Unconventional resource

Unconventional resources are oil or natural gas resources, that occur in geological formations requiring specialized extraction or production techniques to recover the hydrocarbon economically. For oil and gas, conventional deposits are porous and permeable underground rock formations with interconnected pore spaces that contain oil or natural gas. Generally, these resources are trapped in geological structures where extraction is not economically feasible using conventional methods. However, advances in extraction and production technologies can make these resources economically recoverable, allowing them to become viable fossil fuel reserves.

Unconventional resources are being developed increasingly as decades of oil and natural gas production have led to the depletion or maturation of many conventional resources. As a result, new technologies continue to be developed that allow for the more economical extraction of unconventional oil and natural gas resources that were previously uneconomical or technically difficult to recover. The development of these unconventional resources has significant economic potential, as a substantial portion of the world's oil and natural gas resources is estimated to occur in unconventional deposits.

Unconventional Oil

Unconventional oil is a type of petroleum that requires specialized extraction or production techniques beyond those used for conventional oil reservoirs. This type of oil is generally more costly and difficult to extract and refine and is often associated with greater environmentally impacts that conventional oil production. Many unconventional oils, particularly bitumen and extra-heavy oil, are denser than conventional crude oil and require additional processing and upgrading before they can be refined into usable fuels. Examples of unconventional oil includes shale oil, oil sands (natural bitumen deposits), and extra-heavy oil. Conventional oil fields contributed 97% of global oil output in 2000, but by 2024 this share had fallen to 77% because of the rising production from unconventional fields. Although it is more difficult and costly to extract unconventional oil, it is becoming more common as the demand for oil is increasing and more research is being done to see how unconventional oil can be made more simple and cost-effective to produce.

• Unconventional Oil Resources
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  Figure 1. Bitumen soaked sandstone.
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  Figure 2. Oil shale.

Unconventional Natural Gas

Unconventional natural gas is found in geological formations that require specialized extraction techniques for economical production. Unconventional natural gas includes tight gas (natural gas trapped in low-permeability rocks rock formations), shale gas (natural gas locked in shale formations), or coalbed methane (natural gas contained within coal seams). The extraction of unconventional natural gas can raise environmental concerns, particularly because hydraulic fracturing is commonly used to produce shale gas. Additionally, the management and disposal of water produced during coalbed methane extraction can present environmental challenges.