Estimating Reserves

Preliminary estimates of LNAPL made during the investigative phases of a project are usually based on the results of short-term pumping tests, approximations of actual LNAPL thickness based on gauging data generated from monitoring wells, and other approximate data. The numerical estimates based on this short-term information are often adequate to define the physical parameters sufficiently for prelim- 

Costs Involved With Site Investigation and Equipment and Energy and Labor and Maintenance, etc. 

FIGURE 11.3 Time-production rate vs. operational cost for a multiphased project. 

A simplified analysis of production decline curves was initially intended for evaluation of individual oil well production however, this type of analysis can also provide reasonable estimates when applied to multiple-well LNAPL recovery systems. This analytical method is applicable to most types of decline curves, whether they tend to follow exponential, hyperbolic, or harmonic forms. The following general differential equation is applicable to all forms of decline curves  

Specific equations that are all solutions for the general equation are presented in Table 11.2. Because each of these equations contains two unknowns, solution 

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An assessment of world potash resources (108) is shown in Table 15. Of the 67 x 10 t of total estimated reserves and resources in Canada, nearly 5 X 10 t is recoverable by conventional mining methods and the remainder by solution mining. As of 1974, Canada had about half of the known world reserves and about 90% of known world resources of potassium. 

Heavy cmde oil is widely distributed, and it is difficult to estimate reserves separate from normal cmde oil reserves or from tar sands deposits. Estimates of petroleum reserves frequendy include a large heavy oil component, which can only be produced at significantly higher cost than light oil. 

Canada, Cuba, and Russia have the largest economic reserves, whereas the United States has less than 0.1% of the world s estimated reserves. Russia produced about 25%, Canada 22%, and New Caledonia 12% of the world s nickel in 1992. The United States produced less than 1% of the world s nickel in the same year. The net import rehance of the United States as a percent of apparent consumption remained about 75% over the period 1987—1992. 

Table 12.1 Estimated reserves of phosphate rock (in gigatonnes of contained P)...

Tphe Middle East oil crisis increased natural gas needs, and dwindling gas reserves have intensified the need to use our huge coal reserves for the synthesis of gas, especially methane. Energy requirements will double in the next 10 years and triple before the turn of the century. Use of pipeline gas has been increasing by 6% per year, almost double the overall energy demand. The rate of gas discovery in the United States has not kept pace with use, and the estimated reserves of some 2,500 trillion cubic feet could easily be depleted in 25 years. Liquid natural gas is imported to ease shortages, but it is 5-10 times as expensive as natural gas. 

Abiotic Depletion. This takes account of depletion of all non-renewable resources. The impact is calculated as the sum of the resource used for each functional unit divided by the estimated reserves of that resource. 

The US Geological Survey (USGS) produces annual mineral commodity summaries, from which it is possible to crudely estimate reserve lifetimes (Figure 1.2). 

The Restigouche massive sulfide deposit is located in the northwestern part of the Bathurst Mining Camp (BMC), 60 km west of the city of Bathurst, northern New Brunswick. The property is currently controlled by Blue Note Mining and the company reports show that the deposit has an estimated reserve of 1.3 Mt grading 6.53% Zn, 5.05% Pb, and 99.6g/t Ag as of 2007 (Art Hamilton, Pers. Communication). 

In terms of the conventional or traditional sources, natural gas is found in areas close to exposed or buried mountain ranges. Major deposits of natural gas are found in inclined strata where the rock formations dip away from the crest of a buried hill or the ridge of a buried mountain. Some of the common types of formations in which natural gas is found are shown in Fig. I. Although natural gas and crude oil are frequently found together, the largest natural gas reserves (about 70% of the estimated reserves) are in deposits neither in contact with, nor dissolved in, oil. 

Fig. 2. Location of principal natural gas fields in the lower 48 of the United States. Alaska, not shown, ranks third in terms of holding estimated reserves. iBatelle Memorial Institute i...

Oil (also referred to as petroleum) is a complex liquid mixture of organic substances, principally of hydrocarbons containing five to sixteen carbon atoms. Most crude oil, once removed from a well, is sent by pipeline to a refinery, where it is distilled to separate it into gasoline, heating oil, diesel oil, and asphalt. The use of catalysts during the refining process increases the yield of gasoline. In 2001, 25.7 billion barrels of oil were used worldwide, with estimated reserves of 1.05 trillion barrels. (One barrel contains 159 liters.)... 

Zirconium comprises 0.016% (162 ppm) of the Earth s crast and, as a transition element, is only less abundant than Fe, Ti, and Mu. Hafnium is much less abundant at 2.8 ppm, but is stUl comparable in quantity to Cs and Br. The most important minerals of zirconium are zircon (ZrSi04), which is mostly mined in Australia, South Africa, the USA, and Sri Lanka, and baddeleyite (Z1O2), found mostly in Brazil. The estimated reserves exceed a billion tonnes. Australia and South Africa account for about 80% of zircon mining. All zirconium minerals are contaminated by small quantities of hafnium (0.5-2% of Zr content), but in a few (such as alvite, MSi04 XH2O, M = Hf, Zr, Th) the content of Hf is comparable with that of Zr. The above-mentioned similarities in the chemical behavior of these metals explain their close association in Nature and the similarity of their isolation procedures. 

The fundamental problem in increasing the supply of low sulfur domestic fossil fuels to meet demand is indicated in Table III. The cumulative consumption of fossil fuels, both in direct use (e.g., transportation and space heating) and for the generation of electricity during the period 1960-2000, is compared with known recoverable and total estimated domestic reserves. Only for coal are we safely within our known recoverable reserves. On the other hand, for natural gas essentially the total estimated reserves in the ground, irrespective of the economics of recovery, will be depleted. 

Today most oil producing areas have drilling and production regulations in place to put the development of oil fields and oil production on a more orderly and less wasteful basis. For instance, in British Columbia only one well may be drilled per 4 ha (10 acres). Regulations also limit the production rate per well based on a formula, which takes into account the unrestricted production rate for the well on initial testing, estimated reserves present in the particular oil field, and product properties. The regulated production rate of a particular well is controlled by installation of a choke, a plate with a hole of an appropriate size for the required production rate, or by appropriately adjusted valves installed at the wellhead. One estimate of an efficient production rate for a water drive reservoir is that the total annual production of all wells producing from the reservoir be not more than 3-5% of the estimated ultimate yield (not oil-in-place) of the reservoir [16]. 

Nevertheless the potential recoverable synthetic crude oil from the tar sands of this one locale is equivalent to about 95% of the estimated reserves in the Middle East. 

The Dong Pao Rare Earth mine covers a total area of 11 square miles, and has estimated reserves of 5 million tons (Fong Sam 2011). 

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