Estimated ultimate recovery

Having defined some of the statistical rules, we can refer back to our example of estimating ultimate recovery (UR) for an oil field development. Recall that... 

It is well known that reseive estimates made early in the development of a field are often wi ong and that there s a 50 percent change in estimated ultimate recovery in many fields during the first ten years. In addition, the average field lifetime has been a decade longer than initially expected in the North Sea. If you believe in reserve growth, you would conclude that there will not be a petroleum crisis anytime soon. If, on the other hand, you believe that reserves have been overstated and you make negative revisions to reserve estimates, there rvill be a crisis soon. Current known petroleum reserves (proved + P50 probable) in the world are 1.44 trillion barrels of oil, 5,845 trillion cubic feet of gas, and 80 billion barrels of natural... 

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. 

EROEI ETBE ETS EU EUCAR EUR Energy returned on energy invested Ethyl tertiary butyl ether Emission trading scheme European Union European Council for Automotive Research and Development Estimated ultimate recovery... 

Estimated ultimate recovery is also reported by type of entrapment, of which there are two major types (1) Structural trap—an entrapment in which migration of hydrocarbons in the reservoir rock has terminated... 

The estimated ultimate recovery is also reported by the geologic age of the reservoir. It is recognized that problems may arise where the geologic age of a reservoir cannot be determined specifically, such as Permo-Pennsylvanian and Cambro-Ordovician, or where production from reservoirs of different geologic age is combined. 

Estimated ultimate recovery ( UK) is not a resource category as such, but a term which may be applied to an individual accumulation of any status or maturity (discovered or undiscovered). Estimated ultimate recovery is defined as those quantities of petroleum which are estimated, on a given date, to be potentially recoverable from an accumulation, plus those quantities already produced from there. 

The parameters which are included in the estimation of STOMP, GIIP and ultimate recovery, and the controlling factors are shown in the following table. 

In determining an estimate of reserves for an accumulation, all of the above parameters will be used. When constructing an expectation curve for STOIIP, GIIP, or ultimate recovery, a range of values for each input parameter should be used, as discussed in Section 6.2. In determining an appraisal plan, it is necessary to determine which of the parameters contributes most to the uncertainty in STOIIP, GIIP, or UR. 

When estimating the recovery factor, it is important to remember that a range of estimates should be provided as input to the calculation of ultimate recovery, to reflect the uncertainty in the value. 

The ultimate amount of U.S. oil that can be recovered by "implemented technology," technology that presently exists in at least the proven field test stage, is estimated to be 14.5 billion barrels. Using "advanced technology," technology that might be conceivably developed before 2013, adds another 13 billion barrels of oil to the estimate, for a total of 27.5 billion barrels. A comparison of the distribution of ultimate recoveries by method is also shown. 

The fraction of oil-in-place recoverable from conventional petroleum reservoirs varies greatly with the reservoir type, oil viscosity, formation pressure, production rate, and finesse employed. The positive displacement aspect of water drive reservoirs generally gives them the highest ultimate petroleum recoveries, up to 70% of the oil-in-place [14]. Estimates of ultimate recoveries possible from gas cap drive and dissolved gas drive types of reservoirs are usually much lower, 25-50% for the former and 10-30% for the latter. Recovery from gravity drainage reservoirs will be at the lower end of the ranges of the two gas drive reservoir types. 

To estimate ultimate oil recovery, we have to extrapolate the production rate to an economic cutoff at which the production wells are shut-in. In water-flooding and chemical flooding, the economic cutoff is generally 98% water cut. The ultimate oil recovery will be the cumulative oil production by the cutoff. 

As an illustration, a study of the Dollarhide field in west Texas is briefly described. The field has two productive zones separated by a limestone barrier. The lower zone contained approximately 75 % of the OOIP. The field is divided into three fault blocks. OOIP was estimated to be about 138 X10 bbl. The field was developed on 40-acre spacing. Recovery was initially by primary production and then by waterflood, which was quite successful. Ultimate recovery by a combination of primary and secondary production was estimated to be 43.1% OOIP. 

Secondary Recovery. Metal returning from the store of metal in use is referred to as old scrap, in contrast with scrap generated within the copper fabrication process, which is called new scrap (see Recycling). In 1990 the amount of the U.S. copper supply derived from old scrap was 24% of the total copper consumed. About 40% of old scrap is used for producing refined copper most of the remainder is used in the production of brass and bronze ingots (see Copper alloys). About 75% of new scrap is consumed by brass mills, with most of the remainder used in the production of refined copper. Some estimates suggest that as much as 60% of the copper produced is ultimately recycled for reuse. Old scrap combined with new scrap from fabricating plants accounts for about 40% of the metallic input to domestic copper furnaces. 

The definitions above are an abbreviated version of those used in a veiy complex and financially significant exercise with the ultimate goal of estimating resei ves and generating production forecasts in the petroleum industry. Deterministic estimates are derived largely from pore volume calculations to determine volumes of either oil nr gas in-place (OIP, GIP). This volume when multiplied by a recovery factor gives a recoverable quantity of oil or natural gas liquids—commonly oil in standard barrels or natural gas in standard cubic feet at surface conditions. Many prefer to use barrels of oil equivalency (BOE) or total hydrocarbons tor the sum of natural gas, natural gas liquids (NGL), and oil. For comparison purposes 6,000 cubic feet of gas is considered to be equivalent to one standard barrel on a British thermal unit (Btu) basis (42 U.S. gallons). 

The sources, amounts, and composition of injected hazardous wastes are a matter of record, because the Resource Conservation and Recovery Act (RCRA)5,14 requires hazardous waste to be manifested (i.e., a record noting the generator of the waste, its composition or characteristics, and its volume must follow the waste load from its source to its ultimate disposal site). The sources and amounts of injected hazardous waste can be determined, therefore, based on these records. Table 20.2 shows the estimated volume of deep-well-injected wastes by industrial category.3 More than 11 billion gallons of hazardous waste were injected in 1983. Organic chemicals (51%) and petroleum-refining and petrochemical products (25%) accounted for three-quarters of the volume of injected wastes that... 

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,... 

Here, a small known quantity of the component under estimation is added to the sample, which is subsequently subjected to analysis for the total amount of component present. The actual difference in the quantity of components present in samples with or without the added component ultimately gives the recovery of the quantum added component. A good satisfactory recovery builds up the confidence in the accuracy of the method of analysis. 

Lennernas s group at Uppsala has performed extensive studies to confirm the validity of this in vivo experimental set-up at assessing the rate and the extent of drug absorption. Recovery of PEG 4000 (a non-absorbable marker) is more than 95%, which indicates that the absorption barrier is intact. In addition, maintenance of functional viability of the mucosa during perfusion has been demonstrated by the rapid transmucosal transport of D-glucose and L-leucine. Estimation of absorption half-lives from the measured Pefr agree well with half-lives derived from oral dose studies in humans (i.e. physiologically realistic half-lives). Human Peff estimates are well correlated with the fraction absorbed in humans, and served as the basis for BCS development, and hence the technique is ultimately the benchmark by which other in situ intestinal perfusion techniques are compared. The model has been extensively used to... 

Overall recovery of the auxiliary was 64%. On cost estimates for scale up work it was found that the previously mentioned chiral auxiliary route exceeded the desired cost by a factor of six, primarily as a result of the cost of the chiral oxazolidinone and a yield of 33% over 10 steps. The route was ultimately replaced with a classical resolution protocol using mandelic acid, and this has been superseded by asymmetric approaches (see Chapter 12). 

For the target gronp of layers, NglV, the depth was 1800 to 1900 m, the porosity was 30%, permeability was 602 to 1622 md, and the oil viscosity was 90.34 mPa s at the reservoir temperature of 65°C. The permeability variation coefficient was 0.8. In this case, strong bottom and edge water flowed through high-permeability channels. By 1999, the water cut was 80.4%, and the recovery factor was 8.16%. The ultimate oil recovery factor was estimated to be 15%. 

In the United States, the remaining producible reserve is estimated to be 21 billion barrels. Of this 21 billion, cm-rently implemented EOR projects are expected to recover 3 billion barrels. A 1998 report in the Oil and Gas Journal listed a production of 759,653 barrels of oil per day (b/d) from EOR projects in the United States. This amoimt represented about 12% of the total U S. oil prodirctioa A somewhat dated but highly informative study conducted by the U.S. National Petroleum Council (NPC) and pubhshed in 1984 determined that, with current EOR technology, an estimated 14.5 billion barrels of oil could be produced in the United States over a 30-yr period. This amount includes the 3 billion barrels that are expected to be produced from current EOR projects. The 14.5-billion-barrel figure was derived from a series of assumptions and subsequent model predictions. Included in the assumptions was an oil base price of 30 per barrel in constant 1983 U.S. dollars. The ultimate oil recovery was projected to be very sensitive to oil price, as shown in Table I. 

Oil production from the 10 pilot area producing wells increased from 12 to 95 B/D within eight months after beginning polymer flood operations. Oil production has averaged nearly 100 B/D during the past 22 months which represent a peak oil rate approximately one-third the injection rate (Fig. 7). Cumulative recovery on May 1, 1966, was 243 bbl/acre-ft at a producing water-oil ratio of 0.76. Ultimate pilot recovery is estimated to be 350 bbl/acre-ft after six years flood life. These predictions were made from individual well decline curve analysis and theoretical approaches based on Refs. 3 and 4. 

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