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The Hidden World of Oil and Gas: Do you know the surprising differences between conventional and unconventional oil reservoirs?
When we talk about the sources of oil and natural gas, we usually think of underground oil fields and the classic sight of pumping them out through drilling technology. However, the world of oil and gas is not limited to traditional oil fields. In fact, there are huge differences between conventional and unconventional reservoirs, and these differences not only affect production technology, but also have far-reaching environmental and economic consequences.
Basic concepts of conventional oil and gas reservoirs
Conventional oil and gas reservoirs are naturally occurring, usually located at depths of about 4 to 5 kilometers below the earth's surface. Because of its lighter density than water, these oils and gases rise along the aquifer path through buoyancy and eventually flow to the surface. This process may result in some oil and gas reaching the surface through natural seepage, while the rest is sealed by geological barriers, forming pockets where various oil and gas accumulate.
In this case, when the oil and gas reservoir has sufficient permeability, we call it a conventional oil and gas reservoir.
The rise of unconventional oil and gas reservoirs
Unconventional oil and gas reservoirs have significantly different characteristics than conventional oil and gas reservoirs. These resources are generally limited by rock structure because the hydrocarbon phases are tightly bound by strong capillary forces, requiring special evaluation and extraction techniques. In order to achieve energy independence, the United States has turned to unconventional oil and gas resources that have long been known but were expensive to extract in the past, such as shale gas and coal bed methane.
Today's unconventional oil and gas reservoirs span North America and contain a wide variety of resources.
The difference between conventional and unconventional reservoirs
In conventional oil and gas reservoirs, the formation and accumulation of oil and gas are well understood. These oils and gases usually flow naturally to the wellbore due to buoyancy. Once in the wellbore, the oil and gas flow through the pipes to the surface due to pressure differences.
Conventional oil and gas reservoirs can be located and extracted using lower-cost technologies, while unconventional oil and gas reservoirs are widespread and cannot be stably predicted.
Technical and economic risks
There are significant differences in the technical and economic risks faced by the development of these two types of oil and gas reservoirs. The definition and evaluation of conventional oil and gas reservoirs are relatively simple. In contrast, the potential of most unconventional oil and gas reservoirs requires extensive drilling and testing to determine their economic reserves.
Environmental impact
Whether it is conventional or unconventional oil and gas, the issue of carbon dioxide emissions cannot be ignored. However, the carbon footprints of the two are significantly different. Conventional oil and gas uses the natural environment to push oil and gas to the surface, while unconventional oil and gas requires a large amount of energy to extract, which often requires large amounts of fresh water resources.
This artificial transfer of heat and pressure has unavoidable environmental impacts and can have a negative impact on local community infrastructure and economies.
Summary
As energy demand increases and environmental awareness increases, discussions about the operating model of the oil and gas industry and its impact on the environment are becoming increasingly important. Will the extraction of unconventional oil and gas become the main source of energy in the future? This makes us think about what the future direction of development will be?
