Tight gas sands are defined as sandstone formations with less than 0.1 millidarcy permeability. The millidarcy is a unit of measurement related to the ability of a fluid to pass through a porous medium. The degree of permeability depends upon the size and shape of the pores, the size and shape of their interconnections, and the extent of the latter. It has been estimated that total-gas-in-place in the United States may exceed 15,000 trillion cubic feet. The size, location, and quality of the resource varies.
Tight gas sands are considered to be unconventional continuous reservoirs, as opposed to conventional discrete reservoirs that have provided the major part of oil and gas production since the first well was drilled by Col. Drake in Pennsylvania. Continuous reservoirs include not only tight gas sands, but coalbed methane, as well as the tight Devonian Shale reservoirs of the Appalachian and Illinois Basins. Where tight gas sands reservoirs differ from the other unconventional continuous reservoirs is in the nature of the rock, and its very low permeability, < 0.1 millidarcy.
The principals and associates of Austar Gas are pioneers in finding and developing tight gas in the Surat Basin. They also helped Sinopec in discovering tight gas in coal measures in the South Ordos Basin. Sinopec made breakthrough in tight gas production after adopting Austar Gas’s recommendations.