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Unformatted text preview: curs on shut-in. Joule-Thomson Inflow Temperature (and Reservoir Pressure) Definition. Within the reservoir interval there are two
methods to determine reservoir pressures using the shut-in DTS data;
• For a period of time after shut-in, the measured DTS temperatures will reflect the Joule-Thomson inflow temperatures.
When the well shuts in, different pressures in reservoir zones will cause cross-flow between the zones indicating which
intervals have higher or lower reservoir pressures in the near wellbore area. In this paper, reservoir pressure refers to the
pressure in the near well-bore area affecting the Joule-Thomson cooling. The above information is an important input to the gas inflow distribution interpretation and can only be acquired using
continuous DTS measurements. Typically, DTS temperature curves are acquired at 10 to 15 minute intervals during the
flowing and shut-in periods to acquire sufficient data for the analysis. SPE 115816 3 Thermal Well Simulator
As gas flows up a well, it carries heat and exchanges that heat with the surroundings by conduction through the wellbore and
reservoir rock giving a characteristic exponential shape to the temperature curve above the reservoir zones. A typical flowing
gas well reflects the Joule-Thomson cooled inflow temperature at the lowest reservoir zone and then warms up above the
geothermal temperature. This process continues until the rate of heat loss is the same as the velocity of the gas up the tubing
and at this point the temperature profile becomes parallel to the geothermal gradient. Subsequent Joule-Thomson cooled
inflows mixes with the fluid from below causing a sharp decrease in temperature and a modified temperature profile above
the reservoir zone.
In order to interpret flowing well temperature profiles a thermal well simulator has been developed. The flowing
temperature output of the simulator is compared to the measured DTS temperature and relevant parameters are adjusted until
a match is obtained; the gas inflow distribution is then an output of this process.
The simulator that has been developed (Fig 5) has the following main characteristics;
• • Simulate the temperature profile for both steady state flow, i.e. long term production, over the entire well and transient
flow, i.e. a few hours flow, over the non reservoir intervals of the well.
Calculation of Joule-Thomson cooling/warming from compositional properties using a multiple “flash” calculation to
determine the fluid thermal properties.
The thermal modeling code10 used to calculate the axial and Joule-Thomson inflow temperatures requires accurate
pressure measurements throughout the system and a nodal finite-element pressure-analysis technique is employed11. The
thermal model is an axi-symmetric 2D radial well model that calculates the flowing temperatures and pressures in the
well. This model accounts for heat transfer through conduction and convection between the wellbore and the casings,
annular well fluids, cement, and formation as a function of depth, and also between reservoir...
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This note was uploaded on 02/04/2014 for the course PGE 312 taught by Professor Peters during the Spring '08 term at University of Texas.
- Spring '08