NEW Strategies for Finding Natural Gas

The idea that gas is formed by thermal cracking has been the foundation of exploration strategies for decades. It's based largely on pyrolysis simulation experiments that may have been flawed. They were carried out under oxic conditions that poison natural catalysts and thus block a second low-energy path to gas. Pyrolysis results change dramatically under anoxic conditions. Shales that generate nothing below 300oC under oxic conditions generate gas at 50oC under anoxic conditions. They generate five times more gas at 50oC than thermogenic gas at 350oC. It is catalytic gas generated by active transition metals that are deactivated under oxic conditions.

There are two paths to natural gas, a high-energy thermal path controlled by time and temperature, and a low-energy catalytic path controlled by rock activity and fluid flow. The idea that gas is generated primarily in high-maturity rocks is based on experimental conditions that may have no relevance to the natural process. A new model of gas formation is emerging that differs in almost all respects from older models. Low-temperature catalytic gas generation redefines the time-temperature dimensions of gas habitats, suggesting strategies for finding gas not previously recognized. New ways of extracting energy from carbonaceous deposits are also suggested. In situ gas generation stimulated by gas flow is one possibility currently receiving attention in our laboratory.