Rapid deployment of specialized response team quells difficult underwater blowout

Fig. 1. Due to the conflagration, the derrick collapsed and scattered debris across the platform.

A well drilled in South America was scheduled for workover to access and evaluate new hydrocarbon resources. The well was drilled in 1967, in a water depth of 90 ft, to a total depth of 5,571 ft. In first-quarter 2016, during a workover operation from a single-well platform, a blowout occurred with devastating consequences to the barge rig equipment and well platform, Fig. 1. Consequently, due to the conflagration, the derrick collapsed and scattered debris across the platform.

Experienced engineering team deployed. The crew safely abandoned the barge rig while the operator implemented the emergency response plan. The company contacted Boots & Coots for assistance with the well control incident. The well control team was mobilized rapidly to the location, to assess the situation and assist the operator on the response plan and operation. The Boots & Coots Services team has a variety of emergency response services ready to address the industry’s most challenging well control problems. The engineering specialists are on call 24/7 and responded immediately to assist with assessment and mobilization of personnel and equipment. The equipment is staged strategically at worldwide locations and can be readily deployed to most any country. The company can provide:

Prevention services. Contingency planning can prevent well control emergencies or lessen their effects. Boots & Coots offers a wide array of prevention services, from well control contingency plans to insurance through the Energy Risk Control program, to inspection services, etc. For dealing with well control emergencies, the firm builds on a wealth of knowledge among its team of engineers and can bring the collective experience to challenges ranging from well blowouts to relief well implementation.

Control of well insurance program. The Energy Risk Control program is a unique bundled package that includes a full range of Boots & Coots well control services, prevention services, and post-response services as part of the operator’s extra-expense insurance package.

Well control engineering. When drilling a relief well, accurate target well interception and successful well killing operations are highly challenging. Flawless execution depends on a combination of experience, technology, and other resources. The necessary critical tasks demand high levels of competency in engineering and project management. The company has the capabilities and access to a comprehensive range of Halliburton services to successfully manage a relief well project.

Well special services. Boots & Coots has extensive global experience in hot tapping, gate valve drilling and freeze job operations.

Subsea response. The company offers a unique suite of subsea response services including the first air mobile capping stack, containment systems, and physics-based modeling capability.

Fig. 2. A schematic of the damaged casing and tubing strings that collapsed over the well.

In South America, the team initially inspected and assessed the condition of the barge and well. Gas was flowing into the lake bed and then to the water surface, where it caught fire, Fig. 2.

Fig. 3. Debris from the vicinity of the well is recovered from the lake bed.

An underwater survey showed that the well platform, casing, and tubing strings had been bent and collapsed on the well, increasing operational challenges. Additional debris littered the lake bed surrounding the wellhead, which restricted access and the ability to clearly monitor the wellhead, Fig. 3. Furthermore, the turbulence from the gas flow through the debris disturbed silt and clay on the lake bed and obstructed visibility around the well.

Debris removal was performed with the help of divers, who were able to recover part of the collapsed casing during the operation. While monitoring the well condition and gas flow behavior, plans were updated periodically to mitigate risks and ensure overall operational safety. Fortunately, the flow from the well ceased during early stages of the debris cleanup operation, which reduced risks tremendously. Subsequently, all the debris from the vicinity of the well was removed safely and without incurring personnel injuries.

After removing the debris, a longitudinal crack was observed on the production casing at the base of the lake bed. At this point, the integrity of the production casing for any source control operation was highly questionable.

The well source control procedure required installing a capping stack on the well, so a decision was made to dredge sufficient depths of the lake bed to access competent production casing for the capping operation. A total of 18 ft of the lake bed was dredged with special turbine equipment, to uncover adequate length of competent production casing.

Fig. 4. A modified surface capping stack was lowered to contain the well.

Successful landing. The Boots & Coots engineering team designed a modified surface capping stack, based on the available 11-in. × 33-ft blowout preventer’s surface equipment, Fig. 4. The compromised section of the casing was cut to expose a satisfactory length of competent casing to accommodate the subsea capping operation. Well control specialists oversaw the capping operation and safely conducted the landing to secure the well. The operation successfully contained the well in 46 days, while incurring no safety incidents during the operation.