Helix Performance Profile

Q4000 Gulf of Mexico Well Intervention Project

o b j e c t i v e

In June 2012, Helix Energy Solutions Group, Inc.’s

U.S. well intervention subsidiary, Helix Well Ops,

Inc., performed well intervention services on two

subsea wells in the Garden Banks area of the Gulf of

Mexico, with no lost time incidents over the course

of the 20,000 man-hour project. All equipment was

deployed from Helix’s Q4000 semi-submersible to a

depth of 2,081 fsw.

s c o p e o f w o r k

The primary scope of work entailed a temporary well

abandonment operation using Well Ops’ Intervention

Riser System (IRS). This required latching the IRS onto

the well’s vertical tree with a dual string riser system,

connecting it to the surface flowhead, and establishing

a closed return system.

After function and pressure testing to 7,500 psi, the IRS was run and latched to the well,

facilitating multiple downhole intervention operations using slickline, electric line, and

coiled tubing based systems.

The secondary scope of work called for a choke replacement at an adjacent well that

produced back to the same host platform as the project’s primary target well.

Quick Stats

Operations: Temporary abandonment, choke change-out

Project duration: 18 days

Total downtime incurred: 0

Wells serviced: 2

Project notes: Primary and secondary scopes of work completed simultaneously

Q4000’s Intervention Riser System

The operations in the primary target well are summarized

as follows:

• Bull head kill well operations with 11.8 lb per gallon of brine

until 282 barrels were pumped to a final pressure of 1,840 psi.

The operations team then allowed pressures to stabilize and

surface pressure fell to 0 psi.

• Coiled tubing operations deployed into the well while pumping

brine through coiled tubing. Once on the reservoir bottom,

coiled tubing established its target injection rate and squeezed

cement job of production perforations.

• Mechanical plug run and set on slickline in production tubing

above squeezed cement. The mechanical plug was pressure

tested to 1,000 psi.

• Electric line was rigged up and used to punch tubing above

the production packer.

• Circulated out annulus fluid with water based mud to surface

and annulus fluid disposed of properly.

• Cement balanced plug was set in the tubing and annulus

above the packer, through the punched tubing and then

tested to 1,000 psi.

• Once plugs were in place tubing was cut at 17,005 ft

measured depth.

• IRS was brought to the surface allowing the production tree

to be recovered by 360 mT crane.

• Open water portion of the project included the Q4000 recovering

approximately 15,000 ft of production tubing of various sizes from

4.5 in to 6 in from the well and laid out in sections.

• Installed wear bushing for future work and set a bridge plug

and surface plugs to finish the well work.

• The Q4000 demobilized and the client performed a final site

survey before the vessel transited to the next job site.

h e l i x w e l l o p s q 4 0 0 0

Maximum Through Bore Diameter

• 73⁄8 in production bore• 21⁄16 in annulus line

Maximum Working Pressure (MWP)

• 10,000 psi

Maximum Working Depth (MWD)

• 10,000 ft (EH control)

Hydraulics Operating Pressure

• 2,500 psi operational (3,000 psi maximum)

• 160 gallons subsea accumulation

Weight • 120,000 lb (subsea package)

Well Barrier Type • 73⁄8 in hydraulic cutting gate valve (LCV)

• 2 x 73⁄8 in spring-assist fail-safe-closed gate valves (UCV & RTV)

• 3 x annular 21⁄16 in failsafe-closed gate valves

Maximum Through Bore diameter

• 73⁄8 in production• 51⁄8 in wings

Maximum Working Pressure (MWP)

• 10,000 psi

Hydraulics Operating Pressure

1,500 psi operational (3,000 psi maximum)

Hydraulics Operating Pressure

• 2,500 psi operational (3,000 psi maximum)

• 160 gallons subsea accumulation

Weight • Flow head in air is 22,000 lb

Well Barrier Type • 2 x 73⁄8 in hydraulic gate valve• 2 x 51⁄8 in spring-assist fail-safe-closed

gate valves

E Q U I P M E N T U T I L I Z E D Intervention Riser System

Surface Flowhead

C O N C L U S I O N

The project was completed in approximately 18 days, including offshore

mobilization and demobilization of all the equipment used. The Q4000

successfully carried out each of its tasks associated with the well and

operated with 100 percent efficiency, recording zero downtime for repairs

or maintenance. The project was also completed without a single first-aid

incident, injury or any instance of equipment damage. More than 38 safety

meetings contributed to the project’s perfect safety record and as a result,

the client issued a safety and environment incentive bonus for the project.

The scope of work for this project originally comprised of only one well;

however, the client approached Helix Well Ops during the well campaign

and identified a potential side project. Because the Q4000 is able to manage

simultaneous operations, hosts two work class Remotely Operated Vehicles

(ROVs) and has a 360 mT subsea crane that can be operated in place of its

600 mT Multipurpose Tower, simultaneous work could be conducted over

the side in open water.

Using the 360 mT crane and a Helix ROV, Well Ops performed a choke

change out on an adjacent well in the field which incurred very little critical

path time for the vessel and provided an immediate cost savings back to the

client as they were not required to mobilize a separate ROV Support Vessel

with a subsea crane to perform this project.

Hours Days

Total Time Spent on Wells 436 18.17

Total Time Operational 436 18.17

Total Downtime 0 0

Total Man Hours Worked On Project

20,256 —

Time Lost Due to Incident 0 0

Breakdown of Hours

Engineering Schematic of the Intervention Riser System

30.30 ft

12.9 ft at the bumper guards90º out of rotation for clarity

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