Constant entrance hole perforating gun system and method

Patent metadata

Field	Value
Publication number	US-11268357-B2
Application number	US-202017071363-A
Country	US
Kind code	B2
Filing date	Oct 15, 2020
Priority date	Oct 13, 2016
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A perforating gun includes first and second shaped charges. Each of the shaped charges includes a case, a liner, and an explosive. Each liner has a subtended angle about an apex of the liner. A first jet formed by the first shaped charge creates a first entrance hole in a first region of a well casing, and a second jet formed by the second shaped charge, creates a second entrance hole in a second region of the casing. The second region is below the first region in the casing. A ratio of a diameter of the first entrance hole to a diameter of the second entrance hole is 1 when the subtended angle is between 100° and 110°, the ratio is less than 1 when the subtended angle is between 90° and 100°, and the ratio is greater than 1 when the subtended angle is greater than 110°.

First claim

What is claimed is:

1. A perforating gun comprising:
first and second shaped charges, wherein each of the first and second shaped charges includes a case, a liner positioned within said case, and an explosive filled within said liner;
each liner is configured with a subtended angle about an apex of said liner; and
said liner having an exterior surface, said exterior surface substantially straight and conically tapered to form said apex,
wherein a first jet formed with said first shaped charge creates a first entrance hole in a first region of a well casing,
wherein a second jet formed with said second shaped charge creates a second entrance hole in a second region of the well casing, and the second region is below to the first region along a vertical direction, and
wherein a ratio of a diameter of said first entrance hole to a diameter of the second entrance hole is 1 when the subtended angle of each liner is between 100° and 110°, the ratio is less than 1 when the subtended angle of each liner is between 90° and 100°, and the ratio is greater than 1 when the subtended angle of each liner is greater than 110°.

2. The perforating gun of claim 1 , wherein a thickness of said liner is substantially constant and wherein said thickness of said liner ranges from 0.01 to 0.2 inches.

3. The perforating gun of claim 1 , wherein the first region is a top region of the well casing and the second region is a bottom region of the well casing.

4. The perforating gun of claim 1 , wherein a diameter of the first jet is substantially equal to a diameter of the second jet, and a width and length of a first perforation tunnel created by the first jet are substantially equal to a width and length of a second perforation tunnel created by the second shaped charge.

5. The perforating gun of claim 1 , wherein said diameters of said first and second entrance holes in said well casing ranges from 0.15 to 0.75 inches, and wherein a variation of said diameters of said first and second entrance holes in said well casing is less than 7.5%.

6. The perforating gun of claim 4 , wherein said width of said first and second perforation tunnels in said hydrocarbon formation ranges from 0.15 to 1 inches, and wherein a variation of said width of said first and second perforation tunnels in said hydrocarbon formation ranges is less than 5%.

7. The perforating gun of claim 4 , wherein said length of said first and second perforation tunnels in said hydrocarbon formation ranges from 1 to 20 inches and a variation of said length of said first and second perforation tunnels in said hydrocarbon formation is less than 20%.

8. The perforating gun of claim 4 , wherein said diameter of said first and second jets ranges from 0.15 to 0.75 inches and a variation of said diameter of said first and second jets is less than 5%.

9. The perforating gun of claim 1 , wherein a diameter of said perforating gun ranges from 3 to 12 inches.

10. The perforating gun of claim 1 , wherein a position of said first shaped charge in said perforating gun is oriented in an upward direction and a position of said second shaped charge in said perforating gun is oriented in a downward direction.

11. The perforating gun of claim 1 , wherein a thickness of a water gap between the first position and the well casing ranges from 0.15 to 2.5 inches.

12. The perforating gun of claim 1 , wherein a type of said hydrocarbon formation is selected from a group comprising: shale, carbonate, sandstone or clay.

13. First and second shaped charges for use in a well, each of said first and second charges comprising:
a case,
a liner positioned within said case, and
an explosive filled between said case and said liner;
said liner configured with a subtended angle about an apex of said liner; and
said liner having an exterior surface, said exterior surface substantially straight and conically tapered to form said apex,
wherein said first shaped charge forms a first jet when exploded and the first jet forms a first entrance hole at a first position in a well casing of the well, and said second shaped charge forms a second jet when exploded and the second jet forms a second entrance hole at a second position in the well casing,
wherein the first position is above to the second position of the casing along a vertical direction, and
wherein a ratio of a diameter of the first entrance hole to a diameter of the second entrance hole is 1 when the subtended angle of each liner is between 100° and 110°, the ratio is less than 1 when the subtended angle of each liner is between 90° and 100°, and the ratio is greater than 1 when the subtended angle of each liner is greater than 110°.

14. The first and second shaped charges of claim 13 , wherein
said first and second jets each comprises a tip end, a tail end, and an extended portion positioned between said tail end and said tip end; and
a diameter of said extended portion is substantially constant from about said tip end to about said tail end,
wherein said extended portion in the first and second jets is unannihilated in a water gap when first and second jets travel through said water gap in said well casing.

15. The first and second shaped charges of claim 14 , wherein a velocity of said tip end is greater than a velocity of said tail end.

16. The first and second shaped charges of claim 15 , 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.

17. The first and second shaped charges of claim 14 , 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.

18. A stage perforation method using a perforating gun system in a wellbore casing, the method comprising the steps of:
setting up a plug and isolating a stage in the casing;
targeting an entrance hole diameter of said casing;
selecting a subtended angle about an apex of a liner for each charge of a plurality of charges so that a ratio of a diameter of a first entrance hole created by a first charge of the plurality of charges to a diameter of a second entrance hole created by a second charge of the plurality of charges is 1 when the subtended angle of a liner of the first and second charges is between 100.degree. and 110.degree., the ratio is less than 1 when the subtended angle of each liner is between 90.degree. and 100.degree., and the ratio is greater than 1 when the subtended angle of each liner is greater than 110.degree., and a variation of diameters of entrance holes created with said plurality of charges is configured to be less than 7.5%;
positioning said plurality of charges in said well casing;
perforating with said plurality of charges into a hydrocarbon formation;
creating said entrance holes with said entrance hole diameter and completing said stage; and
pumping fracture treatment in said stage at a designed rate without substantially adjusting pumping rate,
wherein the first entrance hole is above the second entrance hole of the casing along a vertical direction, and
wherein said liner has an exterior surface, said exterior surface being substantially straight and conically tapered to form said apex.

Assignees

• Geodynamics Inc

Inventors

• Yang Wenbo
• Snider Philip M
• Hardesty John T
• Wesson David S

Classifications

• E21B43/26

  by forming crevices or fractures · CPC title

• E21B43/119

  Details, e.g. for locating perforating place or direction · CPC title

• E21B43/1185

  Ignition systems · CPC title

• F42B1/028

  characterised by the form of the liner · CPC title

• E21B43/117 Primary

  Shaped-charge perforators (E21B43/118 takes precedence) · CPC title