Summary
Permanent downhole gauges (PDGs) provide a continuous source of downhole
pressure, temperature, and sometimes flow-rate data. Until recently, the
measured temperature data have been largely ignored, although a close
observation of the temperature measurements reveals a response to changes in
flow rate and pressure. This suggests that the temperature measurements may be
a useful source of reservoir information.
In this study, reservoir temperature-transient models were developed for
single- and multiphase-fluid flows, as functions of formation parameters, fluid
properties, and changes in flow rate and pressure. The pressure fields in oil-
and gas-bearing formations are usually transient, and this gives rise to
pressure/temperature effects appearing as temperature change. The magnitudes of
these effects depend on the properties of the formation, flow geometry, time,
and other factors and result in a reservoir temperature distribution that is
changing in both space and time. In this study, these thermometric effects were
modeled as convective, conductive, and transient phenomena with consideration
for time and space dependencies. This mechanistic model included the
Joule-Thomson effects resulting from fluid compressibility and viscous
dissipation in the reservoir during fluid flow.
Because of the nature of the models, the semianalytical solution technique
known as operator splitting was used to solve them, and the solutions
were compared to synthetic and real temperature data. In addition, by matching
the models to different temperature-transient histories obtained from PDGs,
reservoir parameters such as average porosity, near-well permeabilities,
saturation, and some thermal properties of the fluid and formation could be
estimated. A key target of this work was to show that temperature measurements,
often ignored, can be used to estimate reservoir parameters, as a complement to
other more-conventional techniques.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
3 March 2009
- Meeting paper published:
21 September 2008
- Revised manuscript received:
11 March 2010
- Manuscript approved:
22 June 2010
- Published online:
8 December 2010
- Version of record:
9 December 2010
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