True Zone Thickness True Zone Thickness It's a familiar problem: you've got a vertical borehole going through a dipping bed and you need to calculate the true thickness. Or perhaps you have a deviated borehole going through a horizontal bed and you need to calculate its true thickness. This program can handle all the variations of that problem. Some things to remember: --The bed dip is measured in degrees down from horizontal. --The wellbore deviation is measured in degrees away from vertical. --If the dip of the bed from horizontal is less than the dip of the wellbore from horizontal, then all is well and you'll drill through the top and then the bottom of the zone. --If the dip of the bed from horizontal is greater than the dip of the wellbore from horizontal, then you will drill first through the bottom of the bed and then through the top. The program will still give you the right answer because it computes the absolute value of the thickness. --If the dip of the bed from horizontal equals the dip of the wellbore from horizontal, then you won't hit either the top or the bottom and the program will just return a zero for zone thickness (due to not enough information). --Keep all entered dips and deviations in the range of 0 to 90 degrees. --If you are really lazy, enter zero for both bed dip and well deviation, and the program will just subtract the top from the bottom of the zone for you!