1. National Academies Subsea Bolt Performance Workshop
Trent Fleece
BOP Operations Team Lead
11 April 2017

2. Foreword
The following slides were developed using material that is publicly available
connector-failures
The term bolt (bolting) is used generically to refer to all fasteners and connectors throughout this presentation
Note of distinction – there is a subsea blowout preventer stack (BOP) component called a connector. There are two connectors on a subsea BOP:
The top connector connects the lower marine riser package (LMRP) to the subsea BOP
The lower connector connects the BOP to the wellhead

3. Overview Context – BOP equipment overview
Review of historical bolting failure in Gulf of Mexico
NAS questions from March 22nd meeting in Houston
Failure mechanisms
Location of failure
Intergranular fractures
Environmental loads
General industry failure reporting
Industry response to bolting failures
Q&A

4. Acronyms API – American Petroleum Institute BOP – Blowout Preventer
BSR – Blind Shear Ram
DC – Drilling Contractor
EAC – Environmentally Assisted Cracking
GoM – Gulf of Mexico
HE – Hydrogen Embrittlement
HRC – Rockwell Hardness C
LMRP – Lower Marine Riser Package
NOLA – New Orleans
OEM – Original Equipment Manufacturer
Op – Operator/Lessee
RCA – Root Cause Analysis
RCFA – Root Cause Failure Analysis

5. Subsea BOP equipment Three BOP original equipment manufacturers (OEMs)
Left – LMRP – two Annulars and control pods
Right – lower BOP – seven cavity BOP

6. Subsea BOP equipment Left – ram BOP ‘double’ Right – ram BOP ‘triple’
Ambient Conditions at 6,000 ft WD ~2700 psi external pressure, ~ 37° f temperature

7. BOP equipment – blind shear ram
The purpose of the blind shear ram is to close and seal the wellbore
Has the ability to shear drill pipe/casing if across the BOP at time of closure
Loss of BOP integrity above the blind shear ram can be mitigated
Loss of BOP integrity below a blind shear ram has limited mitigation options
BOP stacks are tested to rated working pressure before deployment – typically 15,000 psi per Standard 53

8. Bolting failures in GoM and BSEE Safety Alert
May 2003: Riser bolt/insert failure
Jan 2010: API flange bolt failure – Inconel 718
Nov 2012: BSR bolt failure
Dec 2012: LMRP connector body bolt failure
Jul 2014: API flange bolt failure
Dec 2015: BSR bolt failure
Feb 2016: BSEE Safety Alert 318 issued to GoM operators
April, June 2016: API Bolting Workgroup meets with BSEE in NOLA and Houston
August 2016: BSEE support of API Bolting Workgroup action plan

9. Industry bolting failures
Operator DC
OEM
Component
Hardness
Coating
Mechanism a
Op 1
DC 1
OEM 1
Riser Insert
> 35 HRC
TSA/Zinc
EAC b
Op 2
DC 2
OEM 2
API Flange bolt
718 Inconel NA
Delta phase d
Op 3
Connector body bolt
Zinc e
DC 3
OEM 3
API Flange Bolt
Op 4
DC 4
Cylinder Bolt f
Op 5
BSR Bolt
MP35N
Ductile Overload
Although the term failure is used in the presentation material, it should be noted that on all the incidents there was no loss of primary containment – wellbore fluids were secured by the BOP. The term failure is related to the mechanical integrity of the bolts.

10. Perspective on industry bolting failures
Failures have occurred over a 15+ year time frame
Five different operators, four different drilling contractors, all three OEMs
Six distinct failure types – same component, same material has not failed in the same way
Some operators/drilling contractors who have been deepwater drilling for > 15 years are not known to have experienced a bolting failure
Historically, limited sharing of failure data (RCA) amongst other operators and drilling contractors – no formal mechanism to share data
Historical BOP standards:
Basic requirements for the bolts holding that equipment together

11. NAS questions from meeting in Houston
What is the failure mechanism?
Hydrogen embrittlement (environmentally assisted cracking), ductile overload, fatigue
Where are the failures occurring (i.e., first thread)?
Intergranular fractures?
Environmental loads on equipment?
Failure reporting?

12. a) Riser bolt/insert failure

13. d) Connector body bolt e) API flange
Above – LMRP connector body bolt failure
Left – 3” bolt - API flange failure

14. e) API flange failure

15. e) Banding, micro-hardness and thread root

16. e) EAC/HE Intergranular fracture
Areas of ductile overload on one of the bolts (right)
‘Mixed Mode’ failure (right)
Primarily intergranular (below)

17. Environmental loads
The bending loads observed during this example deployment campaign are within the component capacity of the API 18-3/4” flange for leak criteria up to 10ksi bore pressure as well as the connector and hence do not pose a structural integrity issue with respect to strength

18. Coordinated industry response to bolting failures
API multi-segment task group on bolting failures
28 industry SMEs
Report issued March 2016 with 20 recommendations
The focus was to take a holistic approach and look at all types of bolting failures that could occur in the upstream oil and gas industry, determine contributing factors, identify current mitigations, and recommend changes to industry standards.
API Bolting Workgroup
15 operators, 10 drilling contractors and all three OEMs
~75 individual members
Focus on short term and longer term actions to be implemented on existing equipment

19. API Bolting Workgroup The summary of actions taken by the workgroup:
Defined “critical bolting” as bolting that the failure of which could result in loss of containment of wellbore fluids to the environment
Voluntary industry adoption of API 20 E/F for critical BOP bolting
Voluntary industry upgrade of critical bolting with hardness > 35 HRC
Enhanced QAQC of third party manufactured bolting (i.e., sampling, API 20 E/F requirements)
Updated make-up procedures, with additional engineering rigor and oversight
Elimination of electroplated zinc coatings
Enhanced failure reporting with wider distribution
Consistent with the direction of API standards work
The workgroup submits a quarterly report to BSEE on the progress of each of the above items. Report has input from OEMs, Drilling Contractors and Operators.

20. Failure reporting
BOP Reliability Joint Industry Project reports BOP performance
Reporting for all BOP components (including bolts)
Beta tested in 2014, 1Q 2015 launch
29 participating companies (and growing)
> 2500 BOP component defects recorded in database so far
Working with BSEE for the database to meet regulated failure reporting requirements in the Gulf of Mexico
Objective of the database is to drive defect elimination and compliance with API Standard 53 reporting requirements
Gather high quality, industry-wide, statistically significant data to improve the industry’s approach to BOP maintenance and integrity management and to feed BOP performance data back to the manufacturers
Removed reference to IADC and IOGP so that the slide was not so wordy. Please add talking point that the BOP Reliability Joint Industry Project is supported by the International Association of Drilling Contractors (IADC) and the International Association of Oil and Gas Producers (IOGP)

21. RCA Ken will discuss industry RCA activities
The RCA process is believed to be robust, key findings from the four HE/EAC failures are very similar:
Reduce the hardness (< 35 HRC)
Ensure the stress values are as expected
There is a continuous improvement opportunity for the industry to share learnings more effectively on safety critical equipment
An example of industry collaborating in new ways is the latest blind shear ram bolt RCA
Three operators, three drilling contractors and an equipment manufacturer working together to identify the root cause and implement an improvement as soon as practical

22. Comprehensive bolt action plan
Industry action plan addresses the life of a bolt:
Design (OEM specifications, API specifications)
Material selection (Exotic materials may fail in exotic ways)
Manufacturing (API 20 E/F)
QAQC (API standards, API 20 E/F)
Coating (API 20 E 2nd edition)
Torque (OEM bulletins)
In service monitoring (API Standard 53)
Five year major inspection (API Standard 53)
Replacement bolts (end of life)
Reporting – definition of failure (BOP failure reporting)

23. Summary of coordinated industry actions
The intent of the API Workgroup is to address bolting failures by:
Promoting research related to improving Subsea BOP bolting performance
Improving standards related to bolts and subsea BOP equipment
Short and long term goals to continually improve the currently installed equipment on BOPs
Promoting failure reporting, RCA and shared learnings across the industry
Work with BSEE and NAS to communicate actions to address issues
Focus on elimination of defects on safety critical equipment that can safeguard personnel and protect the environment

24. Summary of industry actions
Update make-up engineering guidance
Perform torque at rig per procedure with additional oversight
Riser change – increased the length of the bolt, increased the width of the bolt
Hardness ≤ 34 HRC QAQC verifying material specifications API 20E manufacturing and testing requirements Riser change – lowered bolt hardness to HRC (from HRC)
Material Resistance
Stress
Environmental Cracking
Environment
Riser - what didn’t change – the cathodic protection scheme
The environmental loads
Investigate and minimize probable sources of environmental cracking
i.e. Hydrogen sources
Eliminate electrodeposited (Zinc) coating on bolting

25. Backup

26. API 20 E/F
API 20 E/F is an API specification with requirements for the qualification, production and documentation of carbon, alloy steel and corrosion resistant alloy (CRA) bolting used in the petroleum and natural gas industries
Key topics covered in API 20 E/F
Raw material requirements
Manufacturing controls (including forging, thread forming)
Heat treatment
Microstructure
Hardness (≤ 34 HRC)
Testing (NDE, dimensional, visual, sampling of heat lots)
Traceability
Licensed manufacturers
Per API 20E, the definition of bolting – Section 3.1.1:
All-thread studs, tap-end studs, double-ended studs, headed bolts, cap screws, screws, and nuts

28. Torque action plan
All three OEMs to issue Engineering Bulletin (EB) clarifying make-up procedure for BOP critical bolting. EB at a minimum will address the following:
Confirm latest revision of procedure to be utilized
Number of passes to final torque
Type of thread compound to be utilized
Make-up pattern clearly identified
Number of threads above the nut (where applicable, i.e.18.75” API Flange)
Calibration of torque wrench per OEM specification
Rig contractors to review OEM Engineering Bulletin and demonstrate compliance to operators, with focus on torque processes, torque values, and associated records and create a plan to address any gaps as soon as reasonably practicable
The intent is to have someone in a supervisory position removed from the job verify the crew performing the work is doing the work correctly (procedure, equipment, etc.)
Supervisory personnel examples – toolpusher, maintenance supervisor, offshore installation manager, subsea supervisor etc.

29. Cut/Paste – Riser RCA actions

30. Deepwater subsea field overview

31. EAC
EAC, which includes hydrogen embrittlement, requires three conditions to exist to lead to failure EAC may cause the material to fail at loads significantly below the rated strength of the material

32. > 35 HRC cracking resistance
Threshold stress intensity factor (Ki scc)