U.S. patent application number 11/862300 was filed with the patent office on 2008-01-17 for systems for reverse-circulation cementing in subterranean formations.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES. Invention is credited to Anthony M. Badalamenti, Karl W. Blanchard, Michael G. Crowder, Ronald R. Faul, James E. Griffith, Henry E. Rogers, Simon Turton.
Application Number | 20080011482 11/862300 |
Document ID | / |
Family ID | 35355399 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080011482 |
Kind Code |
A1 |
Badalamenti; Anthony M. ; et
al. |
January 17, 2008 |
Systems for Reverse-Circulation Cementing in Subterranean
Formations
Abstract
Methods and systems for reverse-circulation cementing in
subterranean formations are provided. An example of a method is a
method of cementing casing in a subterranean well bore, comprising
inserting a casing into the well bore, the casing comprising a
casing shoe; equipping the casing with a well head, and a casing
inner diameter pressure indicator; flowing an equilibrium fluid
into the well bore; flowing a cement composition into the well bore
after the equilibrium fluid; determining from the well-bore
pressure indicator when the well bore pressure has reached a
desired value; discontinuing the flow of cement composition into
the well bore upon determining that the well bore pressure has
reached a desired value; and permitting the cement composition to
set in the subterranean formation. Examples of systems include
systems for cementing casing in a well bore.
Inventors: |
Badalamenti; Anthony M.;
(Katy, TX) ; Blanchard; Karl W.; (Cypress, TX)
; Crowder; Michael G.; (Orlando, OK) ; Faul;
Ronald R.; (Katy, TX) ; Griffith; James E.;
(Loco, OK) ; Rogers; Henry E.; (Duncan, OK)
; Turton; Simon; (Kingwood, TX) |
Correspondence
Address: |
PAUL MORICO;Baker Botts LLP
910 Louisiana St.
One Shell Plaza
Houston
TX
77002
US
|
Assignee: |
HALLIBURTON ENERGY SERVICES
|
Family ID: |
35355399 |
Appl. No.: |
11/862300 |
Filed: |
September 27, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10973322 |
Oct 26, 2004 |
7303008 |
|
|
11862300 |
Sep 27, 2007 |
|
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Current U.S.
Class: |
166/285 |
Current CPC
Class: |
E21B 33/14 20130101;
E21B 47/005 20200501 |
Class at
Publication: |
166/285 |
International
Class: |
E21B 33/04 20060101
E21B033/04 |
Claims
1-69. (canceled)
70. A system for cementing casing in a well bore comprising: a
casing inserted into the well bore and defining an annulus
therebetween, the casing having an inner diameter; a circulation
fluid for flowing into the well bore, the circulation fluid having
a leading edge that comprises a marker, and having a trailing edge,
wherein the flow of the circulation fluid and marker into the well
bore facilitates determination of a volume of cement composition
sufficient to fill a desired portion of the annulus; a cement
composition for flowing into at least a portion of the annulus, the
cement composition having a leading edge in fluid communication
with the trailing edge of the circulation fluid; and a marker
detector in fluid communication with fluid passing through the
inner diameter of the casing.
71. The system of claim 70 wherein the marker detector is located
at a position above a mouth of the well bore.
72. The system of claim 70 wherein the marker detector is located
at a position at about a mouth of the well bore.
73. The system of claim 70 wherein the marker detector is located
at a position below a mouth of the well bore.
74. The system of claim 73 wherein the marker detector is connected
to a wireline disposed within the inner diameter of the casing.
75. The system of claim 73 wherein the casing has a length, and
wherein the marker detector is located at a position within about
the upper 25% of the casing length.
76. The system of claim 73 wherein the casing has a length, and
wherein the marker detector is located at a position below about
the upper 25% of the casing length.
77. The system of claim 70 wherein the cement composition and the
circulation fluid are flowed into the well bore in a reverse
circulation direction.
78. The system of claim 70 wherein the marker detector is a borax
detector.
79. The system of claim 70 wherein the marker detector is a mass
flow meter.
80. The system of claim 70 wherein the marker comprises at least
one of a fiber, a cellophane flake, and a walnut shell.
Description
BACKGROUND OF THE PRESENT INVENTION
[0001] The present invention relates to subterranean cementing
operations, and more particularly, to methods and systems for
reverse-circulation cementing in subterranean formations.
[0002] Hydraulic cement compositions commonly are utilized in
subterranean operations, particularly subterranean well completion
and remedial operations. For example, hydraulic cement compositions
are used in primary cementing operations whereby pipe strings, such
as casings and liners, are cemented in well bores. In performing
primary cementing, hydraulic cement compositions commonly are
pumped into an annular space between the walls of a well bore and
the exterior surface of a pipe string disposed therein. The cement
composition is permitted to set in the annular space, thereby
forming therein an annular sheath of hardened, substantially
impermeable cement that substantially supports and positions the
pipe string in the well bore, and that bonds the exterior surface
of the pipe string to the walls of the well bore. Conventionally,
two pumping methods have been used to place the cement composition
in the annulus. First, the cement composition may be pumped down
the inner diameter of the pipe string, out through a casing shoe
and/or circulation valve at the bottom of the pipe string, and up
through the annulus to a desired location. The direction in which
the cement composition is pumped in this first method is called a
conventional-circulation direction. Second, the cement composition
may be pumped directly down the annulus, thereby displacing any
well fluids present in the annulus by pushing them through the
casing shoe and up the inner diameter of the pipe string. The
direction in which the cement composition is pumped in this second
method is called a reverse-circulation direction.
[0003] In reverse-circulation direction applications, it is
sometimes undesirable for the cement composition to enter the inner
diameter of the pipe string from the annulus through the casing
shoe and/or circulation valve. For example, if an excessive volume
of cement composition is permitted to enter the inner diameter of
the pipe string, the cement composition may rise to a level equal
to that of a hydrocarbon-bearing zone intended to be perforated.
This may be problematic because it may prevent the subsequent
placement of tools (e.g., perforating equipment) adjacent the
hydrocarbon-bearing zone, which may prevent the perforation of the
zone and subsequent production of hydrocarbons therefrom, unless
the excess cement is drilled out. Accordingly, whenever a cement
composition that is reverse-circulated into a subterranean annulus
enters the inner diameter of the pipe string, the excess cement
composition in the pipe string typically is drilled out before
further operations are conducted. The drill-out procedure often
requires additional time, labor, and expense that may be avoided by
preventing the excess cement composition from entering the inner
diameter of the pipe string through the casing shoe and/or
circulation valve.
SUMMARY OF THE PRESENT INVENTION
[0004] The present invention relates to subterranean cementing
operations, and more particularly, to methods and systems for
reverse-circulation cementing in subterranean formations.
[0005] An example of a method of the present invention is a method
of cementing casing in a well bore, comprising: inserting a casing
into the well bore, the casing having an inner diameter and an
outer surface, an annulus being defined between the outer surface
of the casing and an inner wall of the well bore; flowing an
equilibrium fluid into the well bore; flowing a cement composition
into the well bore after flowing the equilibrium fluid into the
well bore; permitting the pressure in the annulus to reach
equilibrium with the pressure in the inner diameter of the casing,
such that flow of cement composition into the well bore ceases; and
permitting the cement composition to set in the well bore.
[0006] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting a
casing into the well bore, the casing having an inner diameter and
an outer surface, an annulus being defined between the outer
surface of the casing and an inner wall of the well bore; flowing
an equilibrium fluid into the well bore; flowing a cement
composition into the well bore after flowing the equilibrium fluid
into the well bore; monitoring the pressure in the inner diameter
of the casing; discontinuing the flow of cement composition into
the well bore upon determining that the pressure in the inner
diameter of the casing has reached a desired value; and permitting
the cement composition to set in the well bore.
[0007] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting
casing into the well bore; flowing a circulation fluid into the
well bore; flowing a marker into the well bore at a desired time
during the flowing of the circulation fluid into the well bore;
determining when the marker reaches a desired location; monitoring
a volume of circulation fluid after flowing the marker into the
well bore, and before determining when the marker reaches a desired
location; determining a volume of cement composition to be flowed
into the well bore; flowing the determined volume of cement
composition into the well bore; and permitting the cement
composition to set in the well bore.
[0008] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting
casing into the well bore; flowing a volume of circulation fluid,
comprising a marker, into the well bore, the volume of circulation
fluid being about equal to an inside volume of the casing; flowing
a cement composition into the well bore after flowing the volume of
circulation fluid; determining when the marker reaches a desired
location; discontinuing flowing the cement composition into the
well bore; and permitting the cement composition to set in the well
bore.
[0009] An example of a system of the present invention is a system
for cementing casing in a well bore comprising: a casing inserted
into the well bore and defining an annulus therebetween; a cement
composition for flowing into at least a portion of the annulus; and
an equilibrium fluid that is positioned within the inner diameter
of the casing and balances the static fluid pressures between the
inner diameter of the casing and the annulus.
[0010] Another example of a system of the present invention is a
system for cementing casing in a well bore comprising: a casing
inserted into the well bore and defining an annulus therebetween,
the casing having an inner diameter; a circulation fluid for
flowing into the well bore, the circulation fluid having a leading
edge that comprises a marker, and having a trailing edge, wherein
the flow of the circulation fluid and marker into the well bore
facilitates determination of a volume of cement composition
sufficient to fill a desired portion of the annulus; a cement
composition for flowing into at least a portion of the annulus, the
cement composition having a leading edge in fluid communication
with the trailing edge of the circulation fluid; and a marker
detector in fluid communication with fluid passing through the
inner diameter of the casing.
[0011] The features and advantages of the present invention will be
readily apparent to those skilled in the art upon a reading of the
description of embodiments, which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more complete understanding of the present disclosure and
advantages thereof may be acquired by referring to the following
description taken in conjunction with the accompanying drawings,
wherein:
[0013] FIG. 1 illustrates a cross-sectional side view of a well
bore and casing.
[0014] FIG. 2A illustrates a cross-sectional side view of a well
bore and casing.
[0015] FIG. 2B illustrates a cross-sectional side view of the well
bore and casing illustrated in FIG. 2A.
[0016] FIG. 3A illustrates a cross-sectional side view of a well
bore and casing.
[0017] FIG. 3B illustrates a cross-sectional side view of the well
bore and casing illustrated in FIG. 3A.
[0018] FIG. 4A illustrates a cross-sectional side view of a well
bore and casing.
[0019] FIG. 4B illustrates a cross-sectional side view of the well
bore and casing illustrated in FIG. 4A.
[0020] While the present invention is susceptible to various
modifications and alternative forms, specific embodiments thereof
have been shown in the drawings and are herein described. It should
be understood, however, that the description herein of specific
embodiments is not intended to limit the invention to the
particular forms disclosed, but on the contrary, the intention is
to cover all modifications, equivalents, and alternatives falling
within the spirit and scope of the present invention as defined by
the appended claims.
DETAILED DESCRIPTION OF EMBODIMENTS
[0021] The present invention relates to subterranean cementing
operations, and more particularly, to methods and systems for
reverse-circulation cementing in subterranean formations.
Generally, any cement compositions suitable for use in subterranean
applications may be suitable for use in the present invention.
[0022] Referring to FIG. 1, a cross-sectional side view of a well
bore is shown. Well bore 1 is an open well bore with casing 3
inserted therein. Annulus 5 is defined between casing 3 and well
bore 1. Casing 3 has casing shoe 4 at its lowermost end and simply
extends from the open well bore at the top. Reservoir 7 is located
proximate to well bore 1. Truck 9 is parked in the vicinity of well
bore 1. Circulation fluid 30 is present within well bore 1 such
that annular fluid surface 6 is approximately level with inner
diameter fluid surface 10. In certain embodiments of the present
invention, circulation fluid 30 that initially is present within
well bore 1 may be a drilling fluid. FIG. 1 represents a typical
well bore configuration prior to a cementing operation.
[0023] One aspect of the present invention provides a method for
pumping a cement composition into annulus 5 without permitting
excessive flow of cement composition into the inside diameter of
casing 3. In certain embodiments wherein the interior volume of
casing 3 has not been calculated, a first step of the method may
involve calculating the interior volume of casing 3. The interior
volume of casing 3 equals the product of .pi. multiplied by the
square of the inside radius "r" of casing 3, multiplied by the
length "h" of casing 3, as illustrated below: V=.pi.r.sup.2h
EQUATION 1
[0024] Next, equilibrium fluid 11 (not shown in FIG. 1) may be
selected having a density equal to the density of cement
composition 15 (not shown in FIG. 1) that will be used to cement
casing 3 in well bore 1. Generally, equilibrium fluid 11 may
comprise any fluid (e.g., a drilling fluid, a spacer fluid, or the
like) having a desired density (e.g., a density greater than the
density of circulation fluid 30), provided that the fluid is
compatible with both circulation fluid 30 and cement composition
15. Examples of suitable spacer fluids are commercially available
from Halliburton Energy Services, Inc., of Duncan, Okla., under the
trade names "TUNED SPACER," and "DUAL SPACER." Equilibrium fluid 11
then may be pumped ahead of cement composition 15 into annulus 5
and into well bore 1 in a reverse-circulation direction.
Equilibrium fluid 11 may travel down annulus 5, through casing shoe
4 and up through the inner diameter of casing 3. When equilibrium
fluid 11 completely fills the inside of casing 3, cement
composition 15 flowing behind equilibrium fluid 11 will completely
fill annulus 5, and the static fluid pressure of equilibrium fluid
11 will balance the static fluid pressure of cement composition 15,
such that the flow of cement composition 15 into annulus 5 may
cease. In particular, annular fluid surface 6 (e.g., the surface of
cement composition 15 in the annulus) will be approximately level
with inner diameter fluid surface 10 (e.g., the surface of
equilibrium fluid 11 in well bore 1). Generally, the leading edge
of cement composition 15 will be at about adjacent the lowermost
end of casing 3 when the flow of cement composition 15 into the
annulus ceases. Generally, the leading edge of cement composition
15 will not penetrate the inner diameter of casing 3.
[0025] In certain embodiments of the present invention, an operator
may elect to fill less than the entire annulus 5 with cement
composition 15. For example, this may be desirable when casing 3
comprises an intermediate casing string (e.g., a casing string
having a depth of 10,000 feet, for example). In certain of these
embodiments, an operator may determine an annular volume that is
desired to be filled with cement composition 15 (e.g., a volume
that is less than the total annular volume), and may determine a
desired volume of equilibrium fluid 11 to be placed ahead of the
desired volume of cement composition 15. For example, if casing 3
comprises an intermediate casing string having a depth of 10,000
feet, for example, the operator may determine that the lower 2,500
feet should be filled with cement composition 15. In such example,
the volume of equilibrium fluid 11 that is to be placed ahead of
cement composition 15 may be calculated such that it fills an
equivalent height within casing 3 (e.g., 2,500 feet in this example
wherein the density of equilibrium fluid equals the density of
cement composition 15), and thus the uppermost height of
equilibrium fluid 11 and the uppermost height of cement composition
15 would equal each other below the surface (e.g., 7,500 feet below
the surface, in this example). Generally, in these embodiments
wherein less than the entire annulus 5 may be filled with cement
composition 15, the remaining volume of annulus 5 would comprise a
fluid (e.g., a drilling fluid, spacer fluid, or equilibrium fluid
11, or the like) above cement composition 15 that is compatible
with cement composition 15 and that has about the same, or greater,
density as circulation fluid 30, thereby providing approximately
equal hydrostatic pressures on both sides of casing 3. Of course,
other combinations of fluid lengths and densities may exist where
the density of equilibrium fluid 11 differs from the density of
cement composition 15. Generally, the resultant hydrostatic
pressure of the fluids placed in the formation ahead of cement
composition 15, which fill the inside of casing 3, will
approximately equal the resultant hydrostatic pressure of the
fluids within annulus 5, including, inter alia, cement composition
15.
[0026] Referring to FIGS. 2A and 2B, cross-sectional side views of
a well bore and casing are shown. The well bore configuration
generally is similar to that previously described with reference to
FIG. 1, though additional features are illustrated in FIGS. 2A and
2B. Well head 2 is attached to the exposed end of casing 3. Return
line 8 extends from well head 2 to reservoir 7, and is in fluid
communication with the inner diameter of casing 3. Return valve 12
is connected in return line 8. In certain embodiments of the
present invention, return valve 12 may be a ball valve, a gate
valve, a plug valve, or the like. An example of a suitable plug
valve is commercially available from Halliburton Energy Services,
Inc., of Duncan, Okla., under the trade name "LO-TORC." Pressure
indicator 13 is attached to casing 3, and indicates the pressure
within casing 3 below well head 2. Supply line 14 is connected to
truck 9 for pumping fluids into annulus 5. As shown in FIG. 2A, the
calculated volume of equilibrium fluid 11 has been pumped into
annulus 5, thereby displacing a portion of circulation fluid 30
from annulus 5 into reservoir 7. Because equilibrium fluid 11 is
intended only to fill the inside diameter of casing 3, annulus 5
may not be completely filled with equilibrium fluid 11 at this
stage of the process, or it may spill over into the inside diameter
of casing 3 through casing shoe 4. Once the calculated volume of
equilibrium fluid 11 (e.g., a volume of equilibrium fluid 11
sufficient to fill the interior volume of casing 3) is pumped into
annulus 5, cement composition 15 then may be pumped into annulus 5
behind equilibrium fluid 11.
[0027] As shown in FIG. 2B, cement composition 15 generally may be
pumped down annulus 5 so as to drive equilibrium fluid 11 through
casing shoe 4 and up through an inner diameter of casing 3. Because
the density of both equilibrium fluid 11 and cement composition 15
exceeds the density of circulation fluid 30, pressure indicator 13
generally will indicate a positive pressure throughout this
process. As inner diameter fluid surface 10 (e.g., the surface of
equilibrium fluid 11 in well bore 1) becomes approximately level
with annular fluid surface 6 (e.g., the surface of cement
composition 15 in annulus 5), the pressure indicated on pressure
indicator 13 will approach zero. At this stage of the operation,
equilibrium fluid 11 generally will completely fill the inner
diameter of casing 3 and cement composition 15 generally will
completely fill annulus 5, although, as noted previously herein, in
certain embodiments of the present invention annulus 5 may be only
partially filled with cement composition 15. Once the pressure
indicated on pressure indicator 13 reads zero, cement composition
15 will have been circulated into position within annulus 5, with
the leading edge of cement composition 15 adjacent to cement shoe
4, and pumping of cement composition 15 into annulus 5 generally
will be halted. Thereafter, cement composition 15 generally will be
allowed to reside in well bore 1 for a period of time sufficient to
permit cement composition 15 to harden or solidify. Once cement
composition 15 has solidified, a production pipe, or coiled tubing
may be inserted into casing 3 to remove equilibrium fluid 11 from
well bore 1. In certain embodiments of the present invention
wherein it is desired to commence production, a completion brine
may be placed in the well bore. In certain embodiments of the
present invention, it may be desirable to place a drilling fluid in
well bore 1 in preparation for drilling out casing shoe 4 and
extending well bore 1 to a desired, deeper depth. For example, if
casing 3 comprises a surface casing string, it may be desirable to
drill out casing shoe 4, extend well bore 1 to a desired depth, and
install additional strings of casing (e.g., intermediate casing
and/or production casing).
[0028] In alternative embodiments of the present invention,
equilibrium fluid 11 may be heavier, or lighter, than cement
composition 15. To ensure that the pressure indicated by pressure
indicator 13 reads zero when the leading edge of cement composition
15 reaches casing shoe 4 (thereby indicating that cement
composition 15 has been circulated into position in annulus 5, and
that pumping of cement composition 15 may be discontinued), the
combined hydrostatic pressure of circulation fluid 30 initially
present in well bore 1 and equilibrium fluid 11 should equal the
hydrostatic pressure of the volume of cement composition 15 that is
desired to be placed in annulus 5. In one embodiment of the present
invention, equilibrium fluid 11 may have a heavier density than the
density of cement composition 15. The required volume of
equilibrium fluid 11 (V.sub.ef11) first may be calculated according
to the following equation:
V.sub.ef11=V.sub.tot(.rho..sub.cc15-.rho..sub.cf30)/(.rho..sub.-
ef11-.rho..sub.cf30) EQUATION 2 where V.sub.tot is the interior
volume of casing 3, .rho..sub.cc15 is the density of cement
composition 15, .rho..sub.cf30 is the density of circulation fluid
30 in the well bore, and .rho..sub.ef11 is the density of
equilibrium fluid 11. As noted earlier, from Equation 1,
V.sub.tot=.pi.r.sup.2h, where r is the inside radius of casing 3
and h is the height or length of casing 3. The following example
illustrates how the required volume of equilibrium fluid (V.sub.ef)
is calculated.
EXAMPLE
[0029] For example, assume that casing 3 has a length of 2,000
feet, and an internal diameter of 5 inches. Assume further that the
desired length of casing 3 to be cemented is 2,000 feet.
Accordingly, the radius of casing 3 will be 2.5 inches. Thus,
V.sub.tot=H .pi. r.sup.2=[(2000 feet)(3.1416)((2.5
inch).sup.2/144)]/(5.614583)=48.6 barrels. Further assume that the
desired cement composition 15 has a density of 80 lbs/ft.sup.3,
that circulation fluid 30 has a density of 65 lbs/ft.sup.3, and
that the desired equilibrium fluid 11 has a density of 100
lbs/ft.sup.3. Accordingly, applying EQUATION 2,
V.sub.ef=V.sub.tot(.rho..sub.cc15-.rho..sub.cf30)/(.rho..sub.ef11-.rho..s-
ub.cf30)=48.6 barrels (80 lbs/ft.sup.3-65 lbs/ft.sup.3)/(100
lbs/ft.sup.3-65 lbs/ft.sup.3)=20.8 barrels. Thus, in this example,
20.8 barrels of equilibrium fluid 11 would be required for use in
order to ensure that the pressure displayed by pressure indicator
13 read zero when the leading edge of cement composition 15 reached
casing shoe 4.
[0030] Where a relatively heavy equilibrium fluid 11 is used, it
may be injected into annulus 5 immediately in front of cement
composition 15. For example, FIG. 3A illustrates equilibrium fluid
11 being placed within annulus 5 in advance of cement composition
15. Because equilibrium fluid 11 and cement composition 15 are
heavier than circulation fluid 30 in the inner diameter of casing
3, the fluids flow in a reverse-circulation direction. Further, the
relatively heavier equilibrium fluid 11 and cement composition 15
induce an elevated pressure in the inner diameter of casing 3, as
would be indicated on pressure indicator 13. Return valve 12 may be
used to reduce or restrict the fluid flow through return line 8 to
a desired rate. For example, return valve 12 may be partially
closed to thereby modulate the rate of fluid flow therethrough.
Alternatively, a choke manifold or an adjustable choke valve may be
placed in return line 8 (e.g., generally downstream of return valve
12). The desired reduction or restriction in the flow rate of fluid
through return line 8 may be determined by, inter alia, iteratively
restricting the flow rate while monitoring the flow rate either
visually or through an optional flowmeter.
[0031] As shown in FIG. 3B, additional portions of cement
composition 15 may be placed in annulus 5 behind equilibrium fluid
11 until annulus 5 is completely filled with cement composition 15.
As equilibrium fluid 11 enters the inner diameter of casing 3
through casing shoe 4, the pressure indicated on pressure indicator
13 begins to decline. Once the hydrostatic fluid pressure generated
by circulation fluid 30 and equilibrium fluid 11 in the inner
diameter of casing 3 becomes approximately equal to the hydrostatic
fluid pressure generated by cement composition 15 in annulus 5, the
fluids will no longer flow through well bore 1, and will be in
static equilibrium, as shown in FIG. 3B, because, in this
embodiment, equilibrium fluid 11 is much heavier than cement
composition 15.
[0032] FIGS. 4A and 4B illustrate alternative embodiments of the
present invention. As illustrated, casing 3 is inserted in well
bore 1. Annulus 5 is defined between casing 3 and well bore 1.
Casing 3 has casing shoe 4. Reservoir 7 and truck 9 are located
near well bore 1. Supply line 14 is connected to truck 9 for
pumping fluids into annulus 5.
[0033] As illustrated with reference to FIGS. 4A and 4B, in certain
of these embodiments of the present invention, the mass flow rate
and/or volumetric flow rate of returning circulation fluid 30 may
be monitored with marker detector 17. In certain embodiments of the
present invention, marker detector 17 may comprise, e.g., mass flow
meters and/or borax detectors 17. Suitable mass flow meters are
commercially available from, inter alia, MicroMotion Corporation of
Boulder, Colo. Tag fluids 16 (e.g., marker pills comprising, inter
alia, fibers, cellophane flakes, walnut shells, and the like) may
be injected into circulation fluid 30 several barrels ahead of
cement composition 15 so that the detection of tag fluids or marker
pills 16 at the leading edge of circulation fluid 30 may signal to
an operator the impending arrival of the leading edge of cement
composition 15 at a desired location (e.g., the impending arrival
of the leading edge of cement composition 15 at about the lowermost
end of casing 3). Generally, the leading edge of cement composition
15 will not penetrate the inner diameter of casing 3.
[0034] As shown in FIG. 4A, tag fluids or marker pills 16 are
injected into annulus 5 as circulation fluid 30 is pumped from
truck 9, down through annulus 5, into the inner diameter of casing
3 through casing shoe 4, up through the inner diameter of casing 3
and through return line 8 into reservoir 7. Generally, circulation
fluid 30 will have a greater density than the density of any
formation fluids (not shown) or other fluids (not shown) that
already may be present within annulus 5. In certain embodiments of
the present invention, when cement composition 15 is flowed into
annulus 5, a leading edge of cement composition 15 will be in fluid
communication with a trailing edge of circulation fluid 30.
[0035] Marker detector 17 may be positioned in a variety of
locations. In certain embodiments of the present invention, marker
pills 16 are observed by marker detector 17 as they pass through
return line 8. In certain embodiments of the present invention,
marker detector 17 may be disposed such that it is in fluid
communication with fluid passing through the inner diameter of
casing 3. In certain embodiments of the present invention, marker
detector 17 may be disposed such that it is in fluid communication
with fluid passing through well head 2. In certain embodiments of
the present invention, marker detector 17 may be disposed such that
it is positioned in the inner diameter of casing 3 at about the
mouth of well bore 1. In certain embodiments of the present
invention, marker detector 17 may be disposed such that it is
positioned in the inner diameter of casing 3, below the mouth of
well bore 1. In certain embodiments of the present invention,
marker detector 17 may be connected to a wireline (not shown) that
is disposed within the inner diameter of casing 3, below the mouth
of well bore 1. In certain embodiments of the present invention,
marker detector 17 may be disposed such that it is positioned in
the inner diameter of casing 3, at a depth within the upper 25% of
the length of casing 3. In certain embodiments of the present
invention, marker detector 17 may be disposed such that it is
positioned in the inner diameter of casing 3, at a depth below
about the upper 25% of the length of casing 3.
[0036] In certain embodiments of the present invention, more than
one sample of tag fluids or marker pills 16 may be injected into
annulus 5, and the volume of circulation fluid 30 injected between
samples of tag fluids or marker pills 16 may be monitored.
[0037] In certain embodiments of the present invention wherein the
inner volume of casing 3 is known, tag fluids or marker pills 16
may be injected into annulus 5 as circulation fluid 30 is pumped
from truck 9, and, after flowing into annulus 5 a volume of
circulation fluid 30 that is about equal to the inner volume of
casing 3, cement composition 15 may be flowed into annulus 5. In
certain of such embodiments, the arrival of tag fluids or marker
pills 16 at marker detector 17 will signal the impending arrival of
the leading edge of cement composition 15 at about the lowermost
end of casing 3 (e.g., at about casing shoe 4), and will indicate
that the flow of cement composition 15 into annulus 5 may be
discontinued.
[0038] As shown in FIG. 4B, tag fluids or marker pills 16
facilitate the injection of the proper amount of cement composition
15 into annulus 5. Knowing the inner diameter volume of casing 3
and having observed the volume of circulation fluid 30 that had
passed through well bore 1 when marker pills 16 were observed at
marker detector 17 facilitates calculation of the volume of cement
composition 15 to be pumped into annulus 5 to fill annulus 5
without permitting cement composition 15 to flow into casing 3. In
certain optional embodiments of the present invention, an optional
flow meter may be used that may comprise a totalizer that may
identify the total volume of circulation fluid 30 that has passed
through well bore 1 at the time when marker pills 16 are detected.
Optionally, the total volume of circulation fluid 30 that has
passed through well bore 1 at the time of detection of marker pills
16 may be estimated by monitoring the fluid level in reservoir 7,
which may have gradations or other markings that may be useful in
determining the fluid volume therein. In certain embodiments of the
present invention, the use of more than one sample of tag fluids or
marker pills 16 may facilitate improved accuracy in measuring,
inter alia, the fluid volume of the inner diameter of casing 3, and
the fluid volume of annulus 5. In certain embodiments of the
present invention, once the fluid volume of annulus 5 has been
measured accurately, a corresponding volume of cement composition
15 may be reverse circulated into annulus 5, as illustrated in FIG.
4B.
[0039] Accordingly, an example of a method of the present invention
is a method of cementing casing in a well bore, comprising:
inserting a casing into the well bore, the casing having an inner
diameter and an outer surface, an annulus being defined between the
outer surface of the casing and an inner wall of the well bore;
flowing an equilibrium fluid into the well bore; flowing a cement
composition into the well bore after flowing the equilibrium fluid
into the well bore; permitting the pressure in the annulus to reach
equilibrium with the pressure in the inner diameter of the casing,
such that flow of cement composition into the well bore ceases; and
permitting the cement composition to set in the well bore.
[0040] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting a
casing into the well bore, the casing having an inner diameter and
an outer surface, an annulus being defined between the outer
surface of the casing and an inner wall of the well bore; flowing
an equilibrium fluid into the well bore; flowing a cement
composition into the well bore after flowing the equilibrium fluid
into the well bore; monitoring the pressure in the inner diameter
of the casing; discontinuing the flow of cement composition into
the well bore upon determining that the pressure in the inner
diameter of the casing has reached a desired value; and permitting
the cement composition to set in the well bore.
[0041] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting
casing into the well bore; flowing a circulation fluid into the
well bore; flowing a marker into the well bore at a desired time
during the flowing of the circulation fluid into the well bore;
determining when the marker reaches a desired location; monitoring
a volume of circulation fluid after flowing the marker into the
well bore, and before determining when the marker reaches a desired
location; determining a volume of cement composition to be flowed
into the well bore; flowing the determined volume of cement
composition into the well bore; and permitting the cement
composition to set in the well bore.
[0042] Another example of a method of the present invention is a
method of cementing casing in a well bore, comprising: inserting
casing into the well bore; flowing a volume of circulation fluid,
comprising a marker, into the well bore, the volume of circulation
fluid being about equal to an inside volume of the casing; flowing
a cement composition into the well bore after flowing the volume of
circulation fluid; determining when the marker reaches a desired
location; discontinuing flowing the cement composition into the
well bore; and permitting the cement composition to set in the well
bore.
[0043] An example of a system of the present invention is a system
for cementing casing in a well bore comprising: a casing inserted
into the well bore and defining an annulus therebetween; a cement
composition for flowing into at least a portion of the annulus; and
an equilibrium fluid that is positioned within the inner diameter
of the casing and balances the static fluid pressures between the
inner diameter of the casing and the annulus.
[0044] Another example of a system of the present invention is a
system for cementing casing in a well bore comprising: a casing
inserted into the well bore and defining an annulus therebetween,
the casing having an inner diameter; a circulation fluid for
flowing into the well bore, the circulation fluid having a leading
edge that comprises a marker, and having a trailing edge, wherein
the flow of the circulation fluid and marker into the well bore
facilitates determination of a volume of cement composition
sufficient to fill a desired portion of the annulus; a cement
composition for flowing into at least a portion of the annulus, the
cement composition having a leading edge in fluid communication
with the trailing edge of the circulation fluid; and a marker
detector in fluid communication with fluid passing through the
inner diameter of the casing.
[0045] Therefore, the present invention is well adapted to carry
out the objects and attain the ends and advantages mentioned as
well as those which are inherent therein. While the invention has
been depicted, and described by reference to embodiments of the
present invention, such a reference does not imply a limitation on
the invention, and no such limitation is to be inferred. The
invention is capable of considerable modification, alternation, and
equivalents in form and function, as will occur to those ordinarily
skilled in the pertinent arts and having the benefit of this
disclosure. The depicted and described embodiments of the present
invention are exemplary only, and are not exhaustive of the scope
of the present invention. Consequently, the invention is intended
to be limited only by the spirit and scope of the appended claims,
giving full cognizance to equivalents in all respects.
* * * * *