+ What are unconventional resources?
The main types of unconventional resources are tight oil and gas, coal bed methane (CBM), shale oil and gas, and gas hydrates. These resources area trapped in areas where the permeability of the surrounding rock is too low to permit standard drilling techniques. Existing technologies, such as hydraulic fracturing and horizontal drilling, have been further developed to access and recover these resources.
+ Shale Gas
Shale is a very fine-grained sedimentary rock, which is easily breakable into thin, parallel layers. These shales can contain natural gas, usually when two thick, black shale deposits ‘sandwich’ a thinner area of shale.
Geologists have long known about the existence of shale gas; “shows” of gas would sometimes be encountered when drilling through shales to reach oil reservoirs. The problem was how to recover this gas. The combination of two developed technologies, hydraulic fracturing and horizontal drilling, are the solution to reach previously unrecoverable resources.
+ Tight Natural Gas
Another form of unconventional natural gas is referred to as tight gas. This is gas that is stuck in an extraordinarily impermeable hard rock, making the underground formation “tight”. Tight gas can also be trapped in sandstone or limestone formations that are atypically impermeable or non-porous (also known as tight sand).
Several technologies exist which allow tight gas to be extracted, including hydraulic fracturing and acidizing. Both processes allow tight gas to flow more readily and at economic rates.
+ Coal bed Methane (CBM)
Coal bed methane is simply the methane found in coal deposits, usually seams which run underground. Unconventional production technologies, including hydraulic fracturing and horizontal drilling, may be used to recover and extract the gas.
+ Shale Oil
Shale oil is an unconventional resource obtained from oil shale, a similar fine-grained sedimentary rock to those containing shale gases. However shale oil has the property of carrying kerogen, a waxy organic substance requiring special processes to flow and be produced. Kerogen is one of the oldest sources of mineral oil and can be refined to create a variety of products.