They are different methods adopted in hydrocarbon volume estimations which can be grouped into the deterministic or probabilistic approaches. Which of these will provide a more realistic result and why? Support materials and publications will be appreciated.
The method of hydrocarbon reserve estimation which yields the most reliable results is the one based on a probabilistic approach.
This is because, even in the best documented cases, it is virtually impossible to characterize precisely every single parameter necessary for the calculation of the reserves. Therefore, a deterministic approach always leaves out some unknown or poorly known element, while the probabilistic approach compensates for this by taking in account (almost) the entire range of values for each parameter.
In a deterministic calculation, by necessity, we must use average numbers (e.g. matrix porosity), while it is better to capture the entire range of values by using a distribution curve rather than a single number. The probabilistic approach samples the entire distribution curve of each parameter to yeld a probabilistic result.
The method of hydrocarbon reserve estimation which yields the most reliable results is the one based on a probabilistic approach.
This is because, even in the best documented cases, it is virtually impossible to characterize precisely every single parameter necessary for the calculation of the reserves. Therefore, a deterministic approach always leaves out some unknown or poorly known element, while the probabilistic approach compensates for this by taking in account (almost) the entire range of values for each parameter.
In a deterministic calculation, by necessity, we must use average numbers (e.g. matrix porosity), while it is better to capture the entire range of values by using a distribution curve rather than a single number. The probabilistic approach samples the entire distribution curve of each parameter to yeld a probabilistic result.
@Bencini, Many thanks for your answer. I sincerely appreciate....Cheers!
It depends on the size and variety of the available data. The most accurate estimation is calculated based on reservoir simulation under uncertainty analysis.
Many other approaches are available to estimate the reserve such as decline curve analysis, material balance equations, the volumetric method under uncertainty analysis. In addition, the reserve estimation depends on cut-off values that are not constant because they change respect to the oil and gas prices, available technology and the planned recovery factor.
Both answers provided above are correct and I will only attempt to connect them.
The most reliable estimate is still an indirect "estimate" of your parameters (as noted by Bencini) to the extent of your available data (ref: Omar). In practice however, your data improves with production, hence your estimation improves incrementally until a point where the marginal difference becomes negligible.
...but then new technology may just tilt the cart of one or two parameters and you start the estimation process all over again. That is why stochastic (i.e probabilistic) estimation method which recognizes all these possibilities from the beginning is the preferred way to go...
Don't forget to add the uncertainty in the along-hole depth determination, as this materially affects the TVT. Note that this is not normally accounted for.
There was not method can be select as a best method each method has strength and weakness also uncertainty and error found in all method so select methods it is depends in several factors amount of data available, type of reservoir, geological and petrophysical properties ....etc
The methods depends on uncertainty and weakness which found in all methods don't forget this point please.
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