U.S. patent application number 11/955339 was filed with the patent office on 2008-11-27 for downhole slurry method for primary cementing a well.
Invention is credited to BOYCE DONALD BURTS, III, BOYCE D. BURTS, JR., FREDDIE L. SABINS, LARRY WATTERS.
Application Number | 20080289826 11/955339 |
Document ID | / |
Family ID | 39678629 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080289826 |
Kind Code |
A1 |
BURTS, JR.; BOYCE D. ; et
al. |
November 27, 2008 |
Downhole Slurry Method For Primary Cementing A Well
Abstract
A method of primary cementing well is provided utilizing a
cement and cement activator cementing composition, in which one of
the components is first placed in the annulus of the well. Next,
the other component is placed in the annulus above the first placed
component. Densities of the components have been selected such that
the density of the second placed component is sufficiently higher
then the density of the first placed component to facilitate
gravity mixing of the two components as the second placed component
moves through the first placed component and in the process
activation occurs.
Inventors: |
BURTS, JR.; BOYCE D.;
(LAFAYETTE, LA) ; BURTS, III; BOYCE DONALD;
(LAFAYETTE, LA) ; SABINS; FREDDIE L.; (HOUSTON,
TX) ; WATTERS; LARRY; (SPRING, TX) |
Correspondence
Address: |
GILBRETH & ASSOCIATES, P.C.
PO BOX 2428
BELLAIRE
TX
77402-2428
US
|
Family ID: |
39678629 |
Appl. No.: |
11/955339 |
Filed: |
December 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11162443 |
Sep 9, 2005 |
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11955339 |
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60608255 |
Sep 9, 2004 |
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60608256 |
Sep 9, 2004 |
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60608257 |
Sep 9, 2004 |
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Current U.S.
Class: |
166/293 ;
166/242.9 |
Current CPC
Class: |
E21B 33/13 20130101;
C04B 40/0666 20130101; C04B 40/0666 20130101; C04B 40/0666
20130101; C04B 40/065 20130101; C04B 40/065 20130101; C04B 28/34
20130101; C04B 40/065 20130101; C04B 28/32 20130101; C04B 28/18
20130101; C09K 8/426 20130101; C04B 40/0666 20130101 |
Class at
Publication: |
166/293 ;
166/242.9 |
International
Class: |
E21B 33/13 20060101
E21B033/13 |
Claims
1. A method of primary cementing a well comprising a well bore and
a pipe residing in the well bore forming an annulus between the
pipe and well bore, the method comprising: (A) providing a cement
component and an cement activator component, each having a density
greater than the density of the well fluid; (B) selecting a first
component and a second component from the group consisting of the
cement component and the cement activator component, wherein the
first component and the second component are different, and the
density of the second component is higher than the density of the
first component; (C) placing the first component in the annulus;
(D) placing the second component in the annulus at a point above
the first component that will allow for gravity flow of the second
component down into contact with the first component.
2. The method of claim 1, wherein steps (C) and (D) are carried out
utilizing one or more of a dump bailer; pumping through tubing,
drillpipe, work strings or tubulars; gravity flow; and bull
heading.
3. The method of claim 1, wherein the activator component comprises
at least one selected from the group consisting of amines, metal
salts, metal halides, and formats.
4. The method of claim 1, wherein the second component is the
cement component, and the first component is the activator
component.
5. The method of claim 1, wherein the well fluid density is in the
range of about 8.33 ppg up to about 20.0 ppg, the activator density
is in the range of about 8.33 ppg up to about 21.0 ppg, and the
cement density is in the range of about 8.54 up to about 22.0
ppg.
6. The method of claim 1, wherein the activator mixes with less
than 2 percent with the well fluid, and the activator mixes with
less than 20% with the cement.
7. A method of primary cementing a well comprising a well bore and
a pipe residing in the well bore forming an annulus between the
pipe and well bore, the method comprising: (A) providing a cement
component and an cement activator component, each having a density
greater than the density of the well fluid; (B) selecting a first
component and a second component from the group consisting of the
cement component and the cement activator component, wherein the
first component and the second component are different, and the
density of the second component is higher than the density of the
first component; (C) placing the first component in the annulus;
(D) placing the second component in the annulus at a point above
the first component that will allow for gravity flow of the second
component down into the first component; and (E) allowing the first
and second components to gravity contact and form a hard
impermeable mass.
8. The method of claim 7, wherein steps (C) and (D) are carried out
utilizing one or more of a dump bailer; pumping through tubing,
drillpipe, work strings or tubulars; gravity flow; and bull
heading.
9. The method of claim 7, wherein the activator component comprises
at least one selected from the group consisting of amines, metal
salts, metal halides, and formats.
10. The method of claim 7, wherein the second component is the
cement component, and the first component is the activator
component.
11. The method of claim 7, wherein the well fluid density is in the
range of about 8.33 ppg up to about 20.0 ppg, the activator density
is in the range of about 8.33 ppg up to about 21.0 ppg, and the
cement density is in the range of about 8.54 up to about 22.0
ppg.
12. The method of claim 7, wherein the activator mixes with less
than 2 percent with the well fluid, and the activator mixes with
less than 20% with the cement.
13. A cemented well comprising: a well bore; a pipe residing in
said well bore forming an annulus between said pipe and well bore;
a first component residing in the annulus; and, a second component
having a density greater than the density of the first component,
and residing in the annulus at a point above the first component
that will allow for gravity flow of the second component down into
the first component, wherein one of the first component and the
second component is a cement component, and the other of the first
component and second component is a cement activator component.
14. A cemented well comprising: a well bore; a pipe residing in
said well bore forming an annulus between said pipe and well bore;
a first component residing in the annulus; and, a second component
having a density greater than the density of the first component,
and in the state of gravity flowing thru the first component,
wherein one of the first component and the second component is a
cement component, and the other of the first component and second
component is a cement activator component.
Description
RELATED APPLICATION DATA
[0001] This application is a continuation of U.S. patent
application Ser. No. 11/162,443, filed Sep. 9, 2005, herein
incorporated by reference, which application claimed
priority/benefit of U.S. Provisional Patent Application Ser. Nos.
60/608,255, 60/608,256, and 60/608,257, all filed Sep. 9, 2004, and
all herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to wells, drilling wells, well
operations, to methods, apparatus and products for drilling wells.
In another aspect, the present invention relates to wells,
cementing wells, and to methods, apparatus and products for
cementing wells. In even another aspect, the present invention
relates to wells, primary cementing wells, and to methods,
apparatus and products for primary cementing wells.
[0004] 2. Brief Description of the Related Art
[0005] In the drilling and completion of an oil or gas well, a
cementing composition is often introduced in the well bore for
cementing pipe string or casing in a process known as primary
cementing. In primary cementing, a cementing composition is pumped
into the annular space between the walls of the well bore and the
casing. The cementing composition sets in the annular space,
supporting and positioning the casing, and forming a substantially
impermeable barrier/mass or cement sheath. An essential function of
cementing is to prevent fluid exchange between the different
formation layers through which the hole passes and to control the
ingress of fluid into the well, in particular to limit the ingress
of water. In production zones, the casing, the cement and the
formation are all perforated over a depth of a few centimeters.
[0006] A variety of cementing compositions exist in the art and
have been used for primary cementing. Considerations for selecting
a cementing composition include relatively short term concerns,
such as set times for the cement slurry, as well as functional and
long term concerns such as whether a composition is environmentally
acceptable, easily mixable, non-settling under static and dynamic
conditions, will develop near one hundred percent placement in the
annular space, resist fluid influx, and have the desired density,
thickening time, set up time, fluid loss, strength development, and
zero free water.
[0007] A number of patents and patent applications are directed to
primary cementing wells, the following of which are only a small
few.
[0008] U.S. Pat. No. 4,768,593, issued Sep. 6, 1988, to Novak
discloses This application discloses a process for drilling and
primary cementing a well using a drilling fluid containing a
polymeric material which may be cemented into a well cement by
irradiation with a suitable radioactive source
[0009] U.S. Pat. No. 5,151,203, issued Sep. 29, 1992, to Riley et
al., discloses a composition for and method of performing primary
cementing operations. The method comprises the use of a water
slurry of a thixotropic cementing composition which rapidly
develops sufficient static gel strength to reduce if not eliminate
annular gas migration.
[0010] U.S. Pat. No. 5,327,969, issued Jul. 12, 1994, to Sabins et
al., discloses a method of preventing gas migration during primary
well cementing. The method basically comprises the steps of
displacing a cement slurry into the annulus between a string of
pipe to be cemented in a well bore and the walls of the well bore,
determining the initial surface pressure in the pipe after the
cement slurry is placed in the annulus, displacing additional
cement slurry into the annulus as is necessary to make up for
losses in the surface pressure due to cement slurry gel strength
development and volume reduction whereby the surface pressure is
maintained substantially equal to the initial surface pressure
until the cement slurry develops a predetermined gel strength
sufficient by itself to prevent gas migration, and then allowing
the cement slurry to set into a hard impermeable mass in the
annulus.
[0011] U.S. Pat. No. 5,343,950, issued Sep. 6, 1994 to Hale et al.,
discloses An extended reach well such as the deviated wells
typically drilled from offshore platforms is drilled using a
drilling fluid comprising blast furnace slag and water which
drilling fluid is circulated during the drilling to lay down a
filter cake. Thereafter, an activator is added and generally, an
alkaline material and additional blast furnace slag, to produce a
cementitious slurry which is passed down a casing and up into an
annulus to effect primary cementing.
[0012] U.S. Pat. No. 5,343,951, issued Sep. 6, 1994 to Cowan et
al., discloses a slim hole well drilled using a drilling fluid
comprising blast furnace slag and water which drilling fluid is
circulated during the drilling to lay down a filter cake.
Thereafter, an activator is added and generally, an alkaline
material and additional blast furnace slag, to produce a
cementitious slurry which is passed down a casing and up into an
annulus to effect primary cementing.
[0013] U.S. Pat. No. 5,370,185, issued Dec. 6, 1994 to Cowan et
al., a cementitious slurry produced by combining an aqueous
drilling fluid with a slurry of Portland cement in oil. Generally
the drilling fluid is an aqueous drilling fluid containing clay
such as prehydrated bentonite. The resulting composition has a
particular utility in primary cementing operations for oil
wells.
[0014] U.S. Pat. No. 5,829,523, issued Nov. 3, 1998 to Sabins et
al., discloses primary well cementing methods and apparatus. The
methods basically comprise the steps of releasing a displacement
plug into the casing to be cemented and pumping a first
displacement fluid behind the displacement plug while measuring the
quantity of the first displacement fluid required to land the
displacement plug on a float collar or the like connected near the
bottom of the casing, releasing a bottom cementing plug into the
casing and pumping a cement slurry behind the bottom cementing plug
in a predetermined quantity and then releasing a top cementing plug
into the casing and pumping a second displacement fluid behind the
top cementing plug in a quantity substantially equal to the
measured quantity of the first displacement fluid thereby ensuring
that the cement slurry is not under or over displaced in the
annulus between the casing and the well bore.
[0015] U.S. Pat. No. 6,065,539, issued May 23, 2000 to Noik et al.,
discloses a method of cementing a casing in a well drilled in the
ground comprises injecting a liquid material comprising
phenol-formol resin from the surface, wherein the resin is modified
by means of a determined amount of furfuryl alcohol, and an amount
of mineral filler unreactive towards the resin is added. The
invention further relates to a thermosetting cementing material
comprising phenol-formol resin. The resin is modified by means of
an amount of furfuryl alcohol and comprises at least a proportion
of an unreactive granular filler.
[0016] U.S. Pat. No. 6,626,991, issued Sep. 30, 2003 to Drochon et
al., discloses a cement slurry for cementing an oil well or the
like, the slurry having a density lying in the range 0.9 g/cm.sup.3
to 1.3 g/cm.sup.3, and being constituted by a solid fraction and a
liquid fraction, having porosity (volume ratio of liquid fraction
over solid fraction) lying in the range 38% to 50%. The solid
fraction is constitued by a mixture of lightweight particles,
microcement and optionally portland cement and gypsum. Such cements
have remarkable mechanical properties due to their very low
porosity in spite of having very low density.
[0017] U.S. Pat. No. 6,776,237, issued Aug. 17, 2004 to Dao et al.,
discloses lightweight cement compositions and methods of cementing
a subterranean zone penetrated by a well bore utilizing the
compositions are provided. A lightweight cement composition of the
invention is basically comprised of a coarse particulate hydraulic
cement, an ultrafine particulate hydraulic cement mixture comprised
of slag cement and a Portland or equivalent cement, fly ash, fumed
silica, hollow glass spheres and water.
[0018] U.S. Pat. No. 6,793,730, issued Sep. 21, 2004 to Reddy et
al., discloses methods for cementing. The methods are basically
comprised of the steps of preparing a cement composition comprised
of hydraulic cement, water, gas, surfactants, a cement early
strength accelerator and a mildly set retarding cement dispersing
agent, placing the cement composition in the annulus between the
casing string and the well bore and allowing the cement composition
to set into a hard impermeable mass. The cement composition used
can alternatively comprise hydraulic cement, a water reducing
additive, a dispersing additive, a set accelerating additive and
water. Also, the cement composition can be made environmentally
benign by using water reducing and dispersing additives, set
retarding additives, and compressive strength and set accelerating
additives which are environmentally degradable.
[0019] U.S. Pat. No. 6,892,814, issued May 17, 2005, to Heathman et
al., discloses cement comprising barite, a process for preparing
such cement, and methods of cementing in a subterranean formation
or well bore using such cement are provided. The cement is prepared
by introducing coarse barite to the cement, the course barite
comprising particles having a particle size primarily greater than
about 125 microns. Preferably, 90 percent of the barite particles
is greater than about 125 microns in size. The presence of the
coarse barite in the cement causes the cement to have a relatively
low viscosity. Introducing the barite to the cement also increases
the density of the cement, thus rendering the cement capable of
controlling high hydrostatic pressures in a well bore.
[0020] In spite of the advances in the prior art, conventional
cement systems suffer from a 6 hour safety margin to dump the
slurry; long set times; low shear bond values; long cement lengths,
and long wait on cement (WOC) times causing high expense.
[0021] Thus, there still exists a need in the art for improved
methods, apparatus and products for cementing wells.
[0022] There also exists a need in the art for improved methods,
apparatus and products for primary cementing operations of
wells.
SUMMARY OF THE INVENTION
[0023] According to one embodiment of the present invention, there
is provided an well comprising a well bore and a pipe residing in
said well bore forming an annulus between the pipe and well bore; a
first component residing in the annulus; and, a second component
having a density greater than the density of the first component,
and positioned in the annulus at a point above the first component
that will allow for gravity flow of the second component down into
the first component. The first component and the second component
are selected from the group consisting of the cement component and
the cement activator component, wherein the first component and the
second component are different, and the density of the second
component is higher than the density of the first component.
[0024] According to even another embodiment of the present
invention, there is provided a method of conducting primary
cementing operations on a well, said well comprising a well bore
and a pipe residing in said well bore forming an annulus between
the pipe and well bore. The method includes providing a cement
component and a cement activator component, each having a density
greater than the density of any well fluid residing in the well.
The method also includes selecting a first component and a second
component from the group consisting of the cement component and the
cement activator component, wherein the first component and the
second component are different, and the density of the second
component is higher than the density of the first component. The
method even further includes placing the first component in the
annulus. The method still further includes placing the second
component in the annulus at a point above the first component that
will allow for gravity flow of the second component down into
contact with the first component.
[0025] According to still another embodiment of the present
invention, there is provided a method of primary cementing a well
comprising a well bore and a pipe residing in said well bore
forming an annulus between the pipe and well bore. The method
includes providing a cement component and a cement activator
component, each having a density greater than the density of any
well fluid residing in the well. The method also includes selecting
a first component and a second component from the group consisting
of the cement component and the cement activator component, wherein
the first component and the second component are different, and the
density of the second component is higher than the density of the
first component. The method even further includes placing the first
component in the annulus. The method still further includes placing
the second component in the annulus at a point above the first
component that will allow for gravity flow of the second component
down into contact with the first component. The method yet further
includes allowing the first and second components to gravity
contact and form a hard impermeable mass in the annulus.
DETAILED DESCRIPTION OF THE INVENTION
[0026] In the practice of present invention, the cementing
composition of the present invention may be utilized in any known
cementing method including any of the primary cementing methods
disclosed in any of the references cited herein, all of which are
herein incorporated by reference. Any known method for placing
and/or positioning components of a cementing composition into an
annulus may be used herein, all of which are herein incorporated by
reference.
[0027] As used herein, a well generally refers to an underground,
substantially vertically-extending well comprising a well bore.
Generally, after a well bore is drilled during which the drilling
fluid used is circulated through the well bore, the circulation of
the drilling fluid is stopped, the well is usually logged and a
string of pipe often called a casing, is run in the well bore.
Generally the casing extends from the ground surface into the well
bore and terminates at a predetermined depth in the well bore. The
outer wall of the casing is generally spaced from the inner wall of
the well bore to form an annulus. After the casing is set, the
drilling fluid in the well bore is conditioned by circulating
drilling fluid downwardly through the interior of the pipe and
upwardly through the annulus between the exterior of the pipe and
the walls of the well bore while removing drilling solids and gas
therefrom. After conditioning, both the pipe and annulus are
substantially filled with drilling fluid.
[0028] The next operation performed on the well is generally the
step of primary cementing. By the process of primary cementing a
hard impermeable barrier mass is formed in the annulus. This mass
may also be referred to as a sheath or cement sheath. Primary
cementing is carried out for a number of reasons including to
prevent migration of fluids in the annulus, to support the casing
or liner string, and to protect of the casing from corrosive
formation fluids. Any of the number of methods known in the art for
placing a cementing composition into an annulus may be used for the
primary cementing compositions and methods of the present
invention.
[0029] In general primary cementing is carried out as follows.
Generally in primary cementing processes the components of a
cementing composition are introduced from a source at the ground
surface into the upper end of the casing and flow downwardly
through the bottom end of the casing. The components of the
cementing composition then flow to the bottom of the well bore
where their flow direction is reversed causing them to flow up the
annulus, thereby placing the components of the cementing
composition in the annulus between the pipe and the walls of the
well bore. In the primary cementing processes of the present
invention, the components of the cementing composition may be
placed into the annulus by any of the number of methods known in
the art. The flow and addition of the components of the cementing
composition is then terminated and the cementing composition is
allowed to set into a hard impermeable mass.
[0030] The method of the present invention for primary cementing a
well involves the use of a two part cementing composition, which is
incorporated into known cementing methods.
[0031] In particular, the preferred two part cementing composition
of the present invention comprises a slurry system comprising a
sealant component and an activator component.
[0032] The cementing composition system utilized in the present
invention may be any material suitable for forming a hard
impermeable mass in the well annulus. Preferably, the sealant is a
cement in the convention sense, that is, a silica based cement
material of which Portland Cement is the best known example. Very
well known in the prior art, Portland cement is manufactured by
crushing, milling, and blending selected raw materials containing
appropriate proportions of lime, iron, silica, and alumina, with
certain Portland cements tailored specifically for plugging
abandoned wells. Other hydraulic cements may be substituted for
Portland cement. Activators for cements are well known, and any
that are suitable for the particular well conditions and operation
parameters may be utilized.
[0033] In the present invention, the slurry system comprises not
only cement and activator, but may optionally include additives to
improve thermal stability, control set time, generate expansion,
and control fluid loss. The additives may be present as independent
components, or may be incorporated into the cement component or the
activator component.
[0034] As utilized in the present invention, the activator serves
to activate/accelerate the set up or curing time for the cement and
thus reduce the wait on cement (WOC) time. The activator causes the
sealant to set under downhole temperature and pressure conditions
at an accelerated rate. Of course, this activator will have to be
carefully selected depending upon the material utilized as the
first component.
[0035] In the present invention, accelerated set times are
generally less than 12 hours, preferably less than 10 hours, more
preferably less than 8 hours, even more preferably less than 6
hours, still more preferably less than 4 hours, and yet more
preferably less than 2 hours.
[0036] The activator will cause the sealant to set under downhole
conditions to cause the sealant to bond to the casing and or other
formation surfaces in the well. The pipe may have coating of oil or
water based drilling mud.
[0037] The activator component may be selected to not only
accelerate cement set, but may optionally be selected to also alter
slurry density, clean downhole surfaces, and/or improve bond.
[0038] Non-limiting examples of cement activators suitable for use
as the second component include various amines, non-limiting
examples of which include triethanol amies and diethanol amines,
various metal salts, non-limiting exaples of which include sodium,
calcium, magnesium, zine, and iron salts, various metal halides,
including but not limited to metal chlorides and metal bromides,
various formates, as well as combinations of the foregoing.
[0039] For example, alkanolamines have been proposed for reducing
the set time of cements, see U.S. Pat. Nos. 2,437,842; 3,553,077;
4,257,814, 4,741,782, and most recently U.S. Pat. No. 6,869,474,
all herein incorporated by reference. As another example,
bromide-based accelerators. In the practice of the present
invention, where the first component is a cement, the second
component preferably comprises an alkanolamine, more preferably
comprises at least one selected from triethanolamine,
diethanolamine, monoethanolamine and mixtures thereof, and even
more preferably comprises triethanolamine.
[0040] The method of the present invention for primary cementing
wells, includes any of the known cementing methods in which is
utilized the two component cementing composition as the cement
material. While a generalized primary cementing method is described
below, it should be understood that any suitable primary cementing
method as is known in the art, including any described above in the
backgound or described in any cited reference (all of which are
herein incorporated by reference), may be utilized with the
cementing composition of the present invention.
[0041] Generally in the practice of the method of the present
invention, one of the components is selected as the first placed
component and placed in the annulus, followed by placement of the
other component as the second placed component in the annulus at a
position above the first component, to allow the second component
to gravity flow into the first component.
[0042] Preferably, in the practice of the present invention, the
activator liquids are heavier than the well fluid and the cement
component is heavier than the activator liquid.
[0043] In general, suitable delivery systems utilize a dump bailer,
coiled tubing and jointed tubing. They require a base to stack up
against such as a packer, petal basket or sand plug. While any
suitable delivery mechanism can be utilized, more specific
non-limiting examples of suitable delivery mechanisms include: dump
bailer run on electric line or slick line; pumping through tubing,
drillpipe, work strings or any tubulars; allowing fall through
fluids via gravity; and pumping into an annulus or pipe without
displacing (i.e., "bull heading").
[0044] It is crucial that the first and second components have
greater densities than the well fluid density. It is also crucial
that the second placed component have a density greater than the
first placed component so that the second placed component may
displace the first component.
[0045] In some instances the selected first and second components
will not have suitable densities, specifically, the densities of
the first and second components may not be greater than that of the
well fluid, or they may not have the suitable density for the order
in which they are desired to be introduced into the well, or the
densities may not have a suitable enough differential to achieve
suitable displacement.
[0046] The present invention provides for the utilization of
weighting agent additives to the first and second components to
change the density of those components. Suitable additives to
change the density include metal salts, preferably calcium
chloride. Other examples of weighting agents include sand, barite,
hemitite, calcium carbonate, FeO, MgO, and manganese ore.
Sufficient amounts of the additive are utilized to achieve the
desired density.
[0047] In the primary cementing method of the present invention
first and second components are provided which have densities
greater than the well fluid, with the component to be placed second
having a greater density than the component to be placed first.
Should the density of the first or second component need
adjustment, a weighting agent as discussed above, will be added as
necessary. The component with the greater density is then
positioned into the annulus, the other component is then placed
above the first placed component so that it may spontaneously
gravity flow into contact with the first placed fluid. The density
difference will allow displacement of the first placed fluid by the
second placed fluid and allow for in-situ mixing.
[0048] It should be appreciated that the rate of displacement and
thus in-situ mixing will increase with increasing density
differential between the first and second components, and decrease
with decreasing density differential between the first and second
components.
[0049] It should also be appreciated that at some point, the
density differential between the first and second components is so
low as to result in too slow of displacement.
[0050] On the other hand, it should further be appreciated that at
some point, the density differential between the first and second
components is so great as to result in too rapid of displacement so
as to avoid much mixing.
[0051] Thus, the density differential should be selected so as to
provide fast enough displacement for the primary cementing
operation, and to facilitate sufficient in-situ mixing, and this
differential can be determined on a case by case basis, for example
by observation in clear container and trial and error.
[0052] Typical densities for the well fluid will be in the range of
about 8.33 ppg up to about 20.0 ppg, with typical densities for the
activator in the range of about 8.33 ppg up to about 21.0 ppg, and
with typical densities for the sealant system in the range of about
8.54 up to about 22.0 ppg.
[0053] It should be understood that other well fluid additives as
are well known in the art may be incorporated into the first and/or
second component, or added before, along with, or after the
introduction of the first and/or second component, non-limiting
examples of which include surfactants, surface bond enhancers
(non-limiting examples include styrene butadiene latex, polyvinal
alcohols, resins, other adhesives), emulsifiers, ph control agents,
fluid loss additives, gas prevention additive, dispersants,
expanding agents, and wetting agents.
[0054] It should also be understood that the activator viscosity
and missablity much be such that the activator will not
substantially mix with the well fluid as it passes thru the well
fluid. Preferably, the activator viscosity and missablity much be
such that the activator will mixes less than 20% with the well
fluid as it falls through it, more preferably less than 10%, and
even more preferably less than 2%.
[0055] It should be further understood that activator and sealant
viscosities and missibility are such that the activator mixes less
than 40% with the sealant as they contact each other, preferably
less then 20%, more preferably less than 10%, and even more
preferably less than 5%.
[0056] Although the present invention has been illustrated by
reference to cement, especially Portland cement, and to an
activator therefore, it should be understood that any cementing
composition having two or more components can be utilized in the
present invention.
[0057] All materials cited herein, including but not limited to any
cited patents, publications, articles, books, journals, brochures,
are herein incorporated by reference.
[0058] While the illustrative embodiments of the invention have
been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the invention. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present invention, including all features which
would be treated as equivalents thereof by those skilled in the art
to which this invention pertains.
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