Installation of ROV-Friendly Cathodic Protection Retrofit Systems on Two Deepwater Subsea Developments

Two deepwater subsea production fields began producing in 1998 in the Ewing Bank Area of the Gulf of Mexico.  The fields contain a total of four (4) subsea wells with wet trees and flowlines back to a fixed platform.  Water depths range between 770 and 1,750 feet. During routine surveillance it was noted that some anodes on the well trees and flowlines had excessive depletion. Since the field was undergoing expansion it was decided to supplement the cathodic protection systems on all the assets to provide an additional 20 years life.  This paper describes the CP design and ROV-friendly methodologies used to install 19 anode arrays with 21 clamped tiebacks onto four flowlines and eight subsea components in 73 hours.  Details on initial system performance verification will also be presented.