General Information

Oil and natural gas occur throughout much of western, south-central, and eastern Kentucky. At the surface, early explorers and settlers found many seeps, evidenced by place names such as Burning Springs, Oil Springs, and Oil Valley. In the subsurface, oil and gas are found where porosity, permeability, traps, and hydrocarbon sources combine to form a reservoir. Drilled wells penetrate the reservoirs to produce the hydrocarbons. Primary production recovers oil or gas that flows or can be pumped to the surface. Naturally occurring brines, remnant waters from the oceans in which the reservoir rocks were deposited, may be produced in association with oil. During primary production, an average of only one-third of the oil in place is produced. After primary oil production, the remaining oil must be recovered by other means. Secondary recovery uses circulated water (and other chemicals or fluids) to displace additional oil and bring it to the surface.

The void space in a rock usually expressed as a percent of the total volume of the rock, the space within a rock that contains any oil, natural gas, or water. Top
A measure of the resistance to the flow of oil, natural gas, or water through a rock (how well connected are the voids). Top
The seal or capping mechanism of a reservoir marking the change in porosity, permeability or other rock properties responsible for holding the oil or natural gas in where it is found. Top
Hydrocarbon Source
Oil and gas are generated in rocks with high organic content. Oil and gas are formed by the influence of heat, pressure, and time; the organic matter is "cooked". The liquid and gaseous hydrocarbons migrate along porous and permeable pathways until they are stopped at the barrier that forms the trap for the reservoir. Top

Brandon C. Nuttall / E-mail to BNUTTALL@KGS.MM.UKY.EDU / last modified 21-Sep-1998