Patent ID: 8939219
Filing Date: 2015-01-27
Classification: E21B

Abstract:
1. A system for monitoring and controlling a service unit for snubbing a pipe, the service unit having stationary heavy slips and a travelling heavy slips operating in tandem to engage and move the pipe into or out of a well in a pipe heavy configuration, and a stationary snubbing slips and a travelling snubbing slips operating in tandem to engage and move the pipe into or out of the well in a pipe light configuration, the system comprising: (a) a first actuation sensor associated with the stationary heavy slips, a second actuation sensor associated with the travelling heavy slips, a third actuation sensor associated with the stationary snubbing slips, and a fourth actuation sensor associated with the travelling snubbing slips, wherein the actuation sensors directly or indirectly detect engagement of the associated slips on the pipe; and (b) a control system operatively connected to the first, second, third and fourth actuation sensors and adapted to receive input signals from the sensors, and configured to execute a method comprising the step of: when the pipe is in the pipe heavy configuration, confirming that one of the heavy slips has engaged the pipe, before fully releasing, or allowing the full release of the other one of the heavy slips, when transferring the pipe load from one of the heavy slips to the other one of the heavy slips; and when the pipe is in the pipe light configuration, confirming that one of the snubbing slips has engaged the pipe, before fully releasing, or allowing the full release of the other one of the snubbing slips, when transferring the pipe load from one of the snubbing slips to the other one of the snubbing slips.