Abstract: A mechanical oscillator which employs unbalanced rotors is coupled to the top end of a drill string which has become stuck in a bore hole. The rotors are driven at a rotation speed such as to generate high level energy at a sonic frequency, this energy being coupled to the drill string. A low impedance load for the oscillator and the top of the drill string is created by supporting the oscillator from the support structure, which may comprise a derrick or the like, by means of a highly elastic support which may include elastomeric stretch bands, springs or other elastomeric support having a linear constant spring rate. In addition, hydraulic cylinders which may be servo driven are used to keep the drive motors for the oscillators in one place as the oscillator structure vibrates. The oscillators are driven at a high energy level to effect high displacement of the top of the drill string which presents a low impedance load to this energy in view of the highly elastic support provided.

Abstract: A cutting tool (10) for removing members downhole from a well bore and adapted to be inserted within a well from the upper end (12) of the casing (14). The cutting tool (10) includes a plurality of elongate blades (32) on the cylindrical body (18) of the cutting tool (10). Cutting elements (42) of a predetermined size and shape are arranged in a symmetrical predetermined pattern on each blade (32) in side-by-side relation in a plurality of predetermined transversely extending rows and a plurality of predetermined generally vertically extending columns. The cutting elements (42) in adjacent transverse rows for each blade (32) are staggered and have different concentric cutting paths. The cutting elements (42E) in corresponding transverse rows on adjacent blades (32A, 32B) are staggered and have different concentric cutting paths. The blades (32A, 32B) of the embodiment of FIGS.

Abstract: A cutting tool (10) for removing metal tubular members held in stationary position downhole from a well bore and adapted to be inserted within a well. The cutting tool (10) includes a plurality of elongate blades (32,34) on the cylindrical body (22) of the cutting tool (10) which extend below the bottom of the tool body (22). Cutting elements (42) of a predetermined size and shape are arranged in a symmetrical predetermined pattern on the lower portion of each blade (32,34) in a plurality of predetermined transversely extending rows below the tool body (22). The cutting elements (42) in adjacent transverse rows for each blade (32) are staggered horizontally and have different concentric cutting paths. Preferably, the cutting elements (42) in corresponding transverse rows on adjacent blades (32,34) are staggered and have different concentric cutting paths.

Abstract: An oil field cutting tool (10) for progressively cutting away a tubular member (14) installed within a well from the upper annular end (12) of the tubular member (14). The cutting tool (10) includes a plurality of elongate blades (32) spaced about the periphery of the cylindrical body (18) of the cutting tool (10). A plurality of cutting elements (42) of a predetermined size and shape are secured in a predetermined pattern on the leading surface of the blades (32) in a plurality of closely spaced parallel rows extending transversely between the sides of the blades (32) and in a plurality of closely spaced parallel columns extending generally longitudinally between the ends of the blades (32).

Abstract: A cutting tool (10) for removing members downhole from a well bore and adapted to be inserted within a well from the upper end (12) of the casing (14). The cutting tool (10) includes a plurality of elongate blades (32) on the cylindrical body (18) of the cutting tool (10). Cutting elements (42) of a predetermined size and shape are arranged in a symmetrical predetermined pattern on each blade (32) in side-by-side relation in a plurality of predetermined tranversely extending rows and a plurality of predetermined generally vertically extending columns. The cutting elements (42) in adjacent transverse rows for each blade (32) are staggered and have different concentric cutting paths. The cutting elements (42E) in corresponding transverse rows on adjacent blades (32A, 32B) are staggered and have different concentric cutting paths. The blades (32A, 32B) of the embodiment of FIGS.

Abstract: A cutting tool (10) for removing members downhole from a well bore and adapted to be inserted within a well from the upper end (12) of the casing (14). The cutting tool (10) includes a plurality of elongate blades (32) on the cylindrical body (18) of the cutting tool (10). Cutting elements (42) of a predetermined size and shape are arranged in a symmetrical predetermined pattern on each blade (32) in side-by-side relation in a plurality of predetermined transversely extending rows and a plurality of predetermined generally vertically extending columns. The cutting elements (42) in adjacent transverse rows for each blade (32) are staggered and have different concentric cutting paths. The cutting elements (42E) in corresponding transverse rows on adjacent blades (32A, 32B) are staggered and have different concentric cutting paths. The blades (32A, 32B) of the embodiment of FIGS.