Page 56: of Offshore Engineer Magazine (Sep/Oct 2019)

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TECH FILES Plugs

Plugging the Cost and Complexity of

Environmental Barriers for P&A

By Cherish Bodman - Operations Coordinator, Coretrax on? dently setting an environmental barrier for installation are connected via two pipelines to the Markham plugging and abandonment (P&A) operations has J6A installation in the Dutch sector, approximately 5.6 kilo- traditionally been limited to mechanical bridge meters from the ST-1 installation.

Cplugs and in? atable devices. At a fraction of the On reaching the end of its economic life, ST-1 was put in cost of conventional tools, Coretrax, the wellbore clean-up warm suspension mode with all wells shut-in and disconnect- and abandonment specialist, is continuing to meet demand for ed from the platform pipework. In March 2018, P&A of the its CX-Enviroplugs as a safer, simpler and more cost-effective wells was performed by the Paragon B391 jack-up and com- alternative for big bore cement plug placement. pleted in around 100 days.

Originally designed to act as a simple base for cement, the Coretrax delivered bridge plugs for the permanent abandon- plug is particularly suited to wells requiring an environmental ment of the wells. In April 2018, a 13-3/8” CX-2 bridge plug barrier to prevent the leakage of oil-based mud. was run in well B2. As a permanent cast iron bridge plug, the

Available in sizes 18-5/8” to 20”, the three-? nned tool, which CX-2 is designed to set with a combination of hydraulic pres- allows self-centralization, now incorporates a compression set sure and mechanical pull and boasts a built-in setting mecha- elastomer element, enabling pressure testing of up to 1,000psi nism for greater ef? ciency. The slick OD and large ID of the to be achieved. The design is also able to pass through a small- released running tool minimizes cement disturbance when pull- er wellhead restriction. Manufactured from drillable materials, ing out of hole. This makes it ideal for cement plug operations.

the device also has a one-way valve and bypass ports across The bridge plug was made up and run in hole to a setting the plug to prevent surging when running in hole. depth of 232 meters and set by Spirit Energy personnel as per

With a patent pending, eight plugs have so far been run Coretrax procedures. It was then tagged with 10,000lbs and test- across Norwegian and UK P&A projects in the North Sea. ed to 500psi with a primary release seen upon return to surface.

The most recent was completed in the Southern North Sea As part of the batch environmental cap operations on both for Spirit Energy. B2 and B3 wells, the operator also deployed two CX-Enviro-

The ST-1 platform in the Greater Markham Area of the plugs for the ? rst time. Here, the disconnect sub was made up

Southern North Sea, for example, ceased gas production in to the drill pipe and the plug made up to the string and run in

April 2016. Discovered in 1984, the ? eld extends over license hole. The 13-3/8” casing stump was then tagged at 220 meters blocks 49/5a and 49/10b on the UKCS and license blocks J3b and weight set down to set the plug. A ball was dropped from and J6 on the Dutch continental shelf. Six wells and a single surface to activate the disconnect tool and pressure increased to 2,200psi. As per procedure, a pressure drop was then ob- served, the disconnect sub sheared, and the plug disconnected.

An open-ended stinger is left and cementing was carried out.

This resulted in well B2 being fully abandoned.

Using the CX-Enviroplug reduces the cost of big bore ce- ment bases by eliminating the need for bridge plugs or in? ates for the environmental cap. In the ST-1 campaign, Coretrax achieved a rig-time saving of approximately 48.7 hours.

Across the ST-1 project, the company also set 10 CX-2 bridge plugs and two CX-Super? ows. This is a fully sacri? - cial combination scraper and brush tool with patented features that can be run with bridge plugs and eliminates the need for a dedicated scraper trip prior to packer or plug setting. By combining scraper blades with a drillable brush it creates a robust and effective solution for the removal of residual ce- ment, scale, small perforation burrs and other foreign debris

Coretrax has been involved in the abandonment from the ID of the casing.

of nearly 20 wells for Spirit Energy.

Source: Coretrax 56 OFFSHORE ENGINEER OEDIGITAL.COM