RE:RE:RE:Clarus ReportIt's an important distinction (MD vs TST). To keep it simple...if you have a dipping formation cut by a vertical hole...the measured depth will be larger than the TST..If you have a dipping formation and a hole drilled at an inclination and azimuth...you still need to do the correction to get the proper TST thickness.used in tonnage calcs. Similarly, the zones have to correlate between the holes to do tonnage estimates or oil reserve estimates...(and.i am.quite familiar with the latter)