Pipe position locator

Abstract

At least one sensor is mounted for monitoring the vertical position of an elevator relative to selected features on a pipe string. Mounting for a variety of sensor types is provided. Optional mounting arrangement permits the sensors to be situated close to a pipe free to move laterally, excess lateral movement of the pipe to move the mounting with reduced shock to the sensors.

The invention having been described, we claim:  
     
         1 . A pipe string feature locator for detecting the vertical position of a pipe string suspended in a well relative to the rig elevator, the locator comprising: 
 a) a drilling rig elevator to function as a carrier for pipe feature sensors and related mounting means; and    b) at least one said pipe feature sensors mounted on said elevator and arranged to sense selected characteristics of pipe extending through the elevator and to produce an output signal indicative of the presence of selected pipe characteristics.    
     
     
         2 . The pipe string feature locator according to  claim 1  wherein said output signal is a change in the resistance to the flow of fluid through a valve actuated in response to changes in the pipe feature changes.  
     
     
         3 . The pipe string feature locator according to  claim 1  wherein said output is an electrical signal, at least part, in a digital format.  
     
     
         4 . The pipe string feature locator according to  claim 1  wherein said diameter sensor is part of a plurality of sensors, each of which has a mechanical element extending from the sensor to the surface of pipe extending through the elevator.  
     
     
         5 . The pipe string feature locator according to  claim 4  wherein said plurality of sensors, each, contribute part of the total signal.  
     
     
         6 . The pipe string feature locator according to  claim 5  wherein said sensors each carry a pulley that moves radially in sympathy with changes in sensed pipe diameter, a filament reeved about all said pulleys such that the movement of the pulleys, collectively, results in a consequent proportional change in the length of filament needed to complete the circuit about all pulleys, said change in needed filament length being satisfied by movement of an input member of a signal conditioner which produces the output signal.  
     
     
         7 . The pipe string feature locator according to  claim 1  wherein said sensor projects a stream of air toward the surface of said pipe, and detects a change in resistance to the air flow caused by changes in the characteristics of the pipe.  
     
     
         8 . The pipe string feature locator according to  claim 7  wherein said signal is conveyed as a pressure change.  
     
     
         9 . The pipe string feature locator according to  claim 1  wherein said sensors are mounted on a transition plate which is laterally movable, within limits, relative to the elevator to which it is attached, by which the sensors can be mounted closer to a pipe capable of lateral movement within the elevator.  
     
     
         10 . The pipe string feature locator according to  claim 1  wherein said sensors emit sound to impinge upon the surface of the pipe, and respond to echo characteristic to determine distance between reference features in the sensor and the pipe, said output signals from each sensor being processes to produce sensed pipe feature related information.  
     
     
         11 . The pipe string feature locator according to  claim 1  wherein the function of said sensor is achieved by the arrangement of at least two sensors on different vertical locations, by which process the sensors collectively accommodate lateral movement of said pipe, both sensing the movement, and the feature change being sensed when one sensor detects pipe string features the other sensor does not detect.  
     
     
         12 . The pipe string feature locator according to  claim 1  wherein said sensor is a light curtain comprising a plurality of laterally spaced light beams projected horizontally across space said pipe may occupy.  
     
     
         13 . The pipe string feature locator according to  claim 1  wherein said sensor is a magnetic field producing and responding arrangement.  
     
     
         14 . The pipe string feature locator according to  claim 1  wherein said sensor is a capacitive arrangement arranged to respond to the proximity of pipe and sensor to change electrical characteristics of the sensor to be interpreted in terms of changes in pipe diameter.  
     
     
         15 . A pipe string feature locator for detecting when a selected characteristic on a pipe string suspended in a well has a preseleced vertical relationship to the rig elevator, the locator comprising: 
 a) sensor means to detect at least one characteristic of the pipe that has a known vertical relationship to a location on the pipe selected for gripping with elevator mounted pipe gripping means and to produce an output signal when the characteristic is sensed;    b) a sensor mounting arrangement that places the sensor means the same distance and direction from the elevator pipe gripping means as the known distance and direction between the characteristic to be sensed and the location on the pipe selected for gripping.