Control
Well-Barrier Testing
Tests verifying well-barrier containment and performance.
Documents
- 202631 Mar
Staged WOMP submission process
NOPSEMA describes its preferred phased submission of well operations management plans, separating lifecycle management processes from construction, production and abandonment detail. The paper explains concept-selection and detailed-design submissions, risk registers, barrier acceptance criteria, change management and regulatory inspections, while allowing titleholders to retain their existing submission structure.
- 2026Mar
Production PINCs
Numbered regulatory inspection questions address production safety systems, well barriers and casing-pressure diagnostics. Checks cover shutdown valve operation, gas and fire detection calibration, firewater pumps, pressure relief and protective devices on process equipment. Conditional approval requirements and specified testing intervals support inspection of production facilities and subsea components.
- 2026Jan
Decommissioning
A regulatory checklist for temporary and permanent well abandonment under Subpart Q. Questions cover prior approval, isolation of open-hole zones and perforated intervals, cement plugging, conditional pressure testing, plug integrity, residual fluid density and wellhead removal. It also checks installation of two independent wellbore barriers, including a mechanical barrier.
- 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.
- 201819 Sep
Well Integrity (Operate Phase)
Inspection guidance for assessing well integrity during operation through management-system document review and role-specific interviews. It examines barrier verification, annulus pressures, operating and load limits, maintenance, change management and end-of-life review. Optional risk-assessment scrutiny covers qualitative assessment, QRA and FMECA, while enforcement guidance links inspection findings to compliance scoring.
- 20171 Oct
Well Examination Scheme - Issue 4
Inspection guidance for assessing well operators’ examination schemes across the well life cycle. It addresses documentary assurance, examiner independence and competence, management of changes, barrier verification and interfaces with installation verification. Interview material and success criteria support consistent recording of findings, compliance scoring and regulatory intervention planning.
- 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.
- 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.
- 201217 Feb
Report - Montara investigation: Volume one
Volume one of an expert witness investigation into the Montara hydrocarbon release sets out the appointment, factual timeline and assessment framework. It examines well construction and suspension, cement isolation, barrier requirements, regulatory comparators and risk-management methods, introducing WAiT integrity assessment and documenting limitations in the supplied records.
- 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.
- 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.
- 200928 Jan
Safety Alert 275 - Wellhead Damage Caused by Hurricane
Following Hurricane Ike, damaged flanged wellhead connections leaked, and one subsurface safety valve initially failed to isolate downhole pressure. The alert examines hurricane loading and failed supports, and recommends visual inspection before restarting wells, followed by isolation, repair and wellhead pressure testing where excessive loading is suspected.
- 2008Nov
2008-054 Investigation of Loss of Well Control, South Pelto Block 10, Well No. 10, OCS-G02925, 14 February 2008, Gulf of Mexico off the Louisiana Coast..
Investigates natural-gas release during wireline scale removal and acid treatment at South Pelto Well No. 10. The panel identified ring-gasket corrosion, likely acceleration by acid treatment and an inoperable subsurface safety valve prolonging the event. It examines wellhead testing, integrity inspections and platform evacuation, recommending reviews of acid-operation policies and emergency plans.
- 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.
- 2008Oct
2008-053 Investigation of Blowout, Main Pass Block 91 Platform A, OCS-G14576, August 23, 2007, Gulf of Mexico, Off the Louisiana Coast.
Investigation of a gas blowout at Main Pass Block 91 Platform A, followed by platform subsidence. The report examines sustained casing pressure, poor cement quality, diagnostic testing and procedural communication failures. It describes unsuccessful kill attempts and relief-well abandonment, while leaving the precise casing-failure mechanism unresolved and recommending abandonment of remaining wells.
- 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.
- 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.
- 199617 Jun
Safety Alert 167 - Retrieval of Back-Pressure Valve Results in Loss of Well Control
A workover incident involving back-pressure valve retrieval released wellbore pressure, expelled fluids and blew rotary bushing inserts onto the drill floor, resulting in one fatality and two injuries. Inspection identified debris in the relief groove and a freely moving poppet. Recommendations address killing the well, equipment functionality, insert retention and checking for trapped pressure.
- 197915 Nov
Safety Alert 89 - Blowout and Fire, 8 Fatalities
An offshore drilling blowout released gas through the mud system after drillpipe and standpipe valves could not be closed. Ignition killed eight men and destroyed the rig. The alert records prolonged well-control efforts and the operator’s planned expansion of pressure testing across mud-system equipment and piping.
- 19776 Dec
Safety Alert 69 - Blowout, Platform Loss
An offshore development well suffered a gas blowout during attempts to kill a deep saltwater flow. Gas jetting formed a seabed crater, undermining the platform legs; personnel evacuated safely before it toppled. The alert reviews drilling warning signs and planned casing-integrity checks, cement evaluation, well-control training and reassessment following operational deviations.
- 19775 May
Safety Alert 64 - Uncontrolled Gas Flow
An offshore drilling alert describes uncontrolled well gas flow after a safety-valve grease fitting failed during well-killing operations. A combustible atmosphere prompted evacuation; the well bridged two days later without injuries, fire or pollution. The operator replaced valve grease fittings with solid plugs and pressure-tested the valves.
- Undated
Mixed-Fluid Release from a Subsea Well
BSEE investigates a mixed-fluid release from Shell’s PN003 subsea well at Mississippi Canyon 943. ROV diagnostics identified the leak, and valve closure and pressure testing restored two barriers. Tubing and control-line separation was suspected, pending recovery and analysis. The report records revised release estimates and planned tubing replacement.
- 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
Wellhead Releases Mud, Water and Cement During Annular Cement Squeezing
Investigation of a wellhead release during annular cement squeezing on Diamond Ocean Champion. A lock-down dog failed or became unscrewed, releasing mud, water and cement. The narrative describes evacuation and subsequent well securing, and records proposed wellhead checks, pressure testing and cementing measures. The attachment contradicts the narrative on evacuation.
- Undated
Synthetic Drilling Mud Pollution Following Casing Installation and Cementing
BSEE investigates synthetic drilling-mud pollution at the Tiber #3 well in Keathley Canyon. The report traces casing installation, cementing, pressure tests and severe mud losses, identifying breakdown at the 22-inch casing shoe as the probable cause. It discusses possible contributing mechanisms, enforcement findings and a proposed district-notification condition for extreme losses.
- 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
Loss of Position and Riser Damage During Hurricane
Investigation of Deepwater Asgard’s loss of position during Hurricane Zeta while connected to a well. Emergency disconnection succeeded, but the marine riser and lower marine riser package sustained damage, including seabed impacts. Findings address inaccurate forecasts, the decision to remain connected, delayed well securing and subsequent storm-preparation changes.
- Undated
Wellhead Gas Leaks During Production Restoration After Hurricane
Investigation of wellhead gas leaks during restoration of platform production after Hurricane Ike. Stretched flange studs compromised seals, while Well G-4’s SCSSV initially failed to seal. The report describes flaring, component replacement and testing, and recommends post-event inspections, isolation and wellhead pressure tests before reopening SCSSVs.
- Undated
Ejected Master Valve Stem Injures Contractor During Temporary Well Abandonment
Investigation of a manual master valve failure during temporary well abandonment at EI 252-G. An ejected valve stem struck a contractor’s hand, fracturing his thumb tip. Personnel were evacuated because well stability was unknown. Findings address a missing retainer nut, valve servicing, contractor oversight and management of change.
- Undated
Oil Release from Permanently Abandoned Subsea Well
Investigation of an oil release from a permanently abandoned subsea well in the Gulf of Mexico examines drilling, cement placement, plug verification and delayed well-control response. The specific cause remained unresolved because deeper plugs could not be reached. Findings identify possible contributing factors and propose research and regulatory changes.
- Undated
Engineered Safety and Environmental Aspects of Well Construction and Fracturing Design
Presentation on engineering well construction and hydraulic fracturing for pressure containment and groundwater protection. It covers casing and liner design, cement evaluation, treating-line ratings and testing, staged pump shutdowns, relief arrangements and wellhead valves. Surface planning addresses fluid storage, spill berms and logistics, alongside examples of fracturing-fluid ingredients.
- Undated
Equinor – Gullfaks C – investigation of fractures in coiled tubing
PSA investigates coiled-tubing fractures during well clean-out following hydraulic fracturing at Gullfaks C. The report identifies hydrogen-sulphide-induced sulphide stress cracking and examines chemical compatibility, planning and risk communication. It describes well securing through the blowout preventer, deck personnel exposure during waste treatment, and shortcomings in applying previous incident experience.
- Undated
Fact Sheet - Proposed vs. Final Arctic Rule
This fact sheet compares proposed and final requirements for Arctic exploratory drilling from mobile offshore drilling units. It explains alternative compliance standards for relief rigs and containment equipment, pre-positioned capping stacks, well protection, retained BOP testing intervals and real-time monitoring flexibility, alongside the rulemaking history.
- Undated
Health and Safety Regulatory Regime in the UK
HSE presentation explaining regulation of onshore oil and gas through well notification, independent examination, safety documentation, operational reporting and enforcement. It follows well integrity from design to abandonment, including cement barriers and verification methods, and outlines safeguards for hydraulic fracturing and protection against respirable crystalline silica exposure.
- Undated
Macondo Executive Summary
Executive summary of the Macondo investigation, examining failed well barriers, blowout preventer performance and temporary abandonment planning. It explains drillpipe buckling through effective compression and considers human factors, contractor interfaces and regulatory oversight. Recommendations address safety-critical elements, blowout prevention testing and further research into riser gas unloading.
- Undated
ND Regulations, Planning and Permissions
Presentation explaining hydraulic fracturing technology and North Dakota regulation across the well lifecycle. It examines water supply sustainability, geological confinement, well construction, chemical disclosure and flowback management. Specific measures include cemented casing strings, pressure testing, witnessed well plugging, restrictions on open-pit storage and permitted underground disposal.
- Undated
Neptune/Odfjell – Gjøa/Deepsea Yantai – investigation of well incident
Investigation of a parted drillstring at Gjøa examines stuck pipe, weaker continuous-circulation connections and multiple drill-pipe sections obstructing the blowout preventer. It analyses mud-weight constraints, missing torque information and deficiencies in change management and risk assessment. Barrier status remained uncertain until cementing secured the well 30 days after the incident.
- Undated
Statoil - Visund - Investigation of well-control incident
Investigation of a well kick during washing at Visund A examines liner-barrier verification, BOP configuration and jammed kelly cock valves that obstructed conventional well killing. Control was restored after the valves opened. Findings address maintenance, risk assessment and exercises; direct and underlying causes remained uncertain.