Abstract: This invention provides a multi-frac composite perforation device having (i) a gun body having an outer wall, (ii) an inner gunpowder box between adjacent perforating charges in the charge frame 1 of said perforation device, and (iii) a structure for gunpowder charge with an outer gunpowder box 4 attached to an outer wall of the charge frame 1, the gun body has a pressure releasing structure corresponding to a closed end of the perforating charge. This invention further provides a method of using the multi-frac composite perforating device to fracture a formation and the choice of gunpowders and gun body thickness with regards to the pressure required for fracturing a formation.

Abstract: This invention provides a structure for gunpowder charge in multi-frac composite perforation devices that is easy to assemble and transport while the charge volume of gunpowder is increased. In one embodiment of the present invention, an triplet outer gunpowder box is attached onto the outer wall of the charge frame and comprises one middle gunpowder box charged with gunpowder of certain burning rate, and two side-hung gunpowder boxes charged with gunpowder of another burning rate. The two side-hung gunpowder boxes are separately located on the two sides of the middle gunpowder box and are connected with the middle gunpowder box as a unit. The middle gunpowder box is located at a position corresponding to the perforating charge, and has an inner groove for orienting the perforating charge and a through hole through which the jet flow passes.

Abstract: This invention provides a structure for gunpowder charge in multi-frac composite perforation devices that is easy to assemble and transport while the charge volume of gunpowder is increased. In one embodiment of the present invention, an triplet outer gunpowder box is attached onto the outer wall of the charge frame and comprises one middle gunpowder box charged with gunpowder of certain burning rate, and two side-hung gunpowder boxes charged with gunpowder of another burning rate. The two side-hung gunpowder boxes are separately located on the two sides of the middle gunpowder box and are connected with the middle gunpowder box as a unit. The middle gunpowder box is located at a position corresponding to the perforating charge, and has an inner groove for orienting the perforating charge and a through hole through which the jet flow passes.

Abstract: The present invention relates to a composite perforating device with scallops on its inner wall to improve the depth of penetration in the oil reservoir during perforation of oil and gas well. In one embodiment, the scallops on the inner wall of the gun body are located at a position corresponding to the open end of a perforating charge. In one embodiment, the scallop may have a stepped-cylindrical or truncated-conical inner peripheral surface and a conical or flat bottom surface. Alternatively, the scallop may have an inner conical surface. The scallops on the inner wall of the gun body increased the burst heights of the perforating charges such that the penetration depth of the perforating device is increased.