US 11,885,223 B2
Method to prevent dual rod drill string drag
Greg L. Slaughter, Jr., Perry, OK (US); Joseph G. Greenlee, Perry, OK (US); and Joe Glenn Worlow, The Villages, FL (US)
Assigned to The Charles Machine Works, Inc., Perry, OK (US)
Filed by The Charles Machine Works, Inc., Perry, OK (US)
Filed on Oct. 16, 2020, as Appl. No. 17/072,872.
Claims priority of provisional application 62/916,339, filed on Oct. 17, 2019.
Prior Publication US 2021/0115777 A1, Apr. 22, 2021
Int. Cl. E21B 7/04 (2006.01); E21B 47/007 (2012.01); E21B 7/00 (2006.01)
CPC E21B 7/046 (2013.01) [E21B 7/002 (2013.01); E21B 47/007 (2020.05)] 20 Claims
OG exemplary drawing
 
1. A system, comprising:
a first motor;
a second motor;
an elongate hollow outer member, rotationally coupled to the first motor;
an elongate inner member, rotationally coupled to the second motor, wherein the elongate inner member is disposed within the hollow outer member and independently rotatable relative thereto,
a first rotation sensor configured to detect the rotation of the elongate hollow outer member and send a first signal;
a second rotation sensor configured to detect the rotation of the elongate inner member and send a second signal; and
a processor comprising a memory, the processor configured to:
store a predetermined drag condition in the memory;
receive the first signal and the second signal;
using the first signal, determine a rotation rate of the elongate hollow outer member;
using the second signal, determine a rotation rate of the elongate inner member; and
compare the rotation rate of the inner member and the rotation rate of the elongate hollow outer member to the predetermined drag condition.