Schlumberger Technology Corporation

Schlumberger Well Services

Gary M Lendermon

Robert A Parrott

Jack F Lands

James E Brooks

Jorge E Lopez De Cardenas

Cliff L Aseltine

A perforating gun includes a multiplicity of shaped charges, the multiplicity of shaped charges including a plurality of planes of charges, each plane of charges including a plurality (N) of shaped charges and a detonating cord running down through the axial center of each of the plurality of planes of charges. The plurality (N) of shaped charges are equally spaced at an angle 360/N about the detonating cord. The plurality of planes of charges: (1) are rotated at an angle of 180/N relative to one another, and (2) are axially packed together along the longitudinal axis of the gun so that the charges in one plane are nearly touching the charges in the adjacent plane, yet they all share the same centered detonating cord. The proximity of one plane to another is close enough such that one plane of charges detonates within a few microseconds of its neighboring plane of charges. The close packing of the shaped charges in the same plane and between adjacent planes: (1) prevent the charge cases from expanding significantly upon detonation, and (2) prevent the charge cases from breaking up into numerous small pieces (large chunks of charge case debris results). A near-maximum packing density for a given cylindrical gun volume produces two unexpected properties: (1) a reduced swelling of the gun's diameter after detonation because of the combination of the near maximum packing density and symmetric detonation of the shaped charges; and (2) a significant reduction in the amount of shaped charge case debris that can escape from the perforating gun.

Perforating gun including a unique high shot density packing arrangement

In the preferred embodiment of the new and improved perforating apparantus that is described herein, a set of end closure members are cooperatively arranged to be inserted into the open ends of a length of typical piping and expanded radially outwardly into contact with the rough and irregular internal wall surface in each end of the pipe. Anchor members and sealing members are arranged on each and closure member for releasably securing and sealingly engaging these end closure members in the ends of the pipe when the end closure members are respectively expanded outwardly so that no machining operations are required to prepare the internal wall surfaces of the pipe before it can be employed as an expendable perforating carrier.

Enclosed perforating gun with expendable carrier

Various charge phasing arrangements in a perforating gun include those uniquely associated with phasing solely along a 180 degree circumference of the perforating gun, for use in but not limited to deviated boreholes. One phasing arrangement comprises four rows of charges, four corresponding rows of recesses in the perforating gun carrier and four corresponding rows of holes in the loading tube, the recesses, holes and charges being constrained within a 180 degree circumference of the perforating gun. The two outermost rows have more recesses, more holes and more charges than do the two innermost rows, since more well fluid is interposed between the two outermost rows and the casing than is interposed between the two innermost rows and the casing of the borehole. Another phasing arrangement comprises five rows of charges, recesses and holes, in lieu of the four of the former embodiment, constrained within the 180 degree circumference, adjacent rows being disposed more closely together in this embodiment than in the former embodiment. A third phasing arrangement comprises eighteen rows of charges, recesses and holes disposed around the entire 360 degrees of the circumference of the gun and borehole. The recesses, holes and charges in all embodiments are uniformly distributed to prevent splitting of the borehole casing, and the charge density in shots per foot for all embodiments of invention is high enough to ensure that a significant quantity of formation fluid is produced from the surrounding formation.

Charge phasing arrangements in a perforating gun

In the representative embodiment of the new and improved perforating apparatus described herein, shaped charge cases are provided with matching upper and lower supports with parallel abutment surfaces and alignment means cooperatively arranged to enable a plurality of these charge cases to be stacked together for erecting an intertwined assembly of cases. By appropriately selecting the combined heights of the matching supports, adjacent ones of the charge cases can be closely spaced one above the other and directed outwardly along selected radial perforating axes at uniform angular spacings.

Growing community of inventors

Missouri City, TX, United States of America

Gary M Lendermon