method, according to claim 7, characterized in that step c) comprises: • injecting water through the SV trunkline, circulating water through the choke module connected to ANM 2, with circulation of this water through the GL line to ANM 2; • circulating water through ANM 2, with entry into ANM 2 through the GL line passing through the PXO valve and returning through the production line to the production header, cleaning all sections of the choke module and being carried along with the production from well 1; • via UEP, closing valves VH-SV2 and VH-PO2 in the choke module connected to well 2; • via ROV, closing valves VR-SV1, VR-SV2 and VR-PO2;• Via ROV, inject MEG through the MQC access between valves VR-PO1 and VR-PO2 at the choke module inlet of well 2, with the aim of inhibiting hydrate formation in the PLEM-Choke production header, in the section where there will be direct contact between the fluid produced by well 1 and the standing water in the header, during the choke module replacement period of well 2; • Via ROV, close valve VR-PO1 at the choke module inlet of well 2, after injecting an adequate volume of MEG; • After closing the valves located at the choke module inlet of well 2, perform a leak test on them using an ROV via MQC interfaces positioned between valves VR-SV1 / VR-SV2 and VR-PO1 / VR-PO2; • If the results are positive in these tests, the choke module connected to well 2 is filled with water and ready to be recovered. 10.A COMMISSIONING METHOD, VIA ROV, FOR A CHOKE MODULE OF THE PLEM SYSTEM, as defined in any one of claims 1 to 6, characterized in that it comprises the following steps: • via ROV, closing valves VR-SV1, VR-SV4, VR-PO1 and VR-PO4; • via ROV, injecting MEG through the MQC accesses between resident valves VR-SV1 / VR-SV2 and VR-PO3 / VR-PO4; • wherein the MEG flow through the SV line enters through the MQC access between valves VR-SV1 / VR-SV2, passes through the module to carry the gas in that section, exits through the MQC access between valves VR-SV3 / VR-SV4, and is collected at that outlet; • The MEG flow through the module's PO duct enters via the MQC access between valves VR-PO3 / VR-PO4 to carry oil inside the module, and exits via the MQC access between valves VR-PO2 / VR-PO1; • After injecting MEG through the MQC accesses, via ROV, close valves VR-SV-2, VR-SV3, VR-PO3, and VR-PO2; • Perform leak tests on the 4 pairs of resident valves (VR-SV1 / VR-SV2, VR-SV3 / VR-SV4). VR-PO1 / VR-PO2, VR-PO3 / VR-PO4) via ROV through MQC interfaces between valves; • via RSV operation, remove the choke module with MEG in the piping.

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