Tight gas
Tight gas is commonly used to refer to
In reality the term "tight" refers to reservoirs where wells are unable to be commercially exploited at current economic conditions in the absence of artificial stimulation or changes in well geometry. It is economic criteria (gas price, opex , capex, royalties and fiscal regime) which define this status and in many cases, as gas/oil prices rise then, projects that have been previously shelved become viable; improvements in technology or changes in available infrastructure may also rehabilitate otherwise stranded gas.
Tight gas reservoirs historically were generally defined as having less than 0.1 milli
Much tight gas was formed 248 million years ago in Paleozoic formations. Cementation and recrystallization changed a conventional gas reserve which reduced the permeability of the rock and natural gas was trapped within these rock formations. Horizontal and directional drilling is used to extract tight gas deposits as they run along the formation which in turn allows more natural gas to enter the well that was dug.
Numerous wells can be drilled to access the gas. Hydraulic fracturing is one of the main methods to access the gas which requires breaking apart the rocks in the formation by pumping fracking fluids in to the wells. This increases permeability and allows gas to flow easily, freeing it from the trap. After that deliquifaction is used to help in the extraction.
Rock with permeabilities as little as one
Examples
Some examples of tight gas reservoirs are:
- Muddy Sandstone/J Sandstone – Wattenberg Gas Field, Denver Basin, Colorado, US
- Mesaverde Group – Piceance Basin, Colorado, US
- Rotliegend – Germany and Netherlands[5]
- Utica – Appalachian Basin, US & Canada
See also
References
- ^ "Tight Gas – an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2021-04-25.
- ^ Ben E. Law and Charles W. Spencer, 1993, "Gas in tight reservoirs-an emerging major source of energy," in David G. Howell (ed.), The Future of Energy Gasses, US Geological Survey, Professional Paper 1570, pp. 233–252.
- ^ Ali Sharif, Tight gas resources in Western Australia, Western Australia Department of Mines and Petroleum, Sept. 2007.
- ^ McCoy, Mark; W. Neal Sams (2007). "Tight Gas Reservoir Simulation: Modeling Discrete Irregular Strata-Bound Fracture Networks and Network Flow, Including Dynamic Recharge from the Matrix" (PDF). National Energy Technology Laboratory. Retrieved 27 October 2011.
- ^ Alan Petzet, "Wintershall starts Dutch North Sea tight gas flow," Oil and Gas Journal, 6 Mar. 2012.