Drilling depth

I have a question for one of our experts on our forum. On one of my well permits it says the depth of the Mississippian is going to be a little over 12 thousand feet deep. But the permit goes on to say total depth is 16 thousand feet. So, is the 16 thousand total depth they show including the horizontal part of the well? And the actual horizontal drilling depth is the 12 thousand feet? Thanks, Tom

TVD, or True Vertical Depth, is the depth of the well. MD or Measured Depth (sometimes TMD or Total Measured Depth) is the sum of TVD+Lateral Length. So if your TVD is 12,000 feet and your MD is 16,000 feet, then your lateral length will be 4,000 feet.

To expand on the above answer: common language used in the industry refers to the turn from vertical to horizontal as the “heel”, and the end where the drilling stopped as the “toe.” TVD is essentially the depth of the heel, and TMD is the length of pipe all the way to the toe.