World reserves of natural gas are abundant and expected to increase up to 2050. World gas production is projected to more than double between 2000 and 2050. However, regional disparities in gas reserves and production costs are expected to modify the regional gas supply pattern in 2050: about half of the total gas production will originate from the CIS and the Middle East.<br />Important uncertainties remain on the EU27 gas demand and supply in the long term. For example, on one hand, the enlargement of the EU modifies the landscape. The question of the penetration of the natural gas in the energy balance is for a “new entrant” an important aspect of their energy policy. On the other hand, the liberalisation of the EU gas market may have important consequences on the strategies of gas producers like Russia.