TL;DR
Contaminated BOP hydraulic fluid causes slow function response and valve sticking. Take a fluid sample, change the filters, and flush the circuit before returning the BOP to service.
What you might see
- hydraulic fluid milky or discolored
- BOP function response time slowing
- hydraulic valve spool sticking
- particle count in oil analysis elevated
Likely causes
Water ingress from a leaking accumulator bladder or tank vent
Particulate contamination from a worn hydraulic pump or corroded line
Fluid mixing from an incorrect fluid type added during topping up
Biological growth in the hydraulic fluid tank from water contamination
Required tools
- Hydraulic fluid sample bottles
- Filter replacement set
- LOTO kit
- Fluid flushing equipment
Safety first
- BOP hydraulic systems are at high pressure (typically 3000 psi). Do not disconnect any hydraulic line without confirming pressure is at zero.
- Hydraulic fluid contamination must be resolved before the BOP is considered ready for well control service. Do not return the BOP to standby with degraded hydraulic fluid.
Procedure
- 1
Take a hydraulic fluid sample from the reservoir and submit for particle count, water content, and viscosity analysis.[1]
- 2
Inspect the reservoir fluid condition visually. Milky fluid indicates water. Dark fluid may indicate oxidation or chemical contamination.[1]
- 3
Inspect and replace all hydraulic filters. A high pressure drop across the filters confirms elevated contamination.
- 4
Check the accumulator bladders for integrity. A failed bladder allows nitrogen to mix with the hydraulic fluid.
- 5
If water contamination is confirmed, drain and flush the reservoir and refill with fresh hydraulic fluid meeting the BOP specification.
- 6
After flushing, verify BOP function response times on each function and compare to baseline.
- 7
Investigate the water ingress source and correct before returning to service.
Sources
Cameron (SLB) Cameron Type U / TL Blowout Preventer (BOP) general technical documentation, Cameron (SLB)
Cameron Type U / TL BOP general hydraulic fluid maintenance and contamination procedures (general)
More guides for Cameron (SLB) Cameron Type U / TL
How to diagnose annular preventer seal wear on a Cameron Type U / TL BOP
Annular preventer seal wear reduces the BOP closing margin. Track the closing pressure trend and test element condition at each BOP pressure test interval.
How to diagnose a ram seal leak on a Cameron Type U / TL blowout preventer
A BOP ram seal leak is a well control equipment integrity failure. Pressure test per the regulatory schedule, identify the leaking seal set, and plan a rebuild.
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