Comparative Economic Analysis of Offshore Platform Decommissioning Methods

Abstract

In this work, three basic approaches for removing offshore facilities-piece small, piece large and single lift methods were considered and applied to six different platforms (A, B, C, D, E and F) using data obtained from Proserv Offshore. The aim is to ascertain the decommissioning costs, salvage values and the onshore real value of each platform in the future when decommissioning will take place. The decommissioning cost for piece large obtained was used to generate piece small and single lift decommissioning costs exploiting analytical method/using relevant relations. The annual interest rate was derived from the data which was provided for 2010 and 2014 and the future decommissioning costs for each method was estimated for all the six platforms. The decommissioning costs (in million US dollars (M$)) for the six platforms A, B, C, D, E and F with respective weights 2012, 15128, 42100, 54660, 112392 and 130178 tons for piece small method are respectively 25.1, 164.5, 851.7, 1321.3, 5051.4 and 6196.5. The salvage values (in M$) for these platforms using the piece small method are 105.76, 217.87, 468.04, 570.64, 1099.47 and 1169.77 respectively while the onshore real values after decommissioning are 80.66, 53.37, -383.66, -750.66, -3951.93 and -5026.73. Results were also obtained for the other two methods. Comparing the results of the different methods it was observed that the most appropriate decommissioning option for Nigeria offshore is piece large with decommissioning cost, salvage Value and onshore real value of 16.7 M$, 100.2 M$ and 83.5 M$ respectively for platform A.