The expansion of “non conventional” production of natural gas (tight gas, gas shale and coal bed methane). A silent revolution

New and advanced exploration, well drilling and completion technologies, like hydraulic fracturing and horizontal drilling, are allowing increasingly better access to non - conventional gas resources at competitive prices, and may have a big impact in global gas markets. This paper presents a review of the state of art and recent developments of unconventional gas production (tight gas, shale gas and coal bed methane): technology, pioneers projects and bigger unconventional fields (like Barnett Shale), actual production, costs trends and potential reserves. At present, most unconventional gas production is located in the U.S. and Canada, while these resources remain underexploited outside North America. The rapid development of unconventional gas resources, particularly in the last three years, has transformed the gas market in North America. In total, unconventional gas resources could add a 60–250% to world gas reserves. The extent to which the boom in U.S. unconventional gas production can spread to other countries remains highly uncertain.