| 主权项 |
1. A system for identifying a force on a member being moved within a well bore by a rig, the rig comprising a moveable unit to which the member is attached so as to be moved within the well bore, and slips for holding the member,
wherein the member is moved in a plurality of cycles, each cycle comprising, in sequence, holding the member in the slips, releasing the slips such that the member moves within the well bore, and applying the slips such that the member is again held by the slips, and the rig comprises a measurement unit arranged to measure a force imparted by the member onto the moveable unit, and being arranged to output first data indicative of a plurality of load values, each data item of said first data being indicative of a said force measured at each of a plurality of points during a said cycle, the system comprising: an interface arranged to receive data from the measurement unit; and a data processing system arranged, for each of a plurality of said cycles to:
identify a plurality of said load values from the received data, each load value corresponding to a different point in time in respect of the cycle;determine second data indicative of a force on the member from the identified plurality of load values, wherein the force is friction between the well bore and the member;determine a trend in the second data whereby to determine whether the force on the member is increasing; andcompare said plurality of load values to a predicted load value, or to identify an average value from said plurality of load values and a minimum value from said plurality of load values and to compare said average value and said minimum value, whereby to determine said second data. |
