The tangible element of exploratory wells is included under drilling, exploration and
other assets under construction pending determination of proved reserves. If an
exploratory well finds proved reserves, these costs are transferred to wells and surveys
under oil and gas properties. If the exploratory well does not find proved reserves the
costs are written off as abortive. Costs are considered abortive when they relate to wells, which are permanently abandoned due to the absence of commercially exploitable
reserves of crude oil or temporarily abandoned with no plans for re-entry in the
foreseeable future.