U.S. patent number RE31,127 [Application Number 06/298,037] was granted by the patent office on 1983-01-18 for oil well cementing process.
This patent grant is currently assigned to Halliburton Company. Invention is credited to Jerry D. Childs, Roosevelt Love.
United States Patent |
RE31,127 |
Childs , et al. |
January 18, 1983 |
Oil well cementing process
Abstract
Oil well cementing compositions and processes are produced using
a high efficiency sulfoalkylated lignin retarder composition and
modifications thereof to produce cement compositions without
gelation problems, having high early strength and with precisely
controllable setting time.
Inventors: |
Childs; Jerry D. (Duncan,
OK), Love; Roosevelt (Duncan, OK) |
Assignee: |
Halliburton Company (Duncan,
OK)
|
Family
ID: |
26970436 |
Appl.
No.: |
06/298,037 |
Filed: |
August 31, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
654497 |
Feb 2, 1976 |
04047567 |
Sep 13, 1977 |
|
|
Current U.S.
Class: |
166/293; 106/696;
106/717; 106/719; 106/815 |
Current CPC
Class: |
C09K
8/46 (20130101); C04B 24/18 (20130101) |
Current International
Class: |
C04B
24/18 (20060101); C04B 24/00 (20060101); C09K
8/42 (20060101); C09K 8/46 (20060101); C04B
007/02 (); C04B 007/35 (); E21B 033/14 () |
Field of
Search: |
;166/293,292 ;106/90,315
;260/124R,124B |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Goheen et al., "Lignite", Kirk-Othmer Encyclopedia of Chemical
Technology, 2d. Ed., vol. 12, Interscience Publishers, Div. of John
Wiley & Sons, Inc., New York, N.Y., 1967, pp. 361-381. .
Schubert, "Light Stability of Polymers-Lignin", Encyclopedia of
Polymer Science and Technology, vol. 8, Interscience Publishers, a
Div. of John Wiley & Sons, Inc., New York, N.Y., 1968, pp.
233-272..
|
Primary Examiner: Novosad; Stephen J.
Attorney, Agent or Firm: deBrucky; G. Keith Weaver; Thomas
R.
Claims
We claim: .[.
1. A process for sealing at an elevated temperature a zone
penetrated by a wellbore using a high efficiency non-gelling
hydraulic cement retarder composition having a high degree of
predictability for controlling rheology and setting time comprising
mixing an aqueous slurry of hydraulic cement with up to about 2% on
a dry cement weight basis of a retarder consisting essentially of a
low molecular weight sulfoalkylated lignin; wherein the
concentration of retarder is calculated to control the setting time
of said hydraulic cement to exceed the pumping time; wherein the
sulfoalkylated lignin has a molecular weight in the range of about
2,000-10,000 and which is substantially sulfoalkylated on the
benzene ring of the lignin molecule in the position ortho to the
free phenolic hydroxy group and the sulfonate group is attached to
the ortho position by an alkylidene radical having one to three
carbon atoms; pumping said hydraulic cement mixture into said zone
and maintaining said hydraulic cement mixture in said zone until a
high compressive strength is attained..].
2. A process for sealing at an elevated temperature a zone
penetrated by a wellbore using a high efficiency non-gelling
hydraulic cement composition having a high degree of predictability
for controlling rheology and setting time comprising mixing an
aqueous slurry of hydraulic cement with up to about 2% on a dry
cement weight basis of a retarder consisting essentially of at
least one water soluble hydroxy carboxylic acid and a low molecular
weight sulfoalkylated lignin; wherein the concentration of retarder
is calculated to control the setting time of said hydraulic cement
to exceed the pumping time; wherein the weight ratio of acid to
lignin is in the range of about 1:0.1-5.0; wherein said carboxylic
acid is a substantially linear aliphatic acid having at least one
terminal carboxyl group in the form of acid, salt of mixtures
thereof; wherein said sulfoalkylated lignin has a molcular weight
in the range of about 2,000-10,000 and which is substantially
sulfoalkylated on the benzene ring in the lignin molecule in the
position ortho to the free phenolic hydroxy group and the sulfonate
group is attached to the ortho position by an alkylidene radical
having one to three carbon atoms; pumping said hydraulic cement
mixture into said zone without gelation and maintaining said
hydraulic cement mixture in said zone until a high compressive
strength is attained.
3. In a process for cementing a zone at an elevated temperature by
pumping an aqueous hydraulic cement slurry into said zone, the
improvement of controlling the setting time of said cement and
preventing gelation of said cement by mixing with said hydraulic
cement a high efficiency non-gelling retarder consisting
essentially of a mixture of at least one water soluble hydroxy
carboxylic acid and a low molecular weight sulfoalkylated lignin;
wherein the concentration of retarder is calculated to control the
setting time of said hydraulic cement to exceed the pumping time;
wherein the weight ratio of said acid to lignin is in the range of
about 1:0.1-5.0; wherein the carboxylic acid is a substantially
linear aliphatic acid having at least one termial carboxyl group in
the form of acid, salt or mixtures thereof; wherein said
sulfoalkylated lignin has a molecular weight in the range of about
2,000-10,000 and which is substantially sulfoalkylated on the
benzene ring in the lignin molecule in the position ortho to the
free phenolic hydroxy group and the sulfonate group is attached to
the ortho position by an alkylidene radical having one to three
carbon atoms.
Description
This invention relates to cement compositions and more particularly
to the use of hydraulic cement compositions for sealing or
cementing subterranean zones or subterranean zones penetrated by a
well such as cementing the annular space in an oil well between the
surrounding formation and casing. In particular the invention
relates to an improved hydraulic cement composition for cementing
zones at elevated temperatures in which the setting time of the
cement composition is controlled or extended by the addition of a
highly efficient non-gelling retarding agent which produces a
hydraulic cement composition having a degree of predictability for
the setting time.
Typically, the subterranean zones are cemented or sealed by pumping
an aqueous hydraulic cement slurry into the zone. In cementing the
annular space of an oil well, the cement slurry is pumped down the
inside of the casing and back up the outside of the casing through
the annular space. Any cement slurry remaining in the casing is
displaced and segregated using plugs and an aqueous displacement
fluid. Frequently the high temperatures encountered in subterranean
zones will cause premature setting of the hydraulic cement. This
requires additives which extend or retard the setting time of the
cement slurry so that there is adequate pumping time in which to
place and displace the aqueous cement slurry in the desired zones.
Previously known retarding agents are frequently unpredictable,
typically produce erratic results with different brands of cement
and frequently cause premature gelation of the cement slurry.
Gelation refers to an abnormal increase of viscosity of the aqueous
cement slurry to a value without a significant increase in the
compressive strength of the cement composition. This increase in
aqueous cement slurry viscosity makes the slurry difficult or
impossible to pump at a viscosity of 70 poise or above which is
defined as the set point herein. The cement composition has not
attained an adequate compressive strength.
Prior art cement compositions and additives are described in the
following list of 14 patents:
U.S. Pat. No. 2,549,507 to Morgan et al
U.S. Pat. No. 2,579,453 to Post et al
U.S. Pat. No. 2,674,321 to Cutforth
U.S. Pat. No. 2,676,170 to Patterson et al
U.S. Pat. No. 2,680,113 to Adler et al
U.S. Pat. No. 2,775,580 to Scarth
U.S. Pat. No. 2,872,278 to Putnam et al
U.S. Pat. No. 3,034,982 to Monroe
U.S. Pat. No. 3,053,673 to Walker
U.S. Pat. No. 3,135,727 to Monroe
U.S. Pat. No. 3,344,063 to Stratton
U.S. Pat. No. 3,748,159 to George
U.S. Pat. No. 3,766,229 to Turner
U.S. Pat. No. 3,821,985 to George.
Fundamentals of oil well cementing are described in the book
PETROLEUM ENGINEERING DRILLING AND WELL COMPLETIONS, by Carl
Gatlin, Prentice Hall, 1960. Background of and information on
hydraulic cement compositions and additives can be found in the
following books:
LIGNIN STRUCTURE AND REACTIONS, ADVANCES IN CHEMISTRY SERIES, 1959,
American Chemical Society, 1966;
MECHANICAL BEHAVIOR OF HIGH POLYMERS, by Turner Alfrey,
Interscience Publishers, 1948; and
HACKH'S CHEMICAL DICTIONARY, 4th Ed., McGraw-Hill, 1969.
The above references and information cited therein are incorporated
herein by reference to the extent necessary.
The hydraulic cement compositions of this invention solve or
eliminate many of the problems pointed out above. The hydraulic
cement compositions of this invention do not have the gelation
problem; the retarder composition is more efficient than prior art
retarder compositions, the retarder has less variation with
different brands of cement; cement compositions have much better
predictability or reproducibility of setting times with a given
brand of cement; and hydraulic cement compositions have better
rheology characteristics. Thus the improved cement compositions of
this invention have practically eliminated the problems of
unpredictability and irreproducibility of results which are
particularly severe in high pressure deep wells where the
temperatures may exceed 300.degree. F. and 15,000 PSI.
The concentration of retarder composition of this invention
required to produce the desired pumping time for or delay in
setting of a cement slurry at a given circulating temperature is
not as critical as with conventional lignosulfonate retarders. The
thickening time at a given retarder concentration is less
temperature dependent than with conventional retarders. This
reduces the possibility of over retarded slurries at cooler
temperatures encountered at the top of long liners or tie back
strings. The retarder compositions of this invention provide the
desired pumping times and allow earlier strength development. When
cementing long strings this can reduce the WOC (waiting on cement
to set) time by 8-12 hours. Thus, the retarder compositions of this
invention are more predictable in performance than conventional
lignosulfonate retarders especially with various brands of cement.
The compositions of this invention act not only as retarders but
also as a dispersing agent which can reduce fluid loss from gel
type or high clay cement slurries. When the retarder composition of
this invention is blended in a cement slurry, viscosity of the
slurry decreases slightly and remains constant or does not increase
significantly until the cement begins to set. This improvement in
rheology or viscosity characteristics with improved predictability
makes use of the compositions much easier than with conventional
retarders. In addition, the retarder compositions of this invention
are generally non-toxic, non-flammable, non-hazardous; compatible
with cements, other additives and with most other well fluids and
mix readily in aqueous systems with minimum agitation.
The high efficiency, non-gelling cement retarder composition of
this invention has a high degree of predictability for controlling
rheology and setting time of hydraulic cement comprising a low
molecular weight sulfoalkylated lignin which is substantially
sulfoalkylated in the lignin molecule at positions on the benzene
ring which are ortho to the phenolic hydroxyl group. In the
sulfoalkyl group the sulfonic acid group (--SO.sub.3 H) is
connected to the ortho position on the benzene ring by a methylene
or substituted methylene groups. This methylene or substituted
methylene group is referred to herein as an alkylidene radical
having one to five carbon atoms. This alkylidene radical with
sulfonic acid radical can be represented by the formula
(--R--SO.sub.3 H) wherein R is the methylene group or alkyl portion
having one to five carbon atoms and preferably one to three carbon
atoms.
The unexpected properties of this retarder are thought to be due to
the differences in average molecular weight or average molecular
size and molecular structure. The evidence showing these
differences is illustrated in the examples which show the
unexpected properties. The sulfoalkylated lignin of this invention
is a low molecular weight material having an average molecular
weight or molecular size in the range of about 2,000-10,000 and
preferably about 3,000-5,000. It is also thought to have a narrow
molecular weight distribution. Prior art lignosulfonate compounds
have a molecular weight or molecular size of about 10,000 and
higher and the sulfonate substituent or radical attached directly
on the carbon atom of the lignin molecule which is in the alpha
position of the phenyl propyl side chain. This phenyl propyl or
aliphatic chain is attached at a position on the benzene ring which
is para to the phenolic hydroxyl group discussed herein. For
lignosulfonate the phenolic hydroxyl group can be replaced by an
alkoxy group as indicated by R.sub.1 --Ph--OR.sub.2 wherein R.sub.1
is the phenyl propyl side chain, Ph is phenyl or the benzene ring
and R.sub.2 is hydrogen or alkyl. The sulfoalkylated retarder
composition of this invention has substantially all of the
sulfoalkyl group (i.e., --R--SO.sub.3 H) in the position ortho to
the phenolic hydroxyl group of the benzene ring of the lignin
molecule.
The sulfoalkylated lignin retarder of this invention does not have
a significant degree of sulfonation at the alpha carbon atom as do
the prior art lignosulfonates. Thus, the sulfoalkylated lignin
retarder of this invention is an entirely different chemical
composition as shown by the unexpected and significantly different
properties shown herein. The sulfoalkylated lignin retarder of this
invention can be considered to be a sulfoalkylated lignin of high
purity, low molecular weight with a narrow molecular weight
distribution. This is thought to be due to the significantly
different procedure used for its preparation.
The sulfoalkylated lignin retarder for compositions of this
invention can be prepared by catalytic oxidation of the sulfite
liquor from a wood pulping process. This oxidation removes
polysaccharides and wood sugars and substantially desulfonates the
lignin molecule which is recovered as a residue. This purified
lignin is separated from the liquid. The high purity, low molecular
weight lignin molecule is then substantially sulfoalkylated by the
addition of sulfonating agent such as sodium sulfite in the
presence of an aldehyde or ketone having one to five carbon atoms
at about 150.degree.-190.degree. C. and 180-220 atmospheres. In
this process, the aldehyde or ketone furnishes the alkylidene group
which attaches at a vacant ortho position on the benzene ring in
the lignin molecule and connects the sulfonate group through a
methylene radical to the benzene ring at a position ortho to the
free phenolic hydroxyl group. Some benzene rings may have more than
one sulfoalkyl group attached and some benzene rings may have no
sulfoalkyl substituents. The sulfur content of the sulfoalkylated
lignin is between about 3-10% and preferably 3-8%.
This sulfonate group can be in the form of the acid, a salt or
combinations thereof. The salt can be in the form of ammonium or
metal salt involving an alkali metal; an alkaline earth metal; or
metals such as iron, copper, zinc, vanadium, titanium, aluminum,
manganese, chromium, cobalt or nickel; or combinations thereof. The
salts which are readily soluble in aqueous systems, such as those
of the alkali metals, sodium and potassium, are preferred although
the salts of alkaline earth metals and other metals can be used
under certain circumstances.
The alkyl portion of the sulfonate substituent is derived from the
aldehyde or ketone used in the sulfoalkylation step. Formaldehyde
is a preferred alkyl source because it simply connects the
sulfonate group to the ortho position by a one-carbon atom
methylene group. Acetone would produce an alkylidene group having a
methyl group on each side of the methylene group; methyl ethyl
ketone would result in a methyl and an ethyl alkyl group attached
to the methylene group; and propionaldehyde would result in an
ethyl group attached to the methylene bridge. Theoretically, any
aldehyde or ketone could be used for forming the alkylidene radical
but the stereo chemistry and solubility must be considered in
selecting the size and configuration of the aldehyde or ketone use
for this component. A preferred sulfoalkylated lignin of this
invention has a molecular weight in the range of about 3,000-4,000,
a one carbon atom alkylidene radical and sulfur content of about
3-8% by weight.
Another preferred hydraulic cement composition of this invention
can be considered to be a modified low molecular weight
sulfoalkylated lignin. This modified retarder composition is a
combination of the high purity substantially sulfoalkylated lignin
described above and at least one water soluble hydroxy carboxylic
acid. These hydroxy carboxylic acids have a synergistic effect of
increasing the effectiveness and operable temperature range of the
basic retarder composition. The preferred carboxylic acids are
substantially alphatic carboxylic acids and preferably polyhydroxy
carboxylic acids having at least one terminal carboxy group which
can be in the form of the acid, a salt or mixtures thereof as
described above for the sulfonate groups.
Particularly preferred polyhydroxy carboxylic acids have a
molecular weight in the range of about 125-250 and have a hydroxyl
group attached to the carbon atom adjacent to the carboxy group as
show by the formula ##STR1## These carboxylic acids include
gluconic acid, tartaric acid and equivalents thereof. These
equivalents include the various stereoisomers of the above acids
particularly the asymmetric or optically active isomers. Thus, the
preferred group of hydroxy carboxylic acids are substantially
linear aliphatic acids having about 4-10 carbon atoms, and
preferably 4-8 carbon atoms. The molecular size and number of
hydroxy and carboxylic groups will affect the water solubility. The
hydroxy carboxylic acid is preferably present with the
sulfoalkylated lignin in a weight ratio of acid to lignin
preferably in the range of about 1:0.1-5.0 and preferably in the
range of about 1:0.2-3.0.
The hydraulic cement compositions of this invention are typically
used in the form of an aqueous slurry of hydraulic cement with a
concentration of retarder mixed in the aqueous slurry to control or
delay the cement setting time so that it exceeds the pumping time
with an adequate safety margin. Sufficient water is added to the
slurry to make the composition pumpable. As used herein the
hydraulic cement is typically a Portland cement which is set by the
water of the slurry in the absence of air which is excluded by
placement of the cement in the zone to be sealed. The low molecular
weight sulfoalkylated lignin retarder of this invention is
preferably present in the aqueous hydraulic cement slurry in a
concentration up to about 2%, and preferably up to 1%, by weight
based on the dry cement. Higher retarder concentrations and other
cement can be used when necessary in unusual circumstances. A
deforming agent is typically added as are fluid loss additives,
friction reducing additives, salts such as sodium chloride and
potassium chloride, weighting additives and other conventional
additives as described in the references cited above. Pozzolana
cement, high alumina cement or high gel (high clay content) cement
can be used for special applications. The low molecular weight
sulfoalkylated retarder composition of this invention has high
reproducibility and predictability when used with most high quality
cements which are typically used in the petroleum industry.
However, certain brands which are not manufactured to standard
specifications, such as those which are not sufficiently calcined
or having varying degrees of free lime remaining in the cement,
will produce substantial variations from the standard high quality
brands. It is not clear whether the free lime causes the problems
or is merely an indication when the problems exist. These
variations can be readily determined by preliminary tests which
make even these substandard cements readily predictable and may
merely require slightly higher retarder concentrations to offset
the chemical composition variations of the cement of excess lime
content.
In a preferred process for using the non-gelling hydraulic cement
composition of this invention having a degree of predictability of
setting time and containing the high efficiency retarder, the
retarder composition is mixed with the hydraulic cement as an
aqueous slurry with the retarder concentration up to about 2% on a
dry cement weight basis. The hydraulic cement mixture is pumped
without gelation into the zone to be sealed or cemented and the
hydraulic cement mixture is maintained in the zone until an
adequate compressive strength is attained. In this process the
retarder concentration preferably up to about 2% on a dry cement
weight basis is calculated to control the setting time of the
hydraulic cement slurry to exceed the pumping time within an
adequate safety margin. Due to the higher efficiency of the
retarder and greater predictability of the hydraulic cementing
compositions of this invention, the portion of the safety margin
previously required for these variations can be substantially
reduced. The safety margin now need primarily allow time only for
unexpected equipment difficulties. This reduction in the safety
margin time or time which the typical oil drilling rig is waiting
for the cement to set can result in a substantial economic
advantage due to the higher efficiency and predictability of the
hydraulic cement compositions of this invention. The modified low
molecular weight sulfoalkylated lignin of this invention or the
combination of the sulfoalkylated lignin with the hydroxy
carboxylic acids improve the efficiency and predictability of the
compositions of this invention even more and therefore are
preferably used. The basic sulfoalkylated lignin retarder
composition of this invention can be used up to a temperature
(i.e., BHCT) slighly in excess of about 210.degree. F. and the
modified retarder composition containing the hydroxy carboxylic
acids can be used up to a temperature of about 400.degree. F.
The molecular weight of the sulfoallkylated portion of the
composition of this invention is determined by diffusion
techniques. These differences between the sulfoalkylated lignin
compositions of this invention and the prior art lignosulfonates
are shown by the examples.
The following examples serve to illustrate various embodiments of
the invention and enable one skilled in the art to practice the
invention. Parts, percentages, proportions and concentrations are
by weight unless indicated otherwise.
Samples of calcium (CaLS) and sodium lignosulfonates (NaLS) and a
preferred sulfomethylated lignin (SML) composition of this
invention were analyzed chemically by spectroscopy using X-ray,
infrared, and ultraviolet radiation techniques. The samples were
prepared and analyzed by standard procedures such as those
described in ABSORPTION SPECTROSCOPY, by Robert P. Bauman, John
Wiley & Sons, Inc., 1962, which is incorporated herein by
reference to the extent necessary. X-ray diffraction merely showed
that both the lignosulfonate and sulfoalkylated lignin were
non-crystalline.
Chemical analysis indicated the following constituents by
weight:
______________________________________ % C % H.sub.2 % Ca % S
______________________________________ CaLS 39.1 4.3 7.6 3.9 NaLS
42.2 4.6 0.3 7.4 SML 45.0 3.8 0.2 6.2
______________________________________
The sulfur content of NaLS and SML was thought to include some
inorganic sulfur (e.g. CaSO.sub.4) entrained from cation exchange
or sulfonation liquor.
For ultraviolet (UV) technique which scanned 190-360 millimicrons
(m.mu.) for both NaLS and SML showed a major peak at about 202-205
millimicrons with shoulder or decreasing peaks at about 230 and
310-320 millimicrons. The samples were in water at a 0.02 gram per
liter concentration and were run in a one cm path length cell.
The infrared (IR) transmittance scan from 2.5-30 microns or 300-400
cm.sup.-1 showed peaks at the following wave lengths (.lambda.) in
cm.sup.-1 :
NaLS*3440; 2940; 2840*; 1590; 1495; 1450; 1415; 1250*; 1200; 1140*;
1035; 930*; 640 and 590.
SML: 3440; 2940; 2840; 1675; 1590; 1495; 1450; 1415; 1355; 1250*;
1200; 1140*; 1070; 1035; 930*; 850; 775; 735; 590 and 525.
The starred values (*) are shoulder peaks or peaks which are not
very distinct. Samples for the IR scan were mulled in NUJOL mineral
oil and run between salt plates.
EXAMPLES
For the following examples each sample was prepared by measuring an
800-gram portion of the designated dry cement into a cylindrical
container of approximately 800 milliliters volume. Dry or powdered
additives are designated as a percentage of the weight of the dry
powdered cement unless indicated otherwise. Dry powdered additives
are measured and blended with cement. A portion of tap water equal
to the weight percentage of the dry cement is slurried with the dry
cement and additives with vigorous mixing. The slurry is stirred
for an additional 30 seconds at a high rate. Liquid additives are
blended into the water. Samples were tested according to standard
procedures as set forth in API Method RP-10B which is incorporated
herein by reference.
For thickening time tests a sample portion is stirred in a
container of about 500 milliliters at a temperature and pressure
schedule determined by API method RP 10B. The container is heated
from ambient temperature under pressure. It contains a direct
reading consistometer which is calibrated with a potentiometer
calibrating device to read directly in units of consistency
(API-RP-10B). The set time of setting point is the time or point at
70 units of consistency or viscosity.
API Method RP-10B provides the following casing schedule for bottom
hole circulating temperature (BHCT) and bottom hole static
temperature (BHST) at the indicated depths:
______________________________________ Depth (ft.) BHCT
(.degree.F.) BHST (.degree.F.)
______________________________________ 8,000 (2440 m)* 125
(51.67.degree. C.)* 200 (93.33.degree. C.)* 10,000 (3050 m) 144
(62.22.degree. C.) 230 (110.00.degree. C.) 12,000 (3660 m) 172
(77.78.degree. C.) 260 (126.67.degree. C.) 14,000 (4270 m) 206
(96.67.degree. C.) 290 (143.33.degree. C.) 15,000 (4575 m) 226
(107.78.degree. C.) 305 (151.66.degree. C.) 16,000 (4880 m) 248
(120.00.degree. C.) 320 (160.00.degree. C.) 18,000 (5490 m) 300
(148.89.degree. C.) 350 (176.67.degree. C.) 20,000 (6100 m) 340
(171.11.degree. C.) 380 (193.33.degree. C.) 22,000 (6710 m) 380
(193.33.degree. C.) 410 (210.00.degree. C.)
______________________________________ *Metric Equivalents
Fluid loss is the number of milliliters or cubic centimeters of
liquid forced through No. 50 Whatman filter paper or through 325
mesh screen according to API publication RP-10B (Section 8).
TABLE I ______________________________________ Predictable Behavior
Thickening Times Hours:Minutes SML* API Casing Simulation Tests %
Retarder 8,000' 10,000' 12,000' 14,000'
______________________________________ Lone Star Class H Cement 38%
H.sub.2 O 0.20 2:35 2:04 1:33 -- 0.25 4:20 2:37 -- -- 0.30 5:50
3:11 2:31 1:58 0.35 -- 5:20 -- -- 0.40 -- -- 4:12 3:01 0.50 -- --
7:18 3:47 0.60 -- -- -- 4:09 0.70 -- -- -- 5:12 Lone Star Class H
Cement 46% H.sub.2 O 0.16 2:43 -- -- -- 0.20 -- 2:25 2:15 1:55 0.24
3:51 -- -- -- 0.30 6:40 3:28 3:01 2:32 0.34 -- -- 3:58 -- 0.35 --
6:13 -- -- 0.38 -- -- 4:17 -- 0.40 -- 11.22 -- 3:32 0.44 -- -- 5:37
-- 0.60 -- -- -- 6:10 ______________________________________
*Sulfomethylated lignin retarder.
Increasing the retarder concentration results in corresponding
increase in thickening time until a saturation point is reached.
Beyond this point, slight increases in the retarder concentration
result in greatly increased thickening times.
TABLE II ______________________________________ Set Times Obtained
with Commercially Available Calcium Lignosulfonate and the Sodium
Salt of Sulfomethylated Lignin.sup.a Percent Set Times - Percent
Sodium Hours:Minutes Retarder Chloride API Casing (by wt. (by wt.
Simulation Tests 206.degree. F.Cement) water) 14,000'
______________________________________ Sulfomethylated Lignin 0.3 0
1:58 0.4 0 3:01 0.5 0 3:47 0.6 0 4:09 0.7 0 5:12 Calcium
Lignosulfonate 0.3 0 3:25 0.4 0 4:05 0.5 0 1:34.sup.b 0.6 0
1:35.sup.b Sulfomethylated Lignin 0.3 18.0 1:44 0.4 18.0 2:27 0.5
18.0 2:45 0.6 18.0 3:42 0.7 18.0 4:33 0.8 18.0 5:12 Calcium
Lignosulfonate 0.2 18.0 1:32.sup.b 0.3 18.0 1:40.sup.b 0.4 18.0
1:48.sup.b 0.5 18.0 2:05.sup.b 0.6 18.0 2:40.sup.b
______________________________________ .sup.a All slurries
consisted of 800 grams Lone Star Class H Cement with 304 grams
(38%) water, and indicated amounts of additive and sodium chloride.
.sup.b Slurry gelation was observed, i.e., viscosity reached 70
units of consistency but slurry had not developed significant
compressive strength at that time. Others reached a viscosity of 70
units and set with compressive strength at approximately the same
time.
AT higher temperatures slurries containing the conventional
retarder tend to form unpumpable heavy gels prior to development of
significant compressive strength, however, use of the
sulfomethylated compound yielded slurries which were well dispersed
until final hard set of the cement was obtained. This is
illustrated in Table II which lists the set time and percent added
retarder for both fresh and salt water slurries containing either
the commercially available calcium salt of lignosulfonate or the
sodium salt of the new sulfomethylated compound. As noted in the
table, many of the slurries containing the calcium salt tended to
form heavy gels (i.e., slurry is unpumpable and thus, considered
set when the viscosity reaches 70 units of consistency even though
it may have gelled with no compressive strength at that time); this
results in an erratic dependence of set time on retarder
cocentration. For example, in the fresh water slurries, increases
in retarder concentration in excess of approximately 0.4% (Table
II) result in decreased rather than the expected increased set
times; this effect is not found for the new compound which shows a
reasonable set time increase as the retarder concentration is
increased in both fresh and salt water slurries.
Predictable Behavior One Cement to Another
TABLE III ______________________________________ Predictable
Behavior One Cement to Another Effect of Cement Brand on Set
Time.sup.a Percent Additive Set Time - (by wt. Hours:Minutes of API
Casing Type of Cement 206.degree. F.ditive cement) 14,000'
______________________________________ Lone Star Class H
Sulfomethylated (Maryneal).sup.b Lignin 0.5 3:37 Lone Star Class H
Calcium (Maryneal).sup.b Lignosulfate 0.5 1:34.sup.h Lone Star
Class H Sulfomethylated (New Orleans).sup.c Lignin 0.5 2:45 Lone
Star Class H Calcium (New Orleans).sup.c Lignosulfate 0.5
0:40.sup.h Trinity Class H.sup.d Sulfomethylated Lignin 0.5 2:46
Trinity Class H.sup.d Calcium Lignosulfate 0.5 3:02.sup.h
Southwestern Sulfomethylated Class H.sup.e Lignin 0.5 3:19
Southwestern Calcium Class H.sup.e Lignosulfate 0.5 4:05 Oklahoma
Class H.sup.f Sulfomethylated Lignin 0.5 3:00 Oklahoma Class
H.sup.f Calcium Lignosulfate 0.5 3:45.sup.h Dyckerhoff Class
B.sup.g Sulfomethylated Lignin 0.5 2:44 Dyckerhoff Class B.sup.g
Calcium Lignosulfate 0.5 2:45
______________________________________ .sup.a Slurries consisted of
800 grams indicated cement, 304 grams (38%) water (by wt. of
cement), and additive with the exception of the slurries containing
Dyckerhoff Class B which contained 368 grams (46%) water. .sup.b
Cement manufactured by Lone Star Industries, Inc., Maryneal, Texas
.sup.c Cement manufactured by Lone Star Industries, Inc., New
Orleans, Louisiana. .sup.d Cement manufactured by Trinity, Portland
Cement Division, Dallas, Ft. Worth, Houston, Texas. .sup.e Cement
manufactured by Southwestern Portland Cement Company, El Paso,
Texas. .sup.f Cement manufactured by OKC Corporation, Pryor,
Oklahoma. .sup.g Cement manufactured by Dyckerhoff Zementwerke AG,
WiesbadenBiebrich, Germany. .sup.h These slurries gelled prior to
hard set.
At constant concentration of the new retarder, reasonably
consistent set times are obtained for slurries containing cements
produced by different manufacturers (Table III). This contrasts
with the similar results for calcium lignosulfonate which vary
drastically from one cement to another.
TABLE IV ______________________________________ Slurry Gelation
Effect Viscosity versus Pumping Time of the Slurries Containing
Calcium Lignosulfonate or the Sodium Salt of Sulfomethylated Lignin
Pumping Times Hours:Minutes Viscosity Type Percent 14,000' API In
Units of of Cement Additive.sup.d Additive Casing - 206.degree. F.
Consistency.sup.e ______________________________________ Lone Star
SML 0.5 0:00 9 Class H 0:30 6 (Maryneal) 0:45 6 1:00 6 1:15 6 1:30
6 2:00 12 2:15 21 3:00 26 3:15 29 3:30 31 3:47.sup.b 70 NaLS 0.5
0:00 1 0:30 4 0:45 13 1:00 37 1:15 41 1:30 45 1:34.sup.c 70
______________________________________ .sup.a Slurries consisted of
cement, 38% water and additive. .sup.b Slurry reached a viscosity
of 70 units and set with compressive strength at approximately the
same time. .sup.c Slurry reached a viscosity of 70 units but had no
compressive strength until approximately two hours later. .sup.d
SML is sulfomethylated lignin and NaLS is sodium lignosulfonate.
.sup.e Consistency measured directly in units of consistency
according to API publication RP10B.
TABLE V ______________________________________ Lower Temperatures
Set Times Obtained with Calcium Lignosulfonate and the Sodium Salt
of Sulfomethylated Lignin Percent Retarder Set Times -
Hours:Minutes (by wt. API Casing Simulation Tests Retarder Cement)
10,000' 12,000' ______________________________________
Sulfomethylated Lignin.sup.a 0.3 -- 2:30 0.4 -- 3:57 0.5 -- 8:00
Calcium Lignosulfonate.sup.a 0.3 -- 3:10 0.4 -- 2:21 0.6 -- 1:40
Sulfomethylated Lignin.sup.b 0.08 2:58 -- 0.12 3:29 -- 0.16 4:00 --
0.20 4:50 -- 0.24 6:33 -- Calcium Lignosulfonate.sup.b 0.40
1:44.sup.c -- 0.80 3:20.sup.c --
______________________________________ .sup.a Slurries consisted of
Dyckerhoff Class G, 44% water and indicated additive. .sup.b Slurry
consisted of Longhorn Class H Cement with 44% water, 35% coarse
silica flour (60-140 mesh), 0.75% CFR2 friction reducer and 18%
sodium chloride salt. CFR2 is betanaphthalene sulfonic acid
condensed wit formaldehyde and mixed with 10% polyvinyl
pyrrolidone. CFR2 is described in U.S. Pat. No. 3,359,225 which is
incorporated herein by reference. .sup.c Slurries showed severe
gelation effects.
TABLE VI ______________________________________ Compressive
Strength Class H Cement with 38% Water Retarder Concentration
Giving 4.0 Hr. Pumping Time on 12,000 ft. Schedule Slurries Pumped
2 hrs. on 12,000 ft. Schedule and placed in Autoclaves at Indicated
Temperature Compressive Strength Compressive Strength Using
Conventional Using SML Lignosulfonate Retarder Cement Retarder
(PSI) Temperature (PSI) 8 hrs. 12 hrs. 24 hrs. .degree.F. 8 hrs. 12
hrs 24 hrs ______________________________________ NS* 290 2260 170
650 1690 2790 NS 2080 2660 200 1010 2020 3980 NS 2270 2840 230 1670
2800 4260 1360 3480 3310 260 2040 3660 5420
______________________________________ *Not Set
Compressive strength tests were run on slurries containing calcium
lignosulfonate or sulfomethylated lignin. The cement employed in
these tests was Lone Star Class H. In these tests, slurries
containing retarder to give four hour pumping times on a 12,000'
casing schedule were used. The slurries were pumped two hours at a
12,000' casing schedule and placed in autoclaves at four different
temperatures to simulate the actual conditions encountered from the
top to the bottom of a cement column in a well. The compressive
strengths were then determined after 8, 12 and 24 hours according
to API publication RP-10B (Section 6). After 8 hours, the slurries
containing lignosulfonate had not set at the lower tempertures.
However, the slurries containing sulfomethylated lignin were all
set with significant strengths. The sulfomethylated lignin slurries
consistently showed more rapid strength development throughout
these tests.
TABLE VII
__________________________________________________________________________
Compatibility With Fluid Loss Additives Compatibility of New
Sulfomethylated Lignin and Common Fluid Loss Additives.sup.a
Consistometer Percent Fluid Loss Additive Sodium Readings Retarder
1.sup.b 2.sup.c Chloride Fluid at 100.degree. F. (Poise) By Wt. %
By Wt. % By Wt. % By Wt. Loss Initial Final Retarder Cement Cement
Cement Water (cc)
__________________________________________________________________________
Sulfomethylated 9 8 Lignin 0.5 0.6 0- -- 44 Calcium 9 10
Lignosulfonate 0.5 0.6 0- 0- 141 Sulfomethylated 10 10 Lignin 0.5
0.6 0- 18.0 98 Calcium 10 10 Lignosulfonate 0.5 0.6 0- 18.0 188
Sulfomethylated 12 12 Lignin 0.5 0- 0.6 0- 38 Calcium 10 10
Lignosulfonate 0.5 0- 0.6 0- 137 Sulfomethylated 12 12 Lignin 0.5
0- 0.6 18.0 82 Calcium 11 11 Lignosulfonate 0.5 0- 0.6 18.0 154
__________________________________________________________________________
.sup. a All slurries contained Lone Star Class H Cement, 28% water,
and indicated amounts of retarder, Halliburton fluid loss additive,
and sodiu chloride. After mixing, the slurries were stirred on the
Halliburton Consistometer for 20 minutes at 100.degree. F. and
fluid loss determination conducted at 100 PSI pressure on a 325
mesh screen at the same temperature. .sup.b 56% HEC (hydroxyethyl
cellulose) with 44% CFR2. .sup.c 60% HEC, 20% defoamer with 20%
CFR2.
TABLE VIII
__________________________________________________________________________
Dispersant and Fluid Loss Properties in Gel Cement Slurries Class H
Cement 12% Gel 11.46 gal. water/sack Fluid Loss cc/30 Min. 100 PSI
% Addition Fann Data No. 50 1000 PSI (By wt. Shear Stress
lb/ft.sup.2 at 80.degree. F. Whatman 325 Mesh Retarder Cement) 600
RPM 300 RPM 200 RPM 100 RPM Paper Screen
__________________________________________________________________________
Sulfomethylated Lignin 0- 1.22 1.16 1.12 1.05 190 372 0.34 0.47
0.34 0.31 0.26 132 265 0.52 0.42 0.27 0.21 0.17 104 188 Calcium
Sodium.sup.a Lignosulfonate 0.34 0.58 0.47 0.43 0.37 149 258 0.52
0.69 0.56 0.51 0.46 113 217
__________________________________________________________________________
.sup.a A mixed calciumsodium lignosulfonate is used in gel cement
slurrie instead of simple calcium lignosulfonate due to the
tendency of the latte to gel slurries of this type.
Sulfomethylated lignin functions in gel cement slurries as a
dispersant and fluid loss additive. Previously, two separate
retarders were required; one for non-gel slurries which was calcium
lignosulfonate and another for gel slurries which was calcium
sodium lignosulfonate.
TABLE IX ______________________________________ Extension with
Tartaric Acid Set Times Obtained with a Mixture of the Sodium Salt
of Sulfomethylated Lignin and Tartaric Acid in a 2:1 Weight Ratio*
Set Times % Retarder Hours:Minutes (By Wt. API Casing Simulation
Tests Cement) 16,000' 18,000' 20,000' 22,000'
______________________________________ 0.4 1:55 -- -- -- 0.5 4:20
-- -- -- 0.6 5:57 1:40 -- -- 0.8 -- 2:31 -- -- 0.9 -- 3:43 -- --
1.0 -- 4:34 -- -- 1.1 -- 5:13 -- 2:00 1.2 -- -- 3:43 -- 1.3 -- --
-- 2:28 1.6 -- -- 5:10 -- 1.8 -- -- 6:32 3:12 2.0 -- -- -- 3:25 2.6
-- -- -- 4:10 ______________________________________ *All slurries
consisted of Lone Star Class H Cement, 35% SSA1, 54% water, and
indicated amounts of retarder. SSA1 is fine silica flour which is
added to cement slurries at high temperature to prevent strength
retrogression. Over 97% of the silica particles pass through a
200mesh (U.S. Std. Sieve Series) screen.
TABLE X ______________________________________ Extension of Set
Times of Slurries Containing Sulfomethylated Lignin by the Addition
of Borax Percent Percent Sulfomethylated Borax Set Time -
Hours:Minutes Lignin (By Wt. (By Wt. API Casing Schedule Cement)
Cement) 15,000' 16,000' ______________________________________ 0.7
0.6 3:00 -- 0.8 0.6 4:22 -- 0.9 0.6 5:12 -- 0.4 0.7 -- 1:54 0.6 0.7
-- 3:54 0.8 0.7 -- 5:20 0.95 0.7 -- 7:10
______________________________________
Set times obtained with sulfomethylated lignin can be extended by
the addition of boric acid or water soluble salt of boric acid
(e.g., salts of ammonia, alkali or alkaline earth metals). This
extension makes possible the use of the sulfomethylated lignin
retarder at higher temperatures. Examples of extenders of this type
are:
1. Boric acid,
2. Na.sub.2 B.sub.4 O.sub.7.10H.sub.2 O (Borax),
3. Na.sub.2 B.sub.5 O.sub.8.5H.sub.2 O,
4. KB.sub.5 O.sub.8.4H.sub.2 O,
5. Li.sub.1 B.sub.5 O.sub.8.5H.sub.2 O,
6. NaBO.sub.2.4H.sub.2 O,
similar compounds and mixtures thereof.
* * * * *