The volatility of the oil price has led to changes in the structure of the oil sector, encompassing both the oil companies and their various contractors. In particular there has been consolidation both horizontally and vertically in the traditional contracting supply chain. In recent years the continued pressures on costs has encouraged sharing of responsibilities between the oil companies and their various contractors in particular there has been consolidation both horizontal and vertically in traditional contracting supply chain. Crude oil behaves much as any other commodity with wide price swings in times of shortage or oversupply. The crude oil price cycle may extend over several years responding to changes in demand as well as OPEC and non-OPEC supply