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•Calculates bottom hole static temperature (BHST) or temperature gradient (TG)
•Calculates bottom hole circulating temperature (BHCT)
•Supports US and Metric units
•Utilizes methodologies and data found in API Recommended Practice 10B-2 Second Edition, April 2013

•True Vertical Depth (1000 - 22000 ft and 300 - 6600 m)
•Measured Depth (≥ True Vertical Depth)
•Temperature Gradient (0.7 - 1.9 °F/100 ft and 1.6 - 3.6 °C/100 m)
•Bottom Hole Static Temperature (87 - 498 °F and 32 - 264 °C)

•Bottom Hole Static Temperature (°F or °C)
•Bottom Hole Circulating Temperature (°F or °C)
•Temperature Gradient (°F/100 ft or °C/100 m)

The tables in Annex D of API RP 10B-2 are a matrix of predicted circulating temperatures for the following well simulation schedules as a function of true vertical depth and temperature gradient.


Temperature predictions are given for true vertical depths ranging from 1,000 ft to 22,000 ft for US units and 300 m to 6,600 m for metric units and temperature gradients ranging from 0.9 to 1.9 for US units and 1.6 to 3.6 for metric units.

To predict bottom hole temperatures, BHT utilizes a standard regression technique. This technique, when used in combination with cited tables in API RP 10B-2 Annex D, allows BHT to predict bottom hole temperatures for any depth-gradient input combination that fall within the bounds of relevant tables.

Smaller temperature gradients than those listed in Annex D have been extrapolated from 0.9 °F/100 ft down to 0.7 °F/100 ft in response to a customer request. Temperature predictions for this gradient range utilize the same regression technique referenced above.

*Note: No extrapolation is performed when using metric units

If the user-defined measured depth value is greater than true vertical depth by 1,000 ft or more or 300 m or more, the well is assumed to be highly deviated, lateral, or horizontal and the predicted bottom hole circulation temperature is set equivalent to the bottom hole static temperature value.

As awesome as we think we are, we know we’re not perfect. What you have is our first attempt to address what we perceived the core needs of our target audience to be. As you begin to integrate this app into your work life we expect errors, short-comings and worthwhile enhancements to become apparent.

While we welcome praise, we find constructive (and respectful) criticism to be of more value. Please don’t hesitate to send us thoughts, comments and questions on any of our products or new products you would like to see. founders@threeedev.com

What's New

Version 3.4.6

UI Enhancements to make it more user-friendly

Ratings and Reviews

Simple, quick and straight forward.


I've had to use two or three apps to get the results I get with this app. I hope the developers stay on top of it. I can already think of a few other things they can add to make it even better. I look forward to the updates.

Extremely helpful!

Christian Rodriguez

I no longer have to carry around a laptop. This is practical, efficient, awesome.

Finally engineering solutions!


I always carry my laptop for this kind of calculation. Thanks for bringing this to my phone!!


3E Development, LLC
2.4 MB
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.
Age Rating
Rated 4+
© 3E Development, LLC


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    With Family Sharing set up, up to six family members can use this app.

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