U.S. patent application number 15/080251 was filed with the patent office on 2017-09-28 for optimal phasing of charges in a perforating system and method.
This patent application is currently assigned to GEODynamics, Inc.. The applicant listed for this patent is GEODynamics, Inc.. Invention is credited to John T. Hardesty.
Application Number | 20170275975 15/080251 |
Document ID | / |
Family ID | 59896862 |
Filed Date | 2017-09-28 |
United States Patent
Application |
20170275975 |
Kind Code |
A1 |
Hardesty; John T. |
September 28, 2017 |
OPTIMAL PHASING OF CHARGES IN A PERFORATING SYSTEM AND METHOD
Abstract
An optimal phasing perforating phased gun system and method for
accurate perforation in a deviated/horizontal wellbore is
disclosed. The system/method includes a gun string assembly (GSA)
deployed in a wellbore with shaped charges in clusters. Within a
cluster, the charges are separated into individual banks with a
phase angle between the charges in each bank and an offset angle
between banks. The number of charges per cluster, the phase angle
and the offset angle are optimized such that there is a maximum
probability of perforating into a low compression region in an
upward and downward direction.
Inventors: |
Hardesty; John T.;
(Weatherford, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GEODynamics, Inc. |
Milsap |
TX |
US |
|
|
Assignee: |
GEODynamics, Inc.
Milsap
TX
|
Family ID: |
59896862 |
Appl. No.: |
15/080251 |
Filed: |
March 24, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/117 20130101;
E21B 43/119 20130101; E21B 43/26 20130101 |
International
Class: |
E21B 43/117 20060101
E21B043/117; E21B 43/26 20060101 E21B043/26 |
Claims
1. A phased perforating gun system for use in a wellbore casing
comprising a plurality of perforating banks; said plurality of
perforating banks arranged in a cluster, wherein: said plurality of
perforating banks comprise a first perforating bank and a second
perforating bank.; said first perforating bank comprises a first
plurality of charges; said first plurality of charges phased at a
first phase angle to each other; the first perforating bank having
no charges in the same transverse plane; said second perforating
bank comprises a second plurality of charges; said second plurality
of charges phased at a second phase angle to each other; the second
perforating bank having no charges in the same transverse plane:
said first phase angle and said second phase angle angularly offset
by a first offset phase angle; said first phase angle equal to 360
degrees divided by a number of said first plurality of charges;
said second phase angle equal to 360 degrees divided by a number of
said second plurality of charges; at least one of said first
plurality of charges or at least one of said second plurality of
charges are configured to perforate within an upward perforation
angle with a probability greater than 50%; said upward perforation
angle ranges from 0 degrees to 30 degrees; at least one of said
first plurality of charges or at least one of said second plurality
of charges are configured to perforate within an downward
perforation angle with a probability greater than 50%; said
downward perforation angle ranges from 0 degrees to 30 degrees; and
said upward perforation angle subtends in an upward direction about
a center of said wellbore casing and said downward perforation
angle subtends in a downward direction about said center of said
wellbore casing.
2. (canceled)
3. The phased perforating gun system of claim 1 wherein said
wellbore casing is substantially horizontal.
4. The phased perforating gun system of claim 1 wherein said
wellbore casing is deviated.
5. The phased perforating gun system of claim 1 wherein said first
plurality of charges are equally spaced and said second plurality
of charges are equally spaced.
6. The phased perforating gun system of claim 1 wherein said first
plurality of charges are unequally spaced and said second plurality
of charges are unequally spaced.
7. The phased perforating gun system of claim 1 wherein a number of
said first plurality of charges range from 2 to 24.
8. The phased perforating gun system of claim 1 wherein a number of
said second plurality of charges range from 2 to 24.
9. The phased perforating gun system of claim 1 wherein said first
phase angle ranges from 15 to 180 degrees.
10. The phased perforating gun system of claim 1 wherein said
second phase angle ranges from 15 to 180 degrees.
11. The phased perforating gun system of claim 1 wherein said first
offset phase angle ranges from 1 to 90 degrees.
12. (canceled)
13. (canceled)
14. The phased perforating gun system of claim 1 wherein said
plurality of perforating banks further comprises a third
perforating bank; said third perforating bank comprises a third
plurality of charges; said third plurality of charges are phased at
a third phase angle to each other; said third phase angle equal to
360 degrees divided by a number of said third plurality of charges;
the third perforating bank having no charges in the same transverse
plane; said first phase angle and said second phase angle are
angularly offset by said first offset phase angle; said second
phase angle and said third phase angle are angularly offset by a
second offset phase angle; when perforating, at least one of said
first plurality of charges, at least one of said second plurality
of charges, and at least one of said third plurality of charges are
configured to perforate within said upward perforation angle and
said downward perforation angle; said upward perforation angle
subtends in said upward direction about said center of said
perforating gun and said downward perforation angle subtends in
said downward direction about said center of said perforating
gun.
15. The phased perforating gun system of claim 14 wherein a number
of said third plurality of charges range from 2 to 24.
16. The phased perforating gun system of claim 14 wherein said
third phase angle ranges from 15 to 180 degrees.
17. The phased perforating gun system of claim 14 wherein said
second offset phase angle ranges from 1 to 90 degrees.
18. The phased perforating gun system of claim 14 wherein said
upward perforation angle ranges from 1 to 30 degrees.
19. The phased perforating gun system of claim 14 wherein said
downward perforation angle ranges from 1 to 30 degrees.
20. The phased perforating gun system of claim 1 wherein said first
plurality of charges and said second plurality of charges are
further angled to place preferred initiation points on a transverse
plane to said wellbore casing.
21. The phased perforating gun system of claim 14 wherein charges
in at least two of said plurality of perforating banks are
configured to place preferred initiation points on a single
transverse plane to said wellbore casing.
22. The phased perforating gun system of claim 14 wherein charges
in at least two of said plurality of perforating banks are
configured to place preferred initiation points on a plurality of
planes; said plurality of planes transverse to said wellbore
casing.
23. The phased perforating gun system of claim 1 wherein said
second perforating bank is rotated about an orienting reference
point by said first offset phase angle.
24. A phased perforating method for use in a wellbore casing
operating in conjunction with a phased perforating gun system
comprising a plurality of perforating banks; said plurality of
perforating banks arranged in a cluster, wherein: said plurality of
perforating banks comprise a first perforating bank and a second
perforating bank; said first perforating bank comprises a first
plurality of charges; said first plurality of charges phased at a
first phase angle to each other; the first perforating bank having
no charges in the same transverse plane; said second perforating
bank comprises a second plurality of charges; said second plurality
of charges phased at a second phase angle to each other; the first
perforating hank having no charges in the same transverse plane;
said first phase angle and said second phase angle angularly offset
by a first offset phase angle; said first phase angle equal to 360
degrees divided by the number of said first plurality of charges;
and said second phase angle equal to 360 degrees divided by number
of said second plurality of charges; wherein said method comprises
the steps of: (1) selecting a gun system for each cluster in a
stage with the best statistical probability for a desired number of
perforations in said cluster; (2) positioning said phased
perforating gun system in said wellbore casing; and (3) perforating
through said phased perforating gun system into a hydrocarbon
formation such that at least one of said first plurality of charges
and at least one of said second plurality of charges perforate
within an upward perforation angle and at least one of said first
plurality of charges and at least one of said second plurality of
charges perforate within a downward perforation angle; said upward
perforation angle subtends in an upward direction about a center of
said perforating gun and said downward perforation angle subtends
in a downward direction about said center of said perforating gun;
said upward perforation angle ranges from 0 degrees to 30 degrees
and said downward perforation angle ranges from 0 degrees to 30
degrees.
25. A phased perforating gun system for use in a wellbore casing
comprising a plurality of perforating banks; said plurality of
perforating banks arranged in a cluster, wherein: said plurality of
perforating banks comprise a first perforating bank and a second
perforating bank; said first perforating bank comprise a first
plurality of charges; said first plurality of charges phased at a
first phase angle to each other; the first perforating bank having
no charges in the same transverse plane; said second perforating
bank comprise a second plurality of charges; said second plurality
of charges phased at a second phase angle to each other; the second
perforating bank having no charges in the same transverse plane;
said first phase angle and said second phase angle angularly offset
by a first offset phase angle; said first phase angle equal to 360
degrees divided by a number of said first plurality of charges; and
said second phase angle equal to 360 degrees divided by a number of
said second plurality of charges.
26. The phased perforating gun system of claim 1 wherein said first
plurality of charges are equally spaced and said second plurality
of charges are equally spaced.
27. The phased perforating gun system of claim 1 wherein a number
of said first plurality of charges range from 2 to 24.
28. The phased perforating gun system of claim 1 wherein a number
of said second plurality of charges range from 2 to 24.
29. The phased perforating gun system of claim 1 wherein said first
phase angle ranges from 15 to 180 degrees.
30. The phased perforating gun system of claim 1 wherein said
second phase angle ranges from 15 to 180 degrees.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to perforation guns
that are used in the oil and gas industry to explosively perforate
well casing and underground hydrocarbon bearing formations, and
more particularly to an optimally phased perforating apparatus for
explosively perforating a well casing and its surrounding
underground hydrocarbon bearing formation.
PRIOR ART AND BACKGROUND OF THE INVENTION
Prior Art Background
[0002] During a well completion process, a gun string assembly is
positioned in an isolated zone in the wellbore casing. The gun
string assembly comprises a plurality of perforating guns coupled
to each other either through tandems or subs. The perforating gun
is then fired, creating holes through the casing and the cement and
into the targeted rock. These perforating holes connect the rock
holding the oil and gas and the well bore. "During the completion
of an oil and/or gas well, it is common to perforate the
hydrocarbon containing formation with explosive charges to allow
inflow of hydrocarbons to the well bore. These charges are loaded
in a perforation gun and are typically shaped charges that produce
an explosive formed penetrating jet in a chosen direction" U.S.
Pat. No. 7,441,601.
[0003] Hydrocarbon fracturing tunnels have certain preferred
orientations where the effectiveness of extracting oil/gas is
greatest i.e., when a perforation is aligned along the tunnels,
oil/gas flows though the perforation tunnels without taking an
alternate path that may become a restrictive path creating high
tortuosity conditions.
[0004] It has been shown in studies that the fractures initiate
close to the wellbore casing in an upward and downward direction.
FIG. 1 (0100) generally illustrates a top view of a horizontal
drilling pad (0104) within the metes and bounds of a lease or
ownership. Multiple horizontal wells (0102) are generally drilled
from a vertical well head (0101). Studies have shown that preferred
fracturing planes (0103) are transversely perpendicular to the
orientation of the horizontal wellbore casings. Multiple preferred
fracturing planes that are parallel to each other may be targeted
for maximum production efficiency. However, horizontal wellbores
are often deviated as much as 100 ft in any direction over the
length of 3 miles. Therefore, the orientation of the gun may not be
horizontal and is often at an angle. The charges in the gun may or
may not be optimally phased when perforating. Field results
indicate that there is a single dominant perforation tunnel per
stage. As there are multiple stages per well, multiple clusters per
stage typically 3 to 15 and multiple perforating guns in each
cluster typically 4-6, there is a need for an optimal phasing of
the charges in each of the perforating guns per cluster so that the
chances of perforating in the dominant channel is increased. A
cross section of the horizontal wellbore casing (0207) drilled in a
wellbore (0206) is further illustrated in FIG. 2 (0200). Due to the
compression of rock (0205) from the surface, the hydrocarbon
formation is pressed downwardly and the region proximal to the
hydrocarbon formation has a discontinuity. The discontinuity
creates a stress (0204) distribution around the wellbore. Studies
from rock mechanics have indicated a high compression region (0201)
about the sides and a low compression region (0203) around the
upward and downward region. Therefore, there is a need to phase the
charges to perforate in the low compression region (0202) so that
fractures initiate in the low compression region for maximum
fracture efficiency. There is a need to phase the charges so that
the chances of placing a perforation tunnel in the effective
regions of low compressive stress are improved. There is a need for
the fracture to initiate at the top and bottom first that has the
least principal stress so that there is enough flow rate to
propagate the fracture. There is a need for a perforating gun that
perforates such that the fracture permeates radially to the
direction of the wellbore in an upward and downward direction.
[0005] By design, each perforation is expected to be involved in
the fracture treatment. If all perforations are involved, and the
perforations are shot with 0.degree., 60.degree., 90.degree.,
120.degree., or 180.degree. phasing, multiple fracture planes may
be created, leading to substantial near wellbore friction and
difficulty in placing the planned fracturing treatment. Field
results indicate that there is a single dominant perforation tunnel
per stage. Therefore, there is a need for minimal multiple fracture
initiations that do not create ineffective fracture planes. Various
prior art phasing in a perforating gun (0302) in a well casing
(0301) is illustrated in FIG. 3. For example, FIG. 3 (0310)
illustrates a 0.degree. phasing where all the charges are phased to
perforate in a downwardly direction. Similarly, FIG. 3 (0320)
illustrates a 0.degree.-180.degree. phasing wherein charges are
phased to perforate in an upward and downward direction. However,
the chances of perforating in an upward and downward direction are
low when the well casing is deviated and the perforating gun is not
horizontal. There is an accuracy issue of positioning the guns
(orienting) with respect to the up/down vector. Field results
indicate that even with orientation of the guns, operational issues
can cause perforations in a non-preferred region. The probability
of perforating in the preferred upward and downward low compression
region is very low for a 0.degree. phasing or a
0.degree.-180.degree. phasing gun.
[0006] FIG. 4 further illustrates a perforating gun (0401) with a
0.degree.-180.degree. phasing wherein charges (0404) are phased to
perforate in an upward and downward direction. As illustrated in
FIG. 4 (0410) the charges (0404) are perfectly aligned to the
preferred direction (0402) and the fracture treatment through the
perforations may produce efficiently. However, since the wells are
not perfectly horizontal and in most case deviated, the gun (0411)
may be rotated as illustrated in FIG. 4 (0420) and the charges
(0404) may be perforating into the high compression region or
sideways and produce ineffective fracture treatment. Therefore, it
is important to perforate to improve the probability of placing the
perforations in the low compression region which are determined to
be on the upward and downward directions.
[0007] FIG. 3 (0330) illustrates a 120.degree. phasing wherein 3
charges are phased at 120.degree. to perforate. The probability of
perforating within 240.degree. of the upward and downward low
compression region is 100%. The chances are decreased to 50% for
perforating within 120.degree. and further decreased to 25% for
perforating within 60.degree. and further decreased to 12.5% for
perforating within 30.degree. of the upward and downward low
compression region is 100%. Therefore, there is a need to improve
the probability to at least 80% for perforating within 30.degree.
of the upward and downward low compression region.
[0008] FIG. 3 (0340) illustrates a 90.degree. phasing wherein 4
charges are phased at 90.degree. to perforate. The probability of
perforating within 90.degree. of the upward and downward low
compression region is 100%. The chances are decreased to 50% for
perforating within 90.degree. and further decreased to 25% for
perforating within 45.degree.. Therefore, there is a need to place
and phase the charges within in a cluster such that the chances of
perforating in the preferred low compression region is at least
75%.
[0009] FIG. 3 (0350) illustrates a 60.degree. phasing wherein 6
charges are phased at 60.degree. to perforate into a hydrocarbon
formation. Prior art perforating guns are generally loaded with 6
shots per foot (SPF) at 60 degree phasing. With the 60.degree.
phasing, the probability of perforating within 60.degree. of the
upward and downward low compression region is 100%. The probability
of perforating within 30.degree. of the upward and downward low
compression region is 50%. Even with a double shot at the same
phasing, the probability remains the same but requires 12 shots
spanning 2 feet. Therefore, there is a need to improve the
probability to at least 80% for perforating within 30.degree. of
the upward and downward low compression region (perforation
angle).
[0010] Currently, 1 to 12 perforation holes per stage are shot
which will reconnect to the predominant fracturing plane during
fracturing treatment. Most stages are completed with 6 shots per
cluster and 6 shots per foot ("spf") and at 60 degrees for obvious
statistical reasons. Some of the perforation tunnels cause energy
and pressure loss during fracturing treatment which reduces the
intended pressure in the fracture tunnels. For example, if a 100
bpm (barrels per minute) fracture fluid is pumped into each
fracture zone at 10000 PSI with an intention to fracture each
perforation tunnel at 2-3 bpm, most of the energy is lost in
ineffective fractures that have higher tortuosity reducing the
injection rate per fracture to substantially less than 2-3 bpm.
Consequently, the extent of fracture length is significantly
reduced resulting in less oil and gas flow during production.
Therefore, there is a need for a system to achieve the highest and
optimal injection rate per perforation tunnel so that a maximum
fracture length is realized. The more energy put through each
perforation tunnel, the more fluid travels through the preferred
fracturing plane, the further the fracture extends. Ideally, 1000
feet of fracture length from the wellbore is desired. Therefore,
there is a need to get longer extension of fractures which have
minimal tortuosity. For example, in order to achieve 2 bpm in each
perforation tunnel, a total injection rate of 100 bpm at 1000 psi
for 48 perforation tunnels requires 12 clusters each with 4
charges. Therefore, there is a need to shoot more zones with 4
perforating holes in each cluster that are oriented 2 up and 2
down. Active orientation systems commonly used such as 0 degrees or
180 degree orientations, have an accuracy of orientation that is
estimated to be +-20 degrees with an external orientation and .+-.-
with an internal orientation. There is a need to improve the
chances of proper placement without an active orientation
system.
[0011] Perforation and fracturing are based on the premise that
every perforation will be in communication with a hydraulic
fracture and will be contributing fluid during the treatment at the
pre-determined rate. Therefore, if any perforation does not
participate, then the incremental rate per perforation of every
other perforation is increased, resulting in higher perforation
friction. Therefore, there is a need to angle and space charges to
facilitate the fracturing process to achieve maximum production
efficiency.
[0012] Prior art U.S. Pat. No. 7,303,017A discloses "a method
includes arranging shaped charges in a perforating gun to produce
perforation holes in a helical pattern that is defined in part by a
phase angle; and choosing four adjacent perforation holes to be
created that are adjacent nearest neighbors. The distances are
determined between three of the four adjacent perforation holes to
be created. A standard deviation is minimized between the three
adjacent perforation holes. The phase angle is set based on the
minimization." However, U.S. Pat. No. 7,303,017A does not teach an
optimal phasing of the charges in the bank so that charges
perforate within desired perforation angles in a low compression
region especially for a deviated well.
Deficiencies in the Prior Art
[0013] The prior art as detailed above suffers from the following
deficiencies: [0014] Prior art perforation phasing systems do not
provide for efficiently reducing tortuosity and energy loss in a
perforation tunnel with minimum number of shots per foot. [0015]
Prior art perforation phasing systems do not provide for longer
extension of fractures which have minimal tortuosity with minimum
number of shots per foot. [0016] Prior art perforation phasing
systems do not provide for the highest and optimal injection rate
per perforation tunnel so that a maximum fracture length is
realized with minimum number of shots per foot in a cluster. [0017]
Prior art perforation phasing systems do not provide for achieving
a probability greater than 50% for perforating within +-15.degree.
of the upward and downward low compression region. [0018] Prior art
perforation phasing systems do not provide for an optimal phasing
of the charges in the perforating gun per cluster in order to
achieve maximum perforation and fracturing efficiency. [0019] Prior
art perforation phasing systems do not have an optimal statistical
chance of perforation placement when less than or more than 6 shots
are placed in a cluster.
[0020] While some of the prior art may teach some solutions to
several of these problems, the core issue of reacting to unsafe gun
pressure has not been addressed by prior art.
OBJECTIVES OF THE INVENTION
[0021] Accordingly, the objectives of the present invention are
(among others) to circumvent the deficiencies in the prior art and
affect the following objectives: [0022] Provide for efficiently
reducing tortuosity and energy loss in a perforation tunnel with
minimum number of shots per foot. [0023] Provide for longer
extension of fractures which have minimal tortuosity with minimum
number of shots per foot. [0024] Provide for the highest and
optimal injection rate per perforation tunnel so that a maximum
fracture length is realized with minimum number of shots per foot
in a cluster. [0025] Provide for improving the probability to at
least 50% for perforating within +-15.degree. of the upward and
downward low compression region. [0026] Provide for an optimal
phasing of the charges in the perforating gun per cluster in order
to achieve maximum perforation and fracturing efficiency. [0027]
Provide for perforation phasing systems that have an optimal
statistical chance of perforation placement when less than or more
than 6 shots are placed in a cluster.
[0028] While these objectives should not be understood to limit the
teachings of the present invention, in general these objectives are
achieved in part or in whole by the disclosed invention that is
discussed in the following sections. One skilled in the art will no
doubt be able to select aspects of the present invention as
disclosed to affect any combination of the objectives described
above.
BRIEF SUMMARY OF THE INVENTION
System Overview
[0029] The present invention in various embodiments addresses one
or more of the above objectives in the following manner. The
present invention provides a system that includes an optimal
phasing perforating phased gun system and method for accurate
perforation in a deviated/horizontal. The system/method includes a
gun string assembly (GSA) deployed in a wellbore with shaped
charges in clusters. Within a cluster, the charges are separated
into individual banks with a phase angle between the charges in
each bank and an offset angle between banks. The number of charges
per cluster, the phase angle and the offset angle are optimized
such that there is a maximum probability of perforating into a low
compression region in an upward and downward direction. The
fracture treatment through the perforations in the low compression
regions create minimal tortuosity paths for longer extension of
fractures that enables efficient oil and gas flow rates during
production.
Method Overview
[0030] The present invention system may be utilized in the context
of an overall optimal phasing perforating method, wherein the
phased perforating gun as described previously is controlled by a
method having the following steps: [0031] (1) selecting a gun
system for each cluster in a stage with the best statistical
probability for the desired number of perforations in that cluster;
[0032] (2) positioning a phased perforating gun system in a
wellbore casing; and [0033] (3) perforating through the phased
perforating gun system into a hydrocarbon formation such that at
least one of the first plurality of charges and at least one of the
second plurality of charges perforate within a upward perforation
angle and a downward perforation angle; the upward perforation
angle subtends in an upward direction about a center of the
perforating gun and the downward perforation angle subtends in a
downward direction about the center of the perforating gun.
[0034] Integration of this and other preferred exemplary embodiment
methods in conjunction with a variety of preferred exemplary
embodiment systems described herein in anticipation by the overall
scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] For a fuller understanding of the advantages provided by the
invention, reference should be made to the following detailed
description together with the accompanying drawings wherein:
[0036] FIG. 1 is a top view of a horizontal drilling pad with
multiple horizontal wells that are drilled from a vertical well
head.
[0037] FIG. 2 is a cross section of the horizontal wellbore casing
drilled in a wellbore in FIG. 1.
[0038] FIG. 3 illustrate various prior art phasing in a perforating
gun in a well casing.
[0039] FIG. 4 illustrates a perforating gun with a
0.degree.-180.degree. phasing of the charges.
[0040] FIG. 5 shows an end view of a perforating gun illustrating
an upward perforation angle and a downward perforation angle.
[0041] FIG. 6 generally illustrates a side perspective view of two
charges phased in a perforating gun defining a phase angle and
charge spacing.
[0042] FIG. 7A illustrates an exemplary 8-shot (charges) 2-bank,
phased at 90.degree. phase angle between charges in each bank,
phased 45.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0043] FIG. 7B illustrates an exemplary 8-shot (charges) 2-bank,
phased at 90.degree. phase angle between charges in each bank,
phased 45.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0044] FIG. 7C illustrates an exemplary 8-shot (charges) 2-bank
non-converging, phased at 90.degree. phase angle between charges in
each bank, phased 45.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0045] FIG. 7D illustrates an exemplary cross section view of
8-shot (charges) 2-bank, phased at 90.degree. phase angle between
charges in each bank, phased 45.degree. offset angle between banks
with a orienting reference point in a perforating gun according to
a preferred embodiment of the present invention.
[0046] FIG. 8 illustrates an exemplary 12-shot (charges) 3-bank,
phased at 120.degree. phase angle between charges in each bank,
phased 30.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0047] FIG. 9A illustrates an exemplary 6-shot (charges) 2-bank,
phased at 120.degree. phase angle between charges in each bank,
phased 60.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0048] FIG. 9B illustrates an exemplary 6-shot (charges) 2-bank
non-converging, phased at 120.degree. phase angle between charges
in each bank, phased 60.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0049] FIG. 10A illustrates an exemplary 6-shot (charges) 3-bank,
phased at 180.degree. phase angle between charges in each bank,
phased 90.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0050] FIG. 10B illustrates an exemplary 6-shot (charges) 3-bank
non-converging, phased at 180.degree. phase angle between charges
in each bank, phased 90.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0051] FIG. 11A illustrates an exemplary 10-shot (charges) 2-bank,
phased at 72.degree. phase angle between charges in each bank,
phased 36.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0052] FIG. 11B illustrates an exemplary 10-shot (charges) 2-bank
non-converging, phased at 72.degree. phase angle between charges in
each bank, phased 36.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0053] FIG. 12A illustrates an exemplary 12-shot (charges) 2-bank,
phased at 60.degree. phase angle between charges in each bank,
phased 30.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0054] FIG. 12B illustrates an exemplary 12-shot (charges) 2-bank
non-converging, phased at 60.degree. phase angle between charges in
each bank, phased 30.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0055] FIG. 13A illustrates an exemplary 12-shot (charges) 3-bank,
phased at 90.degree. phase angle between charges in each bank,
phased 30.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0056] FIG. 13B illustrates an exemplary 12-shot (charges) 3-bank
non-converging, phased at 90.degree. phase angle between charges in
each bank, phased 30.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0057] FIG. 14A illustrates an exemplary 12-shot (charges) 4-bank,
phased at 120.degree. phase angle between charges in each bank,
phased 15.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0058] FIG. 14B illustrates an exemplary 12-shot (charges) 4-bank
non-converging, phased at 120.degree. phase angle between charges
in each bank, phased 15.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0059] FIG. 15A illustrates an exemplary 14-shot (charges) 2-bank,
phased at 51.42.degree. phase angle between charges in each bank,
phased 25.5.degree. offset angle between banks in a perforating gun
according to a preferred embodiment of the present invention.
[0060] FIG. 15B illustrates an exemplary 14-shot (charges) 2-bank
non-converging, phased at 51.42.degree. phase angle between charges
in each bank, phased 25.5.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0061] FIG. 16A illustrates an exemplary 16-shot (charges) 4-bank,
phased at 90.degree. phase angle between charges in each bank,
phased 11.25.degree. offset angle between banks in a perforating
gun according to a preferred embodiment of the present
invention.
[0062] FIG. 16B illustrates an exemplary 16-shot (charges) 4-bank
non-converging, phased at 90.degree. phase angle between charges in
each bank, phased 11.25.degree. offset angle between banks in a
perforating gun according to a preferred embodiment of the present
invention.
[0063] FIG. 17 illustrates a detailed flowchart of a preferred
exemplary optimal phasing perforation method with shaped charges
according to preferred exemplary invention embodiments.
DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS
[0064] While this invention is susceptible of embodiment in many
different forms, there is shown in the drawings and will herein be
described in detailed preferred embodiment of the invention with
the understanding that the present disclosure is to be considered
as an exemplification of the principles of the invention and is not
intended to limit the broad aspect of the invention to the
embodiment illustrated.
[0065] The numerous innovative teachings of the present application
will be described with particular reference to the presently
preferred embodiment, wherein these innovative teachings are
advantageously applied to the particular problems of optimal
phasing perforating gun system and method. However, it should be
understood that this embodiment is only one example of the many
advantageous uses of the innovative teachings herein. In general,
statements made in the specification of the present application do
not necessarily limit any of the various claimed inventions.
Moreover, some statements may apply to some inventive features but
not to others.
[0066] FIG. 5 (0500) generally illustrates an end view of a
wellbore casing (0501). Hereinafter, an "upward perforation angle"
(0504) is defined as the angle subtended in an upward direction
(0511) about a center (0510) of the wellbore casing (0501).
Similarly, a "downward perforation angle" (0514) is defined as the
angle subtended in a downward direction (0512) about a center
(0510) of the wellbore casing (0501). It has been reported that
prior art perforating gun phasing achieve an accuracy within an
upward perforation angle (0503) and a downward perforation angle
(0513) which are +-75.degree.. Most commonly used systems such as 6
SPF at 60.degree. will place perforation in each 60 degree arc if
the 6 shot bank is fully loaded. The chances of placing the
perforation in the 60.degree. arc further goes down if one shot is
left out, i.e., 5 out of 6 shots loaded in a 60.degree. gun. To
achieve maximum fracturing efficiency, it is needed to perforate
within a preferred upward perforation angle and preferred downward
perforation are +-15.degree. so that the perforation is achieved in
an upward low compression region (0505) and a downward low
compression region (0515). Furthermore, field results as indicated
by a dominant perforation hole due to erosion during the fracture
treatment have shown that a dominant tunnel exits on the low side
(0515) 70% of the time, high side (0505) 20% of the time, and other
sides 10% of time. The differences in the upward and downward
production is due to smaller size of the perforation hole in the
upward direction as compared to the size of the perforation hole in
the downward direction. The size of the perforation holes are
different due to the fact that the perforating gun is closer to the
side wall of the casing in the downward direction. The perforating
hole in the downward direction is sometimes twice as large as the
perforating hole in the upward direction. Therefore, there is a
further need to compensate for the disproportionate perforating
hole sizes by orienting the charges to achieve a 50/50% production
from both upward and downward low compression zones.
[0067] FIG. 6 (0600) generally illustrates a side perspective view
of two charges (0602, 0603) phased in a perforating gun (0601).
Hereinafter a "phase angle" between two charges may be defined as
the angle between the perpendicular lines extending from the
charges. For example, angle (0604) defines a phase angle between
charge (0602) and charge (0603). In a 6-shot 6 SPF perforating gun,
the phase angle is 60 degrees. Similarly, in a 4-shot perforating
gun, the phase angle is 90 degrees. Hereinafter "Charge spacing"
may be defined as the spacing between two consecutive charges in a
perforating gun. For example, charge spacing (0605) may be defined
as the spacing between consecutive charges (0602) and (0603).
Preferred Exemplary 8-shot 2-Bank Phased Perforating Gun System
(0700)
[0068] An exemplary embodiment of the present invention may be
generally illustrated in FIG. 7A, wherein a phased perforating gun
assembly is deployed inside a wellbore casing along with 2 banks
(0700, 0710), each of the banks comprise plural shaped charges.
According to a preferred exemplary embodiment, the angular
orientation of the wellbore casing is substantially horizontal.
According to another preferred exemplary embodiment, the angular
orientation of the wellbore casing is deviated. For example,
horizontal wellbores are often deviated as much as 100 ft in any
direction over the length of 3 miles. Therefore, the angular
orientation of the gun may not be horizontal and is often at an
angle with respect to a longitudinal axis of the casing. The
charges in the gun may or may not be optimally phased when
perforating.
[0069] The bank (0700) may comprise charges (0701, 0702, 0703,
0704) and the bank (0710) may comprise charges (0711, 0712, 0713,
0714). The plural shaped charges in the perforating gun together in
bank (0700) and bank (0710) may herein be referred to as "cluster".
Even though four charges have been shown in each of the banks in
FIG. 7A, the banks may comprise more than 2 four shaped charges
according to a preferred exemplary embodiment.
[0070] Referring to FIG. 7A, the perforating gun may include shaped
charges that extend around a central axis of the gun in a helical,
or spiral, pattern. Each shaped charge points radially outwardly
toward a well casing, and adjacent shaped charge in the spiral
pattern are radially separated by a phase angle of 90.degree.. For
example, shaped charge 0701 is radially separated to adjacent
shaped charge 0702 by a phase angle of 90.degree.. Similarly,
shaped charge 0711 is radially separated to adjacent shaped charge
0712 by a phase angle of 90.degree.. According to a preferred
exemplary embodiment, the phase angle of the shaped charges in a
bank may range from 1.degree. to 359.degree.. According to a more
preferred exemplary embodiment, the phase angle of the shaped
charges in a bank may range from 5.degree. to 90.degree.. According
to a most preferred exemplary embodiment, the phase angle of the
shaped charges in a bank may range from 15.degree. to 30.degree..
For example, phase angle of the shaped charge 0711 to adjacent
shaped charge 0712 may range from 1.degree. to 359.degree..
According to yet another preferred exemplary embodiment, the phase
angle of one bank may be equal to the phase angle of another bank
in the cluster. According to yet another, preferred exemplary
embodiment, the phase angle of one bank may be unequal to the phase
angle of another bank in the cluster. According to another
preferred exemplary embodiment, the shaped charges are equally
spaced. For example, the charge spacing between consecutive shaped
charges (0701), (0702) and (0703) may be equal. According to yet
another preferred exemplary embodiment, the shaped charges are not
equally spaced.
[0071] According to a preferred exemplary embodiment, the number of
charges in each of the banks may range from 2 to 24. According to a
more preferred exemplary embodiment, the number of charges in each
of the banks may range from 2 to 8. According to a most preferred
exemplary embodiment, the number of charges in each of the banks
may range from 2 to 6. For example, the bank (0700) may comprise 2
to 24 charges and bank (0710) may comprise 2 to 24 charges.
According to a preferred exemplary embodiment, the offset angle
ranges from 1 to 90.degree.. According to a more preferred
exemplary embodiment, the offset angle of the shaped charges
between the banks may range from 10.degree. to 45.degree..
According to a most preferred exemplary embodiment, the offset
angle of the shaped charges between the banks may range from
15.degree. to 30.degree.. The offset angle may be the phase angle
between charge 0701 and charge 0711. The offset angle between 0702
and 0712 would be same if the phase angles of charges in both the
banks are the same. In the illustration shown in FIG. 7A, the
offset angle is 45.degree.. In this example, the offset angle
between charges 0701 and 0711 is 45.degree.. The offset angle may
range from 1.degree. to 90.degree. depending on the required upward
and downward perforation angles.
[0072] In the illustration presented in FIG. 7A with 4 charges per
bank at a 90.degree. phase angle between charges and a 45.degree.
offset angle ("offset phase angle") between banks 0700 and 0710,
the probability of perforating within a 45.degree. upward
perforation angle is 100%. Similarly, the probability of
perforating within a 22.5.degree. upward perforation angle is 50%.
In contrast, for a prior art 8 charge system with a 90.degree.
phase angle between charges, the probability of perforating within
a 45.degree. upward perforation angle is 50% as compared to the
exemplary 2 bank 8 charge system illustrated in FIG. 7A. An offset
angle between each of the banks increases the probability of shaped
charges perforating within a desired perforation angle so that
fractures initiate in the low compression region for achieving
maximum fracture efficiency. According to a preferred exemplary
embodiment, a perforation angle within 30.degree. with a
probability greater than 75% is achieved.
[0073] The offset angle, also referred to as offset phase angle,
between two banks may also be achieved by physically rotating one
bank with respect to the other bank. As illustrated in FIG. 7D
(0760), bank 0700 may be horizontally oriented with four charges at
90.degree. phase angle and bank 0710 may be horizontally oriented
with four charges at 90.degree. phase angle. The reference
orienting point (0761) may be the same. In this case the offset
angle is zero. The bank 0710 may be physically rotated or twisted
by the amount of the desired offset angle with a rotating means
about a reference point (0761). The configuration of the banks 0700
and 0710 after rotating bank 0710 is generally illustrated in FIG.
7D (0770). When the perforating guns are deployed into a well
casing, the guns may be connected to each other via a sub or a
tandem (0790). The guns may be twisted or rotated about an
orienting reference point (0761) with any widely available twisting
means or mechanism such as ball bearings or threads or screws. The
banks may be rotated about the reference orienting point (0761) to
achieve a desired offset angle. Alternatively, the orienting
reference point may be the same for all banks, but the desired
offset angle may be achieved by phasing the charges in each of the
banks as generally illustrated in FIG. 7A.
[0074] One of the banks within the cluster may be at the best
orientation and therefore be the dominant bank within the cluster.
The clusters will also be balanced as each cluster in a stage will
have a statistical probability of having a bank with charges phased
to perforate within an arc in the low compression zone. For
example, referring to FIG. 7A, bank (0700) comprising charges
(0701, 0702, 0703, 0704) may be the dominant bank while bank (0710)
comprising charges (0711, 0712, 0713, 0714) may be the non-dominant
bank. In this case, charge 0701 may be perforating upwards into the
low compression zone within a 45.degree. upward perforation angle
with a probability of 100%. Similarly, charge 0703 may be
perforating downwards into the low compression zone within a
45.degree. downward perforation angle with a probability of 100%.
Alternatively, bank (0710) may be the dominant bank and charges
0711 and 0714 may be the upward charges perforating into the low
compression region and charges 0712 and 0713 may be the downward
charges perforating into the low compression region. According to a
preferred exemplary embodiment the downward perforation angle and
the upward perforation angle may range from 1.degree. to
45.degree.. According to a preferred exemplary embodiment, within a
stage, the phasing of the charges in the dominant bank in one
cluster may be different than the phasing of the charges in the
dominant bank in another cluster. Variations in placement of
perforation tunnels with respect to low compression stress areas
contributes to variation in "cluster perforation quality". A
variation in cluster perforation quality may imply some clusters in
a stage will be treated unequally. For example, a bank similar to
bank 0700 may be the dominant bank in one cluster and a bank
similar to bank 0710 with a different phasing of charges may be the
dominant bank in another cluster of the same stage. The advantages
of having two different dominant banks with different phasings
(phase angles) in two different clusters enables fracturing fluids
to be distributed evenly without competing. In contrast, if the
dominant banks with similar phasings in different clusters are
treated, fracturing fluids may be dominated by the first dominant
bank while starving the other dominant bank in the downstream
cluster. According to another preferred exemplary embodiment, the
phasing of the charges in the dominant bank in one cluster may be
same as the phasing of the charges in the dominant bank in another
cluster.
[0075] As illustrated in Table 1.0, the number of banks, and
charges per bank may be selected to achieve a desired probability
for a perforation angle within 30.degree. or any other angle. The
combination of charges per bank, number of banks, phase angle and
offset angle may be chosen per cluster based on the diameter of the
perforating gun, the length of the gun and the size of the gun. For
example, a 2 foot gun may accommodate 12 charges or shots with 1
foot loaded and 1 foot for end connections, a 3-ft gun may
accommodate 12 shots and a 4-ft gun may accommodate 18 shots. A
conventional prior art perforating gun is generally loaded with 6
shots per foot (SPF) at a 60 degree phasing. With the 60.degree.
phasing, the probability of perforating within 60.degree. arc which
includes 60.degree. of the upward and downward low compression
region is 100%. The probability of perforating within 30.degree. of
the upward and downward low compression region is 50%. Even with a
doubleshot at the same phasing, the probability remains the same
but requires 12 shots spanning 2 feet. However, the probability
substantially doubles with an exemplary configuration that may
include a 2 bank, 6 charges per bank, 60.degree. phasing, and
30.degree. offset angle. The probability of perforating within
15.degree. of the upward and downward low compression region is
almost 100%. Therefore, the exemplary configurations illustrated in
Table 1.0 provides for a more efficient perforations so that
fractures initiate in the low compression region adjacent to the
perforating gun for achieving maximum fracture efficiency. Prior
art guns may be loaded at the normal shots per foot with charges
loaded at 6 SPF at 60.degree. phasing, 4 SPF at 90.degree. phasing,
5 SPF at 72.degree. phasing and 3 SPF 120.degree. phasing. However,
according to an exemplary embodiment, a 10 shot gun may be loaded
at nearly 6 SPF density or a variable density. According to a
preferred exemplary embodiment, the perforation angle may range
from 0.degree. to 30.degree. and/or within +-15.degree.. The upward
perforation angle may be substantially the same as the downward
perforation angle if the phase angle is the same for all the
charges within a bank.
[0076] The size of the perforation holes are different due to the
fact that the perforating gun is closer to the side wall of the
casing in the downward direction. The perforating hole in the
downward direction is sometimes twice as large as the perforating
hole in the upward direction. According to a preferred exemplary
embodiment, the configurations of Table 1.0, along with orienting
the charges, compensate for the disproportionate perforating hole
sizes to achieve a 50/50% production flow from both upward and
downward low compression zones.
TABLE-US-00001 TABLE 1.0 Offset No Of Phase Phase Perforation
Perforation Perforation Shots Charges Angle Angle Angle with Angle
with Angle with in Per No of in each Between 100% 50% 25% Cluster
bank Banks bank Banks probability probability probability 8 4 2 90
45 45 22.5 11.25 10 5 2 72 36 36 18 9 12 6 2 60 30 30 15 7.5 14 7 2
51.4 28.7 26 13 6.5 15 5 3 72 24 24 12 6 12 4 3 90 30 30 15 7.5
[0077] FIG. 7A (0720) generally illustrates phase angle (0721) vs
charges (0722) for an unrolled gun. The charges in banks 0700 and
0710 are illustrated along with the phase angle and offset angle.
For example, the phase angle (0730) between charge 0701 and charge
0702 is 90.degree.. The offset angle (0740) between charge 0701 and
charge 0711 is 45.degree..
[0078] According to a preferred exemplary embodiment, the charges
in the first bank and the charges in the second bank may be further
angled to place preferred initiation points on a transverse plane
to the wellbore casing. The transverse plane may be perpendicular
to the longitudinal axis of the wellbore casing. The initiation
points may or may not intersect with each other, but charges may be
oriented such that the initiation points intersect the preferred
fracturing plane so that the fractures created from the initiation
points create minimal tortuosity and longer extension of fractures.
The initiation points in the preferred plane are particularly
significant for wellbore completions to achieve maximum efficiency
during oil and gas production. It has been known through several
field studies and field data that the preferred plane is transverse
about the horizontal direction of the wellbore casing. Initiation
points are inherently present in perforation tunnels when shaped
charges perforate. Not every point in the perforation tunnel is
preferred. The preferred initiation points may lie at the end of
the clear tunnel (tip) of the perforation tunnels and furthermore
the preferred initiation points lie in a preferred fracturing
plane. A fracturing fluid is then pumped at high pressures so that
the fracture fluid extends the fractures to the maximum extent in
the preferred perforating orientation. The extent of the fracture
length extending radially outward from the wellbore casing may be
1000 feet according to a preferred exemplary embodiment. According
to another preferred exemplary embodiment, the charges in at least
two of the perforating banks are configured to place preferred
initiation points on a single transverse plane to said wellbore
casing. According to another preferred exemplary embodiment the
charges in at least two of the perforating banks are configured to
place preferred initiation points on a plurality of planes.
Plurality of planes may be transverse to the wellbore casing. For
example, the charges (0701, 0702, 0703, 0704) in bank (0700) may be
oriented such that they intersect a first preferred fracturing
plane while charges (0711, 0712, 0713, 0714) in bank (0710) may be
oriented such that they intersect a second preferred fracturing
plane that may be substantially parallel to the first preferred
fracturing plane. Both the first preferred fracturing plane and the
second preferred fracturing plane are transverse to the
longitudinal axis of the wellbore casing.
Preferred Exemplary 8-Shot 2-Bank Phased Perforating Gun System
[0079] FIG. 7B illustrates an exemplary 8-shot (charges) 2-bank,
phased at 90.degree. phase angle between charges in each bank,
phased at a 45.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
(0750), an end view (0751), and a perspective view (0752) of an
exemplary phased gun system is generally illustrated in FIG. 7B.
The system may comprise a first perforating bank (0700) and a
second perforating bank (0710) similar to the banks illustrated in
FIG. 7A. According to a preferred exemplary embodiment, at least
one of the 4 charges in the first perforating bank and at least one
of the 4 charges in the second perforating bank are configured to
perforate into a low compression region that is proximal to the
well casing. According to a further preferred exemplary embodiment,
the charges in the first perforating bank (0700) and second
perforating bank (0710) are each oriented such that when the
charges perforate, the charges intersect preferred fracturing
planes (0743, 0753) respectively.
Preferred Exemplary 8-Shot 2-Bank Phased Perforating Gun
Non-converging System
[0080] Similar to FIG. 7B, a cross section view (0790), an end view
(0791), and a perspective view (0792) of an exemplary phased gun
system is generally illustrated in FIG. 7C. The system may comprise
4 charges phased at a 90.degree. phase angle in each of a first
perforating bank and a second perforating bank. The first
perforating bank and the second perforating bank are phased at an
offset angle of 45.degree.. The charges may be non-converging and
may not be intersecting a preferred fracturing plane when
perforating.
Preferred Exemplary 9-Shot 3-Bank Phased Perforating Gun System
(0800)
[0081] An exemplary embodiment of the present invention may be
generally illustrated in FIG. 8, wherein a phased perforating gun
is deployed inside a wellbore casing along with 3 banks (0800,
0810, 0820), each of the banks comprise plural shaped charges.
According to a preferred exemplary embodiment, the orientation of
the wellbore casing is substantially horizontal. According to
another preferred exemplary embodiment, the orientation of the
wellbore casing is deviated.
[0082] The bank (0800) may comprise charges (0801, 0802, 0803), the
bank (0810) may comprise charges (0811, 0812, 0813) and the bank
(0820) may comprise charges (0821, 0822, 0823). The plural shaped
charges in the perforating gun together in the bank (0800), the
bank (0810) and the bank (0820) may herein be referred to as
"cluster". Even though three charges have been shown in each of the
banks in FIG. 8, the banks may comprise more than 2 shaped charges
according to a preferred exemplary embodiment.
[0083] Referring to FIG. 8, the perforating gun may include shaped
charges that extend around a central axis of the gun in a helical,
or spiral, pattern. Each shaped charge points radially outwardly
toward a well casing, and adjacent shaped charge in the spiral
pattern are radially separated by a phase angle of 120.degree.. For
example, shaped charge 0821 is radially separated to adjacent
shaped charge 0822 by a phase angle of 120.degree.. Similarly,
shaped charge 0811 is radially separated to adjacent shaped charge
0812 by a phase angle of 120.degree..
[0084] According to a preferred exemplary embodiment, the offset
angle ranges from 1 to 90 degrees. According to a more preferred
exemplary embodiment, the offset angle of the shaped charges
between the banks may range from 10.degree. to 60.degree..
According to a most preferred exemplary embodiment, the offset
angle of the shaped charges between the banks may range from
15.degree. to 30.degree.. The offset angle may be the phase angle
between charge 0801 and charge 0811. The offset angle between 0802
and 0812 would be same if the phase angles of charges in both the
banks are the same. In the illustration shown in FIG. 8, the offset
angle is 30.degree.. In this example, the offset angle between
charges 0801 and 0811 is 30.degree.. The offset angle may range
from 1.degree. to 45.degree. depending on the required upward and
downward perforation angles. According to a preferred exemplary
embodiment, the offset angles between a set of banks may be equal
to an offset angle between a different set of banks. According to a
preferred exemplary embodiment, the offset angles between a set of
banks may not be equal to an offset angle between a different set
of banks. For example, the offset angle between bank 0800 and bank
0810 may be different from the offset angle between bank 0810 and
bank 0820. The offset angle between bank 0800 and bank 0810 may be
the same as the offset angle between bank 0810 and bank 0820.
[0085] In the illustration shown in FIG. 8 with 3 charges per bank
at a 120.degree. phase angle between charges and a 30.degree.
offset angle between each of the banks 0800, 0810 and 0820, the
probability of perforating within a 30.degree. upward perforation
angle is 100%. Similarly, the probability of perforating within a
15.degree. upward perforation angle is 50%. In contrast, for a
prior art 9 charge system with a 45.degree. phase angle between
charges, the probability of perforating within a 30.degree. upward
perforation angle is 75% as compared to the exemplary 3 bank 9
charge system illustrated in FIG. 8. An offset angle between each
of the banks increases the probability of shaped charges
perforating within a desired perforation angle so that fractures
initiate in the low compression region for achieving maximum
fracture efficiency.
[0086] FIG. 8 (0830) generally illustrates phase angle (0831) Vs
location of charges (0832) for an unrolled gun. The charges in
banks 0800, 0810 and 0820 are illustrated along with the phase
angle and offset angle. For example, the phase angle (0850) between
charge 0801 and charge 0802 is 120.degree.. The offset angle (0860)
between charge 0801 and charge 0811 is 30.degree..
[0087] As illustrated in FIG. 7A, the phase angle of the charges is
90.degree. with two oppositely phased charges. For example, charges
0701 and 0702 are phased diametrically opposite to each other. As
illustrated in FIG. 8, the phase angle of the charges is
120.degree. with none of the charges diametrically opposite to each
other. For example, charges 0701 and 0702 are phased diametrically
opposite to each other 0801, 0802 and 0803 are phased with no two
charges diametrically opposite to each other. It is more preferable
to phase charges diametrically opposite to each other such as in
FIG. 7A so that there is a better probability to perforate in the
arc in a low compression zone upwards and downwards.
Preferred Exemplary 6-Shot 2-Bank Phased Perforating Gun System
[0088] FIG. 9A generally illustrates an exemplary 6-shot (charges)
2-bank, phased at 120.degree. phase angle between charges in each
bank, phased 60.degree. offset angle between banks in a perforating
gun according to a preferred embodiment of the present invention. A
cross section view (0900), an end view (0901), and a perspective
view (0902) of an exemplary phased gun system is generally
illustrated in FIG. 9A. The system (0900) may comprise a first
perforating bank (0910) and a second perforating bank (0920). The
first perforating bank (0910) comprising 3 charges phased at
120.degree. phase angle to each other. Similarly the second
perforating bank (0920) comprising 3 charges phased at 120.degree.
phase angle to each other. The first perforating bank (0910) and
the second perforating bank (0920) are phased at an offset angle of
60.degree.. According to a preferred exemplary embodiment, at least
one of the 3 charges in the first perforating bank and at least the
3 charges in the second perforating bank are configured to
perforate into a low compression region that is proximal to the
well casing. The low compression region is similar to the upward
low compression region (0505) and a downward low compression region
(0515) described above in FIG. 5. According to a further preferred
exemplary embodiment, the charges in the first perforating bank
(0910) are oriented such that when the charges perforate, the
charges intersect a preferred fracturing plane (0911). The
preferred fracturing plane may be transverse to the orientation of
the wellbore casing. Similarly, the charges in the second
perforating bank (0920) are oriented such that when the charges
perforate, the charges intersect a preferred fracturing plane
(0911). The preferred fracturing plane (0911) and preferred
fracturing plane (0921) may be parallel to each other as described
above in FIG. 1 (0103). Multiple preferred fracturing planes that
are parallel to each other may be targeted for maximum production
efficiency.
Preferred Exemplary 6-Shot 2-Bank Phased Perforating Gun
Non-converging System
[0089] Similar to FIG. 9A, a cross section view (0930), an end view
(0931), and a perspective view (0932) of an exemplary phased gun
system is generally illustrated in FIG. 9B. The system (0930) may
comprise a first perforating bank (0940) and a second perforating
bank (0950). The first perforating bank (0940) comprising 3 charges
phased at 120.degree. phase angle to each other. Similarly the
second perforating bank (0950) comprising 3 charges phased at
120.degree. phase angle to each other. The first perforating bank
(0940) and the second perforating bank (0950) are phased at an
offset angle of 60.degree.. The charges may be non-converging and
may not be intersecting a preferred fracturing plane when
perforating.
Preferred Exemplary 6-Shot 3-Bank Phased Perforating Gun System
[0090] FIG. 10A illustrates an exemplary 6-shot (charges) 3-bank,
phased at 180.degree. phase angle between charges in each bank,
phased at a 90.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
view (1000), an end view (1001), and a perspective view (1002) of
an exemplary phased gun system is generally illustrated in FIG.
10A. The system (1000) may comprise a first perforating bank
(1010), a second perforating bank (1020) and a third perforating
bank (1030). According to a preferred exemplary embodiment, at
least one of the 2 charges in the first perforating bank, at least
one of the 2 charges in the second perforating bank and at least
one of the 2 charges in the third perforating bank are configured
to perforate into a low compression region that is proximal to the
well casing. According to a further preferred exemplary embodiment,
the charges in the first perforating bank (1010), second
perforating bank and third perforating bank are each oriented such
that when the charges perforate, the charges intersect a preferred
fracturing planes (1011, 1021, 1031) respectively.
Preferred Exemplary 6-Shot 3-Bank Phased Perforating Gun
Non-converging System
[0091] Similar to FIG. 10A, a cross section view (1040), an end
view (1041), and a perspective view (1042) of an exemplary phased
gun system is generally illustrated in FIG. 10B. The system may
comprise 2 charges phased at a 180.degree. phase angle in each of a
first perforating bank (1050), a second perforating bank (1070) and
a third perforating bank (1060). The first perforating bank (1050),
the second perforating bank (1070) and the third perforating bank
(1060) are phased at an offset angle of 90.degree.. The charges may
be non-converging and may not be intersecting a preferred
fracturing plane when perforating.
Preferred Exemplary 10-Shot 2-Bank Phased Perforating Gun
System
[0092] FIG. 11A illustrates an exemplary 10-shot (charges) 2-bank,
phased at 72.degree. phase angle between charges in each bank,
phased at a 36.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
(1100), an end view (1101), and a perspective view (1102) of an
exemplary phased gun system is generally illustrated in FIG. 11A.
The system (1100) may comprise a first perforating bank (1110) and
a second perforating bank (1120). According to a preferred
exemplary embodiment, at least one of the 5 charges in the first
perforating bank and at least one of the 5 charges in the second
perforating bank are configured to perforate into a low compression
region that is proximal to the well casing. According to a further
preferred exemplary embodiment, the charges in the first
perforating bank (1110) and second perforating bank (1120) are each
oriented such that when the charges perforate, the charges
intersect preferred fracturing planes (1111, 1121)
respectively.
Preferred Exemplary 10-Shot 2-Bank Phased Perforating Gun
Non-converging System
[0093] Similar to FIG. 11A, a cross section view (1150), an end
view (1151), and a perspective view (1152) of an exemplary phased
gun system is generally illustrated in FIG. 11B. The system may
comprise 5 charges phased at a 72.degree. phase angle in each of a
first perforating bank (1130) and a second perforating bank (1140).
The first perforating bank (1130) and the second perforating bank
(1140) are phased at an offset angle of 36.degree.. The charges may
be non-converging and may not be intersecting a preferred
fracturing plane when perforating.
Preferred Exemplary 12-Shot 2-Bank Phased Perforating Gun
System
[0094] FIG. 12A illustrates an exemplary 12-shot (charges) 2-bank,
phased at 60.degree. phase angle between charges in each bank,
phased at a 30.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
view (1200), an end view (1201), and a perspective view (1202) of
an exemplary phased gun system is generally illustrated in FIG.
12A. The system (1200) may comprise a first perforating bank (1210)
and a second perforating bank (1220). According to a preferred
exemplary embodiment, at least one of the 6 charges in the first
perforating bank and at least one of the 6 charges in the second
perforating bank are configured to perforate into a low compression
region that is proximal to the well casing. According to a further
preferred exemplary embodiment, the charges in the first
perforating bank (1210) and second perforating bank (1220) are each
oriented such that when the charges perforate, the charges
intersect preferred fracturing planes (1211, 1221)
respectively.
Preferred Exemplary 12-Shot 2-Bank Phased Perforating Gun
Non-converging System
[0095] Similar to FIG. 12A, a cross section view (1250), an end
view (1251), and a perspective view (1252) of an exemplary phased
gun system is generally illustrated in FIG. 12B. The system may
comprise 6 charges phased at a 60.degree. phase angle in each of a
first perforating bank (1230) and a second perforating bank (1240).
The first perforating bank (1230) and the second perforating bank
(1240) are phased at an offset angle of 30.degree.. The charges may
be non-converging and may not be intersecting a preferred
fracturing plane when perforating.
Preferred Exemplary 6-Shot 3-Bank Phased Perforating Gun System
[0096] FIG. 13A illustrates an exemplary 12-shot (charges) 3-bank,
phased at 90.degree. phase angle between charges in each bank,
phased at a 30.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
(1300), an end view (1301), and a perspective view (1302) of an
exemplary phased gun system is generally illustrated in FIG. 13A.
The system (1300) may comprise a first perforating bank (1310), a
second perforating bank (1320) and a third perforating bank (1330).
According to a preferred exemplary embodiment, at least one of the
4 charges in the first perforating bank, at least one of the 4
charges in the second perforating bank and at least one of the 4
charges in the third perforating bank are configured to perforate
into a low compression region that is proximal to the well casing.
According to a further preferred exemplary embodiment, the charges
in the first perforating bank (1310), second perforating bank
(1320) and third perforating bank (1330) are each oriented such
that when the charges perforate, the charges intersect a preferred
fracturing planes (1311, 1321, 1331) respectively.
Preferred Exemplary 12-Shot 3-Bank Phased Perforating Gun
Non-converging System
[0097] Similar to FIG. 13A, a cross section view (1340), an end
view (1341), and a perspective view (1342) of an exemplary phased
gun system is generally illustrated in FIG. 13B. The system may
comprise 4 charges phased at a 90.degree. phase angle in each of a
first perforating bank (1340), a second perforating bank (1350) and
a third perforating bank (1360). The first perforating bank (1340),
the second perforating bank (1350) and the third perforating bank
(1360) are phased at an offset angle of 30.degree.. The charges may
be non-converging and may not be intersecting a preferred
fracturing plane when perforating.
Preferred Exemplary 12-Shot 4-Bank Phased Perforating Gun
System
[0098] FIG. 14A illustrates an exemplary 12-shot (charges) 4-bank,
phased at 120.degree. phase angle between charges in each bank,
phased at a 15.degree. offset angle between banks in a perforating
gun system according to a preferred embodiment. A cross section
view (1400), an end view (1401), and a perspective view (1402) of
an exemplary phased gun system is generally illustrated in FIG.
14A. The system (1400) may comprise a first perforating bank
(1410), a second perforating bank (1420), a third perforating bank
(1430) and a fourth perforating bank (1440). According to a
preferred exemplary embodiment, at least one of the 3 charges in
the first perforating bank, at least one of the 3 charges in the
second perforating bank, at least one of the 3 charges in the third
perforating bank and at least one of the 3 charges in the fourth
perforating bank are configured to perforate into a low compression
region that is proximal to the well casing. According to a further
preferred exemplary embodiment, the charges in the first
perforating bank, second perforating bank, third perforating bank
and fourth perforating bank are each oriented such that when the
charges perforate, the charges intersect preferred fracturing
planes (1411, 1421, 1431, 1441) respectively.
Preferred Exemplary 12-Shot 4-Bank Phased Perforating Gun
Non-converging System
[0099] Similar to FIG. 14A, a cross section view (1490), an end
view (1491), and a perspective view (1492) of an exemplary phased
gun system is generally illustrated in FIG. 14B. The system may
comprise 3 charges phased at 120.degree. phase angle in each of a
first perforating bank (1450), a second perforating bank (1460), a
third perforating bank (1470) and a fourth perforating bank (1480).
The first perforating bank (1450), the second perforating bank
(1460), the third perforating bank (1470) and the fourth
perforating bank (1480) are phased at an offset angle of
15.degree.. The charges may be non-converging and may not be
intersecting a preferred fracturing plane when perforating.
Preferred Exemplary 14-Shot 2-Bank Phased Perforating Gun
System
[0100] FIG. 15A illustrates an exemplary 14-shot (charges) 2-bank,
phased at 51.42.degree. phase angle between charges in each bank,
phased at a 25.5.degree. offset angle between banks in a
perforating gun system according to a preferred embodiment. A cross
section view (1500), an end view (1501), and a perspective view
(1502) of an exemplary phased gun system is generally illustrated
in FIG. 15A. The system (1500) may comprise a first perforating
bank (1510) and a second perforating bank (1520). According to a
preferred exemplary embodiment, at least one of the 7 charges in
the first perforating bank and at least one of the 7 charges in the
second perforating bank are configured to perforate into a low
compression region that is proximal to the well casing. According
to a further preferred exemplary embodiment, the charges in the
first perforating bank (1510) and second perforating bank (1520)
are each oriented such that when the charges perforate, the charges
intersect preferred fracturing planes (1511, 1521)
respectively.
Preferred Exemplary 14-Shot 2-Bank Phased Perforating Gun
Non-converging System
[0101] Similar to FIG. 15A, a cross section view (1550), an end
view (1551), and a perspective view (1552) of an exemplary phased
gun system is generally illustrated in FIG. 15B. The system may
comprise 7 charges phased at a 52.2.degree. phase angle in each of
a first perforating bank (1530) and a second perforating bank
(1540). The first perforating bank (1530) and the second
perforating bank (1540) are phased at an offset angle of
25.5.degree.. The charges may be non-converging and may not be
intersecting a preferred fracturing plane when perforating.
Preferred Exemplary 16-Shot 4-Bank Phased Perforating Gun
System
[0102] FIG. 16A illustrates an exemplary 16-shot (charges) 4-bank,
phased at 90.degree. phase angle between charges in each bank,
phased at a 11.25.degree. offset angle between banks in a
perforating gun system according to a preferred embodiment. A cross
section view (1600), an end view (1601), and a perspective view
(1602) of an exemplary phased gun system is generally illustrated
in FIG. 16A. The system (1600) may comprise a first perforating
bank (1610), a second perforating bank (1620), a third perforating
bank (1630) and a fourth perforating bank (1640). According to a
preferred exemplary embodiment, at least one of the 3 charges in
the first perforating bank, at least one of the 3 charges in the
second perforating bank, at least one of the 3 charges in the third
perforating bank and at least one of the 3 charges in the fourth
perforating bank are configured to perforate into a low compression
region that is proximal to the well casing. According to a further
preferred exemplary embodiment, the charges in the first
perforating bank, second perforating bank, third perforating bank
and fourth perforating bank are each oriented such that when the
charges perforate, the charges intersect preferred fracturing
planes (1611, 1621, 1631, 1641) respectively.
Preferred Exemplary 16-Shot 4-Bank Phased Perforating Gun
Non-converging System
[0103] Similar to FIG. 16A, a cross section view (1690), an end
view (1691), and a perspective view (1692) of an exemplary phased
gun system is generally illustrated in FIG. 16B. The system may
comprise 3 charges phased at 90.degree. phase angle in each of a
first perforating bank (1650), a second perforating bank (1660), a
third perforating bank (1670) and a fourth perforating bank (1680).
The first perforating bank (1650), the second perforating bank
(1660), the third perforating bank (1670) and the fourth
perforating bank (1680) are phased at an offset angle of
11.25.degree.. The charges may be non-converging and may not be
intersecting a preferred fracturing plane when perforating.
Preferred Exemplary Flowchart Embodiment of an Phasing Wellbore
Perforation (1700)
[0104] As generally seen in the flow chart of FIG. 17 (1700), a
preferred exemplary optimal phasing perforation method shaped
charges may be generally described in terms of the following steps:
[0105] (1) selecting a gun system for each cluster in a stage with
the best statistical probability for a desired number of
perforations in that cluster (1701); [0106] (2) positioning a
phased perforating gun in a wellbore casing (1702); and [0107] (3)
perforating through the phased perforating gun into a hydrocarbon
formation such that at least one of a first plurality of charges
and at least one of a second plurality of charges perforate within
an upward perforation angle and a downward perforation angle; the
upward perforation angle subtends in an upward direction about a
center of the perforating gun and the downward perforation angle
subtends in a downward direction about the center of the
perforating gun (1703).
System Summary
[0108] The present invention system anticipates a wide variety of
variations in the basic theme of a phased perforating gun system
for use in a wellbore casing comprising a plurality of perforating
banks; the plurality of perforating banks arranged in a cluster,
wherein:
[0109] the plurality of perforating banks comprise a first
perforating bank and a second perforating bank;
[0110] the first perforating bank comprises a first plurality of
charges; the first plurality of charges phased at a first phase
angle to each other;
[0111] the second perforating bank comprises a second plurality of
charges; the second plurality of charges phased at a second phase
angle to each other;
[0112] the first phase angle and the second phase angle angularly
offset by a first offset phase angle; and
[0113] at least one of the first plurality of charges and at least
one of the second plurality of charges are configured to perforate
into a low compressive region in a hydrocarbon formation; the low
compressive region proximal to the wellbore casing.
[0114] This general system summary may be augmented by the various
elements described herein to produce a wide variety of invention
embodiments consistent with this overall design description.
Method Summary
[0115] The present invention method anticipates a wide variety of
variations in the basic theme of implementation, but can be
generalized as a phased perforating method for use in a wellbore
casing operating in conjunction a phased perforating gun system
comprising a plurality of perforating banks; the plurality of
perforating banks arranged in a cluster, wherein:
[0116] the plurality of perforating banks comprise a first
perforating bank and a second perforating bank;
[0117] the first perforating bank comprises a first plurality of
charges; the first plurality of charges phased at a first phase
angle to each other;
[0118] the second perforating bank comprises a second plurality of
charges; the second plurality of charges phased at a second phase
angle to each other;
[0119] the first phase angle and the second phase angle angularly
offset by a first offset phase angle; and
[0120] at least one of the first plurality of charges and at least
one of the second plurality of charges are configured to perforate
into a low compressive region in a hydrocarbon formation; the low
compressive region proximal to the wellbore casing;
[0121] wherein the method comprises the steps of: [0122] (1)
selecting a gun system for each cluster in a stage with the best
statistical probability for the desired number of perforations in
that cluster; [0123] (2) positioning the phased perforating gun
system in the wellbore casing; and [0124] (3) perforating through
the phased perforating gun into a hydrocarbon formation such that
at least one of the first plurality of charges and at least one of
the second plurality of charges perforate within an upward
perforation angle and a downward perforation angle; the upward
perforation angle subtends in an upward direction about a center of
the perforating gun and the downward perforation angle subtends in
a downward direction about the center of the perforating gun.
[0125] This general method summary may be augmented by the various
elements described herein to produce a wide variety of invention
embodiments consistent with this overall design description.
System/Method Variations
[0126] The present invention anticipates a wide variety of
variations in the basic theme of oil and gas extraction. The
examples presented previously do not represent the entire scope of
possible usages. They are meant to cite a few of the almost
limitless possibilities.
[0127] This basic system and method may be augmented with a variety
of ancillary embodiments, including but not limited to: [0128] An
embodiment wherein when perforating, at least one of the first
plurality of charges and at least one of the second plurality of
charges are configured to perforate within an upward perforation
angle and a downward perforation angle; the upward perforation
angle subtends in an upward direction about a center of the
wellbore casing and the downward perforation angle subtends in a
downward direction about the center of the wellbore casing. [0129]
An embodiment wherein the orientation of the wellbore casing is
substantially horizontal. [0130] An embodiment wherein the
orientation of the wellbore casing is deviated. [0131] An
embodiment wherein the first plurality of charges are equally
spaced and the second plurality of charges are equally spaced.
[0132] An embodiment wherein a number of the first plurality of
charges range from 2 to 24. [0133] An embodiment wherein a number
of the first plurality of charges range from 2 to 24. [0134] An
embodiment wherein the first phase angle ranges from 1 to 359
degrees. [0135] An embodiment wherein the second phase angle ranges
from 1 to 359 degrees. [0136] An embodiment wherein the first
offset phase angle ranges from 1 to 90 degrees. [0137] An
embodiment wherein the upward perforation angle ranges from 0 to 45
degrees. [0138] An embodiment wherein the downward perforation
angle ranges from 0 to 45 degrees. [0139] An embodiment wherein the
plurality of perforating banks further comprises a third
perforating bank; [0140] the third perforating bank comprises a
third plurality of charges; the third plurality of charges are
phased at a third phase angle to each other; [0141] the first phase
angle and the second phase angle are angularly offset by offset
phase angle; the second phase angle and the third phase angle are
angularly offset by the second offset phase angle; [0142] when
perforating, at least one of the first plurality of charges, at
least one of the second plurality of charges, and at least one of
the third plurality of charges are configured to perforate within
an upward perforation angle and a downward perforation angle; the
upward perforation angle subtends in an upward direction about a
center of the perforating gun and the downward perforation angle
subtends in a downward direction about the center of the
perforating gun. [0143] An embodiment wherein a number of the third
plurality of charges range from 2 to 24. [0144] An embodiment
wherein the third phase angle ranges from 1 to 359 degrees. [0145]
An embodiment wherein the second offset phase angle ranges from 1
to 90 degrees. [0146] An embodiment wherein the upward perforation
angle ranges from 1 to 30 degrees. [0147] An embodiment wherein the
downward perforation angle ranges from 1 to 30 degrees. [0148] An
embodiment wherein the first plurality of charges and the second
are further angled to place preferred initiation points on a
transverse plane to the wellbore casing. [0149] An embodiment
wherein charges in at least two of the plurality of perforating
banks are configured to place preferred initiation points on a
single transverse plane to the wellbore casing. [0150] An
embodiment wherein charges in at least two of the plurality of
perforating banks are configured to place preferred initiation
points on a plurality of planes; the plurality of planes transverse
to the wellbore casing. [0151] An embodiment wherein the second
perforating bank is rotated about an orienting reference point by
the first offset phase angle.
[0152] One skilled in the art will recognize that other embodiments
are possible based on combinations of elements taught within the
above invention description.
CONCLUSION
[0153] An optimal phasing perforating phased gun system and method
for accurate perforation in a deviated/horizontal wellbore has been
disclosed. The system/method includes a gun string assembly (GSA)
deployed in a wellbore with shaped charges in clusters. Within a
cluster, the charges are separated into individual banks with a
phase angle between the charges in each bank and an offset angle
between banks. The number of charges per cluster, the phase angle
and the offset angle are optimized such that there is a maximum
probability of perforating into a low compression region in an
upward and downward direction.
* * * * *