WorldWide Drilling Resource

51 WorldWide Drilling Resource ® SEPTEMBER 2013 Frequently-Used Geological Terms Part 23 Glossary adapted from the Dictionary of Geological Terms G - Continued Gasification - Production of fuel gas from coal. Gas-oil Ratio - The amount of gas pro- duced with the oil from an oil well, usually expressed as the number of cubic feet of gas per barrel of oil. Gas Sand - A sand or sandstone con- taining a large quantity of natural gas. Gauge - A measurement (as of linear dimension) according to a standard or system. Gem - A general term for any precious or semiprecious stone. Gemology - The science and study of gemstones, including their source, description, origin, identification, grad- ing, and appraisal. Geochemical Exploration - The search for economic mineral or petroleum deposits by detecting abnormal con- centrations of elements or hydrocar- bons in surface materials or organisms Geochemistry - The study of the dis- tribution and amounts of the chemical elements in minerals, ores, rocks, soils, water, and atmosphere, and their circu- lation in nature. Geode - Anodule of stone having a cavity lined with crystals or mineral matter. Geographic Center - The point on which an area on the earth’s surface would bal- ance if it were a plate of uniform thickness. Geographic Cycle - Cycle of erosion. Geohydrology - A term, often used inter- changeably with hydrogeology , referring to the hydrologic or flow characteristics of subsurface waters. Geological - Pertaining to geology. Geologic Hazard - A geologic condi- tion or phenomenon that presents a risk or potential danger to life and property, either naturally occurring or man-made. Geologic High - An oilfield term for a structure on which rocks occur at a higher position than the surrounding area. Geologic Map - A map where the distri- bution, nature, and age relationships of rock units and the occurrence of struc- tural features are recorded. Geologic Thermometry - Measurement or estimation of the temperatures at which geologic processes occur or have occurred in the past. Geology - The study of planet earth. Geomagnetic - Pertaining to the mag- netic field of the earth. Geomorphology - The study of the clas- sification, description, nature, origin, and WWDR photo of October gemstone opal. development of landforms and their rela- tionship to underlying structures, and the history of geologic changes as recorded by these surface features. More definitions next month!