Wright’s Well Control Services (WWCS) completed a riserless subsea plug & abandonment (P&A) using tubing to pull out of the hole from a Multi-Service Vessel (MSV) in 1,250’ WD in the Gulf of Mexico. DOF Subsea USA provided marine and subsea services. New tools where custom engineered specifically for this project and successfully deployed.
One of the initial challenges addressed by the WWCS team was the one-of-a-kind tree found at the site with an annulus monitoring valve at a 35° angle. After finding no Remotely Operated Vehicle (ROV) tooling on the market offering the ability to nipple down and up on a subsea flange, WWCS designed and built a new torque tool. The new tool unbolted the flange and bolted in a new flange with a 2” hot stab.
The next step was to design and build a hydraulic connector that would allow WWCS to pull away from a section that might have issues while leaving a modified Tree Running Tool (TRT) subsea. This connector was designed to engage and disengage a subsea Blowout Preventer (BOP) and lubricator for additional barriers as needed without time consuming trips to the surface to add and remove the TRT.
WWCS also modified a Tubing Hanger Pulling Tool (THPT) to pull tubing with a crane subsea. The tubing was removed with a bull string on the deck of the MSV with a ROV for guidance as the segments where pulled out one at a time. One of the MSV’s moonpools was used to run the coil string and the umbilical while tubing and casing were pulled from a secondary moonpool.
Steps in the plug & abandonment procedure included: setting six (6) 16.4 ppg Class H neat cement plugs, setting three (3) Cast Iron Bridge Plugs (CIBP), cutting and pulling 37 joints of 3½” tubing, cutting and pulling 750′ of 9⅝” casing, cutting and pulling 13⅜” casing, cutting and pulling 20″ x 30″ casing with a mechanical cutter below mudline (bml), flushing a 6″ pipeline of 3890 barrels (bbls) of fluid with a modified 4” connector, recovering the umbilical tension assembly (UTA) and pipeline end manifold (PLEM), and setting a modified plumbers plug and submar mats on the lines.
“This project was a great success for everyone involved at Wright’s Well Control Services,” said WWCS president David Wright. “In 30 days we successfully executed a very challenging subsea P&A utilizing four new subsea tools including a jumper to flush the pipeline that we designed and built while on location. I’m proud of our crew and support staff. The techniques and tools deployed on this job may change how subsea P&As are conducted going forward.”
“It was great to work with WWCS on this innovative subsea P&A project,” said Brent Boyce, vice president of operations at DOF Subsea USA. “The new tooling designed to flange and re-flange the subsea annulus monitoring system interfaced perfectly with our ROVs. We were able to remove and reinstall the device even at 35 to 45° angle.”
Press Release, July 17, 2012