Low-drag perforating gun scallops and method

Abstract

A perforating gun for making perforations in a well, the perforating gun including a carrier extending along a longitudinal axis X and having a bore; a tube extending along the longitudinal axis X and having a radius smaller than a radius of the carrier so that the tube slides inside the bore of the carrier; a shaped charge placed inside the tube and configured to make a hole through the carrier; and a scallop formed in a body of the carrier, corresponding to a location of the shaped charge along the longitudinal axis X. The scallop has a side surface that makes an angle α with the longitudinal axis X, and the angle α is different from 90 degrees.

What is claimed is: 
     
         1 . A perforating gun for making perforations in a well, the perforating gun comprising:
 a carrier extending along a longitudinal axis X and having a bore;   a tube extending along the longitudinal axis X and having a radius smaller than a radius of the carrier so that the tube slides inside the bore of the carrier;   a shaped charge placed inside the tube and configured to make a hole through the carrier; and   a scallop formed in a body of the carrier, corresponding to a location of the shaped charge along the longitudinal axis X,   wherein the scallop has a side surface that makes an angle α with the longitudinal axis X, and the angle α is different from 90 degrees.   
     
     
         2 . The perforating gun of  claim 1 , wherein the angle α is between 15 and 80 degrees. 
     
     
         3 . The perforating gun of  claim 1 , wherein the scallop is made on an external surface of the body of the carrier. 
     
     
         4 . The perforating gun of  claim 1 , wherein a value of the angle α is correlated with a value of an internal diameter of the carrier. 
     
     
         5 . The perforating gun of  claim 1 , wherein the scallop has a bottom circular circumference and a top non-circular circumference. 
     
     
         6 . The perforating gun of  claim 5 , wherein the top non-circular circumference is elliptical. 
     
     
         7 . The perforating gun of  claim 5 , wherein the top non-circular circumference has first and second diameters, with the first diameter being larger than the second diameter. 
     
     
         8 . The perforating gun of  claim 7 , wherein the first diameter is substantially equal to an outside diameter of the shaped charge. 
     
     
         9 . The perforating gun of  claim 1 , wherein the side surface of the scallop is formed of a first region having a first curvature radius and a second region having a second curvature region. 
     
     
         10 . The perforating gun of  claim 9 , wherein the first curvature radius is smaller than the second curvature radius. 
     
     
         11 . The perforating gun of  claim 1 , wherein a longitudinal axis Z of the shaped charge makes a non-zero angle with a radial axis R of the carrier, and a central point of the scallop is located along the longitudinal axis Z. 
     
     
         12 . A carrier of a perforating gun for making perforations in a well, the carrier comprising:
 a body extending along a longitudinal axis X and having a bore; and   a scallop formed in the body of the carrier, corresponding to a location of a shaped charge of the perforating gun along the longitudinal axis X,   wherein the scallop has a side surface that makes an angle α with the longitudinal axis X, and the angle α is different from 90 degrees.   
     
     
         13 . The carrier of  claim 12 , wherein the angle α is between 15 and 80 degrees. 
     
     
         14 . The carrier of  claim 12 , wherein the scallop is made on an external surface of the body. 
     
     
         15 . The carrier of  claim 12 , wherein a value of the angle α is correlated with a value of an internal diameter of the carrier. 
     
     
         16 . The carrier of  claim 12 , wherein the scallop has a bottom circular circumference and a top non-circular circumference. 
     
     
         17 . The carrier of  claim 16 , wherein the top non-circular circumference is elliptical having first and second diameters, with the first diameter being larger than the second diameter. 
     
     
         18 . The carrier of  claim 17 , wherein the first diameter is substantially equal to an outside diameter of the shaped charge. 
     
     
         19 . The carrier of  claim 12 , wherein the side surface of the scallop is formed of a first region having a first curvature radius and a second region having a second curvature region, and wherein the first curvature radius is smaller than the second curvature radius. 
     
     
         20 . The carrier of  claim 12 , wherein a longitudinal axis Z of the shaped charge makes a non-zero angle with a radial axis R of the carrier, and a central point of the scallop is located on the longitudinal axis Z.