Well plugging apparatus and method

Abstract

An apparatus for plugging a burning or gushing well comprises a hollow tubular plug body (20) sized for insertion into a well casing (112). Provided on the plug body are a retainer module (54) for retaining the plug within the well casing; a sealing sleeve (46) provided for forming a seal between the plug body and the well casing; and a valve assembly (50) for selectively closing a hollow internal passageway of the tubular plug body. The plug body is loaded on a gantry assembly (21), which in turn is carried by a shielded vehicle (24). At the base of the gantry assembly are provided an alignment assembly (37) for aid in approach to the well casing and a cutter assembly (40) for sawing off inordinately protruding casings. In one embodiment, a protective break-away shell (118) circumferentially surrounds at least a portion of the plug body.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. An apparatus for plugging a burning or gushing well, the apparatus comprising: a tubular plug body for sealing insertion and retention in a well casing, the plug body having a selectively closable hollow internal passageway;   a gantry assembly upon which the plug body is suspended above the well casing;   a sensor assembly provided at a lower end of the gantry assembly for sensing proximity to the well casing.   
     
     
       2. The apparatus of claim 1, wherein the sensor assembly comprises: a fork which horizontally extends from the gantry assembly;   a plurality of sensors located on the fork in predetermined positions.   
     
     
       3. The apparatus of claim 2, wherein the fork has two fork members connected to provide the fork with a V-shape, and wherein the plurality of sensors are provided on facing surfaces of the two fork members, the two fork members being oriented to accommodate the well casing therebetween. 
     
     
       4. A method for plugging a burning or gushing well, the method comprising: sensing with a sensor assembly a relative positioning between a well casing and a plug body to be inserted in the well casing, and providing a positioning signal from said sensor assembly in accordance with the sensed relative positioning;   inserting a tubular plug body into the well casing when the positioning signal indicates a proper relative positioning.   
     
     
       5. The method of claim 4, further comprising: locking the plug body into the well casing by actuating a retainer;   forming a seal between the peripheral surface of the plug body and the well casing;   selectively closing the hollow internal passageway of the tubular plug body. .Iadd.   
     
     
       6.  A ball valve assembly comprising: a valve case having an interior space which communicates with first and second axial ports of the valve case;   a ball rotatably positioned within the valve case, the ball having an axial central opening therein;   a first cable having a first end attached within the interior space of the valve case to the ball to rotate selectively the ball to one of a first position and a second position, the first position having the axial central opening of the ball aligned with the axial ports of the valve case and the second position not having the axial central opening of the ball aligned with the axial ports of the valve case, a second end of the first cable being remotely positioned with respect to the valve case. .Iaddend..Iadd.7. The apparatus of claim 6, further comprising a second cable having a second cable first end attached within the interior space of the valve case to the ball and a second cable second end being remotely positioned with respect to the valve case for selectively rotating the ball from the second position to the first position. .Iaddend..Iadd.8. The apparatus of claim 7, wherein within the interior space of the valve case the ball has a raceway provided therein for at least one of the first cable and the second cable. .Iaddend..Iadd.9. The apparatus of claim 7, wherein the valve case has a raceway internally provided therein for at least one of the first cable and the second cable. .Iaddend..Iadd.10. The apparatus of claim 6, wherein within the interior space of the valve case the ball has a raceway provided therein for the cable. .Iaddend..Iadd.11. The apparatus of claim 6, wherein the valve case has a raceway internally provided therein for the cable. .Iaddend.