Prognostics has the potential to be very valuable in many industries. This is especially the case in the petroleum industry where the costs of tool failure are extremely high and continue to increase. Previous attempts have been made to predict the remaining useful life of drilling tools. While the developed methods were shown to be able to accurately predict the remaining useful life, the data requirement was such that they had limited or no viability in "real world" operations. This paper builds on previous work in this area by developing a new life consumption estimation model that has been specifically designed to ensure that it can be viable in the "real world". The developed model was shown to be able to estimate the life consumed of an individual drilling tool to within 4-12% with uncertainties of ±15-35%