Method to prevent dual rod drill string drag
AssigneeThe Charles Machine Works, Inc.
InventorsGreg L. Slaughter, Jr., Joseph G. Greenlee, Joe Glenn Worlow
Life of this patent
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Abstract
An apparatus and method for preventing drill string drag. Rotation encoders are provided for tracking the rotation of an inner and outer member of a dual-member drill string. Based upon the drilling conditions, the readings of the encoder can detect when the inner member is dragging on the outer member. When such a drag condition is detected, a processor can trigger remedial measures, which may include increasing a rotation rate of the inner member, sending a warning signal, stopping operation, or a combination of these.
Claims20
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.
A method for rotating a drill string, the drill string comprising an outer pipe string and an inner pipe string disposed within the outer pipe string, the method comprising:
- storing, in a memory, predetermined drill string rotation conditions indicative of a drag condition between the inner pipe string and the outer pipe string;
- rotating the inner pipe string using a first motor;
- rotating the outer pipe string using a second motor;
- measuring a first rotation rate of the inner pipe string;
- measuring a second rotation rate of the outer pipe string;
- and comparing the first rotation rate and the second rotation rate to the predetermined drill string rotation conditions.
A method for rotating a drill string, the drill string comprising an outer pipe string and an inner pipe string disposed within the outer pipe string, the method comprising:
- storing, in a memory, predetermined drill string rotation conditions indicative of a drag condition between the inner pipe string and the outer pipe string;
- rotating the inner pipe string using a first motor;
- rotating the outer pipe string using a second motor;
- measuring a first rotation rate of the inner pipe string;
- measuring a second rotation rate of the outer pipe string;
- and comparing the first rotation rate and the second rotation rate to the predetermined drill string rotation conditions;
- if the first rotation rate and the second rotation rate meet the predetermined drill string rotation conditions, rotating the inner pipe string at a rotational velocity equal to the rotational velocity of the outer pipe string;
- after the step of rotating the inner pipe string at a rotational velocity equal to the rotational velocity of the outer pipe string, discontinuing rotation of the inner pipe string.
A method for rotating a drill string, the drill string comprising an outer pipe string and an inner pipe string disposed within the outer pipe string, the method comprising:
- providing a backreamer at a distal end of the drill string, the backreamer being rotationally coupled to the outer pipe string;
- providing a first motor, the first motor rotationally coupled to the inner pipe string;
- rotating the outer pipe string using a second motor;
- measuring a first rotation rate of the inner pipe string;
- measuring a second rotation rate of the outer pipe string;
- determining if the first rotation rate exceeds a predetermined threshold;
- and
- if the first rotation rate exceeds a predetermined threshold, rotating the inner pipe string with the first motor such that the first rotation rate and the second rotation rate are equal.
Dependencies are inferred from the claim text.