U.S. patent application number 15/090953 was filed with the patent office on 2016-12-08 for restriction plug element 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, Michael D. Wroblicky.
Application Number | 20160356137 15/090953 |
Document ID | / |
Family ID | 57451766 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160356137 |
Kind Code |
A1 |
Hardesty; John T. ; et
al. |
December 8, 2016 |
RESTRICTION PLUG ELEMENT AND METHOD
Abstract
A restriction plug element and method for positioning plugs to
isolate fracture zones in a horizontal, vertical, or deviated
wellbore is disclosed. The restriction plug element includes a
partial hollow passage with an interior end. The partial passage
enables the plug element to seat in a restriction sleeve member
during treatment and subsequently degrade to form a complete hollow
passage. The complete flow channel dissolves or degrades not only
the outside but also the inside of the wall of the restriction plug
element. Initially the flow is restricted by the closed end in the
partial hollow passage and over time the flow channel opens up by
degradation and allows fluid to pass through in either direction.
During back flow in the well new fluid is circulated into the well
and the restriction plug element continues to degrade.
Inventors: |
Hardesty; John T.;
(Weatherford, TX) ; Wroblicky; Michael D.;
(Weatherford, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GEODynamics, Inc. |
Millsap |
TX |
US |
|
|
Assignee: |
GEODynamics, Inc.
Millsap
TX
|
Family ID: |
57451766 |
Appl. No.: |
15/090953 |
Filed: |
April 5, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14721784 |
May 26, 2015 |
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15090953 |
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14459042 |
Aug 13, 2014 |
9062543 |
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14721784 |
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62081399 |
Nov 18, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 43/14 20130101;
E21B 34/063 20130101; E21B 43/26 20130101 |
International
Class: |
E21B 43/26 20060101
E21B043/26; E21B 33/12 20060101 E21B033/12; E21B 43/14 20060101
E21B043/14; E21B 29/02 20060101 E21B029/02 |
Claims
1. A restriction plug element for use in a wellbore casing, said
restriction plug element comprising a degradable material; said
restriction plug element configured with a partial hollow passage
extending from at least one interior end; said interior end
configured to block fluid communication from upstream to downstream
during fluid treatment; and said partial hollow passage configured
to degrade and form a complete hollow passage to enable said fluid
communication subsequent to said fluid treatment.
2. The restriction plug element of claim 1 wherein said interior
end is further configured with a terminus; said terminus configured
to orient such that said restriction plug element seats in a
restriction sleeve member and restricts substantial fluid bypass
during said fluid treatment.
3. The restriction plug element of claim 1 wherein said partial
hollow passage substantially increases a surface area of contact of
said restriction plug element with fluids expected in said wellbore
casing.
4. The restriction plug element of claim 1 wherein said partial
hollow passage is capped at an open end with a degradable material;
said open end and said interior end forming two ends of said
partial hollow passage.
5. The restriction plug element of claim 1 wherein said partial
hollow passage extends from said interior end to another interior
end.
6. The restriction plug element of claim 1 wherein said partial
hollow passage extends to a surface of said restriction plug
element.
7. The restriction plug element of claim 1 further comprises at
least one of said partial hollow passages extending to said surface
of said restriction plug element on both ends of a flow
channel.
8. The restriction plug element of claim 1 wherein said partial
hollow passage passes through a center of said restriction plug
element.
9. The restriction plug element of claim 1 wherein at least one
said partial hollow passage intersects with at least one other
partial hollow passage.
10. The restriction plug element of claim 1 wherein at least one
said partial hollow passage does not intersect with any other said
partial hollow passage.
11. The restriction plug element of claim 1 wherein at least one
said partial hollow passage comprises a plurality of interior ends;
said plurality of interior ends are configured to be spread
out.
12. The restriction plug element of claim 1 whereby said complete
hollow passage enables said restriction plug element to deform such
that said restriction plug element passes through a restriction
sleeve member in said wellbore casing.
13. The restriction plug element of claim 1 wherein at least one of
said partial hollow passage is aligned to another partial hollow
passage.
14. The restriction plug element of claim 1 wherein a shape of said
restriction plug element is selected from a group comprising:
circular, cylinder, sphere, oval or elongated.
15. The restriction plug element of claim 1 wherein a shape of
cross section of said hollow passage is selected from a group
comprising: circle, square, oval or elongated.
16. A restriction plug element degradation method, said method
operating in conjunction with a restriction plug element (RPE) for
use in a wellbore casing, said restriction plug element comprising
a degradable material; said restriction plug element configured
with at least one partial hollow passage that extends from an
interior end; wherein said method comprises the steps of: (1)
deploying said restriction plug element into said wellbore casing
and blocking fluid communication; (2) orienting said restriction
plug element with said interior end to seat in a restriction sleeve
member and isolating a stage; (3) treating said isolating stage
with fracturing fluids; (4) degrading from said interior end in
said partial hollow passage through contact with wellbore fluids;
(5) creating a complete hollow passage from said partial hollow
passage; and (6) unblocking said fluid communication.
17. The restriction plug element degradation method of claim 16
wherein said orienting step (2) further seals said restriction plug
element to restrict substantial fluid bypass in said treating step
(3).
18. The restriction plug element degradation method of claim 16
wherein said orienting step (2) orients said restriction plug
element such that said hollow passage is unblocked by said
restriction sleeve member.
19. The restriction plug element degradation method of claim 16
wherein said orienting step (2) seats said restriction plug element
but not orientated.
20. The restriction plug element degradation method of claim 16
wherein said degrading step (4) occurs immediately after said
treating step (3).
21. The restriction plug element degradation method of claim 16
wherein said creating step (5) accelerates rate of degradation of
said restriction plug element.
22. The restriction plug element degradation method of claim 16
further comprises the step of degrading said restriction plug
element to deform.
23. The restriction plug element degradation method of claim 16
wherein a ratio of diameter of said restriction plug element to an
inner diameter of said restriction sleeve member ranges from 0.5 to
0.99.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 14/721,784, filed May 26, 2015, which claims
the benefit of U.S. Provisional No. 62/081,399, filed Nov. 18,
2014, which is also a continuation-in-part of U.S. application Ser.
No. 14/459,042, filed Aug. 13, 2014, now U.S. Pat. No. 9,062,543,
the disclosures of which are fully incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to oil and gas
extraction. Specifically, the invention attempts to isolate
fracture zones through selectively positioning restriction elements
within a wellbore casing.
[0003] PRIOR ART AND BACKGROUND OF THE INVENTION
Prior Art Background
[0004] The process of extracting oil and gas typically consists of
operations that include preparation, drilling, completion,
production and abandonment.
[0005] Preparing a drilling site involves ensuring that it can be
properly accessed and that the area where the rig and other
equipment will be placed has been properly graded. Drilling pads
and roads must be built and maintained which includes the spreading
of stone on an impermeable liner to prevent impacts from any spills
but also to allow any rain to drain properly.
[0006] In the drilling of oil and gas wells, a wellbore is formed
using a drill bit that is urged downwardly at a lower end of a
drill string. After drilling the wellbore is lined with a string of
casing. An annular area is thus formed between the string of casing
and the wellbore. A cementing operation is then conducted in order
to fill the annular area with cement. The combination of cement and
casing strengthens the wellbore and facilitates the isolation of
certain areas of the formation behind the casing for the production
of hydrocarbons.
[0007] The first step in completing a well is to create a
connection between the final casing and the rock which is holding
the oil and gas. There are various operations in which it may
become necessary to isolate particular zones within the well. This
is typically accomplished by temporarily plugging off the well
casing at a given point or points with a plug.
[0008] A special tool, called a perforating gun, is lowered to the
rock layer. This 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.
[0009] Since these perforations are only a few inches long and are
performed more than a mile underground, no activity is detectable
on the surface. The perforation gun is then removed before the next
step, hydraulic fracturing. Stimulation fluid, which is a mixture
of over 90% water and sand, plus a few chemical additives, is
pumped under controlled conditions into deep, underground reservoir
formations. The chemicals are used for lubrication and to keep
bacteria from forming and to carry the sand. These chemicals are
typically non-hazardous and range in concentrations from 0.1% to
0.5% by volume and are needed to help improve the performance and
efficiency of the hydraulic fracturing. This stimulation fluid is
pumped at high pressure out through the perforations made by the
perforating gun. This process creates fractures in the shale rock
which contains the oil and natural gas.
[0010] In many instances a single wellbore may traverse multiple
hydrocarbon formations that are otherwise isolated from one another
within the Earth. It is also frequently desired to treat such
hydrocarbon bearing formations with pressurized treatment fluids
prior to producing from those formations. In order to ensure that a
proper treatment is performed on a desired formation, that
formation is typically isolated during treatment from other
formations traversed by the wellbore. To achieve sequential
treatment of multiple formations, the casing adjacent to the toe of
a horizontal, vertical, or deviated wellbore is first perforated
while the other portions of the casing are left unperforated. The
perforated zone is then treated by pumping fluid under pressure
into that zone through perforations. Following treatment a plug is
placed adjacent to the perforated zone. The process is repeated
until all the zones are perforated. The plugs are particularly
useful in accomplishing operations such as isolating perforations
in one portion of a well from perforations in another portion or
for isolating the bottom of a well from a wellhead. The purpose of
the plug is to isolate some portion of the well from another
portion of the well.
[0011] Subsequently, production of hydrocarbons from these zones
requires that the sequentially set plugs be removed from the well.
In order to reestablish flow past the existing plugs an operator
must remove and/or destroy the plugs by milling, drilling, or
dissolving the plugs.
[0012] Restriction plug elements such as balls/plugs with large
aspect ratio approaching 1 and seated in a large inner diameter
restriction sleeve member do not degrade in wellbore fluids. The
plug elements change shape from a circular to flying saucer shape
because water is restricted on the edges and a sand pack that holds
the ball on the seat prevents the plug element from interacting
with the water and wellbore fluids. Therefore there is a need to
add a mechanism to provide more surface area in the restriction
plug element to provide contact with the restriction plug element
after seating in a restriction sleeve member.
Prior Art System Overview (0100)
[0013] As generally seen in the system diagram of FIG. 1 (0100),
prior art systems associated with oil and gas extraction may
include a wellbore casing (0120) laterally drilled into a wellbore.
A plurality of frac plugs (0110, 0111, 0112, 0113) may be set to
isolate multiple hydraulic fracturing zones (0101, 0102, 0103).
Each frac plug is positioned to isolate a hydraulic fracturing zone
from the rest of the unperforated zones. The positions of frac
plugs may be defined by preset sleeves in the wellbore casing. For
example, frac plug (0111) is positioned such that hydraulic
fracturing zone (0101) is isolated from downstream (injection or
toe end) hydraulic fracturing zones (0102, 0103). Subsequently, the
hydraulic fracturing zone (0101) is perforated using a perforation
gun and fractured. Preset plug/sleeve positions in the casing,
precludes change of fracture zone locations after a wellbore casing
has been installed. Therefore, there is a need to position a plug
at a desired location after a wellbore casing has been installed
without depending on a predefined sleeve location integral to the
wellbore casing to position the plug.
[0014] Furthermore, after well completion, sleeves used to set frac
plugs may have a smaller inner diameter constricting fluid flow
when well production is initiated. Therefore, there is a need for
relatively large inner diameter sleeves after well completion that
allow for unrestricted well production fluid flow.
[0015] Additionally, frac plugs can be inadvertently set at
undesired locations in the wellbore casing creating unwanted
constrictions. The constrictions may latch wellbore tools that are
run for future operations and cause unwanted removal process.
Therefore, there is a need to prevent premature set conditions
caused by conventional frac plugs.
Prior Art Method Overview (0200)
[0016] As generally seen in the method of FIG. 2 (0200), prior art
associated with oil and gas extraction includes site preparation
and installation of a wellbore casing (0120) (0201). Preset sleeves
may be installed as an integral part of the wellbore casing (0120)
to position frac plugs for isolation. After setting a frac plug and
isolating a hydraulic fracturing zone in step (0202), a perforating
gun is positioned in the isolated zone in step (0203).
Subsequently, the perforating gun detonates and perforates the
wellbore casing and the cement into the hydrocarbon formation. The
perforating gun is next moved to an adjacent position for further
perforation until the hydraulic fracturing zone is completely
perforated. In step (0204), hydraulic fracturing fluid is pumped
into the perforations at high pressures. The steps comprising
setting up a plug (0202), isolating a hydraulic fracturing zone,
perforating the hydraulic fracturing zone (0203) and pumping
hydraulic fracturing fluids into the perforations (0204), are
repeated until all hydraulic fracturing zones in the wellbore
casing are processed. In step (0205), if all hydraulic fracturing
zones are processed, the plugs are milled out with a milling tool
and the resulting debris is pumped out or removed from the wellbore
casing (0206). In step (0207) hydrocarbons are produced by pumping
out from the hydraulic fracturing stages.
[0017] The step (0206) requires that removal/milling equipment be
run into the well on a conveyance string which may typically be
wire line, coiled tubing or jointed pipe. The process of
perforating and plug setting steps represent separate "trip" into
and out of the wellbore with the required equipment. Each trip is
time consuming and expensive. In addition, the process of drilling
and milling the plugs creates debris that needs to be removed in
another operation. Therefore, there is a need for isolating
multiple hydraulic fracturing zones without the need for a milling
operation. Furthermore, there is a need for positioning restrictive
plug elements that could be removed in a feasible, economic, and
timely manner before producing gas.
Deficiencies in the Prior Art
[0018] The prior art as detailed above suffers from the following
deficiencies: [0019] Prior art systems do not provide for
positioning a ball seat at a desired location after a wellbore
casing has been installed, without depending on a predefined sleeve
location integral to the wellbore casing to position the plug.
[0020] Prior art systems do not provide for isolating multiple
hydraulic fracturing zones without the need for a milling
operation. [0021] Prior art systems do not provide for positioning
restrictive elements that could be removed in a feasible, economic,
and timely manner. [0022] Prior art systems do not provide for
setting larger inner diameter sleeves to allow unrestricted well
production fluid flow. [0023] Prior art systems cause undesired
premature preset conditions preventing further wellbore
operations.
[0024] While some of the prior art may teach some solutions to
several of these problems, the core issue of isolating hydraulic
fracturing zones without the need for a milling operation has not
been addressed by prior art.
OBJECTIVES OF THE INVENTION
[0025] Accordingly, the objectives of the present invention are
(among others) to circumvent the deficiencies in the prior art and
affect the following objectives: [0026] Provide for positioning a
ball seat at a desired location after a wellbore casing has been
installed, without depending on a predefined sleeve location
integral to the wellbore casing to position the plug. [0027]
Provide for isolating multiple hydraulic fracturing zones without
the need for a milling operation. [0028] Provide for positioning
restrictive elements that could be removed in a feasible, economic,
and timely manner. [0029] Provide for setting larger inner diameter
sleeves to allow unrestricted well production fluid flow. [0030]
Provide for eliminating undesired premature preset conditions that
prevent further wellbore operations.
[0031] 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
[0032] The present invention in various embodiments addresses one
or more of the above objectives in the following manner. The
present invention provides a system to isolate fracture zones in a
horizontal, vertical, or deviated wellbore without the need for a
milling operation. The system includes a restriction plug element
for use in a wellbore casing comprising a degradable material. The
restriction plug element configured with a partial hollow passage
extending from at least one interior end configured to block fluid
communication from upstream to downstream during fluid treatment.
The partial hollow passage degrades and forms a complete hollow
passage to enable the fluid communication subsequent to the fluid
treatment.
Method Overview
[0033] The present invention system may be utilized in the context
of an overall gas extraction method, wherein the restriction plug
element described previously is controlled by a method having the
following steps: [0034] (1) deploying the restriction plug element
into the wellbore casing and blocking fluid communication; [0035]
(2) orienting the restriction plug element with the interior end to
seat in a restriction sleeve member and isolating a stage; [0036]
(3) treating the isolated stage with fracturing fluids; [0037] (4)
degrading from the interior end in the partial hollow passage
through contact with wellbore fluids; [0038] (5) creating a
complete hollow passage from the partial hollow passage; and [0039]
(6) unblocking the fluid communication.
[0040] 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
[0041] 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:
[0042] FIG. 1 illustrates a system block overview diagram
describing how prior art systems use plugs to isolate hydraulic
fracturing zones.
[0043] FIG. 2 illustrates a flowchart describing how prior art
systems extract gas from hydrocarbon formations.
[0044] FIG. 3 illustrates an exemplary system side view of a
spherical restriction plug element/restriction sleeve member
overview depicting a presently preferred embodiment of the present
invention.
[0045] FIG. 3a illustrates an exemplary system side view of a
spherical restriction plug element/restriction sleeve member
overview depicting a presently preferred embodiment of the present
invention.
[0046] FIG. 4 illustrates a side perspective view of a spherical
restriction plug element/restriction sleeve member depicting a
preferred exemplary system embodiment.
[0047] FIG. 5 illustrates an exemplary wellbore system overview
depicting multiple stages of a preferred embodiment of the present
invention.
[0048] FIG. 6 illustrates a detailed flowchart of a preferred
exemplary wellbore plug isolation method used in some preferred
exemplary invention embodiments.
[0049] FIG. 7 illustrates a side view of a cylindrical restriction
plug element seated in a restriction sleeve member depicting a
preferred exemplary system embodiment.
[0050] FIG. 8 illustrates a side perspective view of a cylindrical
restriction plug element seated in a restriction sleeve member
depicting a preferred exemplary system embodiment.
[0051] FIG. 9 illustrates a side view of a dart restriction plug
element seated in a restriction sleeve member depicting a preferred
exemplary system embodiment.
[0052] FIG. 10 illustrates a side perspective view of a dart
restriction plug element seated in a restriction sleeve member
depicting a preferred exemplary system embodiment.
[0053] FIG. 10a illustrates a side perspective view of a dart
restriction plug element depicting a preferred exemplary system
embodiment.
[0054] FIG. 10b illustrates another perspective view of a dart
restriction plug element depicting a preferred exemplary system
embodiment.
[0055] FIG. 11 illustrates a side view of a restriction sleeve
member sealed with an elastomeric element depicting a preferred
exemplary system embodiment.
[0056] FIG. 12 illustrates a side perspective view of a restriction
sleeve member sealed with gripping/sealing element depicting a
preferred exemplary system embodiment.
[0057] FIG. 13 illustrates side view of an inner profile of a
restriction sleeve member sealed against an inner surface of a
wellbore casing depicting a preferred exemplary system
embodiment.
[0058] FIG. 14 illustrates a detailed cross section view of a
wellbore setting tool creating a seal according to a preferred
exemplary system embodiment.
[0059] FIG. 15 illustrates a wellbore setting tool creating inner
and outer profiles in the restriction sleeve member depicting a
preferred exemplary system embodiment.
[0060] FIG. 16 illustrates a detailed cross section view of a
wellbore setting tool creating inner profiles in the restriction
sleeve member depicting a preferred exemplary system
embodiment.
[0061] FIG. 17 illustrates a detailed cross section view of a
wellbore setting tool creating inner profiles and outer profiles in
the restriction sleeve member depicting a preferred exemplary
system embodiment.
[0062] FIG. 18 illustrates a cross section view of a wellbore
setting tool setting a restriction sleeve member depicting a
preferred exemplary system embodiment.
[0063] FIG. 19 illustrates a detailed cross section view of a
wellbore setting tool setting a restriction sleeve member depicting
a preferred exemplary system embodiment.
[0064] FIG. 20 illustrates a detailed side section view of a
wellbore setting tool setting a restriction sleeve member depicting
a preferred exemplary system embodiment.
[0065] FIG. 21 illustrates a detailed perspective view of a
wellbore setting tool setting a restriction sleeve member depicting
a preferred exemplary system embodiment.
[0066] FIG. 22 illustrates another detailed perspective view of a
wellbore setting tool setting a restriction sleeve member depicting
a preferred exemplary system embodiment.
[0067] FIG. 23 illustrates a cross section view of a wellbore
setting tool setting a restriction sleeve member and removing the
tool depicting a preferred exemplary system embodiment.
[0068] FIG. 24 illustrates a detailed cross section view of
wellbore setting tool setting a restriction sleeve member depicting
a preferred exemplary system embodiment.
[0069] FIG. 25 illustrates a cross section view of wellbore setting
tool removed from wellbore casing depicting a preferred exemplary
system embodiment.
[0070] FIG. 26 illustrates a cross section view of a spherical
restriction plug element deployed and seated into a restriction
sleeve member depicting a preferred exemplary system
embodiment.
[0071] FIG. 27 illustrates a detailed cross section view of a
spherical restriction plug element deployed into a restriction
sleeve member depicting a preferred exemplary system
embodiment.
[0072] FIG. 28 illustrates a detailed cross section view of a
spherical restriction plug element seated in a restriction sleeve
member depicting a preferred exemplary system embodiment.
[0073] FIG. 29 illustrates a cross section view of wellbore setting
tool setting a restriction sleeve member and seating a second
restriction plug element depicting a preferred exemplary system
embodiment.
[0074] FIG. 30 illustrates a detailed cross section view of
wellbore setting tool setting a second restriction sleeve member
depicting a preferred exemplary system embodiment.
[0075] FIG. 31 illustrates a detailed cross section view of a
spherical restriction plug element seated in a second restriction
sleeve member depicting a preferred exemplary system
embodiment.
[0076] FIG. 32 illustrates a cross section view of a restriction
sleeve member with flow channels according to a preferred exemplary
system embodiment.
[0077] FIG. 33 illustrates a detailed cross section view of a
restriction sleeve member with flow channels according to a
preferred exemplary system embodiment.
[0078] FIG. 34 illustrates a perspective view of a restriction
sleeve member with flow channels according to a preferred exemplary
system embodiment.
[0079] FIG. 35 illustrates a cross section view of a double set
restriction sleeve member according to a preferred exemplary system
embodiment.
[0080] FIG. 36 illustrates a detailed cross section view of a
double set restriction sleeve member according to a preferred
exemplary system embodiment.
[0081] FIG. 37 illustrates a perspective view of a double set
restriction sleeve member according to a preferred exemplary system
embodiment.
[0082] FIG. 38 illustrates a cross section view of a WST setting
restriction sleeve member at single, double and triple locations
according to a preferred exemplary system embodiment.
[0083] FIG. 39 illustrates a cross section view of a WST with
triple set restriction sleeve member according to a preferred
exemplary system embodiment.
[0084] FIG. 40 illustrates a detailed cross section view of a
triple set restriction sleeve member according to a preferred
exemplary system embodiment.
[0085] FIG. 41 illustrates a detailed perspective view of a triple
set restriction sleeve member according to a preferred exemplary
system embodiment.
[0086] FIG. 42 illustrates cross section and perspective views of a
restriction plug element with a partial hollow passage according to
a preferred exemplary system embodiment.
[0087] FIG. 43 illustrates cross section and perspective views of a
restriction plug element with a plurality of partial hollow
passages according to a preferred exemplary system embodiment.
[0088] FIG. 44 illustrates perspective views of a restriction plug
element transforming a partial hollow passage into a complete
hollow passage according to a preferred exemplary system
embodiment.
[0089] FIG. 45 illustrates cross section and perspective views of a
restriction plug element with a partial hollow passage that extends
to a surface on both ends according to a preferred exemplary system
embodiment.
[0090] FIG. 46 illustrates an exemplary flowchart embodiment of a
restriction plug element degradation method.
[0091] FIG. 47 illustrates a mass vs. time chart for a solid ball
and an exemplary restriction plug element with a partial hollow
passage according to a preferred exemplary embodiment.
[0092] FIG. 48 illustrates a diameter vs. time chart for a solid
ball and an exemplary restriction plug element with a partial
hollow passage according to a preferred exemplary embodiment.
DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS
[0093] 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.
[0094] 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 a wellbore
plug isolation 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.
GLOSSARY OF TERMS
[0095] RSM: Restriction Sleeve Member, a cylindrical member
positioned at a selected wellbore location. [0096] RPE: Restriction
Plug Element, an element configured to isolate and block fluid
communication. [0097] CSS: Conforming Seating Surface, a seat
formed within RSM. [0098] ICD: Inner Casing Diameter, inner
diameter of a wellbore casing. [0099] ICS: Inner Casing Surface,
inner surface of a wellbore casing. [0100] ISD: Inner Sleeve
Diameter, inner diameter of a RSM. [0101] ISS: Inner Sleeve
Surface, inner surface of a RSM. [0102] WST: Wellbore Setting Tool,
a tool that functions to set and seal RSMs. [0103] GSA: Gun String
Assembly, a cascaded string of perforating guns coupled to each
other.
Preferred Embodiment System Block Diagram (0300, 0400)
[0104] The present invention may be seen in more detail as
generally illustrated in FIG. 3 (0300) and FIG. 3a (0320), wherein
a wellbore casing (0304) is installed inside a hydrocarbon
formation (0302) and held in place by wellbore cement (0301). The
wellbore casing (0304) may have an inner casing surface (ICS)
associated with an inner casing diameter (ICD) (0308). For example,
ICD (0308) may range from 23/4 inch to 12 inches. A restriction
sleeve member (RSM) (0303) that fits inside of the wellbore casing
is disposed therein by a wellbore setting tool (WST) to seal
against the inside surface of the wellbore casing. The seal may be
leaky or tight depending on the setting of RSM (0303). The RSM
(0303) may be a hollow cylindrical member having an inner sleeve
surface and an outer sleeve surface. The RSM (0303) may be
concentric with the wellbore casing and coaxially fit within the
ICS. In one preferred exemplary embodiment, the seal prevents RSM
(0303) from substantial axially or longitudinally sliding along the
inside surface of the wellbore casing. The RSM (0303) may be
associated with an inner sleeve diameter (ISD) (0307) that is
configured to fit within ICD (0308) of the wellbore casing (0304).
In another preferred exemplary embodiment, ISD (0307) is large
enough to enable unrestricted fluid movement through inner sleeve
surface (ISS) during production. The ratio of ISD (0307) to ICD
(0308) may range from 0.5 to 0.99. For example, ICD may be 4.8
inches and ISD may be 4.1 inches. In the foregoing example, the
ratio of ISD (0307) and ICD (0308) is 0.85. The diameter of ISD
(0307) may further degrade during production from wellbore fluids
enabling fluid flow on almost the original diameter of the well
casing. In a further preferred exemplary embodiment, RSM (0303) may
be made from a material comprising of aluminum, iron, steel,
titanium, tungsten, copper, bronze, brass, plastic, composite,
natural fiber, and carbide. The RSM (0303) may be made of
degradable material or a commercially available material.
[0105] In a preferred exemplary embodiment, the WST may set RSM
(0303) to the ICS in compression mode to form an inner profile on
the RSM (0303). The inner profile could form a tight or leaky seal
preventing substantial axial movement of the RSM (0303). In another
preferred exemplary embodiment, the WST may set RSM (0303) to the
ICS in expansion mode providing more contact surface for sealing
RSM (0303) against ICS. Further details of setting RSM (0303)
through compression and expansion modes are further described below
in FIG. 15.
[0106] In another preferred exemplary embodiment, the WST may set
RSM (0303) using a gripping/sealing element disposed of therein
with RSM (0303) to grip the outside surface of RSM (0303) to ICS.
Further details of setting RSM (0303) through compression and
expansion modes are described below in FIG. 11 (1100).
[0107] In another preferred exemplary embodiment, the WST may set
RSM (0303) at any desired location within wellbore casing (0304).
The desired location may be selected based on information such as
the preferred hydrocarbon formation area, fraction stage, and
wellbore conditions. The desired location may be chosen to create
uneven hydraulic fracturing stages. For example, a shorter
hydraulic fracturing stage may comprise a single perforating
position so that the RSM locations are selected close to each other
to accommodate the perforating position. Similarly, a longer
hydraulic fracturing stage may comprise multiple perforating
positions so that the RSM locations are selected as far to each
other to accommodate the multiple perforating positions. Shorter
and longer hydraulic fracturing positions may be determined based
on the specific information of hydrocarbon formation (0302). A
mudlog analyzes the mud during drilling operations for hydrocarbon
information at locations in the wellbore. Prevailing mudlog
conditions may be monitored to dynamically change the desired
location of RSM (0303).
[0108] The WST may create a conforming seating surface (CSS) (0306)
within RSM (0303). The WST may form a beveled edge on the
production end (heel end) of the RSM (0303) by constricting the
inner diameter region of RSM (0303) to create the CSS (0306). The
inner surface of the CSS (0306) could be formed such that it seats
and retains a restriction plug element (RPE) (0305). The diameter
of the RPE (0305) is chosen such that it is less than the outer
diameter and greater than the inner diameter of RSM (0303). The CSS
(0306) and RPE (0305) may be complementary shaped such that RPE
(0305) seats against CSS (0306). For example, RPE (0306) may be
spherically shaped and the CSS (0306) may be beveled shaped to
enable RPE (0305) to seat in CSS (0306) when a differential
pressure is applied. The RPE (0305) may pressure lock against CSS
(0306) when differential pressure is applied i.e., when the
pressure upstream (production or heel end) of the RSM (0303)
location is greater than the pressure downstream (injection or toe
end) of the RSM (0303). The differential pressure established
across the RSM (0303) locks RPE (0305) in place isolating
downstream (injection or toe end) fluid communication. According to
one preferred exemplary embodiment, RPE (0305) seated in CSS (0306)
isolates a zone to enable hydraulic fracturing operations to be
performed in the zone without affecting downstream (injection or
toe end) hydraulic fracturing stages. The RPE (0305) may also be
configured in other shapes such as a plug, dart or a cylinder. It
should be noted that one skilled in the art would appreciate that
any other shapes conforming to the seating surface may be used for
RPEs to achieve similar isolation affect as described above.
[0109] According to another preferred exemplary embodiment, RPE
(0305) may seat directly in RSM (0303) without the need for a CSS
(0306). In this context, RPE (0305) may lock against the vertical
edges of the RSM (0303) which may necessitate a larger diameter RPE
(0305).
[0110] According to yet another preferred exemplary embodiment, RPE
(0305) may degrade over time in the well fluids eliminating the
need to be removed before production. The RPE (0305) degradation
may also be accelerated by acidic components of hydraulic
fracturing fluids or wellbore fluids, thereby reducing the diameter
of RPE (0305) enabling it to flow out (pump out) of the wellbore
casing or flow back (pump back) to the surface before production
phase commences.
[0111] In another preferred exemplary embodiment, RPE (0305) may be
made of a metallic material, non-metallic material, a carbide
material, or any other commercially available material.
Preferred Embodiment Multistage System Diagram (0500)
[0112] The present invention may be seen in more detail as
generally illustrated in FIG. 5 (0500), wherein a wellbore casing
(0504) is shown after hydraulic fracturing is performed in multiple
stages (fracture intervals) according to a method described
herewith below in FIG. 6 (0600). A plurality of stages (0520, 0521,
0522, 0523) are created by setting RSMs (0511, 0512, 0513) at
desired positions followed by isolating each stage successively
with restriction plug elements RPEs (0501, 0502, 0503). A RSM
(0513) may be set by a WST followed by positioning a perforating
gun string assembly (GSA) in hydraulic fracturing zone (0522) and
perforating the interval. Subsequently, RPE (0503) is deployed and
the stage (0522) is hydraulically fractured. The WST and the
perforating GSA are removed for further operations. Thereafter, RSM
(0512) is set and sealed by WST followed by a perforation
operation. Another RPE (0502) is deployed to seat in RSM (0512) to
form hydraulic fracturing zone (0521). Thereafter the stage (0521)
is hydraulically fracturing. Similarly, hydraulic fracturing zone
(0520) is created and hydraulically fractured.
[0113] According to one aspect of a preferred exemplary embodiment,
RSMs may be set by WST at desired locations to enable RPEs to
create multiple hydraulic fracturing zones in the wellbore casing.
The hydraulic fracturing zones may be equally spaced or unevenly
spaced depending on wellbore conditions or hydrocarbon formation
locations.
[0114] According to another preferred exemplary embodiment, RPEs
are locked in place due to pressure differential established across
RSMs. For example, RPE (0502) is locked in the seat of RSM (0512)
due to a positive pressure differential established across RSM
(0512) i.e., pressure upstream (hydraulic fracturing stages 0520,
0521 and stages towards heel of the wellbore casing) is greater
than pressure downstream (hydraulic fracturing stages 0522, 0523
and stages towards toe of the wellbore casing).
[0115] According to a further preferred exemplary embodiment, RPEs
(0501, 0502, 0503) may degrade over time, flowed back by pumping,
or flowed into the wellbore, after completion of all stages in the
wellbore, eliminating the need for additional milling
operations.
[0116] According to a further preferred exemplary embodiment the
RPE's may change shape or strength such that they may pass through
a RSM in either the production (heel end) or injection direction
(toe end). For example RPE (0512) may degrade and change shape such
that it may pass through RSM (0511) in the production direction or
RSM (0513) in the injection direction. The RPEs may also be
degraded such that they are in between the RSMs of current stage
and a previous stage restricting fluid communication towards the
injection end (toe end) but enabling fluid flow in the production
direction (heel end). For example, RPE (0502) may degrade such that
it is seated against the injection end (toe end) of RSM (0511) that
may have flow channels. Flow channels in the RSM are further
described below in FIG. 32 (3200) and FIG. 34 (3400).
[0117] According to yet another preferred exemplary embodiment,
inner diameters of RSMs (0511, 0512, 0513) may be the same and
large enough to allow unrestricted fluid flow during well
production operations. The RSMs (0511, 0512, 0513) may further
degrade in well fluids to provide an even larger diameter
comparable to the inner diameter of the well casing (0504) allowing
enhanced fluid flow during well production. The degradation could
be accelerated by acids in the hydraulic fracturing fluids.
Preferred Exemplary Restriction Plug Elements (RPE)
[0118] It should be noted that some of the material and designs of
the RPE described below may not be limited and should not be
construed as a limitation. This basic RPE design and materials may
be augmented with a variety of ancillary embodiments, including but
not limited to: [0119] Made of multi layered materials, where at
least one layer of the material melts or deforms at temperature
allowing the size or shape to change. [0120] May be a solid core
with an outer layer of meltable material. [0121] May or may not
have another outer layer, such as a rubber coating. [0122] May be a
single material, non-degradable. [0123] Outer layer may or may not
have holes in it, such that an inner layer could melt and liquid
may escape. [0124] Passage ways through them which are filled with
meltable, degradable, or dissolving materials. [0125] Use of
downhole temperature and pressure, which change during the
stimulation and subsequent well warm up to change the shape of
barriers with laminated multilayered materials. [0126] Use of a
solid core that is degradable or erodible. [0127] Use of acid
soluble alloy balls. [0128] Use of water dissolvable polymer frac
balls. [0129] Use of poly glycolic acid balls.
Preferred Exemplary Wellbore Plug Isolation Flowchart Embodiment
(0600)
[0130] As generally seen in the flow chart of FIG. 6 (0600), a
preferred exemplary wellbore plug isolation method may be generally
described in terms of the following steps: [0131] (1) installing
the wellbore casing (0601); [0132] (2) deploying the WST along with
the RSM to a desired wellbore location in the wellbore casing along
with a perforating gun string assembly (GSA); the WST could be
deployed by wireline, coil tube, or tubing-conveyed perforating
(TCP) (0602); the perforating GSA may comprise plural perforating
guns; [0133] (3) setting the RSM at the desired wellbore location
with the WST; the WST could set RSM with a power charge or pressure
(0603); The power charge generates pressure inside the setting tool
that sets the RSM; the RSM may or may not have a conforming seating
surface (CSS); the CSS may be machined or formed by the WST at the
desired wellbore location; [0134] (4) perforating hydrocarbon
formation with the perforating GSA; the perforating GSA may
perforate one interval at a time followed by pulling the GSA and
perforating the next interval in the stage; the perforation
operation is continued until all the intervals in the stage are
completed; [0135] (5) removing the WST and the perforating GSA from
the wellbore casing; the WST could be removed by wireline, coil
tube, or TCP (0605); [0136] (6) deploying the RPE to seat in the
RSM isolating fluid communication between upstream (heel or
production end) of the RSM and downstream (toe or injection end) of
the RSM and creating a hydraulic fracturing stage; RPE may be
pumped from the surface, deployed by gravity, or set by a tool; If
a CSS is present in the RSM, the RPE may be seated in the CSS; RPE
and CSS complementary shapes enable RPE to seat into the CSS;
positive differential pressure may enable RPE to be driven and
locked into the CSS (0606); [0137] (7) fracturing the hydraulic
fracturing stage; by pumping hydraulic fracturing fluid at high
pressure to create pathways in hydrocarbon formations (0607);
[0138] (8) checking if all hydraulic fracturing stages in the
wellbore casing have been completed, if not so, proceeding to step
(0602); prepare to deploy the WST to a different wellbore location
towards the heel end of the already fractured stage; hydraulic
fracturing stages may be determined by the length of the casing
installed in the hydrocarbon formation; if all stages have been
fractured proceed to step (0609), (0608); [0139] (9) enabling fluid
flow in the production (heel end) direction; fluid flow may been
enabled through flow channels designed in the RSM while the RPEs
are positioned in between the RSMs; fluid flow may also be been
enabled through flow channels designed in the RPEs and RSMs;
alternatively RPEs may also be removed from the wellbore casing or
the RPEs could be flowed back to surface, pumped into the wellbore,
or degraded in the presence of wellbore fluids or acid (0609); and
[0140] (10) commencing oil and gas production from all the
hydraulically fractured stages (0610).
Preferred Embodiment Side View Cylindrical Restriction Plug System
Block Diagram (0700, 0800)
[0141] One preferred embodiment may be seen in more detail as
generally illustrated in FIG. 7 (0700) and FIG. 8 (0800), wherein a
cylindrical restrictive plug element (0702) is seated in CSS (0704)
to provide downstream pressure isolation. A wellbore casing (0701)
is installed in a hydrocarbon formation. A wellbore setting tool
may set RSM (0703) at a desired location and seal it against the
inside surface of the wellbore casing (0701). The WST may form a
CSS (0704) in the RSM (0703) as described by foregoing method
described in FIG. 6 (0600). According to one preferred exemplary
embodiment, a cylindrical shaped restrictive plug element (RPE)
(0702) may be deployed into the wellbore casing to seat in CSS
(0704).
[0142] The diameter of the RPE (0702) is chosen such that it is
less than the outer diameter and greater than the inner diameter of
RSM (0703). The CSS (0704) and RPE (0702) may be complementary
shaped such that RPE (0702) seats against CSS (0704). For example,
RPE (0702) may be cylindrically shaped and CSS (0704) may be
beveled shaped to enable RPE (0702) to seat in CSS (0704) when a
differential pressure is applied. The RPE (0702) may pressure lock
against CSS (0704) when differential pressure is applied.
[0143] It should be noted that, if a CSS is not present in the RSM
(0703) or not formed by the WST, the cylindrical RPE (0702) may
directly seat against the edges of the RSM (0703).
Preferred Embodiment Side View Dart Restriction Plug System Block
Diagram (0900-1020)
[0144] Yet another preferred embodiment may be seen in more detail
as generally illustrated in FIG. 9 (0900), FIG. 10 (1000), FIG. 10a
(1010), and FIG. 10b (1020) wherein a dart shaped restrictive plug
element (0902) is seated in CSS (0904) to provide pressure
isolation. According to a similar process described above in FIG.
7, RPE (0902) is used to isolate and create fracture zones to
enable perforation and hydraulic fracturing operations in the
fracture zones. As shown in the perspective views of the dart RPE
in FIG. 10a (1010) and FIG. 10b (1020), the dart RPE is
complementarily shaped to be seated in the RSM. The dart RPE (0902)
is designed such that the fingers of the RPE (0902) are compressed
during production enabling fluid flow in the production
direction.
Preferred Embodiment Side Cross Section View of a Restriction
Sleeve Member System Block Diagram (1100, 1200)
[0145] One preferred embodiment may be seen in more detail as
generally illustrated in FIG. 11 (1100) and FIG. 12 (1200), wherein
a restrictive sleeve member RSM (1104) is sealed against the inner
surface of a wellbore casing (1101) with a plurality of
gripping/sealing elements (1103). Gripping elements may be
elastomers, carbide buttons, or wicker forms. After a wellbore
casing (1101) is installed, a wellbore setting tool may be deployed
along with RSM (1104) to a desired wellbore location. The WST may
then compress the RSM (1104) to form plural inner profiles (1105)
on the inside surface of the RSM (1104) at the desired location. In
one preferred exemplary embodiment, the inner profiles (1105) may
be formed prior to deploying to the desired wellbore location. The
compressive stress component in the inner profiles (1105) may aid
in sealing the RSM (1104) to the inner surface of a wellbore casing
(1101). A plurality of gripping/sealing elements (1103) may be used
to further strengthen the seal (1106) to prevent substantial axial
or longitudinal movement of RSM (1104). The gripping elements
(1103) may be an elastomer, carbide buttons, or wicker forms that
can tightly grip against the inner surface of the wellbore casing
(1101). The seal (1106) may be formed by plural inner profiles
(1105), plural gripping elements (1103), or a combination of inner
profiles (1105) and gripping elements (1103). Subsequently, the WST
may form a CSS and seat a RPE (1102) to create downstream isolation
(toe end) as described by the foregoing method in FIG. 6
(0600).
Preferred Embodiment Side Cross Section View of Inner and Outer
Profiles of a Restriction Sleeve Member System Block Diagram
(1300-1700)
[0146] Yet another preferred embodiment may be seen in more detail
as generally illustrated in FIG. 13 (1300), wherein a restrictive
sleeve member RSM (1304) is sealed against the inner surface of a
wellbore casing (1301). After a wellbore casing (1301) is
installed, a wellbore setting tool may be deployed along with RSM
(1304) to a desired wellbore location. The WST may then compress
the RSM (1304) to form plural inner profiles (1305) on the inside
surface of the RSM (1304) and plural outer profiles (1303) on the
outside surface of the RSM (1304) at the desired location. In one
preferred exemplary embodiment, the inner profiles (1305) and outer
profiles (1303) may be formed prior to deploying to the desired
wellbore location. The compressive stress component in the inner
profiles (1305) and outer profiles (1303) may aid in sealing the
RSM (1304) to the inner surface of a wellbore casing (1301). The
outer profiles (1303) may directly contact the inner surface of the
wellbore casing at plural points of the protruded profiles to
provide a seal (1306) and prevent axial or longitudinal movement of
the RSM (1304). FIG. 14 (1400) illustrates a detailed cross section
view of a WST forming a seal against the inner surface of the
wellbore casing.
[0147] Similarly, FIG. 15 (1500) illustrates a wireline setting
tool creating inner and outer profiles in restriction sleeve
members for sealing against the inner surface of the wellbore
casing. FIG. 16 illustrates a detailed cross section view of a WST
(1603) that forms an inner profile (1604) in a RSM (1602) to form a
seal (1605) against the inner surface of wellbore casing (1601).
Likewise, FIG. 17 (1700) illustrates a detailed cross section view
of a WST (1703) that forms an inner profile (1704) and an outer
profile (1706) in a RSM (1702) to form a seal (1705) against the
inner surface of wellbore casing (1701). According to a preferred
exemplary embodiment, inner and outer profiles in a RSM forms a
seal against an inner surface of the wellbore casing preventing
substantial axial and longitudinal movement of the RSM during
perforation and hydraulic fracturing process.
Preferred Embodiment Wellbore Setting Tool (WST) System Block
Diagram (1800-2200)
[0148] FIG. 18 (1800) and FIG. 19 (1900) show a front cross section
view of a WST. According to a preferred exemplary embodiment, a
wellbore setting tool (WST) may be seen in more detail as generally
illustrated in FIG. 20 (2000). A WST-RSM sleeve adapter (2001)
holds the RSM (2008) in place until it reaches the desired location
downhole. After the RSM (2008) is at the desired location the
WST-RSM sleeve adapter (2001) facilitates a reactionary force to
engage the RSM (2008). When the WST (2002) is actuated, a RSM
swaging member and plug seat (2005) provides the axial force to
swage an expanding sleeve (2004) outward. A RSM-ICD expanding
sleeve (2004) hoops outward to create a sealing surface between the
RSM (2008) and inner casing diameter (ICD) (2009). After the WST
(2002) actuation is complete, it may hold the RSM (2008) to the ICD
(2009) by means of sealing force and potential use of other
traction adding devices such as carbide buttons or wicker forms.
The WST-RSM piston (2006) transmits the actuation force from the
WST (2002) to the RSM (2008) by means of a shear set, which may be
in the form of a machined ring or shear pins. The connecting rod
(2003) holds the entire assembly together during the setting
process. During activation, the connecting rod (2003) may transmit
the setting force from the WST (2002) to the WST piston (2006).
FIG. 21 (2100) and FIG. 22 (2200) show perspective views of the WST
(2002) in more detail.
Preferred Embodiment Wellbore Plug Isolation System Block Diagram
(2300-3100)
[0149] As generally seen in the aforementioned flow chart of FIG. 6
(0600), the steps implemented for wellbore plug isolation are
illustrated in FIG. 23 (2300)-FIG. 31 (3100).
[0150] As described above in steps (0601), (0602), and (0603) FIG.
23 (2300) shows a wellbore setting tool (WST) (2301) setting a
restriction sleeve member (2303) on the inside surface of a
wellbore casing (2302). The WST (2301) may create a conforming
seating surface (CSS) in the RSM (2303) or the CSS may be
pre-machined. A wireline (2304) or TCP may be used to pump WST
(2301) to a desired location in the wellbore casing (2302). FIG. 24
(2400) shows a detailed view of setting the RSM (2303) at a desired
location.
[0151] FIG. 25 (2500) illustrates the stage perforated with
perforating guns after setting the RSM (2303) and removing WST
(2301) as aforementioned in steps (0604) and (0605).
[0152] FIG. 26 (2600) illustrates a restriction plug element (RPE)
(2601) deployed into the wellbore casing as described in step
(0606). The RPE (2601) may seat in the conforming seating surface
in RSM (2303) or directly in the RSM if the CSS is not present.
After the RPE (2601) is seated, the stage is isolated from toe end
pressure communication. The isolated stage is hydraulically
fractured as described in step (0607). FIG. 27 (2700) shows details
of RPE (2601) deployed into the wellbore casing. FIG. 28 (2800)
shows details of RPE (2601) seated in RSM (2303).
[0153] FIG. 29 (2900) illustrates a WST (2301) setting another RSM
(2903) at another desired location towards the heel of the RSM
(2303). Another RPE (2901) is deployed to seat in the RSM (2903).
The RPE (2901) isolates another stage toeward of the aforementioned
isolated stage. The isolated stage is fractured with hydraulic
fracturing fluids. FIG. 30 (3000) shows a detailed cross section
view of WST (2301) setting RSM (2903) at a desired location. FIG.
31 (3100) shows a detailed cross section view of an RPE (2901)
seated in RSM (2903). When all the stages are complete as described
in (0608) the RPEs may remain in between the RSMs or flowed back or
pumped into the wellbore (0609). According to a preferred exemplary
embodiment, the RPE's and RSM's are degradable which enables larger
inner diameter to efficiently pump oil and gas without restrictions
and obstructions.
Preferred Embodiment Restriction Sleeve Member (RSM) With Flow
Channels Block Diagram (3200-3400)
[0154] A further preferred embodiment may be seen in more detail as
generally illustrated in FIG. 32 (3200), FIG. 33 (3300) and FIG. 34
(3400), wherein a restrictive sleeve member RSM (3306) comprising
flow channels (3301) is set inside a wellbore casing (3305). A
conforming seating surface (CSS) (3303) may be formed in the RSM
(3306). The flow channels (3301) are designed in RSM (3306) to
enable fluid flow during oil and gas production. The flow channels
provide a fluid path in the production direction when restriction
plug elements (RPE) degrade but are not removed after all stages
are hydraulically fractured as aforementioned in FIG. (0600) step
(0609). The channels (3301) are designed such that there is
unrestricted fluid flow in the production direction (heelward)
while the RPEs block fluid communication in the injection direction
(toeward). Leaving the RPEs in place provides a distinct advantage
over the prior art where a milling operation is required to mill
out frac plugs that are positioned to isolate stages.
[0155] According to yet another preferred embodiment, the RSMs may
be designed with fingers on either end to facilitate milling
operation, if needed. Toe end fingers (3302) and heel end fingers
(3304) may be designed on the toe end and heel end the RSM (3306)
respectively. In the context of a milling operation, the toe end
fingers may be pushed towards the heel end fingers of the next RSM
(toeward) such that the fingers are intertwined and interlocked.
Subsequently, all the RSMs may be interlocked with each other
finally eventually mill out in one operation as compared to the
current method of milling each RSM separately.
Preferred Embodiment Wellbore Setting Tool (WST) System Double Set
Block Diagram (3500-3700)
[0156] As generally illustrated in FIG. 35 (3500), FIG. 36 (3600)
and FIG. 37 (3700) a wellbore setting tool sets or seals on both
sides of a restriction sleeve member (RSM) (3601) on the inner
casing surface (ICS) (3604) of a wellbore casing. In this context
the WST swags the RSM on both sides (double set) and sets it to the
inside surface of the wellbore casing. On one end of the RSM
(3601), a RSM-ICD expanding sleeve in the WST may hoop outward to
create a sealing surface between the RSM (3601) and ICS (3604). On
the other side of the RSM (3601), when WST actuation is complete,
the WST may hold the RSM (3601) to the ICS (3604) by means of
sealing force and potential use of other traction adding gripping
devices (3603) such as elastomers, carbide buttons or wicker
forms.
[0157] According to a preferred exemplary embodiment, a double set
option is provided with a WST to seal one end of the RSM directly
to the inner surface of the wellbore casing while the other end is
sealed with a gripping element to prevent substantial axial and
longitudinal movement.
Preferred Embodiment Wellbore Setting Tool (WST) System Multiple
Set Block Diagram (3800-4100)
[0158] As generally illustrated in FIG. 38 (3800), FIG. 39 (3900),
FIG. 40 (4000), and FIG. 41 (4100) a wellbore setting tool sets or
seals RSM at multiple locations. FIG. 38 (3800) shows a WST (3810)
that may set or seal RSM at single location (single set), a WST
(3820) that may set or seal RSM at double locations (double set),
or a WST (3830) that may set or seal RSM 3 locations (triple set).
A more detail illustration of WST (3830) may be seen in FIG. 40
(4000). The WST (3830) sets RSM (4004) at 3 locations (4001),
(4002), and (4003). According to a preferred exemplary embodiment,
WST sets or seals RSM at multiple locations to prevent substantial
axial or longitudinal movement of the RSM. It should be noted that
single, double and triple sets have been shown for illustrative
purposes only and should not be construed as a limitation. The WST
could set or seal RSM at multiple locations and is not limited to
single, double, or triple set as aforementioned. An isometric view
of the triple set can be seen in FIG. 41 (4100).
Preferred Embodiment Restriction Sleeve Member Polished Bore
Receptacle (PBR)
[0159] According to a preferred exemplary embodiment, the
restricted sleeve member could still be configured with or without
a CSS. The inner sleeve surface (ISS) of the RSM may be made of a
polished bore receptacle (PBR). Instead of an independently pumped
down RPE, however, a sealing device could be deployed on a wireline
or as part of a tubular string. The sealing device could then seal
with sealing elements within the restricted diameter of the
internal sleeve surface (ISS), but not in the ICS surface. PBR
surface within the ISS provides a distinct advantage of selectively
sealing RSM at desired wellbore locations to perform treatment or
re-treatment operations between the sealed locations, well
production test, or test for casing integrity.
Preferred Embodiment Restriction Plug Element
[0160] Restriction plug element such as balls with large aspect
ratio approaching 1 and seated in a large inner diameter
restriction sleeve member do not degrade in wellbore fluids. The
plug elements change shape from a circular to flying saucer shape
because water is restricted on the edge and a sand pack that holds
the ball on the seat prevents the plug element from interacting
with the water and wellbore fluids. Therefore there is a need to
add a mechanism to provide more surface area in the restriction
plug element to contact with the restriction plug element after
seating in a restriction sleeve member. According to a preferred
exemplary embodiment, a partially hollow passage, (herein also
referenced as a partial Flow channel) in the restriction plug
element enables the plug element to seat in a restriction sleeve
member during treatment and subsequently degrade to form a complete
hollow passage so that there is a higher probability for water and
wellbore liquids to back flow and degrade the restriction plug
element. The complete flow channel dissolves or degrades not only
the outside but also the inside of the wall of the restriction plug
element. Initially the flow is restricted by the closed end in the
partial hollow passage and over time the flow channel opens up by
degradation and allows fluid to pass through in either direction.
During back flow in the well new fluid is circulated into the well
and the restriction plug element continues to degrade. It should be
noted that the terms "flow channel" and "hollow passage" may
hereinafter be interchangeably used referencing a hollow cavity
within a restriction plug element.
[0161] According to a preferred exemplary embodiment, a restriction
plug element for use in a wellbore casing may comprise a degradable
material and be configured with a partial hollow passage extending
from at least one interior end. The interior end configured to
block fluid communication from upstream to downstream during fluid
treatment and the partial hollow passage configured to degrade and
form a complete hollow passage to enable said fluid communication
subsequent to the fluid treatment.
[0162] According to another preferred exemplary embodiment the
interior end is further configured with an terminus; the terminus
configured to orient such that the restriction plug element seats
in a restriction sleeve member and restricts substantial fluid
bypass during a fluid treatment. The terminus may include any shape
such as a nose, a conical shape, or a tail (arrow terminus). The
orientation feature may enable changing the center of rotation so
that there is a preferred rotation axis while the restriction plug
element is being pumped down. For instance, a ball with a single
hollow passage will preferentially rotate around the axis of that
hollow passage, and therefore orient itself. It should be noted
that ball may orient and may not orient but produce the same effect
seating in a restriction sleeve member.
[0163] The hollow passage may be machined by drilling a cavity into
a body of a degradable material restriction plug element ("ball"),
such that there is a thinner web section that would degrade more
quickly, creating a flow channel through the ball which further
enhances degradation, and more surface area with which to speed the
degradation rate of the composite ball. The pattern and the size of
the holes will have design considerations so that they create a
sufficient flow path or increase in surface area, while not
compromising the seating of the ball. The holes could be drilled
from one side leaving a web, or drilled from the outside to the
center, leaving a small core which would need to degrade. The holes
may be subsequently capped with degradable or non-degradable
material. Small amounts of eutectic metal, or non-degradable metal,
composite, or injection molded structures with flow channels could
be used to support the inner structure of the ball. The altered
center of mass could determine the likelihood that the ball would
seat on any particular orientation. This could be manipulated
advantageously in order to position the ball on the seat as
desired. According to a preferred exemplary embodiment the ball
seals when seated on restriction sleeve member during a fracture
treatment while the holes in the partial hollow passage are not
blocked to prevent the seating. An arrow tail or terminus on the
interior end of the ball may force the ball to land in a sealing
position (holes not on the seat). For example the ball may orient
such that the hollow passage (flow channel) is substantially
parallel to the wellbore casing in a horizontal well.
[0164] As generally illustrated in FIG. 42, a cross section view
(4200) and a perspective view (4210) of a restriction plug element
comprises a degradable material (4202), a hollow passage (4201)
having an interior end (4203) extending to a surface end (4204).
The interior end (4203) and the surface end (4204) may form the two
ends of the hollow passage (4201). Illustrated in the perspective
view (4210) is an arrow shaped terminus (4205) in the interior end
(4203). The thin section (4206) may extend from the interior end
into the solid body of the material (4202). The restriction plug
element (4200) may be dropped into a wellbore casing for isolating
stages. An arrow tail (4205) or terminus on the interior end (4203)
of the element (4200) may force the element to land in a sealing
position (holes not on the seat). The material of the body (4202)
of the restriction plug element may comprise a degradable material.
A partial hollow passage (4201) may extend from an interior end
(4203) in the core of the plug element (4200). The interior end
(4203) in the hollow passage (4201) and the thin section (4205) may
block fluid communication from upstream (heel end) to downstream
(toe end) during fluid treatment. The partial hollow passage (4201)
enables water and other wellbore fluids to come in contact with the
partial hollow passage and enable degradation such that a complete
hollow passage is formed. The complete hollow passage may enable
fluid communication subsequent to the fluid treatment. The hollow
passage (4201) may be machined by drilling a cavity into a body
(4202) of a degradable material restriction plug element ("ball")
(4200), such that there is a thinner web section (4206) that would
degrade more quickly, creating a complete flow channel (4201)
through the ball (4200) which further enhances degradation, and
more surface area with which to speed the degradation rate of the
composite ball (4200). During back flow in the well new fluid is
circulated into the well and the restriction plug element continues
to degrade.
[0165] According to a preferred exemplary embodiment the complete
hollow passage enables the restriction plug element to deform such
that the restriction plug element passes through a restriction
sleeve member in the wellbore casing. According to another
preferred exemplary embodiment a shape of the restriction plug
element is selected from a group comprised of: circular, cylinder,
sphere, oval or elongated. According to yet another preferred
exemplary embodiment a shape of cross section of said hollow
passage is selected from a group comprised of: circle, square, oval
or elongated.
[0166] According to a preferred exemplary embodiment the partial
hollow passage is capped at an open end with a degradable material.
The open end and the interior end forming two ends of said hollow
passage. For example, interior end (4203) and open end or surface
end (4204) may form two ends of hollow passage (4201). The open end
(4204) may be capped with a degradable material that degrades in
the presence of wellbore fluids expected in the wellbore casing.
According to another preferred exemplary embodiment the partial
hollow passage extends to a surface of the restriction plug
element.
[0167] According to another preferred exemplary embodiment the
partial hollow passage may extend from one interior end to another
interior end. For example interior end (4201) may not extend all
the way to the surface but terminate interior to the core leaving a
thin web section similar to section (4206). Therefore, the two ends
of the hollow passage may be interior to the core. The thin
sections of on either ends may degrade and form a complete open
flow channel or passage. According to yet another preferred
exemplary embodiment the partial hollow passage passes through a
center of the restriction plug element. According to a further
preferred exemplary embodiment the partial hollow passage does not
pass through a center of the restriction plug element. For example
passage (4201) may be slightly offset from the center and achieve a
similar result as a passage that passes through the center of the
plug element.
[0168] FIG. 43 generally illustrates a restriction plug element
(4300) comprising a plurality of partial hollow passages (4301,
4302, 4303, 4304, 4305, 4306) that extend from respective interior
end. According to a preferred exemplary embodiment the flow
channels may be aligned to each other. According to another
preferred exemplary embodiment at least one of the partial hollow
passage is aligned to another partial hollow passage.
[0169] For example, flow channel (4301) and flow channel (4304) are
aligned to each other and an axis through the channel may pass
through the center of the restriction plug element (4300).
Similarly flow channel (4302) and flow channel (4305), flow channel
(4303) and flow channel (4306) may be aligned to each other. The
partial flow channels may further degrade and form complete flow
channels extending diametrically or cordially from a surface
end/hole to another surface hole/end. The increased surface area in
the completed flow channels may further enhance the degradation of
the restriction plug element (4300). A perspective view (4310) of
the restriction plug element is generally illustrated in FIG.
43.
[0170] According to a preferred exemplary embodiment at least one
of the partial hollow passage intersects with at least one other
partial hollow passage. For example, partial flow channel (4302)
may be drilled with an angle such that it intersects channel (4301)
or channel (4303) depending on the angle of drilling.
[0171] According to a preferred exemplary embodiment at least one
of the partial hollow passages does not intersect with any other
partial hollow passage. For example, all the partial hollow
passages in FIG. 43 do not intersect with each other before
degradation.
[0172] According to another preferred exemplary embodiment at least
one of the partial hollow passages comprises a plurality of
interior ends. The plurality of interior ends may be spread out or
fanned out. For example, one partial hollow passage may form plural
passage ways with a plurality of interior ends that degrade and
complete the channels. An end view (4310) of restriction plug
element (4300) is generally illustrated in FIG. 43. A perspective
view (4320) along cross section (4330) is generally illustrated in
FIG. 43.
[0173] FIG. 44 generally illustrates perspective view of a partial
flow channel transforming to complete flow channel in a restriction
plug element (4400). Before and during a fracture treatment,
partial flow channels (4401, 4402, 4403, 4404) block fluid
communication from upstream to downstream and in reverse direction.
Subsequent to a fracture treatment, the interior ends of each of
the channels (4401, 4402, 4403, 4404) may degrade towards the
center (4405) of the core and transform into fully complete flow
channels and enabling fluid communication in either direction. The
fully complete channels, illustrated in FIG. 44 (4410), provide for
more surface area for wellbore fluids to come into contact with the
restriction plug element and subsequently degrade the plug element
(4400) in the presence of the wellbore fluids.
[0174] According to another preferred exemplary embodiment, the
restriction plug element may comprise at least one partial hollow
passage extending to a surface of the restriction plug element on
both ends of said flow channel creating a complete passage. For
example, as illustrated in an end view of FIG. 45 (4500), flow
channel (4501) extends from a surface through the center to the
other surface end of the restriction plug element. The complete
hollow passage may provide some of the same benefits as a partial
passage if the ball is configured to seat in such a way as the
passage does not communicate across a restriction sleeve member. If
the complete passage (4501) does communicate across the restriction
sleeve, but is small enough, the same effect of increased surface
area and dissolve rate may be achieved. Other flow channels (4502,
4503, 4504, 4505) are partial flow channels with interior ends that
may degrade in wellbore fluids. The opening of the channel (4501)
may be capped with a degradable material during treatment and block
fluid communication. A cross section view (4510), perspective view
(4520) of section (4506) and a perspective view (4530) of section
(4507) is generally illustrated in FIG. 45.
Preferred Exemplary Flowchart Embodiment of a Restriction Plug
Element Degradation Method (4600)
[0175] As generally seen in the flow chart of FIG. 46 (4600), a
preferred exemplary flowchart embodiment of a restriction plug
element degradation method in conjunction with a restriction plug
element (RPE) for use in a wellbore casing; said restriction plug
element comprising a degradable material; said restriction plug
element configured with at least one partial hollow passage that
extends from an interior end may be generally described in terms of
the following steps: [0176] (1) deploying the restriction plug
element into the wellbore casing and blocking fluid communication
(4601); [0177] The restriction plug element may be pumped down or
dropped down to seat in a restriction sleeve member at a desired
location. [0178] (2) orienting the restriction plug element with
the interior end to seat in a restriction sleeve member and
isolating a stage (4602); [0179] An arrow tail or terminus on the
interior end of the ball may force the ball to land in a sealing
position (holes not on the seat). For example the ball may orient
such that the hollow passage (flow channel) is substantially
parallel to the wellbore casing in a horizontal well. According to
a preferred exemplary embodiment, the orienting step (4602) further
seals the restriction plug element to restrict substantial fluid
bypass in the treating step (4603). According to another preferred
exemplary embodiment the orienting step (4602) orients the
restriction plug element such that the hollow passage is unblocked
by the restriction sleeve member. The terminus may include any
shape such as a nose, a conical shape, or a tail (arrow terminus).
The orientation feature may enable changing the center of rotation
so that there is a preferred rotation axis while the restriction
plug element is being pumped down. For instance, a ball with a
single hollow passage will preferentially rotate around the axis of
that hollow passage, and therefore orient itself. It should be
noted that ball may orient and may not orient but produce the same
effect seating in a restriction sleeve member. Therefore, orienting
step (4602) may be skipped during the degradation method. A
complete passage or partial passage may be designed such that
orienting is important, where it will always orient, or where
orienting is unimportant. The passage may be partial or complete.
The complete hollow passage may provide some of the same benefits
as a partial passage if the ball is configured to seat in such a
way as the passage does not communicate across a restriction sleeve
member. If the complete passage does communicate across the
restriction sleeve, but is small enough, the same effect of
increased surface area and dissolve rate may be achieved. [0180]
(3) treating the isolated stage with fracturing fluids (4603);
[0181] The restriction plug elements seats and seals in a
restriction sleeve member during the treatment stage. [0182] (4)
degrading from the interior end in the partial hollow passage
through contact with wellbore fluids (4604); [0183] The interior
end starts degrading a thin section and allowing contact of well
fluids with the restriction plug element. According to another
preferred exemplary embodiment the degrading step (4604) occurs
immediately after the treating step (4603). [0184] (5) creating a
complete hollow passage from the partial hollow passage (4605); and
The partial hollow passage or flow channel may be transformed into
a complete flow channel when the thin section completely degrades.
According to another preferred exemplary embodiment the creating
step (4605) accelerates rate of degradation of the restriction plug
element. [0185] (6) unblocking the fluid communication (4606).
[0186] According to a further preferred exemplary embodiment the
step of degrading the restriction plug element to deform.
[0187] According to a most preferred exemplary embodiment a ratio
of diameter of the restriction plug element to an inner diameter of
the restriction sleeve member ranges from 0.5 to 0.99.
Mass Vs Time and Diameter Vs Time of a Solid Ball and a Preferred
Exemplary Hollow Passage Restriction Plug Element (4700-4800)
[0188] FIG. 47 (4700) generally illustrates experimental data of a
mass vs. time chart for a solid ball (4702) and a preferred
exemplary partial hollow passage restriction plug element (4701).
The dissolve rate of the exemplary restriction plug is
substantially higher than a solid ball. The exemplary restriction
plug may include drilled hollow passages and orienting features as
aforementioned in FIGS. 42, 43, 44, 45. FIG. 48 (4800) generally
illustrates experimental data of a diameter vs. time chart for a
solid ball (4802) and a preferred exemplary partial hollow passage
restriction plug element (4801). It should be noted that the data
illustrated in FIG. 47 (4700) and FIG. 48 (4800) are taken from the
same experiment for the same solid ball and a ball with a drilled
hole. The exemplary hollow passage restriction plug element also
referred herein as ball with the drilled hole or drilled ball,
reduced diameter at the same rate as the solid ball (i.e. would
stay on seat for the same time) but the reduction in mass was
improved such that the ball with the drilled hole fully dissolved
much more quickly. This is due to the increase in surface area, but
more importantly, the fact that the exemplary hollow passage
restriction plug element dissolves from the inside and the outside
at the same time, thus improving the time to removal of the ball
while plugging the seat for the same amount of time. The charts
(4700, 4800) demonstrate experimental tests where the diameter of
the exemplary ball with drilled hole reduced at the same rate as
the solid ball, but the time to total degradation is significantly
reduced by the addition of the hollow passage. The shape of the
internal hollow can be manipulated in order to change the
characteristic of the dissolve rate and the exposure of the surface
area of the drilled ball to wellbore fluids. For example, at a time
stamp of 60 hours the diameters of the solid ball and the drilled
ball is substantially the same at approximately 3.75 in. However at
the same time stamp of 60 hours, the mass of the solid ball is
approximately 410 grams and the mass of the drilled ball is 210
grams. The preferred exemplary chart clearly demonstrates the
reduction in mass was improved such that the ball with the drilled
hole fully dissolved much more quickly. Furthermore, this is due to
the increase in surface area, but more importantly, the fact that
the exemplary hollow passage restriction plug element dissolves
from the inside and the outside at the same time, thus improving
the time to removal of the ball while plugging the seat for the
same amount of time.
System Summary
[0189] The present invention system anticipates a wide variety of
variations in the basic theme of extracting gas utilizing wellbore
casings, but can be generalized as a restriction plug element for
use in a wellbore casing, the restriction plug element comprising a
degradable material; the restriction plug element configured with a
partial hollow passage extending from at least one interior end;
the interior end configured to block fluid communication from
upstream to downstream during fluid treatment; and the partial
hollow passage configured to degrade and form a complete hollow
passage to enable the fluid communication subsequent to the fluid
treatment.
[0190] 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
[0191] The present invention method anticipates a wide variety of
variations in the basic theme of implementation, but can be
generalized as a restriction plug element degradation method, the
method operating in conjunction with a restriction plug element
(RPE) for use in a wellbore casing, the restriction plug element
comprising a degradable material; the restriction plug element
configured with at least one partial hollow passage that extends
from an interior end; [0192] wherein the method comprises the steps
of: [0193] (1) deploying the restriction plug element into the
wellbore casing and blocking fluid communication; [0194] (2)
orienting the restriction plug element with the interior end to
seat in a restriction sleeve member and isolating a stage; [0195]
(3) treating the isolated stage with fracturing fluids; [0196] (4)
degrading from the interior end in the partial hollow passage
through contact with wellbore fluids; [0197] (5) creating a
complete hollow passage from the partial hollow passage; and [0198]
(6) unblocking the fluid communication.
[0199] 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
[0200] 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.
[0201] This basic system and method may be augmented with a variety
of ancillary embodiments, including but not limited to: [0202] An
embodiment wherein the interior end is further configured with an
arrow terminus; the arrow terminus configured to orient such that
the restriction plug element seats in a restriction sleeve member
and restricts substantial fluid bypass during the fluid treatment.
[0203] An embodiment wherein the partial hollow passage
substantially increases a surface area of contact of the
restriction plug element with fluids expected in the wellbore
casing. [0204] An embodiment wherein the partial hollow passage is
capped at an open end with a degradable material; the open end and
the interior end forming two ends of the hollow passage. [0205] An
embodiment wherein the partial hollow passage extends from the
interior end to another interior end. [0206] An embodiment wherein
the partial hollow passage extends to a surface of the restriction
plug element. [0207] An embodiment further comprises at least one
partial hollow passage extending to a surface of the restriction
plug element on both ends of the flow channel. [0208] An embodiment
wherein the partial hollow passage passes through a center of the
restriction plug element. [0209] An embodiment wherein at least one
of the partial hollow passages intersects with at least one other
partial hollow passage. [0210] An embodiment wherein at least one
of the partial hollow passages does not intersect with any other
partial hollow passage. [0211] An embodiment wherein at least one
of the partial hollow passages comprises a plurality of interior
ends; the plurality of interior ends are configured to be spread
out. [0212] An embodiment whereby the complete hollow passage
enables the restriction plug element to deform such that the
restriction plug element passes through a restriction sleeve member
in the wellbore casing. [0213] An embodiment wherein at least one
of the partial hollow passages is aligned to another partial hollow
passage. [0214] An embodiment wherein a shape of the restriction
plug element is selected from a group comprised of: circular,
cylinder, sphere, oval or elongated. [0215] An embodiment wherein a
shape of cross section of the hollow passage is selected from a
group comprised of: circle, square, oval or elongated.
[0216] One skilled in the art will recognize that other embodiments
are possible based on combinations of elements taught within the
above invention description.
CONCLUSION
[0217] A restriction plug element and method for positioning plugs
to isolate fracture zones in a horizontal, vertical, or deviated
wellbore has been disclosed. The restriction plug element includes
a partial hollow passage with an interior end. The partial passage
enables the plug element to seat in a restriction sleeve member
during treatment and subsequently degrade to form a complete hollow
passage. The complete flow channel dissolves or degrades not only
the outside but also the inside of the wall of the restriction plug
element. Initially the flow is restricted by the closed end in the
partial hollow passage and over time the flow channel opens up by
degradation and allows fluid to pass through in either direction.
During back flow in the well, new fluid is circulated into the well
and the restriction plug element continues to degrade.
CLAIMS
[0218] Although a preferred embodiment of the present invention has
been illustrated in the accompanying drawings and described in the
foregoing Description, it will be understood that the invention is
not limited to the embodiments disclosed, but is capable of
numerous rearrangements, modifications, and substitutions without
departing from the spirit of the invention as set forth and defined
by the following claims.
* * * * *