Neil Greig, Sales Manager at Helix Well Ops, presented at the Offshore Well Intervention West Africa 2021 conference to showcase the Helix Q7000 DP Class 3 semisubmersible vessel which has continued to prove its capabilities across multiple campaigns in West Africa.
Greig noted that Helix has accrued a lot of experience with well access and has successfully entered more than 1500 wells globally. The company has an impressive fleet featuring the Q4000, Q5000, Siem Helix 1 and the Siem Helix 2 vessels all of which are capable of a wide variety of applications. It is through their practice with these vessels that Helix has been able to launch themselves effectively into campaigns in West Africa with the Q7000 (which has similar topside equipment to its siblings) and has achieved efficiency from the start.
Greig explained that the newest vessel was delivered as part of the Subsea Services Alliance between Helix and Schlumberger and so benefits from the expertise of both companies. By leveraging their combined knowledge, they have been able to reduce the crew size from wireline and slickline from 14 down to 8 and have reduced the coil tubing crew by 5. If an arbitrary figure of US$1000 per person per day is taken for crew cost this translates to savings of at least US$1mn per 100 day campaign. This is not too mention the cost savings of reduced crew changes, helicopter transfers and bed spaces etc.
The Q7000 is suited to deepwater applications down to 3,000 metres but is also designed to work in shallower water with an 80 metre range. The Intervention Riser System (IRS) on board enables access to both convention and horizontal subsea trees in depths down to 10,000 feet and is capable of applications including coiled tubing, electric line, slickline, cementing, well abandonment and tree change outs.
The story so far
Greig explained that so far the Q7000 has performed three campaigns with Exxon Mobil, Total and Chevron (all in Nigeria) and is currently in the field under contract from SNEPCo.
In the first project, the vessel successfully delivered a five well campaign with scopes of work including the acquisition of reservoir data, water shut offs / zonal isolations, hydrate milling / CT clean up, and remedial safety valve operations. This was performed some 65 miles from Nigeria in more than 1000 metre depths.
At certain points of the campaign instead of fully recovering the IRS it was lifted free of the well and then the vessel moved to the next location with the IRS held at depth, this reduced time for deployment recovery operation significantly.
The campaign had a number of challenging ‘firsts’ for Helix involving a Nigerian crew with a bran new system and an untried IRS. Greig was happy to report that all the personnel and equipment involved performed flawlessly and at a time when Covid-19 was disrupting travel.
The highlights of this project included:
• First deployment of the new IRS, which was left in the water for 70 days straight.
• Five wells in a single IRS deployment.
• Project executed in 25 days less than planned.
• 96.86% uptime (1,752 hours or 73 days).
• Four subsea well hops.
• Zero LTI, walk to work, no lifts across deck.
• First coiled tubing hydrate milling in Nigeria.
• Zero delays in mobilisation of tools and personnel.
For the second project early in 2021 Helix was tasked with performing work on five wells across two fields. The scope of work included TRSSSSV lockout and WRSSV install on three wells, acid stimulation on CT across screens and acid stimulation on CT across screens followed by well clean up (flaring). These were conducted in ultra deep water down to 1560 metres, 90 miles off the coast of Nigeria.
Once again all involved performed exceptionally well with highlights including:
• >98% uptime.
• Three subsea well hops.
• Zero LTI walk to work and no lifts across deck.
• First well clean up test on Q7000.
• Zero delays in mobilisation of tools and personnel.
• Improvements in vessel efficiencies.
Greig concluded, “The Q7000 is something between a rig and a light well intervention vessel. It can’t drill a new well, it is not sized for that, but it is sized for more efficient heavier intervention campaigns. With rigs, when they go into intervention mode you need to get the associated equipment brought on. The Q7000 achieves huge efficiency advantages by having the equipment already there and bunny hopping between wells also saves time and money. Additionally, being able to swap between services is also a real benefit.
“There is nothing specific I can share for work in the future involving this vessel, but ‘build it and they shall come’ mentality seems to be working. There is currently a huge appetite to go after oil and if you have an asset in the field to do that its going to make sense people will wan to use it. We are certainly seeing an increase in work and this is great for everyone involved.”
