A process for producing methane, carbon dioxide, gaseous and liquid hydrocarbons, and other valuable products from subterranean carbon bearing formations, in-situ. The process utilizes indigenous and/or non-indigenous microbial consortia that are capable of converting a carbon-bearing material such as shale or coal to desired products. The process comprises injecting fluid into a carbon bearing deposit with at least one injection well and removing injected fluid and product from the deposit through at least one production well, and controlling fluid pressure within at least a portion of the deposit by use of the injected fluid, the pressure being controlled such that the fluid pressure within at least a portion of the deposit exceeds the fluid pressure that normally exists in that portion.