Nitrogen determination of bottomhole pressure
- Petro-Canada Oil and Gas, Calgary, Alberta (Canada)
Ascertaining bottomhole pressure (BHP) by nitrogen (N{sub 2}) injection is fairly simple: overfill tubing with N{sub 2}, accurately measure wellhead pressure and determine gas gradient for pressurized N{sub 2}. Gas gradients can be roughly estimated from N{sub 2} tables commonly found in handbooks or more accurately determined using computer software. N{sub 2} is inert, relatively inexpensive and, generally, easily obtained. Unlike many other gases, such as CO{sub 2}, N{sub 2} will not go through a phase change in the range of pressures and temperatures typically encountered. Field comparisons of slickline gradient measurements and capillary (bubble tube) pressure sensors have confirmed that the expected accuracy of the N{sub 2} gradient method is {+-} 100 kPa (14.7 psi).
- OSTI ID:
- 435738
- Journal Information:
- World Oil, Journal Name: World Oil Journal Issue: 2 Vol. 218; ISSN 0043-8790; ISSN WOOIAS
- Country of Publication:
- United States
- Language:
- English
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