Equipment
Blowout Preventer
Well-control equipment used to seal, shear or control the wellbore.
Newest 100 Documents
All 118 in search- 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.
- 2026Jan
Well Operations
An inspection guide presenting compliance questions for well operations under Subpart G, with regulatory authorities and enforcement codes. It covers casing and liner integrity, surface and subsea blowout preventer configuration, pressure and function testing, maintenance and records, alongside specific requirements for coiled tubing and snubbing systems.
- 2025Dec
Office PINC List
An office compliance checklist pairs regulatory questions with cited authorities and enforcement codes. It covers operational approvals, structural records, financial security, well-control competence, spill preparedness, drilling and decommissioning. Further checks address pipeline maintenance and reporting, reservoir conservation, production measurement, and geological and geophysical permits and data submissions.
- 202430 May
2024-01 64 Investigation of March 25, 2022, Hydraulic Workover Unit Failure Fatality
BSEE investigates a fatal hydraulic workover unit collapse at Main Pass Block 64 Platform #19. Severely corroded structural casing buckled after crane support was removed, and a worker tied to the unit was pulled into the water. Findings examine load assessment, Anchor Spool stabilisation, oversized equipment and unclear operator–contractor responsibilities.
- 20231 Feb
Drill string severed/parted while laying down drill pipe
During drill-pipe laydown, the crew heated an over-torqued connection with a propane weed burner after closing the BOP rams. Following separation of the connection, the driller hoisted the remaining string into the still-closed pipe rams, causing it to part approximately four feet below the elevators.
- 202214 Nov
MUX Cables and Hotline Hose Damage results in BOP Control Pods Losing Power and Communications
A subsea blowout preventer experienced partial communications loss while latched to a well. Excessive tension during harsh weather and extreme heave damaged the hotline hose and yellow and blue pod multiplexed communication cables. BOP control and operability remained available through the Acoustic Pod and subsea ROV panel.
- 202130 Apr
Blind Shear Door Blown Off BOP Body
A blind shear ram door blew off a blowout preventer during pressure testing at 109 bars, below the planned 570 bars. It was found on an adjacent equipment container. Earlier inspection and ram replacement involved opening the doors; anti-rotation bars were not engaged during reassembly.
- 202130 Apr
Uncontrolled release of Hydraulic Gooseneck Ring
During BOP retrieval through the splash zone, reduced resistance and rig movement produced a pendulum effect. The riser struck the stored gooseneck ring, which fell onto the flex joint. The BOP was then raised and secured; damage to the storage dogs and their locking mechanism caused downtime.
- 202119 Jan
Well Control - Issue 6
An offshore well-control inspection guide using questions, model answers and success criteria to assess operational arrangements. It examines conventional, high-pressure high-temperature and managed pressure drilling, including BOP assurance, kick detection, hydraulic modelling, fingerprinting, pressure relief, contingency procedures and crew training. Inspection scoring supports subsequent regulatory intervention planning.
- 202027 Nov
Blind Shear Rams Damaged after Inadvertently Closing on Tool String
During completion operations in the Gulf of Mexico, blind shear rams struck a test tool after drill pipe inadvertently backed off while releasing it. The alert describes equipment damage and delayed reporting, and recommends considering prompt notification, stack inspection, verification of test conditions and compliance with independent third-party requirements.
- 20209 Oct
Trapped Pressure Ejects Rod From Chamber and Strikes Subsea Technician in the Face
A subsea technician was injured when trapped pressure ejected a sheared indicator rod during blowout preventer pressure testing. Previously damaged rods had remained unrepaired, and a workaround omitted their hazard. BSEE recommends considering OEM maintenance, proper work procedures, avoiding out-of-service equipment and recognising trapped pressure in job safety analyses.
- 202027 May
Blow Out Preventer (BOP) Drops to Seabed
This alert describes a blowout preventer falling to the seabed during deployment on marine riser. A subsea engineer inadvertently triggered the emergency disconnect sequence after mistaking its button for the wellhead connector valve override, separating the preventer from the lower marine riser package.
- 201913 Aug
Safety Alert 364 - Improper Riser Tension Leads to Subsea BOP Falling Off Wellhead Mandrel and Failure of Riser Adapter
A subsea BOP tilted during disconnection after insufficient riser tension overloaded its adapter, which subsequently failed, leaving the BOP on the seafloor. The well had been plugged and no pollution occurred. BSEE recommends considering calculated unlatching procedures, tension verification hold points, safe operating parameters and renewed risk assessments for well-to-well BOP moves.
- 201912 Jun
Pryor Trust Fatal Gas Well Blowout and Fire
Investigation of an Oklahoma gas-well blowout and fire that killed five workers in the driller’s cabin. It examines underbalanced drilling, tripping methods, missed influx indications, disabled alarms, procedural and change-management deficiencies, blocked escape routes and unsuccessful blowout-preventer closure. Recommendations address drilling regulation, barrier assurance, alarm design and operating practices.
- 2019
Proposed Well Control Rule Revisions Fact Sheet
Technical fact sheet summarising BSEE’s final revisions to well-control regulations for offshore oil and gas operations. It explains changes to real-time monitoring, independent verification, accumulator requirements and alternating BOP testing schedules, alongside retained provisions for double shear rams, maintenance, ROV intervention and source control.
- 201819 Apr
Small Bore Tubing Failure on BOP Control System
This alert describes a hydraulic-fluid release during maintenance when a BOP stack control system was started. Small-bore tubing separated from the system’s 3,000 PSI manifold. An estimated 196 litres (51 gallons) of fluid escaped into a bunded area.
- 201718 Oct
Safety Alert 325 - Bolt Failures
BSEE describes subsea connector bolt failures during a BOP high-pressure test, with leakage but no loss of well control or injury. Material suitability and heat treatment remained suspected causes under investigation. Recommendations address replacement of affected-lot bolts, material compliance, installation and maintenance procedures, and timely failure reporting.
- 20173 Jul
Environmental Alert 001/2017
This alert examines capping-stack deployment where a 15,000 psi BOP contains a lower-stack annular preventer rated to 10,000 psi. For the described HPHT blowout configuration, it identifies the wellhead connector, after lower BOP removal, as the only attachment position tested to 15,000 psi, and requires consideration in oil-pollution emergency response strategies.
- 201628 Jun
Environmental Assessment
Final environmental assessment comparing regulatory alternatives for exploratory drilling in the Beaufort and Chukchi seas. It evaluates direct, indirect and cumulative effects of drilling-waste capture, well monitoring, source control, relief rigs and spill preparedness, balancing potential environmental benefits against additional operational disturbance and risks associated with more frequent BOP testing.
- 201620 Apr
Macondo Blowout and Explosion
Volume 3 examines human and organisational factors in the Macondo incident, including temporary abandonment, negative-test interpretation and riser gas handling. It analyses barrier assurance, change management, incident learning, process-safety indicators and corporate governance, contrasting written policies with operational practice and proposing improvements to major accident prevention.
- 20162 Feb
Safety Alert 318 - Connector and Bolt Failures
BSEE warns of recurring connector and bolt failures in offshore risers and subsea blowout preventers, potentially indicating a systemic industry problem. Operators should work with manufacturers to verify metallurgical documentation, ensure installation and maintenance practices meet OEM requirements, including torque processes, and report failures promptly.
- 201528 Aug
Finger/hand injuries
Two incidents concern a severed finger during blowout preventer ram unlocking and fractured fingers during lifting of a pup joint bundle. The flash identifies absent isolation and communication in the first case, and load proximity and handling deficiencies in the second. Corrective measures include guarding, job hazard analysis and stop-work interventions.
- 2015Jul
2015-002 ST 220 Investigation of Loss of Well Control and Fire, Gulf of Mexico, July 23, 2013, South Timbalier Area Block 220, Well No. A-3 OCS-G 24980
BSEE investigates the South Timbalier A-3 blowout and subsequent fire during well completion on Hercules 265. It examines temperature-dependent brine density, seepage losses, kick recognition, shut-in procedures and unsuccessful BOP sealing. The report documents evacuation, depletion-relief drilling, regulatory findings and recommendations; the ignition source remains unknown.
- 20159 Apr
Employee’s Finger Amputated
An employee unlocking a blowout preventer ram inserted a finger into the OEM sight slot to check that the locking screw was fully withdrawn. The crew chief operated the ram control valve while the finger remained in the slot, resulting in amputation of the left index finger. The hydraulic system was positioned 50 feet away.
- 20153 Mar
Environmental Alert 001/2015
An environmental alert describes damage to both multiplex BOP control lines on a MODU in the Canada–Newfoundland and Labrador Offshore Area after a securing saddle slipped approximately one metre. It highlights attachment robustness, installation procedures, management oversight, periodic inspection and readiness testing of acoustic, auto-mode and ROV back-up controls.
- 201510 Feb
Environmental Assessment
Draft environmental assessment comparing proposed Arctic exploratory drilling rules with alternatives, including no action. It examines pollution prevention, blowout-preventer testing, well monitoring, containment equipment and relief-rig availability in the Beaufort and Chukchi Seas. Analysis considers potential spill consequences, marine wildlife, subsistence practices and additional operational effects.
- 20145 Jun
Macondo Investigation Overview
Overview of the CSB investigation into the Macondo blowout during temporary well abandonment on Deepwater Horizon. It outlines the multi-volume report’s technical, organisational and regulatory scope, highlighting blowout preventer limitations, safety culture and international regulatory comparisons. It also describes evidence gathering, public hearings and obstacles to the investigation.
- 20145 Jun
Macondo Volume 1 Final Report
Volume 1 examines the Macondo blowout during temporary abandonment aboard Deepwater Horizon. It explains deepwater drilling, cement barriers, drilling-fluid pressure and positive and negative pressure tests. The report describes inadequate barrier assurance, separator overload and drillpipe buckling that inhibited BOP sealing, followed by explosions, fire and fatal injuries.
- 20145 Jun
Macondo Volume 2 Final Report
Volume 2 examines the Deepwater Horizon blowout preventer’s failure to seal the Macondo well, including off-centre drillpipe buckling, miswired solenoid valves and emergency-system assurance gaps. It uses forensic testing and modelling to assess barrier performance, comparing regulatory approaches and recommending lifecycle management and independent verification of safety-critical elements.
- 201329 Jan
Safety Alert 303 - Lower Marine Riser Package (LMRP) Connector Failure
BSEE reports synthetic-base mud discharge following an LMRP H-4 connector integrity failure and additional connector bolt failures. Preliminary evidence identified hydrogen-embrittlement-related stress corrosion cracking as a contributor, with improper electroplating treatment a possible cause. The alert calls for affected-bolt identification, independent certification and vendor quality-assurance reviews, including heat-treatment compliance.
- 20122 Jul
Safety Alert 302 - Pressure beneath a Surface Bridge Plug Blows Work String out of Well
During well abandonment, pressure beneath a surface bridge plug expelled 385 feet of work string and the bottom-hole assembly before the BOP sealed the well. Debris struck a diesel tank, releasing approximately five gallons into the Gulf. BSEE recommends reviewing re-entry procedures and accounting for pressure beneath plugs.
- 20129 Mar
Safety Alert 300 - Unplanned Emergency Disconnect Sequence (EDS) of the Lower Marine Riser Package
An unplanned emergency disconnect occurred during powered troubleshooting of a semisubmersible rig’s BOP control panel, activating shear rams and disconnecting the lower marine riser package. Completion fluid escaped through failed-open valves. The alert distinguishes network faults from the activation mechanism and recommends job safety analysis, power disconnection, supervisory consultation and ribbon cable retention.
- 201217 Feb
Report - Montara investigation: Volume three
Third volume of an expert witness investigation into the Montara hydrocarbon release. It reconstructs the operational timeline, charts H1-ST1 integrity during construction, suspension and re-entry, and evaluates barrier acceptance and verification. Technical responses examine corrosion caps, annular seals, cement isolation, change management and opportunities for risk assessment.
- 201217 Feb
Report - Montara investigation: Volume two
The second volume of an expert witness investigation examines nine issues surrounding the Montara hydrocarbon release. It assesses cement volumes, slurry properties, over-displacement, casing-shoe testing and corrosion-cap handling. Documentary analysis considers well suspension, barrier adequacy and programme changes, with proposed improvements to verification, contingency procedures and risk assessment.
- 201120 Sep
Failure of BOP Ram Yolk Results in a Natural Gas Release from BOP
A rigless snubbing operation experienced a natural gas release during ram-to-ram staging of production tubing. A broken stripping-ram yoke prevented adequate closing pressure and sealing. The operator closed the upper rams; damaged rams were subsequently removed for analysis. The BOP remained within its required certification period.
- 201114 Apr
Safety Alert 294 - Blowout Preventer Automatic Mode (Deadman) Activation
BOEMRE warns that a blowout preventer’s blind shear ram may reopen when power is restored following deadman activation. The alert recommends reviewing activation procedures and control logic, describes a possible blocking procedure, and explains requirements for seafloor testing and regulatory review during drilling permit approval.
- 200915 Dec
Safety Alert 284 - Diverter Flow Event
A semi-submersible completion operation experienced expanding formation gas in the riser and diverter discharge. The investigation established no specific cause, identifying possible packer communication, omitted reverse circulation and fluid-monitoring difficulties. Recommendations address brine pills, pressure monitoring, BOP sweeping, consideration of further circulation or bullheading, piping documentation and display scaling.
- 200925 Feb
Explosion/Flash Fire on Rig Floor Following Gas Release
An alert describes a well-control incident following drill-pipe logging and tripping. An influx was circulated using the Driller’s Method, but returns were lost. Repeated opening of the blowout preventer released mud and gas through the rig table. An explosive flash fire injured eight people, who were evacuated to hospital.
- 20088 Dec
Safety Alert 274 - Wireline BOP and Lubricator Ejection into GOM
A wireline BOP and lubricator were ejected into the Gulf of Mexico during DX plug retrieval, severely injuring the operator’s face. The alert identifies omitted lubricator testing, inadequate pressure equalisation and an unsuitable pulling tool for a modified plug, alongside failures in job safety analysis, stop-work practice and management of change.
- 2008Oct
2008-049 Investigation of Blowout Eugene Island, Block 28 Well No. 4, OCS-G 05479, December 03, 2007, Gulf of Mexico, Off the Louisiana Coast.
Investigation of a workover blowout at Eugene Island Block 28, offshore Louisiana. Production tubing parted during pulling, allowing well pressure to eject tubing before preventers contained the annulus. Metallurgical examination identified fatigue cracking and flow-cut wall thinning. The report reviews barrier tests, work procedures and subsequent snubbing operations to kill the well.
- 200826 Jun
Installing Annular BOP Results in RWC
An alert describes a finger injury during installation of an annular preventer onto a BOP stack. While the preventer hung from a crane, a worker attempted to start a nut on a stud. The annular shifted, trapping and pinching two fingers between the nut and its underside.
- 200826 Mar
Dropped String – High Potential Incident Results from Pulling Against Closed BOP Pipe Rams
An alert describes drill pipe parting and dropping into a well while the final stands were being pulled against closed BOP top pipe rams. Following a leaking cement-plug and casing pressure test, the driller assisted with disconnecting cementing equipment before resuming pipe removal without opening the rams.
- 200730 Jul
Safety Alert 252 - Retrieving Storm Packers
A storm-packer retrieval released gas and workover fluid, dislodging rotary bushings, injuring one person and splashing two others. An undetected gas bubble was identified, but its exact cause remained undetermined. MMS recommends retrieval procedures, a safety valve, kill-weight fluid, annular-preventer closure and restricting rig-floor personnel.
- 200711 Jul
Safety Alert 251 - Collapse of Pipe Supporting Coil Tubing Causes Drowning
During abandonment work on a hurricane-toppled caisson, production tubing supporting a BOP stack buckled. A technician attached to the stack by a fall protection harness was pulled into the ocean and drowned. The alert identifies planning shortcomings and recommends experienced review, consideration of contractor involvement, and communication across shifts.
- 20061 Sep
Residual Pressure in BOP Results in Finger Being Trapped
A worker’s hand was trapped while repositioning a slipped gasket during BOP door closure. Although the control lever had been moved to stop, residual pressure kept the door moving for a few seconds. Hospital examination found no broken bones or muscle damage, and the worker returned to full duty.
- 20061 Aug
Poor Communications Results in Pipe Being Pulled in Two
Following bull heading and a tour change, an incoming driller opened the annular preventer and attempted to hoist drill pipe while the top pipe rams remained closed. A tool joint struck the rams and the pipe parted at the rig floor. No injuries occurred; the alert identifies poor communication.
- 20061 May
Near Miss – Drill String Parts When BOP Pipe Rams are Left Closed
A drilling near miss occurred when the drill string was raised with BOP pipe rams still closed following an H2S drill. The string parted at the slips, and approximately four feet of broken pipe fell from elevators approximately 15–20 feet above the rotary table, brushing a floor hand’s shoulder without significant injury.
- 20061 Mar
Safety Alert 238 - Floorhand Crushed During a Through-Rotary Man-Riding Operation
A floorhand suffered a serious crushing injury when a BOP stack shifted during through-rotary man-riding work while a derrickman separately loosened winch connections. The alert recommends procedure review, signed permits and coordinated JSA meetings, and suggests considering lifting from the Texas deck and halting secondary operations.
- 200531 May
Safety Alert 231 - Human Engineering Factors Result in Increasing Number of Riser Disconnects
This alert reviews accidental and emergency riser disconnects in deepwater operations, highlighting human error, hydraulic connection mistakes and station-keeping failures. It recommends reviewing existing requirements for deliberate sequential disconnection, protected controls and documented subsea function testing. An accompanying table summarises eleven events involving drilling and production risers.
- 200518 Feb
Safety Alert 18 - Well-Control Equipment Circumvention
An MMS alert describes loss of well control during workover/completion after completion-fluid pumping stopped and a tubing hanger lockdown pin was removed, bypassing blowout prevention. Seawater and hydrocarbons escaped. It distinguishes direct from possible contributing causes and recommends improved hanger-landing procedures, well-control training and job safety analyses.
- 20043 Sep
Test Assembly Makeup Results in a Fatality
A fatal incident occurred during pressure testing on a rig. The top-drive connection was disconnected to align a torque tube key slot and close the lower IBOP. During reconnection, the tong bite broke, allowing the test assembly to rotate and strike the worker with its side outlet and lo-torque valve.
- 200424 Jun
Safety Alert 221 - Hanger Failure and Ejection Lead to Well Control Incident
During a workover, hanger hold-down pins sheared at 6,150 psi, ejecting the hanger and tubing. Investigation identified inadequate pin engagement caused by a design flaw. The alert identifies affected Cameron products, recommends multiple well barriers and advises operators to consider shear rams for wells presenting unusual control problems.
- 20037 Dec
Trapped Pressure in Annular Results in a Near Miss
A near miss during maintenance of a 13 5/8-inch 10K annular blowout preventer involved sudden cap ejection while a second pull-down bolt was being removed. The cap rose 4–5 ft, landing slightly off centre on the assembly. Three remaining bolts sheared; no personnel were injured.
- 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.
- 20037 May
Trapped Pressure Following Casing Test
A casing pressure test reached 1500 psi after cement and the float collar were drilled out using a mud motor. Pressure failed to bleed back through the motor. Opening the BOP subsequently expelled the rotary table’s inner bushings, despite an instruction to stand back. No injuries were reported.
- 200231 Oct
Safety Alert 205 - Blowout Results in Fatality and Injuries
An MMS alert describes a drilling blowout in which two men suffered hot-mud burns and one was lost during evacuation, presumed dead. Findings include a frozen safety valve, removed drill-pipe float and absent shear rams. Recommendations address backup valves, actuation and pressure testing, and reviews of pre-spud meetings and night-time illumination.
- 20019 Apr
Near Miss – Sticking BOP Control Valve
An alert describes uncommanded shear-ram closure during remote BOP function testing, which squashed but did not shear a drill-pipe joint. A crewman noticed the closed indicator before the test string was lifted. It also mentions another recent event in which lifting with closed shear rams parted a string, dropping the remainder.
- 20005 Jun
Failure of Annular BOP Element
This alert describes a newly installed element in an annular blowout preventer cracking and failing during testing after delivery to a rig. It highlights the preventer’s critical role in well control and the potentially extremely hazardous condition resulting from its failure.
- 20003 Apr
Safety Alert 187 - Coiled Tubing Incidents
Two Gulf of Mexico coiled-tubing operations suffered tubing separation after encountering unknown obstructions. Failed well-control interventions and absent back-pressure valves led to uncontrolled flow and platform evacuation. The alert recommends hazard analysis, force limits, backflow protection, supervision, communication, equipment-specific procedures, training and weekly well-control drills.
- 20003 Mar
Safety Alert 186 - Accidental Disconnect of Marine Drilling Risers
Two accidental marine riser disconnects involved selection of the wrong control button and installation of a disconnect-switch lock-out device. The latter incident lost riser hydrostatic pressure and surface BOP control. The alert recommends assessing changes and communicating current activities, and stresses reliable backup BOP actuation.
- 19996 Dec
Pressure Trapped in Sub Sea BOP Stack DDV Solenoid Housing
During testing of a subsea BOP stack, the blue pod’s shear accumulator failed to charge and a faulty DDV was suspected. Its solenoid housing was tilted, with four bolts sheared. Removing the remaining two bolts to investigate caused the housing top to fly into a bulkhead.
- 1999
OCS Report 1999
Statistical compilation of 1999 Outer Continental Shelf incidents in the Gulf of Mexico and Pacific regions, using TIMS records. It compares operational trends and presents case accounts of blowouts, fires, injuries, crane failures, collisions and pollution, including equipment behaviour, investigation findings and emergency responses. Appendices provide historical comparisons.
- 19986 May
Crew Change Communications
During tripping at crew change, shear rams were activated while personnel believed the tubing was clear. The rams cut the tubing, dropping 420 feet (128 metres) into the well. Concurrent work was taking place in the cellar. Fishing recovered the tubing, with two days of rig time lost.
- 19986 May
Drilling Breaks
A rig continued drilling after a drilling break, then suffered lightning damage to its pit-volume monitoring system and loss of one mud pump. A gas bubble entered the wellbore. Annular preventer damage and apparent upper-ram failure preceded successful closure of the lower rams and killing of the well.
- 1998
OCS Report 1998
This report compiles 1998 Outer Continental Shelf oil and gas incidents by region and event type, combining case narratives with graphical analysis. Pacific and Gulf of Mexico data cover well-control events, fires, collisions, fatalities, injuries and pollution. Cases examine equipment failures, work procedures and response measures, retaining uncertainty in reported causes.
- 1996
Calendar Year 1995-1996
Regional compilation of Outer Continental Shelf incidents reported for 1995–1996, combining case narratives with graphical summaries. It covers well-control events, collisions, explosions, fires, fatalities, injuries and pollution in the Gulf of Mexico and Pacific regions. Incident types within a single event are counted separately, and some investigations remained pending.
- 1994
CY 1991-1994 Addendum
This addendum records a fatal workover incident at well B-2 in South Marsh Island. Retrieving a back-pressure valve released trapped pressure and expelled well fluids and objects, killing one worker and injuring two. It identifies probable gas migration beneath the valve and describes pipe rams shutting in the well.
- 198623 Jan
Safety Alert 144 - Uncontrolled Shallow Gas Flow
A shallow gas flow during surface-hole drilling escalated when a diverter line parted and damaged the rig air supply. Loss of air pressure reopened annular preventers and prevented pipe-ram operation. The alert describes subsequent well control and modifications to diverter-line geometry and accumulator regulators with manual overrides.
- 198313 May
Safety Alert 111 - Blowout and Fire
A platform well blew out after a diverter valve failed to open, the separator line plugged with gumbo and parted, and the annular preventer failed. Personnel evacuated without injury. The alert recommends frequent diverter operation, protected controls, less restrictive diversion where plugging is likely, and planned drilling parameters in severe gumbo areas.
- 198130 Jun
Safety Alert 103 - Blowout
A Gulf of Mexico drilling blowout flowed through the drill string rather than the annulus. An inadvertently open fill-up valve and inaccessible lower kelly cock feature in the account; gas ignited and one fatality followed evacuation. The alert recommends immediate valve closure after pressure checks and accessible kelly positioning where possible.
- 19785 Sep
Safety Alert 73 - Gas Leak from Subsea BOP Stack While Circulating Out Kick
A semisubmersible rig was evacuated after gas escaped from its subsea BOP stack during kick circulation. A non-conforming ring gasket failed to seal, and escaping fluids damaged a hydraulic line, preventing BOP operation and riser release. The alert records the operator’s planned gasket quality controls and flange-standoff verification procedures.
- 197726 Sep
Safety Alert 66 - Blowouts from Surface Casing, Conductor Casing Annulus
This alert describes delayed shallow gas flows between conductor and surface casing after cementing, sometimes requiring abandonment or vessel relocation. It attributes the flows tentatively to reduced cement-column hydrostatic head and outlines logging, casing movement, slurry selection, returns monitoring and conditional retention of blowout-preventer capability.
- 19752 Jun
Safety Alert 24 - Shallow Gas Blowouts, One Rig Lost
This alert describes two shallow-gas blowouts on offshore drilling rigs: a jack-up capsized after evacuation, while a semi-submersible suffered riser-diverter damage and lost buoyancy. It records the operator’s planned changes to casing and liner placement, mud weights, bottom-hole assembly design, drilling surveillance and riser-diverter reliability.
- 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
Emergency Disconnect During Completion Operations Releases Zinc Bromide
BSEE investigates a weather-related emergency disconnect during completion operations aboard Noble Stanley Lafosse in the Gulf of Mexico. A misaligned thruster compromised station keeping, while the well suspension procedure remained incomplete. Zinc bromide discharge was revised to approximately 420 barrels. The report examines failed barrier tests and subsequent thruster correction.
- Undated
Casing Weld Failure During Well Abandonment
Investigation of a casing weld failure during well abandonment. Reverse circulation following bit plugging led to casing rupture at recently welded seams. The report examines pressure testing, unchanged pump safety-device settings, inadequate job safety analysis and unapproved welding in place of cold cutting. No injuries or environmental spills occurred.
- Undated
Annular Blowout Preventer Failure Released Control Fluid and Drilling Mud
Investigation of an annular blowout preventer failure that released control fluid and synthetic-base drilling mud to sea. The report examines debris damage, seal failure and deformation during troubleshooting, records ROV observations and well suspension, and discusses maintenance schedules, operating restrictions and potential control-system and component design changes.
- Undated
IBOP Actuator Plate Fell onto Rig Floor During Drilling
An investigation examines an IBOP actuator plate falling approximately 140 feet onto the rig floor during drilling in Walker Ridge block 469. Tight clearances allowed contact between plates and lever arms, shearing retaining bolts. Manufacturer-led corrective work involved grinding potential impact areas; BSEE notified other rigs using the same equipment.
- Undated
Unintended Emergency Disconnect Releases Completion Fluid During BOP Control Troubleshooting
An investigation examines an unintended emergency disconnect on ENSCO 8500 that released 849 barrels of calcium chloride completion fluid to sea. Troubleshooting live BOP control-panel wiring caused a relay voltage drop. Findings identify absent work authorisation, task risk assessment and procedures, alongside failures to communicate and follow an engineering bulletin.
- Undated
BOP Test Stump Fell Overboard During LMRP–BOP Connection Leak Testing
An investigation records a BOP test stump falling overboard during leak testing of the LMRP–BOP connection above the moon pool. Inadvertent activation released the stump. The report identifies unrecognised management-of-change needs and absent lockout/tagout, and records planned procedural changes. No damage or pollution resulted; the stump could not be recovered.
- Undated
Accidental BOP Wellhead Disconnect During Completion Operations
Investigation of an accidental BOP wellhead disconnect on Ocean Saratoga during completion operations. Crossed Yellow Pod hoses, deficient procedures and missed verification opportunities allowed the fault to remain undetected. The incident released calcium bromide completion fluid. Contractor directives address dual-pod testing, connector verification, competence and communications.
- Undated
Drill Pipe Accidentally Sheared While Setting Test Plug
Investigation of accidental drill-pipe shearing on H&P 203 while setting a test plug. A shear-ram contact switch was stuck closed, allowing the rams to fire when the operating button was pressed. The report identifies absent warning provision and records a subsequent control-logic change to flash an indicator for stuck switches.
- Undated
Gas Release Ejects Rotary Bushings During Storm Packer Retrieval
An investigation of gas released beneath a storm packer during workover retrieval describes fluid ejecting rotary bushings and causing minor foot bruising and swelling. It examines barrier testing, annular preventer closure and the possible contribution of missing detailed unseating procedures and an absent specialist tool man.
- Undated
Prolonged Well-Control Event Following Swabbing During Short Trip
Investigation of a prolonged well-control event following swabbing during a short trip. The report attributes liner-shoe breakdown to pressure from the influx and describes alternating influxes and lost returns. Repeated use of the Driller’s Method and annular-preventer containment are documented, alongside mud-supply delays caused by high seas.
- Undated
Well-Control Event During Rig Completion Operations
Investigation of a well-control event during completion operations on the Noble Lorris Bouzigard in the Gulf of Mexico. The report examines possible packer leakage, gas migration and omitted reverse circulation, without identifying a definitive cause. It discusses pressure-locked safety equipment, fluid monitoring difficulties, well-kill operations and recommendations for completion practice.
- Undated
Work String and Bottom Hole Assembly Ejected During Well Abandonment
Investigation of a well-control incident during abandonment work on 15 May 2012. Pressure below a cast iron bridge plug ejected the work string and bottom hole assembly, damaging equipment and a diesel tank. Blowout preventers sealed the wellbore; no injuries occurred. The report considers alternative plug-removal techniques and improved zonal isolation.
- 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
Technician’s Hand Trapped During Blowout Preventer Gripper Assembly Maintenance
BSEE investigates a serious hand injury during maintenance of a blowout preventer blue pod gripper assembly. A connector plate trapped a technician’s left hand against a landing sleeve. Findings identify improper hand placement, inadequate pre-job analysis, poor communication and procedural omissions; the technician required evacuation and surgery.
- Undated
Synthetic Oil-Based Mud Spill During Exploration Drilling
BSEE investigates a synthetic oil-based mud spill during exploration drilling at Garden Banks Block 427. Examination identified failure of the subsea blowout preventer’s upper variable bore ram bonnet-door cartridge seal. Possible contributing factors included accumulated debris, inadequate cleaning and flushing, and inadequate communication of a known seal-integrity risk.
- Undated
Pressurised BOP Fluid Release Injured Engineer During SPM Valve O-Ring Replacement
A subsea engineer on the West Auriga drillship suffered facial injuries when pressurised BOP fluid escaped during SPM valve O-ring replacement. The investigation identified residual pressure, a gauge stuck at zero, a leaking relief valve, closed isolation valves, inadequate assessment of the added task and awkward valve positioning.
- Undated
BOP Stack Disconnected and Fell During Marine Riser Running
Investigation of a BOP stack disconnecting during marine riser running on the Noble Clyde Boudreaux and falling approximately 1,400 feet to the seabed. The report identifies probable locking-circuit and wiring faults, discusses possible valve leakage and connector contamination, and records redundant locking measures and connector replacement.
- Undated
Synthetic-Based Mud Leak During Casing Pack-Off and Wellhead Connection Testing
The investigation documents a total loss of 20 barrels of synthetic-based mud during casing pack-off and wellhead connection testing. ROV observations and surface inspection identified leakage and washed seal areas. The report attributes the leak to a hydrate seal interfering with metal-to-metal sealing and records no recommendations for the regional safety office.
- Undated
Workstring Ejection During Tubing Cutting
Investigation of a workstring ejection during tubing cutting at VR 398 Well A002. Sand and wireline debris obstructed the DX plug’s equalising ports, while a leaking overshot packoff gave a false indication of pressure equalisation. Blowout preventer closure controlled the well; the report records equipment damage and recommends a safety alert.
- Undated
Pressure Burst Expels BOP and Lubricator During Wireline Plug Removal
Investigation of a wireline incident at VR-267-I platform during removal of a modified DX plug. Unequalised pressure and an unsuitable pulling tool preceded a pressure burst that expelled the BOP and lubricator. The operator suffered facial injuries while falling to escape. Findings address pressure testing, approved procedures, job safety analysis and stop-work practices.
- Undated
Hydraulic Fluid Discharge Following BOP Control-Computer Switch
An investigation records hydraulic-fluid pollution following a BOP control-computer switch that generated a spurious release signal and activated riser-tensioner valves. Venting went unnoticed for seven hours; 250 gallons entered the sea. The LMRP remained connected. Measures included temporary recoil-system isolation, proposed closed-loop recovery, software corrections and requested alarm-priority changes.
- Undated
Lower Annular Damaged During Surface Pressure Testing
An investigation examines damage to a lower annular during surface pressure testing. Its operating chamber, rated at 3,000 psi, reached at least 10,000 psi while the test pump ran unattended. Findings identify communication failures, testing the wrong chamber, inadequate risk assessment and failure to secure the pump before addressing the engineer.
- Undated
Finger Trapped by Bolt During BOP Installation
An investigation examines a finger fracture during BOP installation for well abandonment at ST. 26-D. While the crane lowered the assembly, a misaligned bolt moved upwards and trapped the worker’s finger. The report identifies hazardous hand placement and discusses slippery gloves and simultaneous alignment of twelve bolts as possible contributors.
- Undated
BOP Stack Fell to Seabed After Mistaken Emergency Disconnect Activation
An investigation examines mistaken emergency disconnect activation during BOP recovery on Diamond Ocean Blackhornet. The stack fell approximately 2,330 feet to the seabed, without injury or environmental impact. Findings discuss acronym confusion, informal testing and absent pre-job planning; operator plans address notifications, supervision and restrictions on testing with the BOP unlatched.
- Undated
Test Assembly Propelled Upwards During BOP Pressure Testing
An investigation examines equipment damage during BOP pressure testing on Nabors 17 at West Delta 73. A missing bull plug allowed pressure beneath a Greens cup tester to propel the test assembly upwards. Findings identify training, job safety analysis and instruction deficiencies, and unused stop-work authority. No injuries occurred.
- Undated
Synthetic-Base Mud Release from Subsea Blowout Preventer
This investigation examines synthetic-base mud pollution from a subsea blowout preventer following return from Hurricane Ike evacuation. Opening rams without pressure equalisation caused seal failure and washout. Pressure testing and ROV observation revealed the leak; the report describes discharged pollutant volume, seal upgrades and recovery of the stack for repairs.