The decline of production, increasing demand of fossil-fuel, increase in urbanization and industrialization, have triggered the search for production of gas from unconventional resources (i.e. shale Gas, tight gas and coal bed methane). The current imbalance in demand and supply of conventional hydrocarbon resources, if continues, without exploitation of unconventional resources, a time will come when these resources will be significantly depleted.
“Conventional gas resources are buoyancy-driven deposits, occurring as discrete accumulations in structural and/or stratigraphic traps, whereas unconventional gas resources are generally not buoyancy-driven accumulations. They are regionally pervasive accumulations, most commonly independent of structural and stratigraphic traps” (Law and Curtis, 2002).
Elsewhere, i.e. in the United States, production from unconventional sources has increased almost 65%, from 5.4 Tcf/year in 1998 to 8.9 Tcf/year in 2007 (Arthur et al., 2008) and unconventional production now accounts for as much as 46% of the total U.S. manufacture. Over the last decade, geologists, engineers and petro-physicists have to come to a common consensus with a need to better understand and predict reservoir properties in low-permeability reservoirs and use that information in resource evaluation, reservoir characterization and management.
Expansion of natural gas supplies to domestic consumers continued at a higher pace during 2012-13, and gas consumption in domestic sector increased by 13% compared to 2011-12 (Pakistan Energy Year Book, 2012). With the conventional resources unable to fulfil this need, there is an enormous volume of unconventional oil and gas available to fill this gap with the decline of conventional fossil fuel next 5 to 20 years.
Pakistan shale gas reserves are estimated to be about 51 trillion cubic feet and thus stands 9th in the world’s top ten countries which have technically recoverable shale gas deposits (US E.I.A, June 2013). With the development in the horizontal drilling techniques and hydraulic fracturing, the scope of the shale gas potential has increased and has become a reality.
Pakistan has more than 827,365 sq.km sedimentary basin area (611,307 sq. km Onshore and 216,058 sq.km Offshore), with thick sequences of shale formations (OGDCL 2013). The major sedimentary basin of Pakistan, i.e. the Indus Basin, which spreads over almost all provinces has so far given way to the maximum hydrocarbons discoveries and these areas need to be explored for unconventional resources like, Shale Gas.