Well logging
Well logging is a technique used in the oil and gas industry for recording rock and fluid properties to find hydrocarbon zones in the geological formations below the Earth's crust. A logging procedure consists of lowering a 'logging tool' on the end of a wireline into an oil well (or hole) to measure the rock and fluid properties of the formation. An interpretation of these measurements is then made to locate and quantify potential depth zones containing oil and gas (hydrocarbons). Logging tools developed over the years measure the electrical, acoustic, radioactive, electromagnetic, and other properties of the rocks and their contained fluids. Logging is usually performed as the logging tools are pulled out of the hole. This data is recorded to a printed record called a 'Well Log' and is normally transmitted digitally to office locations. Well logging is performed at various intervals during the drilling of the well and when the total depth is drilled, which could range in depths from 300 m to 8000 m (1000 ft to 25,000 ft) or more.
Mud Logging
Another kind of logging technique used is 'Mud Logging'. A Mud Logger works when drilling is going on. The Mud Logger analyzes the rock samples coming out of the circulating mud/fluids off 'flow line' from the drill string/pipe. Similar to a Well Log, a 'Mud Log' is prepared by the Mud logging company. A mud log displays the Gas present in the formation by using Gas Chromatograph techniques. A mud log also describes the formation geology.
Use of Information
The well log and the mud log are usually transferred in 'real time' to the operating company, which uses these logs to make operational decisions about the well and to make interpretations about the quantity of hydrocarbons present.
Major well logging and mud logging companies
Both these jobs are performed by Oil & Gas Service companies. Well Logging companies are:
External links
Some Mud logging companies are:
- Geoservices,
- Baker Inteq (part of Baker Hughes),
- Datalog.