Abstract: A cutting tool (22) having elongate cutter arms (36) mounted about a pivot pin (40) for outward swinging movement. Cutting blades (58, 60) are mounted on the lower ends of the cutter arms (36) and have a plurality of closely fitting hard carbide cutting elements (90) secured thereto and forming an inclined leading planar cutting surface (82) inclined from the upper end of the associated blade (58, 60) at an angle A between one (1) degree and twenty (20) degrees relative to the direction of rotation. The cutting elements (90) have parallel rear and front faces (90A, 90B) connected by a peripheral side surface (90C) extending perpendicularly to the parallel faces (90A, 90B).

Abstract: A milling tool (10) for processively cutting away a section of casing (14) installed within a well from the upper annular end (12) of the casing (14). The milling tool (10) includes a plurality of elongate blades (32) equally spaced from each other at intervals between one and three inches about the periphery of the cylindrical body (18) of the milling tool (10). The blades (32) are inclined with respect to the axis of rotation and hard carbide cutting discs (34) arranged in horizontal rows on the blades (32) form the inclined leading planar face of the blades (32), and the lowermost row of discs (34) forms a cutting edge with a negative rake engaging the upper end (12) of the casing (14) in a cutting operation.

Abstract: A stabilizer (36) mounted on a mandrel (14) of a workstring (12) within a casing (10) of a well bore hole. The stabilizer (36) has an upper carrier (38) fixed to the mandrel (14) and a lower carrier (40) mounted on the mandrel (14) for relative sliding movement. Shoes (70) are mounted by links or arms (64, 74) to bearing housing (50, 80) on the carriers (38, 40). The bearing housings (50, 80) are mounted for relative rotation on the carriers (38, 40) and permit the mandrel (14) and workstring (12) to rotate relative to the shoes (70) upon fluid actuation of lower carrier (40) and engagement of the casing (10) by the shoes (70).

Abstract: A locking pipe sub is disclosed including a threaded pin connection for engaging, for example, a pipe stuck in a well bore. The threads on the pin are formed in two sections which are adapted to align upon initial make-up of the sub to the stuck pipe, but to misalign, both axially and radially, when reverse torque is applied to the sub. The result is to create axial and radial forces between the threads of the sub and the threads of the stuck pipe which positively lock the sub against disconnection from the pipe except with the use of a releasing tool.

Abstract: A method and apparatus are disclosed for sequentially treating two vertically separated zones in a well bore, utilizing a packer having a fluid passageway therethrough set between the zones, a pressure shearable plug at the lower end of the packer, and a retrievable fluid plug at the upper end of the packer. Once the packer, with the shear plug on its lower end, is set in the well bore between the two zones, the retrievable plug is placed in the upper end of the packer to isolate the shear plug from well pressure in the upper zone, and the desired treating steps are performed on the upper zone. The retrievable fluid plug is then removed and tubing run to the packer to establish communication with the shearable fluid plug. The shearable plug permits static pressure testing of the tubing string and seals before communication is established with the lower zone, and then may be removed by elevating fluid pressure to sufficiently shear the plug.

Abstract: A method and apparatus are disclosed for sequentially treating two vertically separated zones in a well bore, utilizing a packer having a fluid passageway therethrough set between the zones, a pressure shearable plug at the lower end of the packer, and a retrievable fluid plug at the upper end of the packer. Once the packer, with the shear plug on its lower end, is set in the well bore between the two zones, the retrievable plug is placed in the upper end of the packer to isolate the shear plug from well pressure in the upper zone, and the desired treating steps are performed on the upper zone. The retrievable fluid plug is then removed and tubing run to the packer to establish communication with the shearable fluid plug. The shearable plug permits static pressure testing of the tubing string and seals before communication is established with the lower zone, and then may be removed by elevating fluid pressure to sufficiently shear the plug.

Abstract: A method and apparatus are disclosed for sequentially treating two vertically separated zones in a well bore, utilizing a packer having a fluid passageway therethrough set between the zones, a pressure shearable plug at the lower end of the packer, and a retrievable fluid plug at the upper end of the packer. Once the packer, with the shear plug on its lower end, is set in the well bore between the two zones, the retrievable plug is placed in the upper end of the packer to isolate the shear plug from well pressure in the upper zone, and the desired treating steps are performed on the upper zone. The retrievable fluid plug is then removed and tubing run to the packer to establish communication with the shearable fluid plug. The shearable plug permits static pressure testing of the tubing string and seals before communication is established with the lower zone, and then may be removed by elevating fluid pressure to sufficiently shear the plug.

Abstract: A method and apparatus are disclosed for drilling a bore hole using a dual concentric drill pipe. Air is supplied through the outer pipe to the bit to cool the bit and jet cuttings upwardly in the bore hole to a suction inlet leading from the bore hole to the inner pipe. A negative pressure is applied to the inner pipe to bail the cuttings up the inner pipe. Makeup air flows down the annulus in the bore hole to the suction inlet and prevents upward movement of dust in the bore hole. A bore hole enlarging bit is disclosed and has expansible cutters which are expanded by hydraulic fluid pressure. In one form, the expansible cutters can also be retracted by hydraulic fluid pressure. The enlarging bit is employed to enlarge a pilot bore hole from a selected beginning location to the bottom of the pilot bore hole to form a blast chamber.

Abstract: A rotary bore hole enlarging bit is connected to a rotary pipe string having a drilling fluid flow path and an actuator flow path. The bit comprises a body structure including inner and outer telescopic body sections, expansible and retractible arms carrying cutters on the outer body section and an expander on the inner body section engageable with the arms to expand the arms and cutters upon telescopic movement of body sections in one relative direction. A piston and cylinder is provided between the inner and outer body sections to secure relative telescopic movement between the body sections. A first passage is disposed in the body structure and expansible arms and cutters for conducting drilling fluid to the cutters from the drilling fluid flow path, there being a second passage in the body structure for conducting actuator fluid to the piston and cylinder from the actuator fluid flow path.

Abstract: A method and apparatus are disclosed for sequentially treating two vertically separated zones in a well bore, utilizing a packer having a fluid passageway therethrough set between the zones, a pressure shearable plug at the lower end of the packer, and a retrievable fluid plug at the upper end of the packer. Once the packer, with the shear plug on its lower end, is set in the well bore between the two zones, the retrievable plug is placed in the upper end of the packer to isolate the shear plug from well pressure in the upper zone, and the desired treating steps are performed on the upper zone. The retrievable fluid plug is then removed and tubing run to the packer to establish communication with the shearable fluid plug. The shearable plug permits static pressure testing of the tubing string and seals before communication is established with the lower zone, and then may be removed by elevating fluid pressure to sufficiently shear the plug.

Abstract: A junk basket having a housing with cutting means on the lower end thereof and junk retaining means supported within the housing, a valve assembly mounted within the housing above the junk retaining means and including a tubular valve housing valve means for controlling flow through the valve housing, pressure responsive operating means for actuating the valve means whereby the valve means is moved between open and closed positions responsive to the stopping and starting of the flow of drilling fluids through the housing, means providing circulating of fluid through the valve housing and the basket housing when the valve means is closed, cam means for supporting the valve means in open position in one position of the cam means and releasing support from the valve means to allow it to close in a second position and stepping means for actuating the cam means between its first and second positions responsive to the starting and stopping of flow of drilling fluid through the housing.

Abstract: Apparatus is disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe via a cross-over sub, through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. After the cutters are fully expanded, additional air is utilized to clean and cool the cutters. Air is returned through the inner pipe of the dual concentric pipe string. A venturi device is utilized to induce return flow through the inner pipe during enlargement of the hole and to vacuum residue when enlargement is completed. The dual concentric pipe string is made up of lengths of pipe providing threaded, sealed joint.

Abstract: Apparatus is disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth dormation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe, a cross-over sub and through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expandible bit while a limited portion of the air supplied cools the cutters. The dual concentric pipe is made up by joints having pin and box structures which provide inner and outer flow passages and shoulders which abut between the outer members and which are resiliently sealed between the inner members.

Abstract: The method is disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe, through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a milited portion of the air supplied cools the cutters. After the cutters are fully expanded, additional air is utilized to clean and cool the cutters. Air is returned through the inner pipe of the dual concentric pipe string. A venturi device is utilized to induce return flow through the inner pipe during enlargement of the hole and to vacuum residue when enlargement is completed. The dual concentric pipe string is made up of lengths of pipe providing threaded, sealed joints.

Abstract: A pilot hole of a preselected diameter is drilled with a suitable bit in an earth formation to a desired depth. The bit is withdrawn from the hole, and an expandable hole opener or underreamer run in the pilot hole with its cutters fully retracted and closely adjacent to each other. When the depth is reached at which enlargement of the pilot hole is to commence to produce a blast chamber, the cutters are forced laterally outwardly by fluid pressure while the hole opener is rotated, without moving the hole opener axially of the pilot hole, to cut the wall of the pilot hole and increase its diameter to the extent determined by maximum expansion of the cutters, thereby forming the upper end of the enlarged blast chamber.

Abstract: Method and apparatus are disclosed for drilling a pilot hole and subsequently enlarging the pilot hole in earth formation. A dual concentric pipe string is used for circulating air downwardly through the outer pipe, through a pilot bit and upwardly through the bore hole outside the pipe string to bail cuttings, during drilling of the pilot hole. The air pressure expands the cutters of an expansible bit while a limited portion of the air supplied cools the cutters. After the cutters are fully expanded, additional air is utilized to clean and cool the cutters. Air is returned through the inner pipe of the dual concentric pipe string. A venturi device is utilized to induce return flow through the inner pipe during enlargement of the hole and to vacuum residue when enlargement is completed. The dual concentric pipe string is made up of lengths of pipe providing threaded, sealed joints.

Abstract: The upper end of a rotary drill bit having initially retracted expansible cutters is connected to a stabilizer having initially retracted expansible stabilizer members, the upper end of the stabilizer being connectable to a rotary drill pipe string. The apparatus is lowered in a bore hole on the drilling string and rotated, the cutters being expanded to cut into the bore hole and enlarge it to a desired diameter, the apparatus being lowered to progressively continue enlarging the hole in a downward direction. Upon the stabilizer moving into the enlarged hole, its stabilizer members are expanded laterally to an extent conforming to the enlarged hole diameter, being engageable with the wall of the bore hole to stabilize the bit therebelow.