U.S. patent application number 11/961458 was filed with the patent office on 2009-06-25 for methods for introducing pulsing to cementing operations.
Invention is credited to Henry Rogers, Roger Schultz, Earl Webb.
Application Number | 20090159282 11/961458 |
Document ID | / |
Family ID | 40787228 |
Filed Date | 2009-06-25 |
United States Patent
Application |
20090159282 |
Kind Code |
A1 |
Webb; Earl ; et al. |
June 25, 2009 |
Methods for Introducing Pulsing to Cementing Operations
Abstract
A method for bonding a well bore to a casing may include several
steps. Casing may be introduced into the well bore and pulses of
fluid may be directed from within the casing into the well bore. An
annulus between an inner surface of the well bore and an outer
surface of the casing may be filled with fluid. A method for
reducing fluid or gas migration into a fluid in the annulus may
include inducing pressure pulses in the fluid before the fluid has
cured.
Inventors: |
Webb; Earl; (Duncan, OK)
; Rogers; Henry; (Duncan, OK) ; Schultz;
Roger; (Ninnekah, OK) |
Correspondence
Address: |
JOHN W. WUSTENBERG
P.O. BOX 1431
DUNCAN
OK
73536
US
|
Family ID: |
40787228 |
Appl. No.: |
11/961458 |
Filed: |
December 20, 2007 |
Current U.S.
Class: |
166/286 |
Current CPC
Class: |
E21B 28/00 20130101;
E21B 33/14 20130101 |
Class at
Publication: |
166/286 |
International
Class: |
E21B 33/13 20060101
E21B033/13 |
Claims
1. A method for bonding a well bore to a casing therein, comprising
the steps of: introducing the casing into the well bore; directing
pulses of fluid from within the casing into the well bore; and
filling an annulus between an inner surface of the well bore and an
outer surface of the casing with the fluid.
2. The method of claim 1, wherein the fluid is a cement.
3. The method of claim 1, wherein the step of directing pulses of
fluid is performed while moving the casing further into the well
bore.
4. The method of claim 1, further comprising the step of selecting
a frequency and pressure level for the pulses of fluid so as to
reduce filter cake formed on the inner surface of the well
bore.
5. The method of claim 2, further comprising the step of selecting
a frequency and pressure level for the pulses of fluid so as to
reduce the amount non-cement material on the casing.
6. The method of claim 5, further comprising the step of selecting
a frequency and pressure level for the pulses of fluid so as to
reduce filter cake formed on the inner surface of the well bore,
such that the pulses have a dual-step profile.
7. The method of claim 1, further comprising the step of vibrating
the casing at a resonance frequency for the casing.
8. The method of claim 7, wherein the step of vibrating the casing
at a resonance frequency comprises the step of directing pulses of
fluid into the well bore at a frequency and pressure selected to
induce resonance vibrations in the casing.
9. The method of claim 1, further comprising the step of vibrating
well fluid at a resonance frequency for the well fluid.
10. (canceled)
11. (canceled)
12. A method for reducing fluid or gas migration into a fluid in an
annulus formed between a surface of a well bore in a formation and
a casing, comprising the step of inducing pressure pulses in the
fluid before the fluid has cured, further comprising the step of
selecting a frequency and amplitude for the pressure pulses such
that the pressure pulses prevent shear damage of the fluid during
curing.
13. The method of claim 12, wherein the step of inducing pressure
pulses in fluid before the fluid has cured comprises the step of
inducing a low-amplitude pressure pulse.
14. The method of claim 12, wherein the step of inducing pressure
pulses in fluid before the fluid has cured comprises the step of
inducing a low-frequency pressure pulse.
15. A method for reducing fluid or gas migration into a fluid in an
annulus formed between a surface of a well bore in a formation and
a casing, comprising the step of inducing pressure pulses in the
fluid before the fluid has cured, wherein the step of inducing
pressure pulses in fluid before the cement has cured comprises the
step of inducing a pressure pulse having a dual-step profile.
Description
BACKGROUND
[0001] The present invention relates to cementing operations, and,
more particularly, methods and apparatuses for providing more
competent cement bonds during and after cementing operations in
well bores.
[0002] Settable compositions such as cement slurries may be used in
primary cementing operations in which pipe strings, such as casing
and liners, are cemented in well bores. In performing primary
cementing, a cement may be pumped through the casing into an
annulus between the walls of a well bore and the casing disposed
therein. The cement typically is pumped into this annulus until it
reaches a predetermined height in the well bore to provide zonal
isolation. The cement cures in the annulus, thereby forming an
annular sheath of hardened cement (e.g. a cement sheath) that
supports and positions the pipe string in the well bore and bonds
the exterior surface of the pipe string to the walls of the well
bore.
[0003] Fluid or gas influx into the annulus and cement therein
during the cement curing or "gelling" stage is quite common. This
fluid or gas influx can damage the cement bond between the well
bore formation and the exterior surface of the casing. Moreover,
the buildup of residues such as filter cake on or in the surface of
the well bore also can prevent a complete bond between the cement
and the well bore. FIG. 1 illustrates an example of such damage and
incomplete bonding in a small section of formation 100 containing
well bore 101 with casing 102. Cement 103 fills annulus 104 between
the walls of well bore 101 and the exterior surface of casing 102.
Pockets 105 and 106 illustrate examples of damage caused by fluid
or gas influx. If the fluid or gas invasion is severe, channels
will form between formation 100 and the exterior surface of casing
102, such as channels 107 and 108. Influx damage can occur at the
interface between cement 103 and well bore 100, or in the cement
103 itself. Filter cake 109 also can prevent complete bonding
between well bore 101 and cement 103. Conventional methods of
filter cake removal often rely on mechanical means such as
scratchers with pipe reciprocation or require that cement 103 reach
a specific annular velocity. These removal methods can be
time-consuming and often leave filter cake residues behind,
impeding bonding between cement 103 and well bore 101.
SUMMARY
[0004] The present invention relates to cementing operations, and,
more particularly, methods and apparatuses for providing more
competent cement bonds during and after cementing operations in
well bores.
[0005] A method for bonding a well bore to a casing therein, may
comprise the steps of introducing the casing into the well bore,
directing pulses of fluid from within the casing into the well
bore, and filling an annulus between an inner surface of the well
bore and an outer surface of the casing with the fluid. The step of
directing pulses of fluid may performed while moving the casing
further into the well bore. Additionally or alternatively, the
method may further comprise the step of selecting a frequency and
pressure level for the pulses of fluid so as to reduce filter cake
formed on the inner surface of the well bore. Additionally or
alternatively, the method may further comprise the step of
vibrating well fluid at a resonance frequency for the well fluid.
Additionally or alternatively, the method may further comprise the
step of vibrating the casing at a resonance frequency for the
casing. Vibrating the casing at a resonance frequency may comprise
the step of directing pulses of fluid into the well bore at a
frequency and pressure selected to induce resonance vibrations in
the casing. Additionally, or alternatively, the fluid may be a
cement. If the fluid is a cement, the method may further comprise
the step of selecting a frequency and pressure level for the pulses
of fluid so as to reduce the amount non-cement material on the
casing, and the method may further comprise the step of selecting a
frequency and pressure level for the pulses of fluid so as to
reduce filter cake formed on the inner surface of the well bore,
such that the pulses have a dual-step profile.
[0006] A method for reducing fluid or gas migration into a fluid in
an annulus formed between a surface of a well bore in a formation
and a casing, may comprising the step of inducing pressure pulses
in the fluid before the fluid has cured. The fluid may be a cement.
The method may further comprise the step of selecting a frequency
and amplitude for the pressure pulses such that the pressure pulses
prevent shear damage of the fluid during curing. The step of
inducing pressure pulses in fluid before the fluid has cured may
comprise the step of inducing a low-amplitude pressure pulse.
Additionally, or alternatively, the step of inducing pressure
pulses in fluid before the fluid has cured may comprise the step of
inducing a low-frequency pressure pulse. Alternatively, the step of
inducing pressure pulses in fluid before the cement has cured may
comprise the step of inducing a pressure pulse having a dual-step
profile.
[0007] The features and advantages of the present invention will be
readily apparent to those skilled in the art. While numerous
changes may be made by those skilled in the art, such changes are
within the spirit of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These drawings illustrate certain aspects of some of the
embodiments of the present invention, and should not be used to
limit or define the invention.
[0009] FIG. 1 illustrates conventional cement bonding.
[0010] FIG. 2 illustrates a method for bonding a well bore to a
casing in accordance with one embodiment of the present
invention.
[0011] FIG. 3 illustrates an alternate embodiment of a method for
bonding a well bore to a casing.
[0012] FIG. 4 illustrates yet another embodiment of a method for
bonding a well bore to a casing.
[0013] FIG. 5 illustrates various pressure pulses in accordance
with one embodiment of the present invention.
[0014] FIG. 6 illustrates a shear damage profile in accordance with
one embodiment of the present invention.
[0015] FIG. 7 illustrates a fluidic oscillator in accordance with
one embodiment of the present invention.
[0016] FIG. 8 illustrates an alternate embodiment of a method for
bonding a well bore to a casing.
[0017] FIG. 9 illustrates yet another embodiment of a method for
bonding a well bore to a casing.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] The present invention relates to cementing operations, and,
more particularly, methods and apparatuses for providing more
competent cement bonds during and after cementing operations in
well bores.
[0019] These methods and apparatuses may result in less fluid
influx during the pre and post gelling stage of a cement slurry or
other fluid, resulting in significant savings in time and cost, and
improved hydrocarbon recovery.
[0020] Typically, a cementing operation involves attaching float
shoe 110 to an end of casing 102 and introducing casing 102 into
well bore 101. Cement 103 may then flow down the interior of casing
102 and out through float shoe 110 into annulus 104. Alternatively,
a reverse cementing operation may be used to place cement 103 in
annulus 104. In either instance, as cement 103 enters annulus 104,
it displaces material such as drilling fluid, filter cake, gas, or
debris occupying annulus 104. Typically, as cement 103 enters
annulus 104, some material occupying annulus 104 remains,
particularly near the walls of well bore 101 and casing 102. In
other words, a displacement efficiency of the material is typically
significantly below 100% efficiency, which would correspond to the
instance when cement 103 completely displaces the material
occupying annulus 104. Low displacement efficiency results in
undesirable channeling and pocketing, which causes the cement bond
to be compromised.
[0021] The material may be more completely replaced by cement 103
when pulsing or oscillation is used during the introduction of
cement 103 into annulus 104. A number of devices rely on fluid
oscillation effects to create pulsating fluid flow. Generally,
these devices connect to a source of fluid flow, provide a
mechanism for oscillating the fluid flow between two different
locations within the device and emit fluid pulses downstream of the
source of fluid flow. These "fluidic oscillator" 112 devices
require no moving parts to generate the oscillations and have been
used in various applications for which pulsating fluid flow is
desired, such as massaging showerheads, flow meters, and
windshield-wiper-fluid-supply units. Specialized fluidic oscillator
devices have been developed for the oilfield industry, such as, for
example, the Pulsonix TF tool offered by Halliburton Energy
Services, Inc. of Duncan, Okla.
[0022] In addition to providing for more complete displacement of
materials in annulus 104, fluidic oscillator 112 may help mitigate
fluid and/or gas migration during cement cure time. As shown in
FIG. 2, fluidic oscillator 112 may be present in float shoe 110. In
this embodiment, a feedback loop may be scaled and adapted to allow
desired flow rates and cement passages to allow application into a
Super Seal II float shoe by matching flow areas of the 23/4''' or
41/4'' Super Seal II Valves. This may allow for filter cake 109
removal while running in hole using a top drive unit. Filter cake
109 may be removed more effectively by direct fluid impingement of
the well bore 101. Once total depth ("TD") is reached reduced well
conditioning time (bottoms up) may be required, since filter cake
may be removed hydraulically while running in hole, instead of
requiring cleaning at a specific annular velocity or by mechanical
means such as scratchers and pipe reciprocation. Pulsing may break
down gel strength, fragmenting or breaking down filter cake
109.
[0023] Referring now to FIG. 3, an additional benefit of fluidic
oscillator 112 in float shoe 110 may be available in either
standard or top drive applications. As a result of the oscillatory
effect at float shoe 110, cement 103 is displaced more effectively
at the walls of well bore 101 and casing 102. The oscillation
effect tends to place cement 103 further into formation 100,
compacting cement 103, which results in fewer voids due to filter
cake contamination entrapment or consistency issues. Another
potential advantage is that casing 102 may be set into resonance by
the oscillation at float shoe 110. This resonance tends to prevent
voids at the wall of casing 102. The resonance and compaction
effect continuously occurs from the beginning of the displacement
until the top plug lands or pumping is discontinued. Alternatively,
or additionally, frequency may be set such that the well bore
fluids are set into resonance.
[0024] Since each well will have different frequency variables,
such as fluid, rate, and geometry, it may be particularly useful
for fluidic oscillator 112 to have variable components. A
fluctuating or variable fluidic oscillator 112 may be used to allow
for alternating resonance of casing 102 and well bore fluids. A
high frequency component, a low frequency component, or a
combination of the two may enhance the effectiveness of the system.
These components may be further combined with either high or low
amplitude components, or both. To reach the various resonance
ranges, variable rate or "dual-step profile" pumping may be used.
Alternatively, two or more fluidic oscillators 112 could be used to
alternate between two or more resonances.
[0025] As an alternative to alternating between multiple
frequencies and/or amplitudes, a specific design may be used for a
specific well bore fluid system. As more cement 103 is pumped,
resonant frequency will change. Thus it may be desirable for
fluidic oscillator 112 to change based on changes in the system.
This may be a result of monitoring of instrumentation measuring the
level of excitation. This may be done with a sensor such as a
hydrophone, a pressure transducer, a flow device, an accelerometer,
or any number of other devices known in the art. This monitoring
may allow for fluidic oscillator 112 to maintain resonance.
[0026] Referring now to FIG. 4, in an alternative embodiment, low
frequency, low pressure pulses are induced after the plug has
landed and the curing has begun. A pressure pulsation tool 114 may
be optimized from its normal high amplitude/low frequency
configuration to a low amplitude/low frequency tool by way of
configurable inserts and pump rate control. Pressure pulsation tool
114 may be encapsulated in a canister and used in conjunction with
a reservoir system to create a surface cement pulsation system to
apply low pressure/low frequency pressure pulses to annulus 104 to
delay the curing time and prevent fluid migration as a result of
cement volume reduction.
[0027] Idealized pressure wave forms can be controlled to provide
optimal pulsation and help prevent shear of cement 103 during
dehydration. Examples of what the inventors envision as optimal
pressure pulses are illustrated in FIG. 5. These profiles may
prevent shear damage to cement 103, as indicated in FIG. 6.
[0028] Yet another embodiment involves a low cost "tubing" size
fluidic oscillator 112, as shown in FIG. 7. This fluidic oscillator
112 may be composed of phenolic inserts cemented into a low cost
case. Cement 103 may be fairly resistant to acid, thus allowing
application to hydraulic work order ("HWO") or Well Intervention
applications in addition to cementing applications.
[0029] The concept of "pulsing" the top plug after catching cement
is illustrated in FIG. 8. A pulse generator capable of pumping
cement may allow for pulsing on the fly or, as illustrated, pulsing
of the displacement fluid could be accomplished.
[0030] Pulsation or oscillation may be used to set more competent
balanced plugs. Shown in FIG. 9 is an oscillation guide shoe 113
used with either the tubing release tool ("TRT") or bottom hole
kickoff assembly ("BHKA") tool. Retrieving drillpipe adapter and
collet retainer 115 may be removed as releasing plug 116 is latched
and collet is disengaged, releasing tubing. Alternatively, pressure
pulsation may be used during hesitant squeeze cementing (not
shown).
[0031] This disclosure covers two basic fluid energy principles:
fluidic oscillation and pressure pulsing technology. These two
principles can be used during or after the cementing job. This
technology is adaptable for both primary cementing and setting of
balanced plugs.
[0032] This technology potentially could reduce sustained casing
pressure which is a major concern particularly offshore. Earlier
methods do not consider the advantage of inducing fluid energies by
fluidic oscillation or pressure pulsation methods. This methodology
greatly enhances the chances for competent cement bonding.
[0033] Therefore, the present invention is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein.
Furthermore, no limitations are intended to the details of
construction or design herein shown, other than as described in the
claims below. It is therefore evident that the particular
illustrative embodiments disclosed above may be altered or modified
and all such variations are considered within the scope and spirit
of the present invention. In particular, every range of values (of
the form, "from about a to about b," or, equivalently, "from
approximately a to b," or, equivalently, "from approximately a-b")
disclosed herein is to be understood as referring to the power set
(the set of all subsets) of the respective range of values, and set
forth every range encompassed within the broader range of values.
Also, the terms in the claims have their plain, ordinary meaning
unless otherwise explicitly and clearly defined by the
patentee.
* * * * *