Patent ID: 8943944
Filing Date: 2015-02-03
Classification: E21B

Abstract:
1. A structure for gunpowder charge for a multi-frac composite perforation device that comprises an inner gunpowder box between adjacent perforating charges in the charge frame 1 of said perforation device, said structure for gunpowder charge comprises a outer gunpowder box 4 attached to the outer wall of the charge frame 1 , wherein said outer gunpowder box 4 comprises a middle gunpowder box 3 and two side-hung gunpowder boxes 2 A and 2 B, wherein said boxes 2 A and 2 B are separately located on the two sides of said middle gunpowder box 3 , and wherein the gunpowders charged in said inner gunpowder box and outer gunpowder box 4 are classified into three types: high burning rate gunpowder having combustion endpoint of 25˜80 ms, middle burning rate gunpowder having combustion endpoint of 80˜280 ms and low burning rate gunpowder having combustion endpoint of 300˜800 ms.