Definition - What does Tight Sands mean?
Tight Sands, also known as tight gas reservoir is a reservoir which contains gas that is very tightly packed in sandstone. Though natural gas is available in these reservoirs, extracting the gas out of them is a difficult task as these reservoirs are impermeable and non-porous and need heavy investment to develop them. Tight sands is sometimes also called tight sand gas reservoir.
Petropedia explains Tight Sands
Natural gas can be produced from two natural gas streams, i.e., conventional natural gas stream and unconventional natural gas stream. Conventional natural gas stream is relatively easy to find, develop, produce and low investment is required whereas in an unconventional natural gas more advanced technologies need to be used in order to extract natural gas out of the reservoir and thus, high investment cost.
Tight sands is one of the unconventional natural gas reservoirs that have low-permeable, non-porous and hard rock sandstone reservoir, in which gas is trapped in an extremely tight formation. This reservoir cannot produce economic flow rates or recover economic volume of natural gas unless the well is stimulated with advanced technologies such as horizontal drilling and hydraulic fracturing.
As per EIA, 310 tcf of recoverable natural gas finds exist in USA which can be extracted with the help of horizontal drilling and hydraulic fracturing. This is approximately 17% of the total recoverable gas in USA. Also in USA, about 25% of natural gas is produced from tight sands and other unconventional sources of gas.
Some of the other unconventional natural gas sources apart from tight sands are:
- Shale gas
- Coal bed methane (CBD)
- Geo pressurized zones
- Arctic and subsea hydrates