Kelsow Work Instruction Subsea Well Control Hydraulic Panel Operation
Table of Contents Overview............................................................................ 2 Hydraulic Panel Isolation........................................................... 3 LP Hydraulics....................................................................... 4 HP Hydraulics....................................................................... 5 Regulator Failure................................................................... 6 Kelsow Work Instruction 2008
Overview Subsea Well Control Hydraulic Panel Operation The operation of the well control hydraulic panel is a critical task performed by the outside production technician on offshore production platforms and FPSO. The outside production technician must be familiar with the low pressure and high pressure operation of the hydraulics, including the isolation of the panel for maintenance and troubleshooting. A common problem encountered is the failure of the pressure regulators, and the isolation of the failed unit and commissioning of the back-up unit must be carried out promptly to avoid costly down-time of the production wells. This Kelsow Work Instruction details the operation of the panel and the steps to perform these isolations effectively and safely on this critical equipment. By having this work instruction on hand at the hydraulic panel location, can ensure this information is readily available for the technician to perform the operations promptly, with the necessary information on hand to minimise production downtime. Kelsow Work Instruction 2008 2
Hydraulic Panel Isolation LP Hydraulics Last Valve Off (LVO) from hydraulic panel to XV- 7001/7002 on turret, and to WHP. HP Hydraulics Last Valve Off (LVO) from hydraulic panel to WHP and SSSVs. Supply from Accumulators to Hydraulic Panel - Isolation Valves Kelsow Work Instruction 2008 3
LP Hydraulics Current Set-Up of LP Hydraulic Pumps & Accumulator Setpoints Lead Pump P8601B Setpoint 33.0 MPa. Pump cut-in 4.4 MPa below setpoint (28.6 MPa) when in auto control, cut-out at 33.0 MPa. Lag Pump P8601A Setpoint 33.0 MPa. Pump cut-in 7.4 MPa below setpoint (25.6 MPa) when in auto control, cut-out at 30.5 MPa. Common Parameters High Pressure Alarm 35.0 MPa (0.6 MPa deadband). Low Pressure Alarm 24.4 MPa (1.0 MPa deadband). LP Hydraulic Pumps Set up to run as Lead & Lag (both A + B). If ESD 1 or 2, push reset on each pump s start panel, and re-start all pumps manually. If WHP-SSD, only need to start 2 x LP pumps. After starting pumps, setpoint of 33.0 MPa accumulator pressure must be reached, before pumps will maintain pressure automatically. May need to shut LVO on hydraulic panel to achieve this. One red light on pressure switch will go out, one will stay on, to indicate pressure switch reset. If pumps will not start, wait until accumulator has bled down below 33.0 Mpa. Same principal applies to HP Hydraulics. LP Accumulator Pressures If both red lights are on, pumps have not reset Kelsow Work Instruction 2008 4
HP Hydraulics Current Set-Up of HP Hydraulic Pumps & Accumulator Setpoints Lead Pump P8602B Setpoint 50.0 MPa. Pump cut-in 4.5 MPa below setpoint when in auto control (45.5 MPa), cut-out at 50.0 MPa. Lag Pump P8602A Setpoint 50.0 MPA. Pump cut-in 7.0 MPa below setpoint when in auto control (43.0 MPa), cut-out at 46.5 MPa. Common Parameters High Pressure Alarm 51.0 MPa (0.5 MPa deadband). - Low Pressure Alarm 43.5 MPa (2.0 MPa deadband). HP Hydraulic Pumps Set up to run as Lead & Lag (both A + B). If ESD 1 or 2, push reset on each pump s start panel, and re-start all pumps manually. If WHP-SSD, only need to start 2 x LP pumps. After starting pumps, setpoint of 51 MPa accumulator pressure must be reached, before pumps will maintain pressure automatically. The LVO on hydraulic panel may need to be shut to achieve this. One red light on pressure switch will go out, one will stay on, to indicate pressure switch is reset. If pumps won t start, wait until accumulator has bled down below 51 Mpa setpoint. Same principal applies to LP Hydraulics. HP Accumulator Pressures If both red lights are on, pumps have not reset Kelsow Work Instruction 2008 5
Regulator Failure Regulator Failure If regulator surging or relief valve failed, change over regulators. If it is known no leaks exist between FPSO & WHP Shut Hydraulics LVO, to seal in pressure from FPSO to WHP. Change over regulator duty, reopen LVO. If known leaks exist between FPSO & WHP Method to change over regulators on the run: Shut upstream block valve of failed regulator, wind regulator out to relieve pressure. Open upstream block valve of standby regulator, and wind in to build up pressure. Shut downstream block valve of failed regulator, then open downstream block valve of the now commissioned standby regulator. Adjust on-line regulator to correct pressure. Regulator Downstream Block Valves LP Hydraulics Last Valve Off FPSO Regulator Upstream Block Valves Kelsow Work Instruction 2008 6
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