Fugro will supply four 200hp FCV 3000 work class ROV systems and innovative BOP tooling which will be installed onboard three mobile drilling units and one field support vessel.
Three ROV systems have been mobilised from Fugro’s Singapore base and are now operating in Moho Nord. Two of them are onboard ultra-deep water drill ships and will be working in water depths of approximately 1,200 metres. The fourth system will be installed on a semi-submersible vessel, which is under construction in China and expected to join operations with its ROV later this year.
A central task is subsea BOP intervention and testing, using an ROV equipped with a BOP skid specifically designed for this project by Fugro. Primary responsibility for controlling the BOP lies with the rig, but the ROV operated BOP skids are also used to operate the BOP in accordance with Total’s requirements. When a subsea BOP is installed, under Total’s test procedures various rams are operated and tested on a regular basis. The ROVs also routinely inject glycol into the BOP to prevent hydrate build-up.
“Moho Nord is the first major field in which rig BOP test closures have been carried out using Fugro’s new BOP skid system,” said Richard Mathieson, Fugro Subsea’s ROV services project manager. “This uses a special high-flow pump on the ROV to drive further pumps located on the BOP skid, allowing the transfer of large volumes of water-based fluid from the skid reservoirs into the rig’s BOP hydraulic rams when directed.”
Other ROV tasks include setting up regular fluid injection, drilling re-entry, bullseye checks and routine video monitoring, inspection, cleaning and intervention tasks on and around the BOP, as well as alignment control during manifold installation. The ROV on board the field support vessel recently installed transponder arrays on the seafloor to accurately position the drill ship at its drilling location.
Each operational drill ship carries three ROV personnel for 12-hour coverage, and this can be increased to six people and 24-hour coverage for certain operations such as BOP installation and recovery.
Fugro is expanding its existing Pointe Noire base to provide operational, maintenance and repair services and also training on FCV ROVs and tooling for expatriate and Congolese personnel.