Method of and apparatus for perforating boreholes

• US 4,153,118 A
• Filed: 03/28/1977
• Issued: 05/08/1979
• Est. Priority Date: 03/28/1977
• Status: Expired due to Term

• Current Assignee: Michael L. Hart
• Original Assignee: Michael L. Hart
• Inventors: Hart, Michael L.
• Primary Examiner(s): Pate, III, William
• Application Number:
  US05/781,991
• Time in Patent Office: 771 Days
• Field of Search: 175/4.51, 175/4.52, 175/77, 175/81, 175/4.55, 166/55, 166/297
• US Class Current: 175/4.51
• CPC Class Codes: E21B 43/119 Details, e.g. for locating perforating place or direction

Abstract

A perforator apparatus includes an elongate body having a center of gravity and characterized by a longitudinal axis extending through the center of gravity. The body is supported at a point substantially laterally displaced from the axis having the center of gravity therein, so that the body of the perforator apparatus pivots into a predetermined orientation under the action of gravity when the apparatus is lowered into a nonvertically aligned borehole. The apparatus includes structure for discharging perforating charges in directions having a predetermined orientation relative to a line extending from the point of suspension through the axis having the center of gravity therein. By this means the directions of the perforating charges may be oriented relative to a thin portion of a cement structure extended between the borehole and a casing disposed therein.

Claims

1. A method of perforating non-vertically oriented boreholes comprising:

suspending a well perforator apparatus from a point substantially laterally displaced from an axis extending through the center of gravity of the well perforator apparatus;

lowering the thus suspended perforator apparatus into the borehole to be perforated so that the center of gravity of the well perforator apparatus is aligned with the low side of the borehole under the action of gravity;

actuating the thus positioned well perforating apparatus to discharge a perforating charge in a predetermined direction with respect to the alignment of the center of gravity of the well perforating apparatus with the low side of the borehole;

the well perforator apparatus having a central axis;

the center of gravity of the well perforator apparatus being located on an axis substantially laterally displaced from the central axis; and

the suspending step being carried out by suspending the well perforator apparatus from a point substantially aligned with the central axis.

2. A method of perforating non-vertically oriented boreholes comprising:

suspending a well perforator apparatus from a point substantially laterally displaced from an axis extending through the center of gravity of the well perforator apparatus;

said well perforator apparatus having a central axis, with the center of gravity of the apparatus being substantially laterally displaced from the central axis, and wherein the suspending step is carried out by suspending the apparatus from a point substantially laterally displaced from the central axis;

lowering the thus suspended perforator apparatus into the borehole to be perforated so that the center of gravity of the well perforator apparatus is aligned with the low side of the borehole under the action of gravity operating directly on the well perforator apparatus to effect pivotal movement of the axis extending through the center of gravity of the well perforator apparatus about an axis extending through the point of suspension thereof; and

actuating the thus positioned well perforating apparatus to discharge a perforating charge in a predetermined direction with respect to the alignment of the center of gravity of the well perforating apparatus with the low side of the borehole.

3. A well perforating apparatus comprising:

an elongated body having a center of gravity and characterized by a longitudinal axis extending through the center of gravity;

means for suspending the body from a point substantially laterally displaced from the axis extending through the center of gravity so that the body is oriented under the action of gravity with the center of gravity thereof toward the low side of a non-vertically oriented borehole;

means for discharging at least one well perforating charge from the body in a predetermined direction with respect to the center of gravity and the point of suspension thereof;

the body having a central axis;

the center of gravity being situated on an axis substantially laterally displaced from the central axis; and

the body being suspended from a point substantially aligned with the central axis.

4. A well perforating apparatus comprising:

an elongated body having a center of gravity and characterized by a longitudinal axis extending through the center of gravity;

means for suspending the body from a point substantially laterally displaced from the axis extending through the center of gravity so that the body is oriented under the action of gravity acting directly on the elongated body to effect pivotal movement of the axis extending through the center of gravity of the elongated body about an axis extending through the point of suspension of the elongated body and thereby positioning the center of gravity thereof toward the low side of a non-vertically oriented borehole;

said body having a central axis, with the center of gravity thereof being situated on an axis substantially laterally displaced from the central axis, and wherein the body is suspended from a point substantially and laterally displaced on a central axis; and

means for discharging at least one well perforating charge from the body in a predetermined direction with respect to the center of gravity and the point of suspension thereof.