Constant entrance hole perforating gun system and method
A shaped charge comprising a case, a liner positioned within the case, and an explosive filled within the case. The liner is shaped with a subtended angle ranging from 100° to 120° about an apex, a radius, and an aspect ratio such that a jet formed with the explosive creates an entrance hole in a well casing. The jet creates a perforation tunnel in a hydrocarbon formation, wherein a diameter of the jet, a diameter of the entrance hole diameter, and a width and length of the perforation tunnel are substantially constant and unaffected with changes in design and environmental factors such as a thickness and composition of the well casing, position of the charge in the perforating gun, position of the perforating gun in the well casing, a water gap in the wellbore casing, and type of the hydrocarbon formation.
1. A shaped charge for use in a perforating gun, said charge comprising:
a case,
a liner positioned within said case, and
an explosive filled within said liner;
said liner shape configured with a subtended angle about an apex of said liner such that a jet formed with said explosive creates an entrance hole in a well casing;
said subtended angle of said liner is larger than 90° and smaller than 120°;
said liner having an exterior surface, said exterior surface substantially straight and conically tapered to form said apex;
said jet creates a perforation tunnel in a hydrocarbon formation;
wherein a diameter of said jet is substantially equal to a diameter of a second jet created by a second shaped charge, a diameter of said entrance hole is substantially equal to a diameter of a second entrance hole created by said second shaped charge, and a width and length of said perforation tunnel are substantially equal to a width and length of a second perforation tunnel created by said second shaped charge.
2. The shaped charge of claim 1 wherein a thickness of said liner is substantially constant.
3. The shaped charge of claim 1 wherein said diameter of said entrance hole in said well casing ranges from 0.15 to 0.75 inches.
4. The shaped charge of claim 1 wherein a variation of said diameter of said entrance hole in said well casing is less than 7.5%.
5. The shaped charge of claim 1 wherein said width of said perforation tunnel in said hydrocarbon formation ranges from 0.15 to 1 inches.
6. The shaped charge of claim 1 wherein a variation of said width of said perforation tunnel in said hydrocarbon formation ranges is less than 5%.
7. The shaped charge of claim 1 wherein said length of said perforation tunnel in said hydrocarbon formation ranges from 1 to 20 inches.
8. The shaped charge of claim 1 wherein a variation of said length of said perforation tunnel in said hydrocarbon formation is less than 20%.
9. The shaped charge of claim 1 wherein said diameter of said jet ranges from 0.15 to 0.75 inches.
10. The shaped charge of claim 1 wherein a variation of said diameter of said jet is less than 5%.
11. The shaped charge of claim 1 wherein a thickness of said well casing ranges from 0.20 to 0.75 inches.
12. The shaped charge of claim 1 wherein a diameter of said well casing ranges from 4 to 6 inches.
13. The shaped charge of claim 1 wherein a diameter of said gun ranges from 3 to 12 inches.
14. The shaped charge of claim 1 wherein a position of said charge in said perforating gun is oriented in an upward direction.
15. The shaped charge of claim 1 wherein a position of said charge in said perforating gun is oriented in a downward direction.
16. The shaped charge of claim 1 wherein a position of said perforating gun in said well casing is centralized.
17. The shaped charge of claim 1 wherein a position of said perforating gun in said well casing is decentralized.
18. The shaped charge of claim 1 wherein a thickness of a water gap ranges from 0.15 to 2.5 inches.
19. The shaped charge of claim 1 wherein a type of said hydrocarbon formation is selected from a group comprising: shale, carbonate, sandstone or clay.
20. The shaped charge of claim 1 wherein said charge is selected from a group comprising: reactive, or conventional charges.
21. A shaped charge for use in a perforating gun, said charge comprising:
a case,
a liner positioned within said case, and
an explosive filled between said case and said liner;
said liner shape configured with a subtended angle about an apex of said liner such that said explosive forms a constant jet when exploded;
said liner having an exterior surface, said exterior surface substantially straight and conically tapered to form said apex;
said subtended angle of said liner is larger than 90° and smaller than 120°;
said jet further comprising a tip end, a tail end, and an extended portion positioned between said tail end and said tip end;
a diameter of said extended portion is substantially constant from about said tip end to about said tail end; and
wherein a diameter of an entrance hole created by said jet is substantially equal to a diameter of a second entrance hole created by a second shaped charge.
22. The shaped charge of claim 21 wherein said extended portion in said jet is unannihilated in a water gap when said jet travels through said water gap in said well casing.
23. The shaped charge of claim 21 wherein a velocity of said tip end is slightly greater than a velocity of said tail end.
24. The shaped charge of claim 21 wherein said extended portion is substantially not stretched; said extended portion maintaining said diameter after entry into a hydrocarbon formation until said tip end enters said formation.
25. The shaped charge of claim 21 wherein said extended portion is substantially not stretched; said extended portion maintaining said diameter before entry into a hydrocarbon formation until said tip end enters said formation.
26. A stage perforation method using a perforating gun system in a wellbore casing; said system comprising a plurality of shaped charges; each of said plurality of charges are configured to create an entrance hole in said casing; each of said plurality of charges are configured with a liner having a subtended angle about an apex of said liner; said liner having an exterior surface, said exterior surface substantially straight and conically tapered to form said apex; said subtended angle of said liner is larger than 90° and smaller than 120°; a variation of diameters of entrance holes created with said plurality of charges is configured to be less than 7.5%; wherein said method comprises the steps of:
(1) setting up a plug and isolating a stage;
(2) targeting an entrance hole diameter of said entrance hole;
(3) selecting an explosive load, a subtended angle, a radius and an aspect ratio for each of said plurality of charges;
(4) positioning said system along with said plurality of charges in said well casing;
(5) perforating with said plurality of charges into a hydrocarbon formation;
(6) creating said entrance hole with said entrance hole diameter and completing said stage; and
(7) pumping fracture treatment in said stage at a designed rate without substantially adjusting pumping rate.
27. A shaped charge for use in a perforating gun, said charge comprising:
a case,
a liner positioned within said case, and
an explosive filled within said liner;
said liner shape configured with a subtended angle about an apex of said liner such that a jet formed with said explosive creates an entrance hole in a well casing; said subtended angle of said liner is larger than 90° and smaller than 120°;
said liner not substantially shaped elliptically, oval, or semi-oval;
said jet creates a perforation tunnel in a hydrocarbon formation; wherein a diameter of said jet is substantially equal to a diameter of a second jet created by a second shaped charge in a second perforating gun, a diameter of said entrance hole is substantially equal to a diameter of a second entrance created by said second shaped charge in said second perforating gun, and a width and length of said perforation tunnel are substantially constant equal to a width and length of a second perforation tunnel created by said second shaped charge in said second perforating gun.
28. The shaped charge of claim 27 wherein said second shaped charge is positioned in a second perforating gun.