Tool face offset

Replies to This Discussion

Permalink Reply by Overshot on April 1, 2011 at 10:31am

Pete,

Would something like the following be what you're looking for?
http://find-box-end-wrenches-shop.co.cc/product/0/General-Tools-29-Plastic-Protractor-and-Angle-Finder-with-Articulating

Tony

Permalink Reply by Pete Aldrich on April 1, 2011 at 11:31am

Thanks Tony,
What I was looking for were horseshoe shaped half moons with the inside diameter matching the drill collars, about 2 inches wide. On the inside edge the degrees were stamped into the aluminum (0-180 degrees) on both sides. You could put the zero mark on the motor scribe line and visually see the degrees where you dropped your chalk scribe from the MWD collar. I used to work for Teleco (collar mounted tools) and we had these in our kits. I'm thinking they may have been custom made for them, I have not seen them since then, late Eighties, early Nineties. Since that time I have worked with muleshoe aligned tools but we have just purchased a fixed mount EM tool and I remembered these handy things.
Pete

Permalink Reply by Jeff Steinke on April 1, 2011 at 1:52pm

Baker has these but most of the directional drillers use them as reference only and still hand calculate because more times than not especially in our very busy industry the collars are worn so the protractors will be off as compared to the more accurate hand calculation. Good luck.

Permalink Reply by Pete Aldrich on April 1, 2011 at 4:19pm

Thanks Jeff!
Figures that Baker would have them, they were the ones who bought Teleco way back when. We used to accomodate for wear by holding off equally around the collar with your fingertips and assumed that any minor discrepancies would be covered under the "measure with a micrometer then cut with an axe" rule. Never went the wrong way myself.
Thanks again,
Pete