Patent ID: 8322433

Claim:
A system comprising: a drill string assembly comprising a plurality of pipe joints; a slip joint coupled to the plurality of pipe joints, the slip joint movable from a retracted position to an extended position to compensate for changes in length of the drill string, the extended position having a length greater than the retracted position; wherein the slip joint comprises: a lower slip joint member having a pin end; an upper slip joint member having a box end, the lower slip joint member telescopically engaged with the upper slip joint such that one of the joint members moves within the other joint member, thereby forming an expandable and contractible inner passage between the box end and the pin end; and a coiled cable coupled with a box end communications element disposed proximate the box end and a pin end communications element disposed proximate the pin end, the box and pin end communications element electrically coupled to a communication system; a sensor positioned in the slip joint, wherein the sensor detects a change in length of the slip joint and generates a signal representative of a position of the slip joint wherein the sensor is disposed along the upper slip joint member or the lower slip joint member and is electrically coupled with at least one of the box end and pin end communications elements; and the communication system to transmit the signal from the slip joint to a surface processor.