Recoverable Resources

On a uniform calorific value basis, coal constitutes 69% of the total estimated recoverable resources of fossil fuel in the United States. Petroleum and natural gas are about 7% and oil in oil shale, which is not as of this writing used as a fuel, is about 23%. The 1989 total recoverable reserves of coal are about 500 times the 1989 aimual production (2), whereas the reserves of oil and gas are smaller, the production and consumption rate of oil and gas in the United States is three times that of coal. 

The following terms are often used in the context of quantifying reserves and resources of fossil fuels the Estimated Ultimate Recovery (EUR), also called Ultimate Recoverable Resources (URR), is the sum of past cumulative production, proved reserves at the time of estimation and the possibly recoverable fraction of undiscovered resources. The remaining potential, i.e., the sum of reserves and resources, is the total amount of an energy source that is still to be recovered. The mid-depletion point is the point of time when approximately 50% of the EUR (at field, country or world level) has been produced. 

Different estimates of the ultimately recoverable resources lead to different time windows for the mid-depletion point of oil. Estimates of the EUR at country level can differ, for instance, because of different boundaries between conventional and unconventional occurrences, and depend on assumptions about recovery factors,... 

The projected growth scenarios for conventional gas seem justified from the point of view of ultimately recoverable resources, and unlike for oil, no major discrepancies between projected demand and supply are to be expected in the coming decades. An important aspect of the future availability of natural gas, however, is the creation of the necessary infrastructure for the production and subsequent transport of the gas to the customer. The cumulative investments for the gas-supply infrastructure until 2030 are estimated to amount to US 3.9 trillion (IEA, 2006). 

When selecting a site for an injection well, it is crucial to understand the hydro-geological conditions to ensure any existing or potential fresh water supplies do not become contaminated. Potable aquifers are more likely to be found at shallower depths, while deep aquifers are more likely to be lower in quality and are less likely to be used as a water source (Mickley 2006). Siting injection wells away from areas known to by seismically active also helps to reduce the possibility of contaminating aquifers. The use of injection wells should also be avoided near recoverable resources like ores, coal, oil and gas (Mickley 2006). The selected receiving aquifer must be able to contain the volume of concentrate for the expected life of the plant (Chelme-Ayala et al. 2009). 

J. D. Parent. A Survey of the United States and Total World Production, Proves Reserves, and Remaining Recoverable Resources of Fossil Fuels and Uranium as of December 31,1977, Institute of Gas Technology, Chicago, March (1979). 

Coal is by far the world s most abundant fossil fuel, with a total recoverable resource of about 1000 billion (1012) tons. It is a complex mixture of many compounds that contain a high percentage of carbon and hydrogen, but many other elements are also present as impurities. The composition of coal varies considerably depending on its age and location. A typical bituminous coal has the approximate composition 80% C, 5% H, 8% O, 3% S, and 2% N. The manifold structures of coal are very complex and not clearly defined. 

FIGURE F-2 Annual production scenarios for the mean resource estimate showing sharp and rounded peaks, 1900-2125. Growth rate leading to either peak is 2 percent. Sharp peak occurs in 2037 followed by decline at reserve to production ratio of 10. Rounded peak occurs in 2030 followed by decline at 5 percent. U.S. volumes were added to the USGS (2000) foreign volumes estimate to obtain a world total of 3,000 billion barrels (mean value) of ultimately recoverable resources. SOURCE EIA (2000). 

Contractors under a contract for services, like employees, can be sned for breach of contract where they are shown not to have taken reasonable care in their dnties. In practice, however, because of their limited recoverable resources, it is far more likely that they will be dismissed. The position of contractors as independent for the purpose of prosecution for neghgence is complex. Independence implies that the contractor worked outside employer management and employer practice. This is rarely the case and contractors are treated by the law as employees. 

Resource Estimate of recoverable resource Resource base... 

This method is based on the usage of the resource each year, starting with an estimate of the amount of resource that can be removed (recovered) and its cost. Since it may be difficult to make an initial estimate of the amount of recoverable resource, the estimate can be revised at a later date. To use this method, a cost depletion factor, p for the year t is defined... 

Proved reserves—That portion of recoverable resources that is demonstrated by actual production or conclusive formation tests to be technically, economically, and legally producible under existing economic and operating conditions. 

Technically recoverable resources—The total amount of resources, discovered and undiscovered, thought to be recoverable with available technology, regardless of economics. 

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