Force Monitoring Tractor

Abstract

A downhole tractor assembly that is configured for open-hole applications. The assembly includes a force monitoring mechanism to help monitor and control forces imparted through a drive mechanism of the tractor in real time. As such, damage to open-hole formations due to excessive tractoring forces may be minimized along with mechanical damage to the tractor. Furthermore, the drive mechanism of the tractor may include multiple sondes and bowsprings with gripping saddles specially configured for contacting the well wall across a large area in a non-point and line manner so as to avoid digging into and damaging the well wall during tractoring.

We claim: 
     
         1 . A downhole tractor for positioning in an open hole well, the tractor comprising: an elongated body; a driving mechanism coupled to said elongated body and configured for deploying relative thereto for interfacing a wall of the well; and a force monitoring mechanism coupled to said driving mechanism for monitoring force thereon during the interfacing. 
     
     
         2 . The downhole tractor of  claim 1  further comprising an expandable arm of said elongated body, said expandable arm coupled to said driving mechanism for the deploying. 
     
     
         3 . The downhole tractor of  claim 2 , further comprising a hydraulic chamber of said elongated body in communication with said expandable arm. 
     
     
         4 . The downhole tractor of  claim 3 , wherein said force monitoring mechanism comprises a pressure sensor in communication with said hydraulic chamber for the monitoring. 
     
     
         5 . The downhole tractor of  claim 4  wherein said force monitoring mechanism further comprises a processor coupled to said pressure sensor to regulate inflation and deflation of said hydraulic chamber based on information from said pressure sensor. 
     
     
         6 . The downhole tractor of  claim 1  wherein the driving mechanism is of a configuration that includes one of a sonde, a track, a chain, wheels and a pad. 
     
     
         7 . The downhole tractor of  claim 6  wherein the sonde comprises a bowspring for the interfacing. 
     
     
         8 . The downhole tractor of  claim 7  further comprising a gripping saddle of the bowspring for contacting the wall in a non-point and line manner during the interfacing. 
     
     
         9 . A downhole tractor for positioning in an open hole well, the tractor comprising: a bowspring with a gripping saddle for interfacing a wall of the well; an expandable arm coupled to said bowspring and deployable from an elongated body of the tractor to effectuate the interfacing; and a force monitoring mechanism coupled to said bowspring to monitor a force thereon during the interfacing. 
     
     
         10 . The downhole tractor of  claim 9  wherein the gripping saddle is configured to contact the wall in a non-point and line manner during the interfacing. 
     
     
         11 . The downhole tractor of  claim 9  wherein the gripping saddle comprises a surface of tungsten carbide for the interfacing. 
     
     
         12 . The downhole tractor of  claim 9  wherein the force monitoring mechanism further comprises: a pressure sensor in communication with said bowspring; and a processor coupled to said pressure sensor to regulate the force based on information obtained from said pressure sensor. 
     
     
         13 . A method of tractoring in an open hole well, the method comprising: positioning the tractor in the well; interfacing a wall of the well with a driving mechanism of the tractor for the tractoring; and monitoring a force on the driving mechanism during said interfacing. 
     
     
         14 . The method of  claim 13  wherein said monitoring comprises acquiring pressure information from a pressure sensor in communication with the driving mechanism. 
     
     
         15 . The method of  claim 14  further comprising establishing one of well diameter and tractor location from the pressure information. 
     
     
         16 . The method of  claim 14  further comprising adjusting the force on the driving mechanism based on the pressure information.