The Role of Fracking in Shale Gas DevelopmentTue, 01/22/2013 - 12:00
Even though shale gas was discovered a long time ago, it was not developed commercially until recently because the necessary technologies were not available. The main solutions that allow for the commercial development of shale gas include: seismic data acquisition, processing and analysis, core analysis, and petrophysical measurement collectively lead to better reservoir understanding; new drilling technologies reduce the time to reach total drilling depth; horizontal wells maximize the contact with the reservoir during drilling and completions; hydraulic fracking releases hydrocarbons for extraction; and improved reservoir management tools to optimize production management.
Gas in shale is stored in three ways – free gas stored within natural fractures, free gas within the rock pores, and adsorbed gas on organic material – which aects the speed and e·ciency of shale gas production, and the hydraulic fracking approach required to optimize production. Since shale gas reservoirs have low permeability, reservoir pressure declines before production is stabilized. Experience in US basins indicates that production levels in shale gas wells typically decline by 65-80% in the first year. To reach viable production rates, shale rock must be hydraulically fractured or fracked. Through multi-stage fracturing and horizontal wells an artificial reservoir is created, and by fracturing wells eectively, higher production and recovery rates can be achieved. Therefore, eective reservoir characterization is essential to optimize production based on a better identification of its properties, including the producing interval and the flow channels inside the fractures.
“In order to correctly deploy fracking solutions, a deep understanding of the geology of the region is required,” explains the Director of the IMP, Vinicio Suro Pérez, “which includes an assessment of the permeability and porosity of the region in order to not only select the best drilling site, but to also understand the thickness of the shale formation. Once the geological information is obtained and the well location identified, a vertical well is drilled followed by a horizontal well, where frack plugs are located to introduce the liquid and initiate the fracking process.”
Most of Mexico’s regions where shale gas is located – north, northeast, and Gulf coast – are facing water scarcity, which complicates shale gas production since the fracking of shale gas wells requires large volumes of water. In addition to further depleting the already limited clean water reserves in these regions, the use of water for fracking could potentially aect the quality of drinking water, since any leak into water aquifers has the potential to damage Mexican drinking water reserves. This makes it crucial to adequately address the water issue during the essential fracking of shale oil and gas wells.