{{Unreferenced, date=April 2008
A permanent downhole gauge (PDG) is a pressure and/or temperature
gauge
Gauge ( or ) may refer to:
Measurement
* Gauge (instrument), any of a variety of measuring instruments
* Gauge (firearms)
* Wire gauge, a measure of the size of a wire
** American wire gauge, a common measure of nonferrous wire diameter, es ...
permanently installed in an
oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
or
gas well
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may ...
. Typically they are installed in tubing in the well and can measure the tubing pressure or annulus pressure or both. Systems installed in well casing to read formation pressure directly, suspended systems, and systems built in coil (continuous) tubing are also available. The data that PDGs provide are useful to Reservoir Engineers in determining the quantities of oil or gas contained below the Earth's surface in an oil or gas reservoir and also which method of production is best.
Permanent downhole gauges – are installed in oil and gas wells for the purposes of observation and optimization. The most prolific function of a downhole gauge is to monitor pressure at a single point or multiple points in a well. Temperature is the second most monitored factor. Permanent downhole gauges continue to evolve into many different types of sensors.
# pressure
# temperature
# distributive temperature
# noise
# strain
# flow
The information provided by a permanently mounted sensor enables smart well technology. A "smart well" is a well that can monitor information and make adjustments automatically. The adjustments will optimize production or protect the well. The vast majority of producing oil and gas wells in the world have no such instrumentation or capabilities. PDG's are important tools for optimal production and protection of our most important non-renewable resources.