Sunday, November 23, 2014

DISCHARGE OF DRILLING MUD INTO THE GULF OF MEXICO FROM DEFECTIVE EQUIPMENT. LOWER MARINE RISER PACKAGE (LMRP) CONNECTOR FAILURE



discharge of drilling mud into the gulf of mexico from defective equipment.  Lower Marine Riser Package (LMRP) Connector Failure




There have been quite a few incidents where drilling mud has been discharged to the Gulf of Mexico from defective drilling equipment.  On January 24, 2013, BSEE personnel met with industry to discuss initial findings associated with a pollution incident involving the discharge of synthetic base mud (SBM) into the Gulf of Mexico (GOM) due to a loss of integrity of a LMRP H-4 connector.  During this meeting, a qualified third-party presented preliminary evidence that the stress corrosion cracking caused by hydrogen embrittlement was a contributor to the incident.  It was introduced that zinc electroplating without proper baking, as per ASTM B633, was a possible cause of hydrogen embrittlement.  During this meeting, BSEE was informed of two other rigs as having H-4 connector bolt failures.

On January 25, 2013, BSEE received information from the connector vendor which identified rigs as having blowout preventer (BOP) stack connectors that may contain bolts that may no longer be fit for purpose.  BSEE issued emails to the associated operators of the subset of rigs with current well operations in the Gulf of Mexico.  The content of the emails notified these operators of the initial findings and gave specific instructions on securing the current well operations in order to retrieve the LMRP and/or BOP to the surface, if not already on the surface.  These operators were directed to then suspend operations until the existing bolts on the LMRP connector/wellhead connector could be changed out with bolts that have been certified by an independent third-party to be in compliance with recommended heat treatment practices or the existing bolts have been examined and certified by an independent third-party that they are fit for purpose. 




In order to ensure all of these affected bolts are identified and proper corrective action is taken, BSEE recommends the following:

Operators are hereby urged to make an inventory of your contracted rigs [currently involved in well operations in the Gulf of Mexico Outer Continental Shelf (GOM) or planned to conduct well operations in the GOM] and investigate the bolts of the LMRP and Wellhead connectors.  For detailed instructions on identifying affected bolts please refer to the Safety Notice issued by GE Oil and Gas on January 25, 2013, titled, “H4 Connector Bolt Inspection Required(P/N H10004-2)” at the following: http://www.ge-energy.com/connector-update.jsp

If you have H-4 connectors, as identified in GE’s safety notice, and have verified through documentation that the connector contains any affected bolts, you should immediately notify BSEE. You should also consult with your contractors and subcontractors to determine the appropriate inspection, disposition and/or corrective actions. BSEE will require an independent third-party certification that confirms proper inspection and refurbishment processes were completed prior to reinstallation of any affected bolts.

Operators should review the QA/QC programs for all equipment vendors (contracted and sub-contracted) to ensure that all equipment is being manufactured to the required specifications. Special attention should be given to ensure proper heat treating has taken place in accordance with the specifications.







AUGUST 2014 – SUMMARY OF FINDINGS

On December 18, 2012, while the Transocean Discoverer India was performing drilling operations at the Keathley Canyon (KC) KC-736 lease block in the Gulf of Mexico, the rig’s lower marine riser package (LMRP) separated from the blowout preventer (BOP) stack resulting in the release of approximately 432 barrels of synthetic-based drilling fluids into the Gulf of Mexico. Chevron, the designated operator, reported to the Bureau of Safety and Environmental Enforcement (BSEE) that the incident was the result of the failure of H4 connector bolts manufactured by GE Oil and Gas (formerly Vetco-Gray), on the LMRP.

Based on the initial analysis of the failure performed by Transocean, Chevron, and GE, GE sent replacement bolts for all known H4 connectors to customers worldwide. After learning of the December 18th incident, BSEE worked with GE to ensure that the company replaced any faulty bolts that were in use in equipment deployed on the Outer Continental Shelf (OCS), in a timely manner. This process resulted in the replacement of more than 10,000 bolts over a relatively short time frame and short-term disruption of related deepwater activities.

Verification of the structural integrity of a critical component like H4 connector bolts, which are currently deployed on the OCS and globally, is essential for both worker safety and the protection of the environment. Accordingly, in January 2013, BSEE tasked the Quality Control-Failure Incident Team (QC-FIT) to evaluate the possibility of additional bolt failures and make recommendations to mitigate potential risks of future failures, either domestically or internationally. BSEE charged the team, comprised of BSEE engineers and other technical personnel, with evaluating the currently available information including: (1) the Chevron/Transocean/GE root-cause analysis, (2) GE ’s connection design, manufacturing, and quality control processes, and (3) other information related to the performance of this equipment. During its inquiry, the QC-FIT was made aware of other offshore oil and gas failures related to bolts, studs, inserts and connectors, appearing to share similar contributing factors. BSEE management requested the QC-FIT to evaluate whether the causes of these other failures were related and whether evidence existed of an industry-wide issue.

The QC-FIT conducted visits with drilling contractors, equipment manufacturers, and a classification society; contacted BSEE’s counterparts in the International Regulators’ Forum (IRF); met with three operators- BP, Shell, and Chevron in the Gulf of Mexico; reviewed reports of similar incidents of bolt and connector failures in subsea environments; and researched technical documents and standards. These activities provided significant information on the material properties used in subsea applications, corrosion behaviors, manufacturing processes and protective coatings of bolts in environments similar to those of this application.

This report is based on the review of available data and input from various sources and was reviewed by an independent technical consultant.



KEY FINDINGS

The failure of the GE H4 connector bolts was primarily caused by hydrogen induced stress corrosion cracking (SCC) due to hydrogen embrittlement, which led to the fracturing of the installed bolts. This finding is consistent with the conclusions of the Transocean/Chevron/GE root cause analysis.

A GE subcontractor relied on an older 1998 version of the American Society for Testing and Materials (ASTM) B633 standard and therefore, the bolts did not receive the required post electroplating treatment. This finding is consistent with the Transocean/Chevron/GE submitted root cause analysis report.

The GE quality management system (QMS) in place at the time, which met the industry standards and certification programs, qualified and audited only first-tier level suppliers (GE’s contractors) and not others in the supply chain. In this incident, since a third-tier level supplier (subcontractor) performed the electroplating coating of the bolts, GE’s QMS was unable to detect the issue. Neither Transocean nor Chevron in their management system assessment of contractor qualification, nor the programs that ensure the mechanical integrity of critical equipment detected this sub-tier supplier issue.

An inadequate coat of paint on the portion of the bolt heads was determined to be a potential contributory factor. The GE inspection procedures, in place at the time, did not adequately address this potential issue.

In 2003, a drilling riser bolt insert failure occurred in which the hardness of the inserts and cathodic protection systems were identified as areas of concern. Although the OEM and the Minerals Management Service (MMS) issued general cathodic protection guidelines in 2005 and several operators changed their internal specifications for the maximum hardness of bolts, there is no evidence of a successfully coordinated effort by industry to address the potential safety concerns associated with the issue. A more comprehensive incident and data sharing effort by industry over the past 10 years could possibly have flagged this issue earlier and resulted in the setting of consistent standards on the hardness of bolts/inserts or on the optimal applied voltage for cathodic protection on drillships.1

Existing industry standards do not adequately address bolting/connector performance in subsea marine applications. For example, although API Specification 16A provides requirements for BOP connectors, it does not contain material property requirements for the connection bolting used for subsea applications. Furthermore, other industry standards that apply to subsea equipment have different maximum hardness limit requirements for bolts.

OPEN ISSUES

Areas of inquiry where the QC-FIT was unable to make conclusive findings:

The QC-FIT noted that a number of incidents appeared to have occurred on Transocean owned rigs. The data set is too small to determine if this percentage is a statistical significant result that supports a conclusion that Transocean’s operating or maintenance practices may be increasing the likelihood of a failure. However, there are some potential factors that could have played a role in these failures. The QC-FIT noted that either the lack of adequate cathode protection or the use of dissimilar metals near the H4 bolts could have caused accelerated corrosion of the bolts. QC-FIT also concluded that the information and issues regarding cathodic protection, operation, and maintenance need to be explored further.



 It remains unclear whether the material selection plating requirements for service class (SC) SC2 bolts are appropriate for the marine environment when these bolts are used per ASTM B633. GE maintains that this material selection is appropriate. GE also contends that API thickness restrictions would make a coating thickness beyond a SC2 specified thickness untenable. Further assessment of the appropriateness of this plating material needs to be performed and clarified in future editions of ASTM B633 as needed. BSEE suggests developing a joint industry technical forum to evaluate these issues.



KEY RECOMMENDATIONS

The QC-FIT formulated recommendations that BSEE should take (detailed in the body of this report) to mitigate the likelihood of future failures that could impact safety and/or the environment. These are:

1. Improve industry standards.

 BSEE should encourage industry to develop a consistent set of standards for connections and connection fasteners used in all offshore subsea systems, including a requirement that allows tracking connection components during their service life. This should include clear and consistent guidance on material hardness, yield strength and ultimate tensile strength requirements. (The release of API Spec 20E; First Edition, August 2012 "Alloy and Carbon Steel Bolting for use in the Petroleum and Natural Gas Industries" should address some of the concerns regarding manufacture of bolts, studs, etc.)

BSEE should request that ASTM further revise its relevant standards to provide additional clarity related to the design and use of coatings for marine service.

BSEE should request that industry develop an improved quality management standard that addresses the use of subcontractors by manufacturers through multiple tiers in the manufacturing chain. The industry and BSEE should also review API RP75 (SEMS) and the BSEE SEMS regulation (Subpart S) to ensure that the sections on mechanical integrity and contractor qualification are sufficiently robust.

BSEE should request that industry issue guidance or a standard on the optimal applied voltage limits for cathodic protection systems for use on drillships/modus.



2. Initiate joint industry research initiatives. BSEE should facilitate, support, and encourage specific studies that compare and contrast the connection and connection fastener design, material, maintenance, and quality specifications to identify potential requirement gaps and inconsistencies across the industry. The impact of cathodic protection systems on the performance of connectors should also be evaluated.



3. Promote Failure Reporting. BSEE should encourage industry to adopt a failure reporting system that allows data on failures and potential failures involving critical equipment to be collected, analyzed, and reported to the industry and BSEE. This information will better allow the industry and BSEE to identify trends and take corrective action before any injuries or impact to the environment occurs.



4. Develop regulations that ensure specific design standards are met. If necessary, BSEE should develop proposed regulations and/or notices to lessees to implement improved standards for connections and connection fasteners and cathodic protection systems.

BSEE remains interested in GE’s and any others ongoing tests and may take further steps to address potential safety risks as indicated.