Definition
Back-Off — A back-off is the deliberate unscrewing of a drill string connection at or above the free point, usually with left-hand torque and a string shot, to separate the free pipe from a stuck portion so the free section can be recovered before fishing.
Also known as: back-off, backoff, back off
What a back-off does
A back-off separates a stuck drill string into a recoverable upper part and a stuck lower part — the fish. After the free point is located, the operator selects the deepest free connection and unscrews it downhole so the free pipe above can be tripped out. This clears the hole down to the top of the fish and lets a purpose-built fishing string be run to attempt recovery of the stuck portion.
How it is performed
Left-hand torque is applied and held at the chosen connection while a string shot — a wireline- conveyed explosive charge — is detonated at that joint. The shock momentarily loosens the threads, and the reserved left-hand torque unscrews the connection at that point. Accurate free-point data and careful torque control are critical so the string parts at the intended joint rather than a deeper or shallower one.
Why it matters for rentals
A back-off is the prelude to fishing, which requires overshots, spears, jars, and mills on short notice.
After backing off, recover the fish with our fishing tools, or contact us to assemble the catching and jarring string you need.