In previous months, the typical wellbore design for a major operator in the Delaware Basin had been a 3 string well utilizing a 13 ½” surface hole, 9 ⅞” intermediate, and 6 ¾” production. With the current down market, the operator like every other operator has been looking for other ways to bring down cost and have better efficiency. One way they sought partially increased performance was by bumping up to a bigger casing profile, yet still utilizing a 3 string well design by drilling a 16” surface, 12 ¼” intermediate, and 8 ½” production hole.
They saw a large step change in performance in the 8 ½” production hole, but saw a substantial decrease in efficiency in the now 12 ¼” intermediate section. The performance change was great enough in the production hole to make the operator explore ways to optimize performance in the intermediate to make it more economical.
This new 12 ¼” deep intermediate was taking an average of 5 BHA’s to reach section Total Depth (TD), running almost every bit company possible and not seeing any positive results. After a hand full of wells, the operator dedicated the top part of the section to a competitor and the bottom hole (the demanding interval) to Ulterra’s U616M. The U616M had the fastest average ROP in the top section of the interval as well, but they saw faster instantaneous ROP with the competitor bit and thought they could improve and achieve a higher average. That didn’t happen.
Ulterra started looking into Rock Strength Analysis (RSA) and Electronic Drilling Recording (EDR) data to come up with an overall game plan of how to attack this interval. There were several meetings with the engineering team over this project which combined our bit knowledge with their overall knowledge of the application. Ulterra chose a bit and recommended parameters to try and achieve a more PDC friendly environment within this interbedded formation, reaching almost 30,000 KSI in some parts.
Ulterra proved that the U616M was the fastest bit on the 1 trial run the operator had at the beginning of the program. We recognized that we could get much deeper with the U616M in the drill out BHA with optimized drilling parameters, coupled with the right bit design and cutter technology for the interval. Ulterra showed that if the operator can get deeper on BHA #1 the chances of achieving a 2-3 bit interval would be greatly increased due to the outstanding performance we were already seeing in the bottom section of the interval, and with the U616M dull conditions when pulled at section TD.
Ulterra did just that.
In the drill out, the U616M made it from 2,073 ft to 8,469 ft in one run at 113.2 ft/hr. In the previous offset well, the first competitor bit made it to 7,000 ft at 98 ft/hr, while the second tripped at 8,000 ft averaging 48 ft/hr. So with one bit Ulterra drilled 469 ft further and at a much faster pace than 2 competitor bits.
Ulterra then went in for the second BHA in this interval and made it all the way to section TD at 10,193 ft at 111.2 ft/hr. With this well using 100% Ulterra it drilled 4.6 days faster than the average well of this design, and 2.27 days faster than the Best Demonstrated Performance (BDP) well. This was all achieved tby a great transparent working relationship between the operator, the service company, as well as great bit designs from the men behind the scenes.
By: Tyler Browder, National Account Representative