Wellbore logging system

Abstract

A logging system for use in a borehole formed in an earth formation, comprising a tubular element to be installed in the borehole, and a logging member including a conduit having an inlet opening and being movable in radial direction of the tubular element between a retracted position in which the logging member is substantially arranged within the tubular element and an extended position in which the logging member extends beyond the tubular element so that said inlet opening is in fluid communication with the earth formation when the tubular element is installed in the borehole, the logging system further comprising an activating device for moving the logging member between the retracted position and the extended position thereof.

We claim:  
     
         1 . A logging system for use in a borehole formed in an earth formation, comprising a tubular element to be installed in the borehole, and a logging member including a conduit having an inlet opening and being movable in a radial direction of the tubular element between a retracted position in which the logging member is substantially arranged within the tubular element and an extended position in which the logging member extends beyond the tubular element so that said inlet opening is in fluid communication with the earth formation when the tubular element is installed in the borehole, the logging system further comprising an activating device for moving the logging member between the retracted position and the extended position thereof.  
     
     
         2 . The logging system of    claim 1   , wherein the logging member includes a pad which extends against the borehole wall when the tubular element is installed in the borehole and the logging member is in its extended position.  
     
     
         3 . The logging system of    claim 2   , further comprising a telescoping member interconnecting the pad and the tubular element and being arranged to perform a telescoping movement so as to move the logging member between the retracted position and the extended position thereof.  
     
     
         4 . The logging system of    claim 2   , wherein the pad forms a primary pad and the activating device includes a secondary pad arranged to bias the logging member from the retracted position to the extended position thereof.  
     
     
         5 . The logging system of    claim 4   , wherein the activating device is provided with a fluid chamber, and the secondary pad is provided with a tube arranged to provide fluid communication between said conduit and the fluid chamber when the secondary pad is biased against the logging member.  
     
     
         6 . The logging system of    claim 4   , wherein said conduit is provided with a valve preventing flow of earth formation fluid into the tubular element when the valve is in the closed position, and wherein the secondary pad is arranged to open the valve when the secondary pad biases against the logging member.  
     
     
         7 . The logging system of    claim 1   , wherein the activating device is removably arranged within the tubular element.  
     
     
         8 . The logging system of    claim 1   , wherein the activating device is provided with means for determining a characteristic of earth formation fluid entering the conduit when said inlet opening is in fluid communication with the earth formation.  
     
     
         9 . The logging system of    claim 8   , wherein said characteristic includes a pressure of the earth formation fluid entering the conduit.  
     
     
         10 . The logging system of    claim 1   , wherein at least one of the logging member and the activating device forms an RFT logging tool.  
     
     
         11 . The logging system of claim l, wherein the tubular element forms one of a wellbore casing, a wellbore liner and a drill string.  
     
     
         12 . The logging system of    claim 1   , wherein the tubular element is internally provided with a latching assembly for latching the activating device to the tubular element.