Bouri Field Platforms, Libya: Review and Statistical Analysis of Cathodic Protection Inspection Data

Bouri Field is located in the Mediterranean Sea, about 120 km North West of Tripoli – in waters 160-170 m deep. The field includes the following main assets: drilling-production platforms (two); inter-field pipeline; sub-sea wells; FSO. The two platforms, launched in 1987 and 1988, are the biggest ones in the Mediterranean Sea. Submerged structures are protected against seawater corrosion by means of aluminium alloy galvanic anodes. The original design life of the cathodic protection system was 35 years; however the Bouri CP System Performance Study has indicated that the expected life span of the CP system can be extended by 15 years.

During the past operating life, a number of Underwater Inspection Campaigns have been carried out and a significant amount of data has been collected over a period of more than 20 years. These data, in particular structure potentials and anode consumptions, have been gathered and reviewed. The analysis included: follow up of the structure polarization; assessment of the actual protection current density demand; comparisons with the requirements of the international normative. Furthermore, a statistical analysis aimed at establishing the criteria for the optimization of future underwater inspections has been applied to the whole set of potential measurements data. The paper illustrates the main evidences from data review, the adopted statistical approach and results of the statistical analysis.