Millikan, C. There is nothing more important in petroleum engineering than a definiteknowledge of the pressure at the bottom of an oil well at any existingoperating condition, and the relation of this pressure to the pressure withinthe producing formation. A knowledge of bottom-hole pressures is fundamental indetermining the most efficient methods of recovery and the most efficientlifting procedure, yet there is less information about these pressures thanabout any other part of the general problem of producing oil. Bottom-hole pressure may be calculated or determined by several methods. On aninactive well it may be calculated from the fluid head or, if the well is shutin, by adding the casinghead pressure, the static head of the gas and the fluidhead. In wells flowing naturally through tubing the pressure at the bottom ofthe tubing may be calculated by adding the pressure at the casinghead betweenthe tubing and the casing and the pressure due to the weight of the column ofgas, but there is always possibility of error caused by fluid being in theannular space above the bottom of the tubing.
Roxar Downhole Pressure and Temperature Gauges | Emerson US
You must log in to edit PetroWiki. Help with editing. Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. More information.
By measuring pressure and temperature at a single point with a single quartz crystal, the Signature CQG gauge significantly reduces thermal effects. Small residual effects are further minimized with real-time dynamic compensation. This unique capability also speeds pressure response to truly capture dynamic downhole conditions. Get reservoir-representative fluid samples and high-resolution pressure measurements with multicycle flexibility in a single run and at ultrahigh temperatures. Monitor and manage wellbore events as they happen, validate pressure data while you test, and ensure that you've met your test objectives before ending your test.
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.