U.S. patent application number 15/992101 was filed with the patent office on 2018-12-06 for disappearing plug.
This patent application is currently assigned to Advanced Frac Systems LLC. The applicant listed for this patent is Advanced Frac Systems LLC. Invention is credited to Henry Joe Jordan, JR..
Application Number | 20180347342 15/992101 |
Document ID | / |
Family ID | 64455679 |
Filed Date | 2018-12-06 |
United States Patent
Application |
20180347342 |
Kind Code |
A1 |
Jordan, JR.; Henry Joe |
December 6, 2018 |
DISAPPEARING PLUG
Abstract
In an embodiment of the present invention utilizes a frac plug
having a large diameter through bore wherein the through bore is at
least 75% of the outer diameter of the plug. A tracer assembly is
then affixed to a lower end of frac plug. The frac plug tracer
assembly is run into a wellbore where the frac plug is then set,
perforated, and fracked. The obstruction within the frac plug
through bore is then removed. In some instances, the instruction
may be a ball, dart, or other obturator and in some instances the
obstruction may be a dissolvable plug. With the obstruction within
the frac plug through bore removed wellbore fluids from the
hydrocarbon formation may flow upward through and around the tracer
assembly picking up chemical traces which are then carried to the
surface to be analyzed.
Inventors: |
Jordan, JR.; Henry Joe;
(Willis, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Advanced Frac Systems LLC |
Houston |
TX |
US |
|
|
Assignee: |
Advanced Frac Systems LLC
Houston
TX
|
Family ID: |
64455679 |
Appl. No.: |
15/992101 |
Filed: |
May 29, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62512630 |
May 30, 2017 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 34/063 20130101;
E21B 33/1208 20130101; E21B 43/261 20130101; E21B 47/11
20200501 |
International
Class: |
E21B 47/10 20060101
E21B047/10; E21B 43/26 20060101 E21B043/26; E21B 33/12 20060101
E21B033/12 |
Claims
1. A device for placing chemicals within a wellbore comprising, a
plug having a through bore and a slip about its exterior
circumference for gripping the wellbore, a tracer assembly
including a tracer, wherein the tracer assembly is attached to the
plug, wherein an annular chamber is formed between the exterior
circumference of the tracer assembly and the interior circumference
of the wellbore, ports formed through the tracer assembly allowing
a fluid to flow between the annular chamber and an interior of the
tracer assembly.
2. The device of claim 1 wherein, the through bore's internal
diameter is at least 75% of the plug's outer diameter.
3. The device of claim 1 further comprising, a ball to seal on the
through bore.
4. The device of claim 1 further comprising, a dissolvable plug
within the through bore.
5. The device of claim 1 wherein, the tracer assembly includes at
least two tracers.
6. The device of claim 1 wherein, the tracer is radioactive.
7. The device of claim 1 wherein, the tracer is chemical.
8. A method of placing a tracer the wellbore comprising, assembling
a plug and tracer assembly, placing the plug having a through bore
and tracer assembly within a wellbore, sealing the plug and
fracking a producing zone, removing the plug, entraining a tracer
from the tracer assembly into a produced fluid.
9. The method of claim 8 wherein, the through bore's internal
diameter is at least 75% of the plug's outer diameter.
10. The device of claim 8 further comprising, a ball to seal on the
through bore.
11. The device of claim 8 further comprising, a dissolvable plug
within the through bore.
12. The device of claim 8 wherein, the tracer assembly includes at
least two tracers.
13. The device of claim 8 wherein, the tracer is radioactive.
14. The device of claim 8 wherein, the tracer is chemical.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 62/512,630 that was filed on May 30, 2017.
BACKGROUND
[0002] One method of completing a well is known as plug and perf.
The plug and perf operation typically begins after the well has
been drilled and cased. Once the operator is ready to begin the
plug and perf operation a perforating tool is assembled on the
surface. The perforating tool typically incorporates a plug on the
lower end. The plug, once moved into position and set, will lock
into the casing walls and form a fluid tight seal preventing fluid
from moving past the plug. Just above the plug is a setting tool.
The setting tool, once actuated, moves the plug from an unset
position where the plug can be run into the well to a set position
where, as previously mentioned, the plug locks into the casing and
blocks fluid flow. Just above the setting tool is the perforating
gun. The perforating gun usually but not always consists of one or
more shaped charges that, upon detonation, will form holes in the
casing wall. Any type of perforating tool may be used such as a
jetting tool, etc.
[0003] Once assembled on the surface the perforating tool is run
into the well to the desired depth. Once the desired depth is
reached the setting tool is actuated to move the plug from its
unset position to its set position locking the plug in place. The
setting tool then disconnects from the plug. After disconnection
the setting tool and the perforating gun are raised to some point
above the now set plug, preferably to a location adjacent to a
hydrocarbon formation. Once the perforating gun is in place the
perforating gun is actuated thereby forming holes or perforations
through the casing wall. The perforating gun and setting tool are
then usually but not always removed from the wellbore.
[0004] With the perforating gun and setting tools removed from the
wellbore the well may be fractured through the perforations formed
by the perforating gun. Fracturing usually occurs by pumping
high-pressure fluid through the casing to the plug once the fluid
reaches the plug it can no longer flow downward as the plug forms a
fluid tight seal and is locked to the. High-pressure fluid then
flows laterally outward through the holes in the casing. The fluid
cracks and/or removes the cement adjacent to the perforations
continuing to move outward into the rock formations fracturing the
rock and allowing hydrocarbons to flow in towards the casing, once
the fracking ceases.
[0005] Once the well has been fraced at the first location a second
perforating tool may be assembled on the surface and then run into
the wellbore to a second location above the location of the first
perforations. The procedure is then repeated until all known
formations have been accessed through the casing by perforations.
After the plug and pert operations are completed the plugs are
removed from the well. In some instances, the plugs may dissolve in
other instances the plugs may be drilled. In other instances, the
plugs have large internal bores with a seat within the plug
allowing a ball, dart, or other obturator to form a seal with the
seat to block downward flow. By having an obturator, during reverse
flow, such as when hydrocarbons are being produced to the surface,
the ball will lift off of the plug seat allowing fluid to flow
upwards through the plug. In other instances, the plugs may have a
dissolvable core such that after the perforating operation the
internal bore of the plug will dissolve allowing production through
the center of the plug while the plug and any items attached to the
plug remain in place within the wellbore.
[0006] Once the plugs are removed hydrocarbons from each of the
various formations flow into the interior of the casing and
following the path of least resistance to the surface. One of the
downsides of allowing the hydrocarbons from the various formations
to co-mingle within the interior of the casing is that it is
difficult to tell whether or not fluid is being produced from a
particular formation and what is the makeup of the fluid being
produced from a particular formation, i.e. has the formation
watered out or is it still producing hydrocarbons. Presently
determining the production characteristics of a well requires
running expensive logging operations into the well after the plug
and perf job is completed.
SUMMARY
[0007] It has been found that by adding a chemical or other tracer
at various locations along the wellbore, once the fluid reaches the
surface the fluid may be analyzed with the various markers i.e.
tracers and formation production parameters may be assessed.
[0008] It is the objective of some operators to understand the
effectiveness of the plug and pert frac job by understanding which
portions of the reservoir are contributing the maximum production.
In the present embodiment the operator would use a big bore frac
plug as the bottom portion of the perforating tool. The big bore
frac plug has, as the name implies, a large internal diameter and
seals against downward fluid flow with a ball, dart, or other
obturating device on a seat within the big bore frac plug.
Preferably the ball, dart, plug core, or other obturator is
dissolvable. In some instances, dissolution of the ball takes place
in the presence of hydrocarbons or water and in other instances a
chemical agent is supplied to either accelerate or cause
dissolution of the obturator. The chemical dissolution agent may be
supplied with the frac fluid or as a delayed release component of
the obturator or frac plug.
[0009] In a present embodiment the big bore frac plug is modified
to allow chemical tracers to be attached to the big bore frac plug
either directly or within a chemical tracer carrier. In some
instances, the chemical tracers are attached to the lower portion
of the big bore frac plug, in other instances the chemical tracers
are attached above the big bore frac plug, and in still other
instances the chemical tracers are carried within the big bore frac
plug. It is envisioned that the big bore frac plug is adapted so
that a tracer carrier having the same internal diameter as the big
bore frac plug is fitted to receive chemical tracers and is able to
be easily attached to the big bore frac plug such as by threading,
shear pins, etc. Additionally, the tracer carrier allows the
wellbore fluid to interact with the chemical tracers such that the
wellbore fluid will carry a portion of the chemical tracer with the
fluid to the surface.
[0010] Once the big bore frac plug is run into the hole and set,
using either a wire line or coil tubing setting tool, the running
assembly is then disconnected from the plug and the perforations
are created above the plug by locating and firing the perforating
guns. The spent guns and setting tool are then removed from the
well. After removal, an obturator such as a dissolvable frac ball
is dropped to land on the frac plug creating the isolation between
an upper (newly perforated) zone and a lower (recently stimulated)
zone. A further function of the ball is to isolate the frac job to
be performed on the upper zone from the tracer carrier located
below the frac plug.
[0011] Once all zones have been fractured, the operator may perform
well cleanup or flowback operations to bring the well onto
production. The dissolvable frac balls or plug core begin
dissolving and disappear in a designated period of time. The big
bore frac plug's relatively large internal diameter as compared to
its outer diameter, usually over 75%, provide minimum restriction
through the internal diameter allowing the well to flow. Once the
well is cleaned up, the well may be shut in for a designated
interval. The shut-in interval allows the chemical tracer carriers
to release the initial chemical tracer loads into the fluid the
chemical tracer is exposed to. Following the pre-planned period of
chemical build up time, the well is then turned back on to flow and
a chemical sample is captured at the surface allowing the operator
to develop a profile of the flow contribution (media type and
production levels) from the various well sections to understand the
effectiveness of the frac job in the well completion plan. Knowing
the well flow characteristics helps the operator in designing
future wells for optimize performance in the same reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 depicts a wellbore after the casing has been run into
the wellbore and plugs with tracers have been installed.
[0013] FIG. 2 is a close-up side view of a wellbore and a tracer
assembly.
DETAILED DESCRIPTION
[0014] The description that follows includes exemplary apparatus,
methods, techniques, or instruction sequences that embody
techniques of the inventive subject matter. However, it is
understood that the described embodiments may be practiced without
these specific details.
[0015] FIG. 1 depicts a wellbore 10 after the casing 30 has been
run into the wellbore 10. The casing has a toe plug 26 at the lower
end 32 of the wellbore 10. The wellbore 10 has been fractured
creating a first zone 40 and a first producing zone 12. A first
plug 20 including a tracer assembly 21 has been set in place above
first producing zone 12. A first ball 42 has been landed atop first
plug 20 allowing the casing 30 to be perforated adjacent a second
producing zone 14 creating a second zone 43. A second plug 22
including a tracer assembly 23 has been set in place above second
zone 43. A second ball 44 has been landed atop second plug 22
allowing the casing 30 to be perforated adjacent a third producing
zone 16 creating a third zone 46. A third plug 24 including a
tracer assembly 25 has been set in place above third zone 46. A
third ball 48 has been landed atop third plug 24 allowing the
casing 30 to be perforated adjacent a fourth producing zone 18
creating a fourth zone 50. With all zones perforated the operator
may shut-in the well for a predetermined period of time to allow
fluids adjacent to each tracer assembly 21, 23, and 25 to become
appropriately loaded with the various tracers. The tracers may be
chemical, biological, radioactive, electronic, or mechanical. In
some instances, the tracer assemblies may carry chemicals such as
paraffin inhibitors, biocides, corrosion inhibitors, or other
chemicals useful in a wellbore.
[0016] FIG. 2 is a close-up side view of wellbore 10 at tracer
assembly 23. In this instance second plug 22 is shown in its set
position gripping casing 30. In this instance while the dissolvable
frac ball 44 is shown in its seated position the well is being
produced so that fluids flowing from producing zone 14 into second
zone 43 are then flowing towards third zone 46 through and around
tracer assembly 23. Arrow 76 depicts the flow path of fluids
flowing from producing zone 14 into second zone 43. As the fluids
approach tracer assembly 23 which is locked into position within
the casing 30 by the large internal diameter frac plug 22. As
indicated by arrow 78 some of the fluid may flow through the center
of the tracer assembly 23 while some of the fluid flows into an
annular chamber 80 created by the casing 30 and the outer diameter
of the tracer assembly 23. The fluid flow path into annular chamber
80 and then through various ports 70 along the length of the tracer
assembly 23 as indicated by arrow 74. As the fluid flows through
various ports 70 and around tracer assembly 23 the fluid picks up
small portions of the tracer in tracer assembly 23. The fluid then
carries the tracer to the surface where the operator is able to
utilize the tracer from each of the tracer assemblies 21, 23, and
25 to determine the composition of the fluid produced at a
particular location as well as the volume of fluid produced from
each producing zone.
[0017] The methods and materials described as being used in a
particular embodiment may be used in any other embodiment. While
the embodiments are described with reference to various
implementations and exploitations, it will be understood that these
embodiments are illustrative and that the scope of the inventive
subject matter is not limited to them. Many variations,
modifications, additions and improvements are possible.
[0018] Plural instances may be provided for components, operations
or structures described herein as a single instance. In general,
structures and functionality presented as separate components in
the exemplary configurations may be implemented as a combined
structure or component. Similarly, structures and functionality
presented as a single component may be implemented as separate
components. These and other variations, modifications, additions,
and improvements may fall within the scope of the inventive subject
matter.
* * * * *