Downhole temperature rule of thumb

[Unotec]

Is there a rule of thumb to estimate downhole temperatures? say, xxxºC/m?
I know that some formations might present higher than normal/expected temperatures due to geological factors, but under normal conditions. Does such a rule of thumb exist?

 

[DownholeGreg]

Unotec,
As you mention, conditions vary depending on region, etc., so using a "rule-of-thumb" is risky. A typical downhole logging tool is designed to operate at 20,000 psi and 200C. If you assume a "common" mud weight (12 PPG?) and get a corresponding depth for the 20,000 psi pressure, a temperature gradient could be calculated. Again, this can vary greatly.....

 

[Unotec]

Thanks, I actually looked into wells in the sorrounding area and found a trend that seems to work. I verified the downhole temperature of a few of my wells and the prediction was off by a degree or two. Quite acceptable for my purpose.

 

[john1964]

Hi Unotec,
This is old data from Kermit E Brown hand book on Gas lift-

Normal temperature expected in a New Well along Texas & Louisiana Gulf Coast.
74 deg F +1.6 deg F /100 feet.
Example-
Given a 10,000 feet well. What temperature is expected at bottom?
74 def F + 1.6 deg F X (10,000/100)= 74 + 160 = 234 deg F.

Hope this will help.
Regards,
John

 

[MATE45]

Western Canadian Sedimentary Basin temperature gradient of 0.036 ?C/m (0.0295 °F/ft)