05.07.2009
The petroleum resource management system (SPE-PRMS) divides the estimates to 3 possibilities groups:
Low Estimate (P90) – There should be at least a 90% probability (P90) that the quantities actually recovered will equal or exceed the conservative (low) estimate.
Best Estimate (P50) – There should be at least a 50% probability (P50) that the quantities actually recovered will equal or exceed the best estimate.
High Estimate (P10) – There should be at least a 10% probability (P10) that the quantities actually recovered will equal or exceed the high estimate.
The meaning of the parameter “Mean” or “Gross Mean Resources” (average potential of gas or oil reserves, as applicable) (the “Mean”) is the arithmetic mean of all these possibilities, or “the arithmetic average of all the possible outcomes”
Refers to the mean potential of gas reserves available in a gas field, somewhere between the P90 and P10 estimates. If this mean potential is stated to be 140 bcm the proven reserves may be as high as 200 bcm or as low as 80 bcm, with further certainty achieved after appraisal drilling and other drillings have been carried out.
Calculation of the “Mean” is done by running X number of observations in a probabilistic model and dividing their sum in the number of observations (X). It can be defined simplistically as the total sum of 30,000 values divided by 30,000. if you run a probabilistic model 1000 or x times, sum up all outcomes and divide by 1000 or x, you have the arithmetic mean.
It is important to point out that the mean value is different to the “best estimate” value and could be higher or lower. If one compares “mean” and P50, the two results would only be the same for a symmetrical normal distribution of values, namely for a bell curve,
The quantity of heat in Btu produced by the complete combustion in dry air of one standard cubic foot of dry ideal gas and the condensation of all the water formed, with the initial and final temperature and pressure being 60 degrees Fahrenheit and 14.696 psia respectively. Usually contrasted with Net Heating Value
Total consumption of a particular energy source(s) or fuel(s) by a group of buildings, divided by the total floor space of those buildings
The sum of the net electricity production supplied by Israel Electric and the amount of Israel Electric’s self-consumption necessary for operating the electricity production units to produce the net electricity supplied by Israel Electric.
The amount of heat released by a specific quantity of fuel. The gross heating value of a fuel is defined as the amount of heat released by a specified quantity (initially at 25°C) once it is combusted and the products have returned to a temperature of 25°C. The difference between the higher heating value and the lower heating value depends on the chemical composition of the fuel. In the case of pure carbon or carbon dioxide, both heating values are almost identical. See also higher heating value and lower heating value of natural gas.
The layout of an electricity utility’s transmission and distribution network