Natural gas hydrates are ice-like materials formed under low temperature and high pressure conditions. Natural gas hydrates consist of water molecules interconnected through hydrogen bonds which create an open structural lattice that has the ability to encage smaller hydrocarbons from natural gas or liquid hydrocarbons as guest molecules. Interest in natural gas hydrates as a potential energy resource has grown significantly in recent years as awareness of the volumes of recoverable gas becomes more focused (Sloan & Koh, 2008). The size of this resource has significant implications for worldwide energy supplies should it become technically and economically viable to produce. Although great efforts are being made, there are several unresolved challenges related to all parts in the process towards full scale hydrate reservoir exploitation. Some important issues are: 1) Localize, characterize, and evaluate resources, 2) technology for safe and economic production 3) safety and seafloor stability issues related to drilling and production. This chapter gives a brief introduction to natural gas hydrate and its physical properties. Some important characteristics of hydrate accumulations in nature are also discussed. Experimental results presented in this chapter emphasis recent work performed by the authors and others where we investigate the possibilities for producing natural gas from gas hydrate by CO2 replacement. By exposing the hydrate structure to a thermodynamically preferred hydrate former, CO2, it is shown that a spontaneous conversion from methane hydrate to CO2 hydrate occured. Several experiments have shown this conversion in which the large cavities of hydrates prefer occupation by CO2 (Lee et al., 2003; Jadhawar et al. 2005; Ota et al., 2005; Graue et al., 2008). This is also supported by simulations (Phale et al., 2006; Kvamme et al., 2007). Other production schemes proposed in the open literature are also reviewed in this chapter.