05.07.2009

An anticline is an example of rocks which were previously flat, but have been bent into an arch. It is thus an arch-shaped fold in which rock layers are upwardly convex. The oldest rock layers form the core of the fold, and outward from the core progressively younger rocks occur. Anticlines form many excellent hydrocarbon traps, particularly in folds with reservoir-quality rocks in their core and impermeable seals in the outer layers of the fold. Oil that finds its way into a reservoir rock that has been bent into an arch will flow to the crest of the arch and get stuck (provided of course that there is a trap rock above the arch to seal the oil in place). Opposite of syncline.

Sorry, this entry is only available in עברית.

The accumulation of stratigraphic sequences by deposition that stacks beds atop each other

Records sound waves through the rocks and indicates the rock’s porosity. Acoustic is pertaining to sound. A record of the measurement of porosity done by comparing depth to the time it takes for a sonic impulse to travel through a given length of formation. The rate of travel of the sound wave through a rock depends on the composition of the formation and the fluids it contains. Because the type of formation can be ascertained by other logs, and because sonic transit time varies with relative amounts of rock and fluid, porosity can usually be determined in this way

To amass or collect. When oil and gas migrate into porous formations, the quantity collected is called an accumulation

Refers to back-up fuel required by for instance a natural gas generated IPP according to the terms of his license, to ensure that the plant can continue to operate if gas is not available for any reason. Alternatively, it is the fuel which an interruptible customer stores ready for use if his gas supply is interrupted.

A unit of volume often used in oil reservoir analysis, equivalent to the volume (as of oil or water) necessary to cover 1 acre to a depth of 1 foot. One of the most common units of measure used for reservoir capacity. In the U.S., the thickness of a pay zone is measured in feet, and the area of the reservoir is measured in acres. An acre-foot is a volume of reservoir rock that is one acre in area and one foot thick

The formation of groups or clusters of particles (aggregates) in a fluid

An element in a two-part pricing method used in transactions that include a capacity and an energy charge element. The actual flow or energy charge tariff is calculated based on the amount of natural gas actually flowing in the system as opposed to the capacity being purchased in advanced. INGL’s tariff, for example, is made up of a capacity tariff and a flow tariff.