Sandstone and carbonates are the primary rocks of reservoirs.
When determining the feasibility and performance of a reservoir system, two economic factors matter most: rate and amount of hydrocarbons recovered. According to Dan Hartmann, Edward Beaumont and Edward Coalson, research scientists and authors of "Treatise of Petroleum Geology Handbook," in geologic terms, pore type and pore-fluid interaction are the most important elements in determining how reservoir systems will perform in controlled and variable situations. Sandstone and carbonates are the most commonly found rock types in reservoirs and, although they share similarities in some physical characteristics, others such as composition, porosity, and permeability differ significantly.
Instructions
1. Recognize the components. Porosity and permeability of sandstone rely on several factors, some of which include cementation, compaction and pressure. The interrelationship between reservoir porosity, permeability, thickness and lateral distribution determine reservoir quality.
2. Identify the formula. Dykstra-Parsons coefficient of permeability variation demonstrates reservoir uniformity through the analysis of permeability values and is computed as permeability variance (V) equals permeability mean (M) minus permeability mean (M) plus standard deviation (?) divided by permeability mean (M).
3. Calculate permeability variance. For a given permeability mean of 50, and permeability mean plus standard deviation of 84.1, calculate permeability variance as V = (k50-k84.1)/k50. Charting tools are available using standard spreadsheets in Microsoft Excel and Minitab and a permeability calculator at the Ruben Charles website.
Tags: permeability mean, permeability variance, mean plus, mean plus standard, permeability mean plus
