Activity
ROV Operations
Deployment, recovery and operation of underwater remotely operated vehicles.
Documents
- 202631 Mar
Source control planning and procedures information paper
This information paper sets out regulatory expectations for offshore loss-of-well-control preparedness across environment plans, well operations management plans and safety cases. It covers capping-stack selection and deployment, relief-well design and dynamic kill analysis, plume modelling, subsea dispersant supply, water-column monitoring, response-time modelling, coordinated operations and readiness exercises.
- 202622 Jan
Dropped GRP cover during subsea lifting
A GRP manifold cover detached during subsea relocation and dropped approximately 7 m, without injury or damage to the manifold or bottom structure. Findings identified excessive loading during a crane mode transition and erroneous lifting-rod calculations. Revised lift planning removed the mode switch and used deployment lifting points; keeping divers clear prevented potential serious injury.
- 202531 Jul
Near miss: High voltage arc inside tether termination manifold
A dislodged HPU conductor caused arcing inside an ROV tether termination manifold. Subsequent checks identified reduced insulation resistance and gas, whose origin was unconfirmed without testing. The flash examines unapproved termination lugs and records re-termination, system testing and recommendations to assess crimping tools and review procedures and gas-venting precautions.
- 202518 Jun
BSEE: Umbilical termination failure leads to dropped ROV
An ROV dropped to the seafloor during recovery when its umbilical parted at the cursor rail transition. Faulty resin casing and improperly arranged armoured strands compromised the attachment despite a previous successful pull test. BSEE recommends termination inspection procedures, re-termination training and pre-job connection checks. No personnel harm or seabed asset damage occurred.
- 20254 Apr
BSEE Safety Alert 499 - Failed Umbilical Termination Results in Dropped Remotely Operated Vehicle (ROV)
An ROV dropped to the seafloor during recovery when its umbilical termination failed at a cursor transition point. Faulty resin and improperly positioned armoured strands were identified despite a previous successful pull test. BSEE recommends termination inspection procedures, training and pre-job connection checks. No personnel harm or seabed asset damage occurred.
- 202520 Feb
NOPSEMA – Fauna entanglement
An IMCA safety flash relays a NOPSEMA alert about a shark trapped in a rope loop on an electrical flying lead and freed using an ROV knife without additional harm. It discusses marine fauna interactions with subsea equipment and measures to consider, including installation-aid removal, alternative designs and protective guards.
- 202427 Nov
LTI: Finger injury during emergency recovery of ROV
During emergency ROV recovery using an FRC and crane, a worker’s left ring finger was pinched while releasing a hook secured to the crane wire, causing amputation to approximately the nail bed. The flash identifies an unplanned, unassessed release step and records revised procedures, risk assessment and regular recovery training.
- 20243 Oct
Fauna entanglement
An environmental alert describes a shark caught in a rope loop on a subsea electrical flying lead and released using an ROV knife without additional harm. It discusses evaluating fauna interaction risks, considering installation-aid removal and safer designs, guarding injury mechanisms, verifying controls and meeting protected-species incident reporting requirements.
- 20242 Jul
ROV dropped to seabed
An ROV fell to the seabed after recovery-system latching problems and umbilical separation. Cold, dirty grease slowed the latch, while the operator could not see the locked-position indicator. The flash identifies maintenance, procedure and supervision shortcomings and describes cleaning, functional verification and renewed procedural assurance.
- 202311 Jan
Lost ROV incident
An ROV became trapped in a platform jacket during routine inspection in strong tidal current. Tether damage interrupted power and telemetry; subsequent recovery failed and the vehicle was lost. The flash identifies inadequate recovery procedures, understaffing and premature beacon battery exhaustion, and records procedural revisions and a current display added to the pilot interface.
- 20219 Dec
ROV main lift failure
An ROV/TMS assembly fell to the seabed during a test-dive launch when its umbilical termination slipped through the socketing; nobody was harmed. Investigation identified inadequate cone size, uneven strand distribution, excessive docking force and resin-related shape changes. Corrective actions included a larger cone and adjustment of docking-head dampers.
- 20212 Dec
UHMPE pull-in rope damaged during mooring connection to buoy
During a subsea buoy mooring connection, a UHMPE pull-in rope escaped ROV control, damaging its arm, while the rope’s other end entered a propeller and was cut. The flash identifies current, propulsion wash, insufficient catenary monitoring and underestimated deck friction, and records amendments to the installation procedure and task plan.
- 202116 Jun
Dropped object – Door detached from TMS during dive
An ROV tether management system lost an aluminium door subsea after both bottom latches failed. The investigation identified an omitted check for secondary retention. The flash recommends checking fixings and reviewing dive checklists; DROPS cone analysis judged damage to nearby subsea assets very unlikely.
- 202123 Apr
Failed Seal on Subsea Safety Valve Causes Leak
A subsea safety-valve seal failure allowed hydrocarbons into hydraulic lines at a Gulf of Mexico production platform, releasing an estimated three to 50 barrels of hydraulic fluid and oil. The alert describes ROV sampling and leak isolation, and recommends considering hydraulic-system monitoring, alarm configuration and pressure management during leaks and platform evacuation.
- 202121 Jan
Risk-Based Inspections of Subsea Leak Detection Technology Reveals Gaps in System Processes
BSEE reviews three subsea oil leaks and inspection findings showing weaknesses in leak-detection procedures and management processes. Operators and contractors are asked to consider clearer alarm response responsibilities, personnel training, system testing, configuration change control and ROV surveys. The alert emphasises investigating abnormal flow and learning from previous detection failures.
- 202017 Mar
Trencher angle inadvertently altered
Accidental joystick activation during offshore trenching raised the cutting wheel and reduced cutting depth, unnoticed during a shift handover and computer reboot. No equipment or permanent material damage occurred. The flash examines interface design and alarm tolerances, describing revised alarm settings, cessation of trenching during handovers and joystick deactivation.
- 201922 Nov
Cabling in ROV hanger inadvertently severed by the ROV launch and recovery frame
A vessel’s ROV launch and recovery frame struck a bulkhead cable tray, severing electrical cables and hydraulic hoses serving equipment. The damage emerged when an emergency firefighting pump would not start during weekly testing. A documented collision risk had not changed working instructions; actions included procedural review, recovery monitoring and an engineered solution under installation.
- 201922 Nov
Main ROV lift wire umbilical and bullet parted
An inspection-class ROV and its tether management system fell to the seabed during recovery after the main lift connection parted. The flash examines a recently re-terminated, load-tested bullet connection, failed potting compound and high ambient temperatures, and records procedural changes addressing temperature limits, compound quantities and storage details.
- 201925 Jul
Mattress beam landed very close to divers
A mattress lifting beam was lowered dangerously close to saturation divers recovering concrete mattresses on the seabed. The flash identifies lost visual monitoring, poor visibility and failure to stop work. Follow-up checks addressed load separation, diver–crane communications, ROV monitoring, beam visibility aids and incident reporting.
- 201925 Apr
Safety Alert 348 - Chemical Leak in Flying Lead Discovered by ROV
An ROV survey discovered a subsea paraffin-inhibitor leak from a hydraulic flying lead in the Gulf of Mexico. Outer-jacket damage compromised collapse resistance; loss of positive pressure resulted in collapse and tearing. BSEE recommends considering pressure-maintaining procedures, training, check valves, low-pressure alarms, inventory monitoring and regular ROV inspections.
- 201821 Dec
Umbilical termination failure and loss of ROV
An ROV and its TMS fell to the seabed during recovery after an umbilical termination detached. Examination identified poor termination workmanship and defects, alongside inadequate subcontractor skill and quality verification. Revised procedures require photographic evidence of assembly steps, with quality surveillance recommended for subcontractors. No personnel were injured.
- 20183 Aug
High potential near miss: unplanned handling of unexploded ordnance
A high-potential near miss involved recovering and handling wartime munitions during subsea debris clearance. ROV operations continued after ammunition emerged, and crew handled recovered items before specialist advice prompted their return to the seabed. The flash identifies information, identification and management failures, calling for reinforced stop-work authority, change management and revised procedures.
- 20184 Jun
Near miss: potential dropped objects on temporary buoy modules (TBMs)
Two near misses involved loose objects discovered on temporary buoyancy modules retrieved to deck during tension leg platform installation. One concerned unrecovered subsea lamps and missing subcontractor notification; the other involved an inadequately lashed retaining pin removed by an ROV. Actions addressed material recovery procedures and reinforced stop-work authority.
- 201711 Aug
Power loss within dive control
A vessel’s dive-control electronics lost power during ROV recovery on a shared power bus. Low supply voltage activated the UPS internal bypass, after which circuit breakers tripped. The dive was aborted without injury. Actions included keeping the bus tie breaker open, disabling internal bypass and introducing daily UPS health checks.
- 20173 May
Near-miss: Gas release from subsea pipeline
A gas release occurred during subsea spool connection while divers were in the bell for shift changeover. The vessel moved clear and an ROV released the crane hook safely. Findings highlight missing refinery communication about valve opening; recommendations address permit understanding, inter-site communication, H2S preparedness, drills and equipment testing.
- 201612 Sep
Safety Alert 323 - Subsea Flowline Failure Causes Pollution Incident and Delayed Detection Leads to Larger Spill Volume
A subsea flowline released production fluids while personnel interpreted alarms as slugging or plugging, delaying shut-in for several hours. With the failure cause still under investigation, BSEE recommends thorough alarm investigation, revised leak-detection escalation, monitoring of operating data, conditional ROV integrity checks and transient analysis of small-volume leaks.
- 20162 Aug
Loss of 3 tonne lift bags owing to equipment failure
During a saturation dive, lifting-link failures released closed salvage lift bags attached to a pipeline. Metallurgical testing revealed strength below the certified rating and weaknesses associated with bent, welded rings. The member concluded that certificates were counterfeit. Remaining bags were condemned and punctured by ROV before diver recovery.
- 20152 Oct
Dropped object near-miss: ROV wire rope
An ROV positioning near-miss aboard a vessel released approximately 36 m of wire rope weighing 430 kg after the dome contacted a guide wire, which detached from its gantry termination. The flash reports equipment deterioration and procedural shortcomings, recommending certified guideline wires, secondary retention and specific maintenance procedures.
- 20155 Jun
ROV main lift umbilical failure
An ROV lift umbilical parted during recovery, dropping the vehicle to the seabed in 1360 m water depth. Recovery found no damage or injuries. Investigation identified hidden internal damage linked to inadequate lubricant penetration despite certification and scheduled maintenance. The flash recommends strand inspections and improved destructive-test reporting.
- 20152 Apr
Winch brake failure
An ROV winch brake failure released approximately 800 m of umbilical in less than 90 seconds, followed by a motor fire; nobody was injured. Analysis suggested a probable secondary brake release-line blockage, without establishing a definitive cause. Manufacturer checks addressed release-pressure decay and motor-to-brake load transfer.
- 201516 Jan
Unplanned release of 960 litres of hydraulic oil
During vessel transit between piling locations, unintended crane control activation lowered a suspended hammer, tightening its hydraulic umbilical until the coupling parted and the restraint chain snapped. The release totalled 960 litres of hydraulic oil. Identified measures addressed crane inactivity, communications, hose isolation, ROV observation and potential pollution-reduction arrangements.
- 201425 Nov
Dropped object incidents
Three vessel incidents involve ROV hangar securing hooks, a tensioner pad dropped during manual transfer, and a plastic LARS swing-gate arm falling during ROV recovery. The flash discusses dropped-object surveys, secondary retention, restricted access, permits and risk assessment, and encourages crews to identify and secure potential dropped objects.
- 201417 Jul
Main ROV lift umbilical parted
An ROV recovery incident involved a parted lift umbilical, with the vehicle and tether management system falling to the seabed and later being recovered. Investigation identified unrestricted winch pull with a short, thin umbilical and malfunctioning latches. Corrective actions addressed latch indications and procedures limiting pull below umbilical breaking strain.
- 201416 Apr
Fatality during air diving operations
A diver was fatally struck by a high-pressure water jet while relocating a marker buoy beside a leaking live injection pipeline. Reduced visibility and extreme noise hindered the dive. The flash discusses risk understanding, initial ROV inspection, safe depressurisation, task-specific hazard analysis and formal communication of work instructions.
- 201320 Dec
Near-miss: ROV shackle (potential dropped object)
An ROV shackle pin partially disengaged during subsea boulder removal. The grab was safely landed before assessment, recovery and rigging changes. Potential causes included snagged R-clips and repeated rigging slackening. The flash discusses split-pin securing and, where possible, replacing ROV shackles with a direct bow-shackle and soft-sling arrangement.
- 201329 Nov
High potential dropped object – steel bar, 10 m
During ROV deployment, a steel guide bar weighing approximately 20 kg fell approximately 10 m onto moonpool doors without injury or damage. Umbilical rubbing had loosened its securing bolts following a system upgrade. Recommendations address guide clearance, bolt tightening, secondary retention, planned inspections and management of future alterations.
- 201318 Jun
High potential near-miss: Dropped ROV/TMS leading to equipment damage
This safety flash describes an ROV/TMS and docking head falling from approximately 1 m during launch, following a guide bar falling more than 4 m. Preliminary findings link weld and clevis failures to possible operation with locked damping cylinders. It examines conflicting procedures, design suitability and missed maintenance indications.
- 20133 May
Loss of ROV after umbilical termination failure and damage to ROV during recovery
An ROV and its tether management system were lost during launch following umbilical termination failure. Recovery caused further damage when sharp bullet edges cut a soft sling. The flash examines socket seating, curing and possible un-axial loading, and recommends revised termination procedures, checked bullet design and an emergency recovery strop.
- 201318 Jan
Luff ram clevis failures
Reports repeated luffing-ram clevis failures on an ROV launch and recovery system during testing, recovery and launch. Investigation identified corrosion and deformation, with corrosion partly attributed to an omitted maintenance step; root-cause analysis remained ongoing. Planned maintenance was updated to include rod-eye gap checks, valve adjustment verification and visual inspections.
- 201125 Nov
Near-miss: Dropped taut wire clump weight
During diving operations, a recovered port taut wire parted while being slewed inboard, dropping its 315 kg clump weight clear of divers and subsea assets. A worn, sharp-edged wire guide had damaged the wire. The flash discusses dropped-object cones, ROV checks of landing locations, repairs and review of inspection routines.
- 201127 Oct
Equipment damage – dropped ROV/tether management system (TMS)
A work-class ROV fell to the deck from between 1.5 m and 2.0 m during launch, sustaining significant damage. Unrecognised disengaged latches and unnecessary umbilical slack were reported. Corrective measures included latch alarms, position markers, cameras, communication checks and revised task analysis, alongside engineering reviews addressing interlock development.
- 200922 Dec
Loss of ROV: dropped object
An ROV and its tether management system fell to the seabed during recovery after umbilical termination failure. Investigation identified excessive internal bullet friction preventing proper cast wedging and unclear maintenance instructions. Corrective actions included armour-strand inspections, recurring cast photography and replacement of carbon-steel bullets with stainless-steel versions.
- 200910 Nov
Near-miss: ROV fuse bolt failure
An ROV manipulator fuse bolt ejected its head during pre-dive testing, narrowly missing a technician without injury. Investigation linked the failure to damage sustained during heavy work on the previous dive. The flash recommends manual jaw operation before energising hydraulics, directing arms away from people and assets, and controlling access during deck checks.
- 20092 Jun
Electric shock near-miss
An ROV technician received an electric shock while rerouting a tether, without injury. Energising the tether management system produced induced voltage in isolated conductors, while two earthing clips had become dislodged. The flash examines insecure earthing connections and recommends design improvements, high-voltage training and warning signage.
- 20095 Mar
Bolt failures on Lawson ROV launch and recovery systems
This safety flash alerts members to a Lawson Engineers notice concerning bolt failure in a 3000m launch and recovery system. The failure allowed a latched-in tether management system and ROV to fall onto the deck. The supplied page provides no further incident analysis or recommended controls.
- 200810 Apr
Fatal accident in connection with the operation of an A-frame based launch and recovery system (LARS) used for ROV operations
A safety flash describes a fatal trapping incident during ROV umbilical maintenance aboard a vessel in a floating dock. A blackout coincided with uncontrolled winch spooling that lifted the tether management system. Analysis identifies six interacting technical mechanisms and details wiring, controller software and hydraulic isolation modifications to improve emergency stopping.
- 200618 Sep
Warning regarding Imenco Minilatch – ROV fell onto deck
This safety flash relays an alert concerning the Imenco Minilatch after an ROV fell from its launch and retrieval latch onto a support vessel’s deck. The brief notice identifies the equipment involved but provides no incident date, cause, injury information or specific preventive measures.
- 200531 Oct
Crane wire failure
A crane wire parted during night-time recovery of a work-class ROV onto a survey vessel. The investigation linked prior over-recovery to sheave damage and crushed wire, followed by impact loading through the splash zone. Corrective actions addressed inspection checklists, reporting findings, management of change and risk assessments.
- 20052 May
ROV free-fall incident
A work-class ROV fell approximately 10 metres into the sea during recovery, causing minor damage but no injuries. The investigation identified a procedural lapse and suspected combined umbilical tension involving the winch and A-frame. Recommendations addressed docking-device design, annual destructive umbilical testing, procedures, training and visual operating-envelope indicators.
- 200311 Jun
Safety Alert 213 - Marine Riser Failure
A drillship conducting dual activity in approximately 6,000 feet of water suffered marine riser failure while pulling drillpipe. ROV examination identified separated riser sections and mud release of undetermined quantity. Well-control equipment operated as designed, with additional shear rams activated by ROV. The alert highlights well shut-in requirements pending investigation.
- 200229 May
Safety Alert 200 - Subsea Equipment Failure Leads to Deepwater GOM Pollution
An incorrectly seated replacement choke was expelled during restart of a deepwater subsea oil well, releasing crude oil and gas. The alert examines unsuccessful ROV visual verification, delayed shut-in and confusing monitoring displays. Recommendations address pre-job emergency discussions, visually verifiable intervention equipment and clearer control-room systems with reduced need for safety-system bypasses.
- 20012 Aug
Failure of ROV lift umbilical winch brake – Update
This safety flash updates an earlier report of uncontrolled ROV umbilical winch run-off involving a MacArtney CORMAX unit manufactured by Norlau. The manufacturer acknowledged a design problem and recommended low-speed operation only pending a technical solution. Longer-term resolution may involve modifications to the winch system.
- 20012 Aug
ROV winch failure
An ROV launch on a semi-submersible drilling rig ended in uncontrolled winch payout after gearbox bearing failure ejected the output shaft. Input-side braking remained functional but could not control the drum. Nobody was injured. Actions initiated included quarterly gearbox oil analysis and retrofitting retaining plates to similar winches.
- 20011 Aug
Failure of ROV lift umbilical winch brake
A CORMAC ROV umbilical winch suffered uncontrolled payout after excessive brake-plate wear, losing the ROV and umbilical without injury. The flash explains how a pay-in command aided payout and describes motor-against-brake torque testing and company response instructions as short-term measures while a possible manufacturer-agreed modification was investigated.
- 1999Apr
Sinking of stern trawler Gaul with loss of 36 lives
Investigation of Gaul’s loss with 36 crew on North Cape Bank in February 1974, using an ROV wreck survey, video mosaics and hydrodynamic model experiments. The report concludes that breaking waves caused a knock-down followed by downflooding through open closures, and recommends reopening the Formal Investigation.
- 19991 Jan
Subsea lifting and dropped loads
Four incidents concern dropped subsea loads and an inadvertently released ROV. The flash discusses basket drag and snatch loading, displaced shackle retention, single-link load transfer and possible seized latch rollers. Reported measures include strengthened brackets, vessel-specific sea-state limits, secure shackle retention, revised transfer procedures and latch checks.
- 19981 May
Crane wire failure
During ROV recovery, a crane wire failed and the vehicle struck a rail before falling inboard. Investigation identified weakening through hook retraction into the sheave and subsequent overstressing during articulation. Instructions address personnel clearance, maintaining wire slack and replacing damaged or overstressed wire at the earliest opportunity.
- Undated
Subsea Tree Dropped During Retrieval Damages Jumper
Investigation of a subsea tree dropped during retrieval from Marubeni’s A002 well, damaging the A004 jumper. Findings examine incomplete retrieval-tool testing, omitted over-pull verification, obstructing ROV debris, an ambiguous locking indicator and misunderstood safe-zone instructions. The report records subsequent recovery and repairs, with no district recommendations at that time.
- Undated
Riser Adapter Fails During Disconnection and BOP Stack Falls to Seabed
BSEE investigates a riser adapter failure during disconnection following temporary well abandonment. Reduced riser tension allowed the BOP stack to tilt and subsequently fall to the seabed. Finite element analysis supported the failure explanation. Findings identify inadequate procedures and undefined safe operating parameters; the plugged well caused no attributed pollution.
- Undated
02 - 17 - 2016 17:15 G14224 GB 216 Pollution
Investigates a zinc bromide release during permanent well abandonment at Garden Banks Block 216. Hess estimated 22 barrels entered offshore waters. Subsea vent safety valves left open were identified as the probable cause, with incomplete procedures and drawings possible contributors. An ROV required a different tool to close the valves fully.
- Undated
ROV Descended to Seabed During Recovery After Umbilical Winch Free-Spooling
Investigation of an ROV recovery incident aboard Deepwater Atlas in which an umbilical winch free-spooled and the vehicle descended to the seabed. Contractor and manufacturer analyses attributed gear damage to inadequate lubrication. Emergency stopping depended on the failed gearing. The report examines maintenance evidence, crew response and limitations of the investigation.
- Undated
Kill-Line Gooseneck Disconnection Released Mud During BOP Flushing Preparations
Investigation of a kill-line gooseneck disconnection during preparations to flush BOP lines, releasing approximately 48 barrels of synthetic-base mud into Gulf waters. ROV inspection identified the disconnection. The report attributes it to an absent retainer pin and tugger-line tension, with supervisory and make-up procedure failures contributing.
- Undated
Glycol and Seawater Release Through Subsea Valve During Well Abandonment
BSEE investigates a Gulf of Mexico pollution incident during coiled-tubing well abandonment. Approximately 188 barrels of a 50/50 mono ethylene glycol and seawater mixture escaped through a subsea tree valve. Findings identify unverified valve alignment and inadequate closure-verification procedures; ROV intervention and subsequent pressure testing restored containment.
- Undated
Synthetic Oil-Based Drilling Mud Loss from Marine Riser
BSEE investigates synthetic oil-based drilling mud loss from the Rowan Reliance marine riser. Inspection identified a missing Seal Sub at the first riser joint connection. The report examines torque settings, ROV observations and possible procedural, handover and organisational contributors, records noncompliance findings, and recommends a concurrent SEMS audit.
- Undated
Shallow Water Flow from Wellhead Cement Port During Riserless Drilling
BSEE investigates shallow water flow from a wellhead cement port during riserless drilling at Garden Banks Block 962. Fluid analysis detected limited hydrocarbons. Logging and ROV monitoring examined cement channelling; investigators identified salt contamination as the probable cause. Shell subsequently decided to temporarily abandon the well.
- Undated
Drill Pipe and Bottom Hole Assembly Dropped During Well Abandonment
Investigation of drill pipe and a bottom hole assembly dropped during well abandonment from the Helix Q-4000. Weight-indicator records placed separation on 31 March, before discovery on 1 April 2022. The report identifies inadequate connection torque, describes ROV surveys and ultrasonic inspection, and reports no subsea infrastructure damage.
- Undated
Subsea Chemical Leaks Discovered During ROV Survey
BSEE investigates two subsea chemical leaks associated with the De Soto Canyon 4 well, discovered during an ROV survey. The report examines hose-jacket damage, loss of collapse resistance and failure to maintain positive pressure. It discusses uncertain discharge estimates, isolation and repair, and proposed procedural, training, check-valve and low-pressure alarm measures.
- Undated
Oil Release from Shut-In Subsea Well
BSEE investigates an oil release from Shell’s shut-in subsea VA007 well at Mississippi Canyon 940. ROV diagnostics and valve closures stopped the leak; subsequent e-line work identified parted production tubing at a coupling. The spill was estimated at seven barrels over several days. The reason for tubing failure remained unknown.
- Undated
Drilling Riser Failure on Discoverer Enterprise
Investigation of a drilling riser failure on Discoverer Enterprise examines connector insert cracking, hydrogen embrittlement and progressive connection failure. It documents wellbore sealing, subsea recovery and potential synthetic-mud discharge. Recommendations address insert and bolt redesign, hardness limits, coating removal and more frequent magnetic particle inspection.
- Undated
Hand Trapped Between Launch A-Frame and Pedestal During ROV Deployment
BSEE investigates a hand injury during ROV deployment from the West Neptune drillship. A deckman trapped his left hand between the launch A-frame and lower pedestal. The report identifies gaps in task risk assessment and red-zone identification, and records planned assessment updates, labelled observation zones and a physical barrier.
- Undated
Subsea Methanol Leak from Injection Tree Valve
BSEE investigates a subsea methanol leak at Mississippi Canyon 503 detected during scheduled maintenance. ROV diagnostics and photographs identified the methanol injection tree valve as the leak source. Internal seal leakage was considered likely, but the cause remained unconfirmed. Repairs included mechanical isolation and installation of a blind flange.
- Undated
Drill String Separated During Drilling and Trapped ROV Tether
BSEE investigates drill-string separation during drilling at Garden Banks Block 959. An unforeseen torque event exceeded a double-shouldered connection’s limits, damaging threads and allowing separation. Falling pipe trapped an ROV tether, restricting movement without interrupting wellhead monitoring. No injuries were reported, and the district made no recurrence-prevention recommendations.
- Undated
Oil Leak from Well at Submerged Platform
Investigation of oil pollution from Well C-007 at the submerged Grand Isle 47C platform, destroyed by Hurricane Katrina. The report identifies a leaking casing valve, traces recurring releases and describes ROV source identification, continuous vessel recovery, spill notifications, collection-dome construction and contingency planning for a relief well.
- Undated
Umbilical Breach Released Methanol and Ethylene Glycol During Abandonment
Investigation of an umbilical breach during abandonment at Boomvang SPAR, releasing approximately 41 barrels of methanol and ethylene glycol. The report identifies marine growth trapping centralisers and a suspected cutting impact. Subsurface guides prevented visual confirmation, while the winch lacked load or tension monitoring. ROV observations documented tube damage.
- Undated
Typhoon Tension-Leg Platform Capsizes During Hurricane Rita
Investigation of the Typhoon tension-leg platform’s capsizing during Hurricane Rita identifies loss of mooring-system integrity at pontoon 1 as the most probable cause. Hull inspections, ROV surveys, photogrammetry and modelling examine connector damage and alternative explanations. The report records hydrocarbon pollution and recommends studying the mooring system’s continued acceptability.
- Undated
Subsea Safety-Valve Leak Released Well Fluids Through Hydraulic Controls
BSEE investigates a Thunder Horse shutdown followed by discovery of a subsea safety-valve leak. Failed rod piston seals allowed well fluids into hydraulic controls and subsea venting, with an estimated 3–50 barrels released. The report examines ROV inspections, sampling and valve tests, and recommends operator training and hurricane-related precautions.
- Undated
Drilling Mud Leaked Through Subsea Riser Connection
Investigation of synthetic oil-based drilling mud escaping through a subsea riser connection. An ROV located the leak after inadequate fluid returns were noticed. The report identifies worn seals, with rig movement and underwater currents contributing, and records cessation after approximately eight hours. Existing pre-run seal inspections were to receive greater emphasis.
- Undated
Subsea Mud Boost Valve Leaks During Attempts to Open It
An investigation examines a subsea mud boost valve leak during attempts to open it using an ROV and hydraulic jack. Approximately 67 barrels of synthetic oil-based mud reached the sea floor. Findings identify a loose retention pin, actuator rod failure and a flange assembled with two gaskets.
- Undated
Subsea Flowline Gas Release During Replacement Control Module Testing
Investigation of a subsea flowline gas release during testing of a replacement control module at Viosca Knoll 989 A. An ROV located bubbles at a bend; testing stopped and the pipeline was isolated. Talos suspected a previous field repair and possible corrosion, but the exact cause remained undetermined pending inspection and testing.
- Undated
2023-001 GC40 BSEE Panel Investigation Final Report GC40
BSEE investigates a subsea flowline jumper failure involving hydrogen embrittlement of four flange studs and an estimated 479-barrel oil release. Metallurgical testing and finite element analysis examine material suitability and loading. Findings address procurement omissions, quality assurance, management of change and leak-detection limitations, with recommendations for operators to consider.
- Undated
Collision, or close-quarter situation, between trawler Ocean Hound and unknown vessel resulting in trawler capsizing with loss of 5 lives
Investigation of Ocean Hound’s loss and five crew deaths in the Dover Strait examines radar recordings, stopped clocks and underwater wreck surveys. It identifies probable close-quarter interaction causing capsize, with physical contact uncertain, followed by probable collision and sinking. Recommendations address vessel identification, reporting, lookout and practical demonstration of emergency escapes.
- Undated
Guidance on decommissioning debris surveys and seabed clearance verification
Guidance distinguishes debris recovery from seabed clearance verification during oil and gas decommissioning. It explains when ROV recovery, geophysical surveys and over-trawl methods are appropriate, considering safety zones, seabed disturbance and protected habitats. It also addresses chain-mat remediation of snagging hazards, regulatory review and marine licensing requirements.
- Undated
Statoil - Åsgard A - Investigation of hydrocarbon leak
Investigation of a subsea gas and condensate release during high pressure cap removal at Åsgard’s S template. The cap was removed with an isolation valve open. Findings examine barrier testing and securing, unclear responsibilities, deficient operational procedures and risk assessment. How the valve changed position remains unknown.