HOW IS SHALE GAS FORMED ?
There are two theories as to how natural gas is formed. The most widely accepted theory, the organic theory, maintains that natural gas formation begins with photosynthesis, where plants use energy from the sun to convert carbon dioxide and water into oxygen and carbohydrates. The remains of these plants and the animal forms that consume them are buried by sediment and as the sediment load increases, heat and pressure from burial converts the carbohydrates into hydrocarbons. Natural gas formation takes place in fine-grained, black, organic, shale source rocks. Continued pressure from burial forces most of the natural gas to migrate from the organic shales into more porous and permeable rock such as sandstone and limestone. The natural gas remaining in the shales is termed shale gas. The other theory of natural gas formation is the inorganic theory which speculates that hydrocarbons did not originate from buried plant and animal material, but instead were trapped inside the Earth as it
