Hole opener for the top hole section of oil/gas wells

A hole opener used in conjunction with drilling in at least one of boulder and rubble stone formations, the hole opener comprising:

• first and second sets of cutters;
• a tubular carrier body;
• first means for fixing the first set of cutters to the tubular carrier body so that the first set of cutters is positioned in a common first lateral plane with respect to a longitudinal axis of the tubular carrier body;
• second means for fixing the second set of cutters to the tubular carrier body so that the second set of cutters is located in a second lateral plane with respect to the longitudinal axis of the tubular carrier body and at an axial distance from the first set of cutters along the longitudinal axis;
• and
• a plurality of wedges;
• wherein the first means combined with each of the cutters of the first set of cutters extends a first radial distance from the longitudinal axis and the second means combined with each of the cutters of the second set of cutters extends a second radial distance from the longitudinal axis, and the first radial distance is less than the second radial distance;
• wherein each of the cutters of the first and second sets of cutters includes a shaft with the shafts of the first and second sets of cutters being respectively releasably coupled to the first and second means;
• wherein for each of the shafts of the first and second sets of cutters the first and second means respectively include an outwardly open conical cavity for accommodating a corresponding shaft of the first and second sets of cutters and two mutually corresponding holes which are laterally oriented relative to the conical cavity, a corresponding one of the plurality of wedges is locatable in the two mutually corresponding holes of each of the first and second means to respectively lock the corresponding shaft of the first and second sets of cutters to the first and second means, each of the shafts of the first and second sets of cutters has a lateral through-hole relative to its corresponding conical cavity in which the corresponding one of the plurality of wedges is located when the cutters of the first and second sets of cutters and locked to the first and second means, and the axis of each of the lateral through-holes forms a non-perpendicular angle with an axis of the corresponding shaft.

A hole opener used in conjunction with drilling in at least one of boulder and rubble stone formations, the hole opener comprising:

• first and second sets of cutters;
• a tubular carrier body;
• a stabilizer disposed on the tubular carrier body;
• a wear ring disposed on the tubular carrier body;
• first means for fixing the first set of cutters to the tubular carrier body so that the first set of cutters is positioned in a common first lateral plane with respect to a longitudinal axis of the tubular body carrier;
• and
• second means for fixing the second set of cutters to the tubular carrier body so that the second set of cutters is located in a second lateral plane with respect to the longitudinal axis of the tubular carrier body and at an axial distance from the first set of cutters along the longitudinal axis;
• wherein the first means combined with each of the cutters of the first set of cutters extends a first radial distance from the longitudinal axis, the second means combined with each of the cutters of the second set of cutters extends a second radial distance from the longitudinal axis, and the first radial distance is less than the second radial distance;
• wherein the stabilizer includes a stabilizing fins each having a radially extending outer end relative to the longitudinal axis and a plurality of wear members, each of the plurality of wear members releasably attached to a corresponding outer end of the stabilizer;
• wherein the stabilizer and the wear ring are separated by a space along the longitudinal axis, the first and second means are located within the space, and the stabilizer and the wear ring are each anchored on the tubular carrier body by at least one of a claw coupling and a jaw clutch.

A hole opener used in conjunction with drilling in at least one of boulder and rubble stone formations, the hole opener comprising:

• first and second sets of cutters, each of the cutters of the first and second sets of cutters having cutter teeth thereon and further including a shaft;
• a tubular carrier body;
• first means for fixing the first set of cutters to the tubular carrier body so that the first set of cutters is positioned in a common first lateral plane with respect to a longitudinal axis of the tubular carrier body;
• second means for fixing the second set of cutters to the tubular carrier body so that the second set of cutters is located in a second lateral plane with respect to the longitudinal axis of the tubular carrier body and at an axial distance from the first set of cutters along the longitudinal axis;
• wherein the first means combined with each of the cutters of the first set of cutters extends a first radial distance from the longitudinal axis, the second means combined with each of the cutters of the second set of cutters extends a second radial distance from the longitudinal axis, and the first radial distance is less than the second radial distance;
• wherein each of the shafts of the cutters of the first and second sets of cutters are rotatably and releasably connected to a corresponding one of the first and second means.