The temperature log has been utilized as an openhole gas entry detection device for over 40 years in wells of the Appalachian Basin.

The air-drilling of the majority of wells in the Appalachian Basin facilitates the use of this log as a qualitative and, in many instances, a quantitative tool in evaluating gas flow from productive intervals.

Historically the temperature log was run in the hole as a down-pass log with an external temperature sensor mounted on the bottom of the tool. However, advances in tool telemetry during the past decade made possible the stacking of logging tools, thus, the external temperature sensor has been moved on many tool strings from the bottom of the tool string to a more central position in the tool stack. This stacked temperature tool data is now recorded during the secondary up-pass portion of a single logging run in order to facilitate the recording of other logs on the primary down-pass.

In order to compare the effects of sensor placement and logging sequence, multiple runs were made in a Columbia Natural Resources well in Roane County, West Virginia, utilizing a single end-mounted temperature tool and a stacked center-mounted temperature tool run during both up and down-passes through productive gas zones.

The resulting temperature log information showed differences in the temperature profiles that were obtained using different tool configurations and different logging sequences.

The information obtained from these runs can be utilized to better understand certain temperature logging anomalies that appear to be inherent in certain tool configurations and logging sequences.

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