The objective of this project is the evaluation and minimization of risks associated with use of Compliant Vertical Access Riser (CVAR) solutions and the comparison of those risks with those of existing dry tree riser and FPS solutions.
This study has shown that the Compliant Vertical Access Riser (CVAR) design concept is a feasible Direct Vertical Access (DVA) and dry tree solution for oil & gas production from the fields in deepwater and ultra-deepwater in the Gulf of Mexico (GOM) and other regions. Feasibility of designing a Tubing CVAR has been shown for a semi-submersible production vessel in 8,000 ft water depth in the GOM, a Tubing CVAR design with a mudline split tree, and wells offset from the platform.
In general the risks associated with well operations (completion, workover) were found to be similar to the industry experience with existing installations, except for the increased wear potential in case of the CVAR design due to its S-shape configuration in the transition region, which would require development of a wear management program. Wear liners or wear bushings have been used to manage wear in the past in drilling risers. The offset of wells in case of the CVAR provides an alternative to doing such operations from a MODU, which would reduce risks associated with the CVAR design.