Wireline Issue 45 - Summer 2019

“Shut-in wells, stranded reserves and of course maximising economic recovery are all very much plans for the coming decades.”

Helix Well Ops UK senior vice president David Carr

The approximately $500 million, semi-submersible vessel represents a strategic investment by Helix in the UKCS, where it will be deployed to address the specific challenges posed by maximising economic recovery (MER) and decommissioning cost reduction. Built at Sembcorp Marine’s Jurong yard, the vessel’s specifications also reflect a combination of the company’s experience from North Sea operations and riser-based operations in the US Gulf, as well as the topside efficiencies created for Brazil monohull vessels which allow for very fast changeovers between work modes. “For good measure, we built this semi- submersible on ship-shaped pontoons so that she can transit at 10 knots, allowing us to support seasonal work in West Africa as well,” Carr adds. Flexibility would seem to be the guiding principle of the Q7000’s development. Capable of working in depths from 80m up to 3,000m, the unit also features twin ROV support with heavy weather launch and recovery systems, a multi-palette skidding system on deck (which means no crane lifting is required to carry out routine operations) and DP3-class positioning, all of which open greater operational windows in terms of weather conditions and sea state. The ability to switch between coiled tubing and wireline quickly also reduces downtime between interventions, while a riserless openwater abandonment module (ROAM) will enable well decommissioning without the need for

a full-bore riser in many cases. Helix anticipates all these capabilities will equal greater cost savings and more value for UK operators. Carr points to a recent case study from the Gulf of Mexico, in which the Q7000’s sister vessel Q4000 completed a 13-well campaign for a large operator over a period of 135 days. In this project, Helix performed a wide array of MER and decommissioning work across seven fields, including three zonal isolations, two coiled tubing clean-outs, two chemical treatments, a milling operation, five stimulations and two abandonments. “Efficiency was added to this operation by ‘hopping’ the IRS well access package subsea, from well to well – a total of 41 miles,” he says. Helix acted as project manager for the operation – which necessitated 44 regulatory submissions – but resulted in over 40,000 barrels per day of additional incremental production achieved across the project, as well as 20,000 bpd of increased water injection capability. While beneficial, in this instance the usual metrics of efficiency and cost are secondary. Carr stresses that using a vessel like the Q4000 made these kinds of production-enhancement operations economical. “The work, and the increased production, would never have happened without this technology,” he notes. In that regard, they are expected to be a key asset as operators and the Oil and Gas Authority (OGA) seek to achieve MER.

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