Summary
Flow-rate metering has a less-than-satisfactory track record in the
industry. Modern sensors offer a solution to this vexing problem. This paper
offers two methods for estimating flow rates, predominantly from temperature
data to complement rate measurements. One approach consists of modeling the
entire wellbore and requires both wellhead pressure (WHP) and wellhead
temperature (WHT), whereas the other uses transient temperature formulation at
a single point in the wellbore to compute the total production rate.
In the entire-wellbore approach, we use a wellbore model handling steady
flow of fluids but unsteady-state heat transfer to estimate production rate,
given wellhead pressure and temperature. The model rigorously accounts various
thermal properties of the fluid and the formation, including Joule-Thompson
(J-T) (Thompson and Joule 1853) heating and/or cooling. In the single-point
approach, a single-point-temperature measurement made anywhere in the wellbore,
including at the wellhead, is needed to estimate the mass rate at a given
timestep. The method entails full transient treatment of the coupled fluid- and
heat-flow problem at hand.
Examples from both gas and oil wells are shown to illustrate the application
of the proposed methodology. Good correspondence between the measured and
calculated results demonstrates the robustness of the proposed methods. These
methods provide important rate information in various settings. For instance,
in mature assets they can fill in the information void between tests or replace
suspect rate data. Even well-instrumented wells can benefit because the methods
can act as a verification tool, particularly in assets where integrated asset
models are used to fine tune rate allocation. In addition, the single-point
approach can provide the much needed rate information during pressure-transient
tests.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
7 July 2008
- Meeting paper published:
21 September 2008
- Revised manuscript received:
13 April 2009
- Manuscript approved:
18 April 2009
- Published online:
5 November 2009
- Version of record:
1 March 2010