Blowout Contingency and Risk-Reduction Measures for High-Rate Subsea Gas Wells in Mexilhao

Lage, Antonio; Jacinto, Carlos; Martins, Francisco E.; Vanni, Guilherme Siqueira; Santos, Otto; Moreiras, Jose

doi:10.2118/99164

Cited by 7 publications

(1 citation statement)

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“…Continuous training and implementation of periodic simulated tests also play an important role in reducing the damage potentially caused by human error or complacency. Situation awareness of the rig operations crew needs to be maintained at a high level of awareness to ensure the highest possible safety standards are applied to all drilling operation [31,35].…”

Section: Wellbore Management and Human Resourcesmentioning

confidence: 99%

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

Ghorbani¹,

Researchers²,

Abdali³

et al. 2021

JCM

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Sustainability in petroleum wells drilling operation systems strongly depends on the use of sustainable materials and a set of technical and safety measures that lead to the survival and proper operation of drilling rig equipment's and personnel. Adherence to the highest levels of standards of tools, materials and methods, although always recommended as the most important option for advancing a safe drilling operation and completing the well efficiently, low risk and stable, but drilling operation is inherently a battle with underground challenges and unexpected dangers. Learning from past such well blowout events and the problems they pose to rapidly control is essential to reduce future impacts including injuries, damage and emissions. Such analysis offers guidance for adapting working practices to improve both prevention and emergency response to such incidents. The causes of blowout during drilling and the necessary technical and safety measures to adopt are reviewed, highlighting how best practices can prevent blowout incidents by improving responses to early warning signals. The particular risks associated with potential shallow gas blowouts are identified and described with the aid of a case study associated with a catastrophic blowout of an onshore well in Iran and the methods used to ultimately control it. The multiple causes of the incident relating to defects in safety systems, equipment and operating procedures are addressed. Lessons learned from the incident reveal the complexity of well control once a blowout incident has occurred and developed into a surface fire. from the stage of the incident to fire control. There is a need for further research into top-hole well kill techniques for wells in a blowout state, as drilling bottom-hole relief wells takes substantial time, during which much surface damage, resource loss and emission typically occurs.

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Section: Wellbore Management and Human Resourcesmentioning

confidence: 99%

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

Ghorbani¹,

Researchers²,

Abdali³

et al. 2021

JCM

View full text Add to dashboard Cite

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An integrated FMEA and MCDA based risk management approach to support life extension of subsea facilities in high-pressure–high-temperature (HPHT) conditions

Shafiee

Animah

2020

Journal of Marine Engineering & Technology

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Shallow Hazards Planning in Nigeria Deepwater—Erha-7 Well

2008

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The Erha-7 well is a deepwater exploration well that was ultimately drilled with a dynamically-positioned rig in 1,074 m water depth within Nigeria's Offshore Mining License (OML) 133 (formerly OPL-209). During the early well planning process, the site investigation team identified numerous, extensive shallow hazards stacked in the area surrounding the Erha-7 geologic targets. These hazards were evaluated by the drill team, site investigation team, and the business unit to optimize the well location and minimize the risk of encountering shallow gas-charged sands. The final well location allowed vertical drilling of the riserless conductor-hole interval and required directional drilling below the conductor to intersect vertically stacked geologic targets. Because of the close proximity to numerous shallow hazards and the limited seismic resolution, the final well location was still deemed to possess a moderate risk of encountering gas-charged shallow sands. This paper discusses the shallow hazards planning involved with the Erha-7 deepwater well. It summarizes the limited industry experience regarding deepwater shallow gas flows and the associated safety considerations. The paper presents the modeling and evaluation of shallow gas flows and dynamic kills used to quantify the potential benefits of drilling a pilot hole, and discusses the sensitivities associated with performing an effective dynamic kill. Finally, a discussion of the dynamic kill plans developed to prevent and effectively mitigate a shallow gas flow. Introduction The Erha field was discovered in 1999 in approximately 1,074 m of water in Nigeria's Offshore Mining License (OML) 133 (formerly OPL-209). The Erha-7 well was a near-field wildcat designed to test a prospective accumulation of hydrocarbons to the north of the main field. Fig. 1 shows the location of OML-133, the Erha field, and the location of the Erha-7 well. Fig. 2 is a bathymetry map of the Erha-7 area. Fig. 3 is a seafloor rendering of the area illustrating the seafloor channel complex. The drilling rig contracted for the Erha-7 well was the fifth generation dynamically positioned drillship Deepwater Discovery. Site investigation revealed numerous, high-amplitude seismic anomalies associated with three different stratigraphic intervals and depths below the mudline (BML). The anomalies are typical of those associated with confined and unconfined deepwater channel complexes. The Erha-7 well was positioned on the proximal margin of a large, sediment filled, confined-channel complex. The channel complex consisted of multiple stacked channels that had migrated laterally through time, making it difficult to find a location within reach of the Erha-7 reservoirs that would not penetrate potentially gas-charged shallow sands. The attenuation of seismic data below high amplitudes in the confined-channel complex and limited lateral resolution further complicated the task. Fig. 4 illustrates the potential shallow hazards surrounding the Erha-7 location, and Fig. 5 shows the summary of shallow hazards prepared by the site investigation team.

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Blowout Contingency and Risk-Reduction Measures for High-Rate Subsea Gas Wells in Mexilhao

Cited by 7 publications

References 0 publications

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

Petroleum Well Blowouts as a Threat to Drilling Operation and Wellbore Sustainability: Causes, Prevention, Safety and Emergency Response

An integrated FMEA and MCDA based risk management approach to support life extension of subsea facilities in high-pressure–high-temperature (HPHT) conditions

Shallow Hazards Planning in Nigeria Deepwater—Erha-7 Well

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