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Hoover Offshore Oil Pipeline System (HOOPS) GA-A244 Bypass and Wye Inspection
December 2017- MTS Houston Luncheon
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The Hoover Offshore Oil Pipeline System (HOOPS) is
a 153 mile common carrier pipeline system that runs
from the Western Gulf of Mexico to Quintana Terminal
- south of Freeport, Texas. It transports crude oil from
a number of offshore production facilities, including:
Shell Perdido, ExxonMobil Hoover-Diana, Anadarko
Gunnison, Boomvang and Nansen to Seaway’s
facilities at Jones Creek and Texas City.
HOOPS was installed in 1999; is operated by EM
Pipeline Company (EMPCo) and has capacity of
100,000 bpd.
The HOOPS system includes:
• Mid point pumping platform at GA-A244 that was
tied in to HOOPS in 2002
• 73 mile pipeline from Hoover/ Diana Platform
upstream of GA-A244
• 81 miles pipeline to Quintana Station downstream
of GA-A244 platform
• 96 mile Alpine Pipeline from Gunnison tied into
GA-A244
• 57 mile BANJO pipeline ties into Boomvanng and
Nansen at GA-A244
• 70 mile Perdido export pipeline ties into a
deepwater subsea tie-in near Hoover
HOOPS Background
Hoover - Diana
Perdido
Gunnison
Boomvang
Nansen
GA-A244
Quintana Station
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• Two pipeline dead legs exist near the GA-A244 platform
on the HOOPS pipeline. Dead Legs are sections of the
pipeline circuit that contain idle, stagnant or intermittently
flowing fluids. Since they are not in continuous services
they are particularly susceptible to corrosion and
degradation.
• The primary scope of work for this project was to
examine the pipe segments in the dead-leg zones for
internal wall loss that might have been caused by
microbial influenced corrosion (MIC), or any other local
internal corrosion mechanism.
• 12” bypass with isolation valve between upstream and
downstream segments
• 16” wye and valve on dead leg spool on upstream side of GA-
A244 platform.
• EMPCo risk assessment of bypass integrity assessed
dead legs as level II on risk matrix
• Concern on MIC exposure and deterioration of internal lining
• Bypass valve has not been opened in 15 years of operation
HOOPS Bypass Inspection - Background
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Objectives • Perform external inspection to determine
level of corrosion present in the subsea dead legs in vicinity of GA-A244
• EMPCo work with EMPC and EMDC for inspection execution guidance.
• Leverage intercompany knowledge with application of subsea in-situ external corrosion inspection technologies and review of inspection data
• Leverage intercompany experience in planning offshore operations to safely access, inspect, and restore the subsea dead leg areas
HOOPS Pipeline Bypass Inspection
GA-A244
Platform
Wye
Dead-leg
Bypass
Dead-leg
Key Activities • Selection of appropriate technologies and contractors for
in-situ corrosion inspection • Contractor Selection – Commercial – Procurement • Contractor, vessel, dive system and crane assurance
inspections • Subcontracting to develop a site-specific kit for the NDT
inspection, including mock-up SIT. • Mobilization of the Dive Support Vessel to GA-A244. • Uncovering each dead leg and preparing the pipe
sections for inspection. • Performing the NDT inspections. • Re-installing grout/sandbags and mattresses to support
and protect each dead leg.
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Site Preparation (1)
Purpose: Clear all cover / material from the areas around
the pipeline area, excavate clearance around dead legs,
and prepare for inspection.
Key Activities:
• Remove/ peel back concrete mattresses
• Break up/ excavate sand bags/ grout bags
• Dredge underneath dead legs
• Temporary supports or fixtures
High probability of concrete 3:1 bags and/or mattresses
placed beneath piping flanges & wishbone piggable wye
during installation.
Assume lifting points on mattresses and sand bags/grout
bags integrity has degraded over 12-15 years since
installation
Evaluate concerns to ROV operation over operating
pipeline with proximity to pipe versus controlled diver
operations. ROV only operation, including tooling, would
be estimated to take substantively longer and cost greater
than and combined ROV / Diving option.
Working areas
(notional)
10’
30’
10’
25’
Support may be required
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Bypass dead leg:
• Limited access around left side of dead leg for currently
available tools (less than 3”)
• Individual tool access requirements and dead zone at ends
limit the range of coverage of an individual tool (varies
between (1-2 -in up to 1”)
• Preference for ring shaped tools to map either in
circumferential or axial directions with automated UT
corrosion mapping with high density on bottom quadrant
• Geometry is made of straight sections with interaction
around tees and valve mid way
• Subsea ball valve has not been stroked in recent history
(10+ years), weigh chance for success
• Actuation of subsea valve by ROV requires modifications
Corrosion Inspection and Valve Check (2)
Wye Dead leg:
• Two different diameters (20”, 16”) with a concentric reducer
• Nearly all of wye branch is composed of long radius induction
bend, ruling out application of long linear UT mapping tools
• Individual tool access requirements and dead zone at ends
could limit inspection of some tools in area adjacent to wye,
reducer, and valve flange
• Few self crawling elements are able navigate long radius
bends
• Preference for UT corrosion mapping at high density of
measurements or multiple passes on bottom quadrant
Proposed
Inspection
area
Proposed
Inspection
area
Valve
Check
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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Planning Process
• Selection of appropriate technologies and contractors for in-situ corrosion
inspection
• Contractor Selection – Commercial – Procurement
• Contractor vetting, vessel, dive system and crane assurance
• Subcontracting of Sonomatic to develop a site-specific kit for the NDT
inspection, including mock-up SIT.
• Procedures development, risk assurance
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ExxonMobil Diving Expectations & GP
ExxonMobil USM Chapter 27 ExxonMobil GP 30-04-01
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Diving Industry Guidelines and Regulations
OGP Report No. 411
United States Coast
Guard
46 CFR Part 197,
Subpart B - "Commercial
Diving Operations."
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Sonomatic AUT Mock-up and SIT
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Sonomatic AUT Mock-up and SIT
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Sonomatic AUT Mock-up and SIT
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Dive Support Vessel Bibby Sapphire
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Bibby Sapphire Saturation System Audit
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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Diver Hands-on Tool training
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Diver Hands-on Tool training
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection
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GA-A244 EMPCo HOOPs Dead Leg Inspection Results
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GA-A244 EMPCo HOOPs Dead Leg Inspection Results Summary
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GA-A244 EMPCo HOOPs Dead Leg Inspection Safety Results
Contractor – Aqueos Subsea, Bibby Subsea
Sub- Contractor – Sonomatic Inspection
Project Duration - 7 days of Execution, 5 days Decompression
38 - Saturation Bell Lock-outs – 345 feet of seawater
220 - hours of Diver Bottom Time
11,652 - Project man hours
0 - Safety or Environmental Incidents
US GoM Diving Safety Work Group 43
The US GoM Diving Safety Workgroup is a US GoM focused, non-competitive and non-commercial group of oil and gas operators, transmission companies, commercial diving companies, supporting sub-contractors, organizations and industry stake holders. The group will provide a unified voice to promote and improve diving safety, through the following:
• identification and sharing of best practices • identify and seek solutions to industry challenges and
issues • review and comment of existing and proposed standards
and guidelines • provide input to the regulators and industry associations
US GoM Diving Safety Workgroup Vision Statement
US GoM Diving Safety Work Group
About the DSWG
History- Concept discussed in 2011 First DSWG General meeting held in February 2012 By-Laws adopted in May 2012 DSWG website rolled out in January 2013 2012 Membership – 33 General Members
24 Affiliate Members
2017 Membership – 55 General Members 66 Affiliate Members
US GoM Diving Safety Work Group
About the DSWG
Continual Interaction with Regulatory and Industry Groups • USCG (U.S. Coast Guard) • ADCI (Association of Diving Contractors International) • IMCA (International Marine Contractors Association) • IOGP (International Oil and Gas Producers) • OOC (Offshore Operators Committee) • API (American Petroleum Institute)
Recognized by these groups
Requested to comment on proposed rules, Recommended Practices, etc.
Representatives from some of these groups regularly attend our meetings
US GoM Diving Safety Work Group
About the DSWG
Accomplishments Through group comments and vetting, provided input
into future USCG Commercial Diving Regulations Provided comments to IMCA on document revisions Provided comments and influence related to Diver
Certification Acknowledgment through face to face meetings
Developed Guidance documents Provided an Industry Forum for Incident, Safety, and
Information Shares (over 300 Incident Shares to date)
US GoM Diving Safety Work Group
About the DSWG
Committees and Developed Documents Live boating Guidelines Underwater Burning Guidelines Underwater Lift-bag Guidelines Hyperbaric Evacuation System Planning Hand Jetting for Underwater Excavation Minimum Manning Levels Emergency Response and Procedures Company Representative Guidelines Recommended Emergency Drills
http://usgomdswg.com
LinkedIn Group
US GoM Diving Safety Work Group
US GoM Diving Safety Work Group – UW Burning Committee Work Group 48
