Saturday, June 13, 2015

Investigation into the January 30, 2014 Loss of Well Control, Lease OCS-G 17921, Vermilion Block 356, Well A-007 Gulf of Mexico Region, Off the Louisiana Coast
















Investigation into the January 30, 2014 Loss of Well Control,
Lease OCS-G 17921, Vermilion Block 356, Well A-007
Gulf of Mexico Region,  Off the Louisiana Coast









On January 30, 2014, at approximately 8:30 a.m., the Rowan Louisiana crew, drilling for Energy Ventures, LLC,  had 13-3/8 inch conductor casing set at 1,217’ measured depth (MD) and 1,200’ true vertical depth (TVD) and had drilled the well to 2,217’MD/1,935’TVD.

The crew started a method known as a “short trip” where the drill pipe is moved in and out of the wellbore in order to gauge whether a hole is clean and/or the mud weight is sufficient.

When pulling the bottom hole assembly (BHA) into the casing shoe, the driller noticed a 30,000 (30K) pound over-pull followed by a 10 barrel (bbl) increase in the rig’s trip tank. 

The crew stopped the short trip, checked for flow (static), made up the top drive to the drill string, and began circulating fluid when the well started to flow resulting in a loss of well control. 

The driller responded by closing the rig’s diverter annular which automatically opened the diverter valve allowing water and gas out of both diverter lines and away from the rig.

The Offshore Installation Manager (OIM), in consultation with the company representative, ordered the adjacent platform shut in and all personnel evacuated from the rig.

The well flowed from the port side diverter line for approximately 36 hours until the flow was killed using a “dynamic kill procedure”.

The Bureau of Safety and Environmental Enforcement Gulf of Mexico Regional Director appointed an Investigation Panel for the purpose of determining the possible cause(s) of the Loss of Well Control, determining regulatory findings (if any), and to make recommendations (if appropriate) on how to strengthen implementation of existing Safety and Environmental Management Systems (SEMS).

The Panel reviewed requested documents, conducted interviews, and met several times to discuss all facts relevant to the incident.

The BSEE Investigation Panel determined that, during the short trip, the BHA was being pulled up through the 13-3/8 inch casing.

As the first stabilizer was pulled into the shoe, it got caught up in a clay build-up within the formation, or “Gumbo”, which caused a 30K pound over-pull and reduction in wellbore pressure due to a “swabbing effect”.

The driller tried to circulate the fluids but the reduced wellbore pressure allowed gas and water to flow up through the casing string to the surface. The Driller, following the pre-approved procedures, closed the diverter annular and opened the overboard diverter lines.

Conclusions

Cause of Loss of Well Control

The Investigation Panel has concluded that the immediate direct cause of the loss of well control was due to the following events:

I.            Drilling into a shallow gas, “high risk”, environment. Pursuant to geologic review as a part of the Application for Permit to Drill a New Well, there were indications of the existence of shallow gas at 1,309 feet and 2,069 feet TVD.

II.            While conducting a short trip operation within the “high risk” zone, the BHA was pulled into the shoe casing where it is believed a combination of clay and drilling mud had built up to form a “Gumbo Ball,”  which is supported by the 30K pounds of overpull during the two attempts to pull out of hole with positive mud returns.  This resulted in the lowering of bottom hole pressure below that of the formation pore pressure to a point where the well was capable of flowing, created by the “swabbing effect”.

Possible Contributing Cause of Loss of Well Control

In addition to the immediate cause, this Investigation Panel has identified the following possible contributing causes to the loss of well control incident:

1)                A Morning Report for the Rowan Louisiana recorded that on January 30, 2014 between 0630-hours to 0830-hours, the rig crew connected to the TDS and began Pumping at 500 gallons per minute after twice attempting to pull the BHA through the casing shoe with 30K pounds of overpull, and receiving returns totalling 11 bbls. It is the conclusion of the Investigation Panel that a possible contributing cause may have been the failure to have the TDS made up and circulation started prior to, and during the “short trip” operation.
Recommendations

The Investigation Panel submits the following recommendations for EnVen and Rowan Companies:

·         When conducting “short trip” operations with the knowledge of shallow gas zones, if and when the BHA is required to be pulled through the casing shoe, make up the TDS and start pumping prior to pulling into the shoe to eliminate the risk of swabbing. Also, consideration should be given to “pumping out” when pulling the BHA out of the hole.

·         Improve communications to ensure all relevant crewmembers are made aware of shallow gas hazards and any guidance to mitigate the hazards.

·         Limit drilling penetration rates, ROP, while drilling into zones with potential shallow gas to reduce build-up of cuttings and drilling mud, “Gumbo.”

Recommendations for BSEE

·         When reviewing Applications for Permit to Drill, the BSEE may consider requesting more detailed shallow hazard mitigation procedures for those applications that involve drilling into an area with previously known shallow hazard incidents.

·         The Investigation Panel recommends the BSEE Lake Charles District Office review the Panel Report in detail and considers any appropriate regulatory violation(s). If regulatory violation(s) are found, the District Office should issue an Incident of Non-Compliance(s) to EnVen or Rowan Company Inc. with any authorities supported by specific findings and bullet the individual items accordingly.
Safety and Environmental Management Systems

The Investigation Panel recommends EnVen and Rowan Companies consider the following relevant to their SEMS Program:

·         Hazard Analysis
Review and strengthen the levels of hazards analysis, hazard mitigation and JSAs that are developed and implemented for the specific drilling environment, shallow gas, operations with the existing or potential safety, health and environmental hazards associated with each step; and the recommended action(s) and/or procedure(s) that will eliminate or reduce these hazards, the risk of a workplace injury or illness, or environmental impacts.

·         Operating Procedure
Review and improve written drilling operation procedures that provide instructions for conducting safe and environmentally sound activities and work practices for identified hazards during operations and the degree of hazard present.

·         Safe Work Practices
Improve communications to ensure all relevant personnel involved in the specific drilling operations are made aware of any known potential hazards, such as the potential for drilling into shallow gas zones, and any guidance to mitigate the hazards.