low temperatur cementing
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A Study of
Low
T cIl lpe ..atu ..c
Ce:m.enting
By W THORVALDSON
(J3th Annual
T ec hn ic al M ee ti ng , C al ga ry , M ay ,
962
STR CT
Since
1957
Dowel l o f Canada has
been conducting
a survey,
in
th e
field an d in th e laboratory, of tem
per at ur es and cementing
strengths
encountered
drilling
in Western
Canada. In an attempt to
rectify
th e
seemingly
i nadequa te cement
s tr engths , several different correc
tive
measures have
been developed,
tested
an d eva luat ed . This paper is
designed to
q u ~ n t th e
i n d u s ~ r y
with
th e
investigatIOn from
th e
mI
t ia l surveys to th e successful cem
enting of a string of
casing
wholly
in perma frost.
INTRODUCTION
W
ELL temperatures
exert
a pro
found
effect
on th e setting
propert ies o f cement
slurries.
Con
sequently, cements must be
carc·
fully formulated so that
adequate
thickening times are obtained fo r a
proper placement
of
th e s lu rry, yet
WOC times
are not
unduly pro
longed.
In the Canadian oil f ields,
especially during the winter
month s, low
temperatures present
a formidable problem,
especially
in
setting
surface casing,
where
th e
formation temperature i s below th e
freezing
point of water_ Oddly
enough. very few d at a a re available
on formation
temperatures
in
th e
depth range
of surface
casing,
or
th e
effects that
these temperatures
have upon cementing practices.
The range
of surface
tempera-
W
M . T ho rv al ds on , Dowen
of
Canada, Division
of
Dow Chmni-
ca l
of Canada, Ltd., Cal.gary, Al -
berta.
64
tures encountered
is
shown
in Fig-
1O'e
1, which
shows
th e
mean tem
peratures characteristic of this
area. Assuming a liberal
temp
erature
gradient
of 2°F. per 100
feet
an d an
average
surface
pipe
depth of 600 feet, it may be seen
that th e B.H.T. varies
from
approx·
imately 50°F . in t he sou th to
17°F.
in
th e
north.
These
temperatures,
although modified
by
th e penetra
tion o f d ri ll ing fluids, are danger
ously
close
to an d
often
below th e
minimum temperature necessary
fo r
t he s et ti ng
of
commonly
used
cements.
As
a n e xampl e
o f th e fo rmatio n
temperatures usual ly encountered
Fignre
2 shows
t he t empe ra tu re
profiles
of two wells
surveyed under
static conditions.
One
of these
wells was located at
Resolute
Bay,
N.W,T_,
th e
other
in
northern
Alaska. Both
of
these
wells are in
th e continuous Perma-frost zone,
indicating
from
1000 to
5
feet
o f Perma-f rost .
Low
TEMPERATURE
CEMENTING
as to accumulate pert inen t
well data
and
perhaps anticipate
potential low temperature
prob
lems,
an extensive investigation of
well
temperaturcs
during
cementing
operations was conducted, studying
wells
in a ll sec tions
of the country
and at a ll seasons of th e
year.
Sub·
surface temperatures were
measur
ed using a
bottom
hole recording
**Metereological Survey
of
Canada.
thermometer
in
some
SUI VC YS.
a
n<
utilizing Surface
Recording Contin
uous
Surveys on o ther s.
A typical survey, made in Centrn
Alberta, is
shown
in j i ' igl l l ( 3. A
total
of
300 sacJ s
o f n ormal
( em
en t slurry containing 2(,;· C akium
chloride accelerator (slur ry weight
14.5 lbs. per
gallon) wa s
used t
cement 303 feet of 107. i.
inC 1l
dia
meter
surface
casing. SUl faee tpm
perature was 20
F. ;
that of tll
slurry was
32 F.
CirCUlating tem
perature was 40 F. an d tile temp
erature of th e
s lu rry n ·turns wa
36 F. Thi s cha rt shows
the record
ed
temperatures
at three diffet pn
wel l dcp ths, as recorded at inter
mittent
time
intervals.
A
similar
example is
shown
i
FigllTe 4. This
well. loeated
in
Northern
Alberta, require(l -la
sacks of oil well ( cment
containin
2 /
c alc ium chlo ri de
aceelerato
(slurrv wcight, 1 1.7
lbs. pC r gallon
in onjer to cement
620
feet of 10
inch surface casing. ]n tlIis casl
surface tempemture was 20 F
while
that
of
th e
slurry
was
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igure I . -Map of princ ipal
Canadian
oil f ie lds
showing
mean temperature isotherms.
vice of CanadaJ
MetereologicaI Ser-
14.5
lbs.
pe r
gallon)
to
cement
491
feet of 8
diameter surface
casing.
Surface temperature
was
20°F.
that
of th e
slurry when int roduced into
th e well was
38°F.,
an d th e circu-
lating temperature was recorded as
40°F. The t empe ra tu re
changes
occurring at th e 420
it depth, dur
in g the first 12 hours following
slurry placement, ar e s hown. This
particUlar cementing
jo b failed
after
24
hours shut-in
time.
A series of laboratory
tests
was
conducted t o det ermine th e com·
TechnologYr
umm r
r
96 lg ry
pressive
strengths
obtainable
from
oi l well cement
slurries
containing
2 calc ium chlori de accele ra to r,
an d
having
a slurry
weight
of 15.6
lbs. per gallon,
allowed
to
se t
t empe ra tu re s r anging f rom 40° to
70°F.
The compressive strengths
attained over a 30-hour per iod are
shown
graphically
in igure
In Canadian oi l field cementing
operations,
most
c ommon ly u se d
slurries f or sur fa ce casing strings
are 15
lbs. per gallon or
less.
Out
of 160 cementing
jobs
evaluated,
only
24
used
slurries
that
were
heavier than 15.2 lbs. pe r gallon.
As
may
be
seen
in
igure
7 which
shows
Z4 hour
compressive
strengths
fo r dif ferent weight slur ries dif-
ferent temperatures ,
a
reduct ion in
slurry weight
resu lts i n
a corres
pondingly lowered compressive
strength.
I t
will
be
noted
however
that
increased
strength
is
attain·
able fo r lower weight slurries by
increasing their curing
temperature.
For example, 6 hours at 70°F.
produced a compressive strength of
65
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8/20/2019 Low Temperatur Cementing
3/8
404 psi,
whereas the same
slurry
in
6 hours at
50°F.
had only a com
pressive strength
of 38 psi . Thus, a
temperature in cre as e o f only
20°F.
re-sulted
in
10 times a s g re at a
com
press ive s tre ng th . Th es e
tests
in
dicated
that
heating
up th e cement
slurry
should
y ie ld benef ic ia l re
sults. insofar
as producing
higher
compressive
strengths
in
the set
cement.
A
number
of
techniques
have been developed to
accomplish
this purpose , and
have
yielded grato
ifying
results
in
the field. In gen
eral,
these techniques
may
be
class
ified
in
three categories: 1 elec
t r ic heat ing;
2 chemical heating;
an d 3 use of h igh Alumina cern·
ents.
ELECTRIC HEATING
METHOD
Electric heating of cement
slur
ries,
a comparatively recent devel
opment,
is
depicted
schematically
in
Figu ·e
8. After th e casing ha s
been cemented, and th e plug dis·
placed, an
e lect ri ca l connect ion i s
made with th e
cas ing and
5
volts
D.C. is applied. Approximately
1000 amps of current flows from th e
cas ing i nt o th e ground.
The
elec
tric circuit is
completed
through
*Patent applied
for.
one or more back-electrodes, loca
ed at a d is tance f rom
th e
we
The
electrical
power
is su pp lie
from a mobile 450 volt, 105
amp
generator, driven by a 700 h.
Allison motor.
In general, field test s showe
that two
types
of
back-electrode
were
suitable fo r this application
(1 )
an
offset
cased
well,
or
2
number of special ly dri ll ed sli
holes containing 2-inch tubing
(n
coverable)
connected
in
paralle
Resu lt s o f field tests compar ing di
ferent types
of installations
an
shown in
Table 1
Figure 2.--Subsurface
temperature
profiles
of two
typical
wells in th e perrna-frost zone, one located
at
Resolute
Bay, N.W.T., and the other
i n Nor th ern
Alaska.
24
WELL
A
CENTR L L ERT
6 12 18
TIME HOURS
1
I
I
f---L
7
I
Oepth: 5
Fl
I
-
Oeplh: 125
Ft
I
r ·
-
--
I
Oep h ;
5
60
40
60
40
60
u
°
_____ NORTH
ALASKA
~ E S O L j U T E \ l j
BAY N.W.T.
w
::>
«
a
:::E
8 0 0 0 c - - - - - c 1 ~ 0 , - - - - ~ 2 0 - - . . . , 3 ~ 0 , - - - - - - - - ; ' 4 0 ~
TEMPERATURE
OF
200
W
W
u
I
400
a
w
0
600
WELL
C
SOUTHERN L ERT
6 0 ~ ~ = = ~ ~ ~ ~
Figure 3.-Temperatur€ survey of well in Central
Alberta,
dur ing sur fa ce
c as in g cementing opera
tions;
temperatures
recorded at 50 ft., 125 ft., and
250 1t. depths.
w
50
or
J
>-
«
40
w
c..
::t
Veplh: 42
Fl
w
>-
30
0 3
6 9
TIME HOURS
o
6
12
TIME HOURS
4
l
-
Vepih: 55 Fi
I
70
WELL
B
NORTHERN
L ERT
60
Figu re 4.-Temperature
survey of wen
in Northern
Alberta, dur ing sur fa ce ca sin g c ementin g ope ra
tions; temperatures recorded at 550 ft .
depth.
Figure 5.-Temperature sur vey o f
well in
Southern
Alberta, during
surface
casing cementing
operations;
temperatures
recorded at 420 f t. d ep th .
66
ournal
anadian Petroleum
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4/8
TABLE
Low
Temperature Cementing Jobs Using
Electric
Heating
700
1000
1025
1000
0' .54
10 '
120' /60' .43
120' /60' .46
120' .72
1
10
4
2
4
2
2
2
2
2
1
2
Back Electrodes
No. Size Depth
1 5 12 517
1 5 h 4880
1
5 12
3135
197'
700'
700'
215'
700'
215'
8
Surface Cwing
Size Depth
5 12 333
8 400'
7
420'
8
215'
540 I n p ara ll el w it h 4b
satisfactory
440 With Red Deer
River
in
parallel satisfactory
460 Without Red Deer River
in parallel
satisfactory
505
With Red Deer
River in
parallel unsatisfactory
*Sur fa ce ca sing o f nearby abandoned well u sed
as
back
electrode.
This phase of th e cementing operation
was considered
satisfactory,
m spit e of th e h igh overall
resistance.
The
relatively
shallow
wel l d ep th
(215
ft )
made
possible
sufficient
heating
at
th e
reduced current of
850
amps.
5a
10 '''
5e 10,.
5b 10,.
4c 8
Job
No
1
2
3
4a
4b
n
Western
Canada,
500 ps i is
usually
accepted as a satisfactory minimum
s treng th for drilling out and subsequent hole deepening.
TABLE
II .
Est imated Strength of
Cement Set
with
Electric Heating
Slurry
Estimated
Weight
Oa1Jl
Curing
Electric
Maximu:rn
Compress
Job
Lbs.
Additive
Time
Heating
Temp.
at
Strength
No
U.S. Gal.
Percent
Hou rs
Time Hrs.
Bottom·oF.
ps i
1
15.6 0
6 hrs.;
4
hrs.
117
800
30 min.
2
15.6
2 12
hrs.
7hrs.;
80.5
800
30
min.
3 15.0 2
10
hrs.
8hrs.
83.5 900
4
15.0
2 9
hrs.
6hrs.;
113
1000
40 min.
5
15.0
2
13
hrs.
8hrs.
87.5 1000
ent, th us ra lsmg its tempera tu re.
In effect, th e unset
cement
acts as
a
heating element.
t
was found
that
enough
heat was genera ted i n
the
cement
by
this method
to jus
tify
the
power
losses elsewhere.
Temperature surveys were run
on a
well
i n Central Alberta during
a
cementing
jo b uti lizing elect ric
heating.
Th e
results are shown
in
Figu re
9
Altogether,
250
sacks of
15.6 lbs . per
gal lon cemen t s lu rry,
containi ng 2
calc ium chlo ri de
accelerator, were
used in
this
well.
Surface
temperature
wa s
32°F
•
slurry t emperature was 46°F., and
circulating
t emperature was
53°F.
The
back·electrode
was loeate d 1320
feet
from
the
well.
The
four
curves
shown
in
this
figure represent:
(1 ) Well
temperatures
immediat
ely
after placement of th e
cement
slurry;
(2)
Well
temperatures after
one
hour
shut-in time, no
elec
tric power applied;
(3) Temperature
survey
after
4
1/ 3 hour s o f power applica
tion;
and
survey
after
power
applica-
(4)
Temperature
5
hours of
tion.
121
173
219
262
300
Temperature
Rise
_
OF.
TABLE
Heat
Liberated
by
Chemical Reaction
Lbs.
NaOH
Heat evolved
_per
gal.
Hal
B.T.U.
1.02 1016
1.55 1542
2.11 2106
2.71 2695
3.31 3289
10
15
20
25
3
Hydrochloric
Acid·
Percent
When
the circuit is complete, the
power is
dissipated
in a number
of
ways: (1 )
losses
i n sur face cables;
(2) los ses in
casing;
(3) losses in
unset cement;
(4) losses
through
the earth; and (5) losses in th e
back-electrodes. These power losses
are manifested
in the form
of hea t,
and
th e purpose of the t reatment
is
to
produce
heat
in
th e
unset
cern-
The beneficial
heating
effect
of
the
electric
current
on
th e cement
slurry may
be
seen in Table
II
which shows est imated
compressive
strength data on
five
different
wells
that
were cemented using the
elec-
Technology Summer 962 algary
67
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8/20/2019 Low Temperatur Cementing
5/8
17 0
15.0 16,0
SLURRY WEIGHT - LB/GAL.
- - -
--t--I -7 o.---I-- ? : --I
,
.
,
7 ·· ._ .
,0°
.
1000
3000, r - - - - : : - : - - - - - : - - r - - - - , - - -_- - - ,
T MP R TUR
70°F
-
60°
F -
50
0
F-············
40
0
F ·_
2000
--------,- .--+1---. . . .-_,
// /
1000
700
-
~ j
. /
-
......
-7/
j
-
I
400
l-
. • I
I
/
I
Z
u.J
200
i .r 1 j
z
u.J
I-
:
/
l-
i
+ i ~ ~ j
< /
u. J
>
100
u.J
>
70
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6/8
TABLE IV.
IJaboTatory Tests o f H igh A lumina Cement Slu rries
Slurry
ont press
Slurry
Weight
Strength
Volume
S l l trr y Co mp o si t io n
Lb Gal
A v g. p si
a
ft .
High
Alumina
Neat
15.32
6745
1.160
High Alumina -
Ash
1:1
14.26
960
2 525
High
Alumina - Ash -
8
Gel
13.34
538
3.109
High Alumina - Ash - 10
Gel
13.16
460
3.257
High Alumina
- Litepoz 2
12.6
551
2.31
High
Alumina
- Litepoz 2
12.8
727
2.19
High Alumina - Litepoz 2 -
6 Gel· 4 CaCl
13.45
828
2.09
High Alumina - Litepoz 2 -
8
Gel
-
4
CaCI
13.49
885
2.11
High
Alumina· Litepoz
2 - 10
Gel
- 4
CaCI
13.54
856
2.13
HlGH
ALUMINA CEMENT
The
most
successful approach to
the
low
temperature problem has
been
th e
use of h ig h Alumina cem
ents. normal
cement
freezes
shortly after
th e
initial
se t
has
taken place
th e
water which
ha s
not yet entered into combination
with
th e
cement
expands
and dis
rupts the cement. At
th e
same
time
chemical
action
ceases.
Even
though
the
cement
may
thaw ou t
later allOWing the chemical action
to recommence
th e
hardening takes
p lace in
a
disrupted
concrete which
is inevitably
much weaker.
During the
initial
set of
high
Alumina cement considerable heat
is generated increasing
th e
temper
ature
of the slurry.
In the
case of
a reasonably rich
mix
and appre
ciable
bulk
of slurry sufficient heat
is generated to p revent
th e
cement
10 0
0
1382
10
1.5 0
1399
10
3.0
0
1742
10
3.0
4
1286
10
3.0 8
1087
10
3.0
12
632
20 0
0
1764
20
1.5 0
1473
20
3.0 0
1490
30
0
0
2200
30
1.5
0
1815
30
3.0
0
1875
40
0
0
5206
40
1.5
0
2679
40
3.0
0
2953
40
3.0
4
1667
40
3.0
8
1173
40
3.0
12
896
24
24
24
24
24
24
24
24
24
24
24
24
I t
was
concluded
that
this method
of
heating
cement
slur ries in low
temperature
holes, is ess entially
simple and
successful. Although
practically no expensive supplemen.
tary
equipment is required
th e bulk
of
the
chemicals required
fo r
this
process makes the
method
imprac
tical in remote locations.
TABLE VI.
Oompressive
Strengths
of
High
Alumina
ements
Curinp Temp.
Oomvr. Strength
Time-Hrs_
OF Salt
el
Average
ps i
72
72
72
72
72
72
at
th e
time
of
cementing
and at
v ari ous time intervals thereafter.
Figure 12 shows a similar jo b con
ducted
through
1500 ft . of 4 -inch
pipe.
These tes ts
indicated
that
due
to
the heating effect of the injected
chemicals the cement should have
a compressive
strength
of at least
500 psi, within 4 to 5 hours time.
TABLE V
Thickening
Times
o f H ig h
Alumina
Cements
High Alumina -
Neat
1 hr .
40
min.
High Alumina -
1.5
NaCI
4
hr .
10min.
High Alumina -
3
NaCl 7
hr .
34 min.
High Alumina -
4
Gel
-
3 NaCI
2
hr .
2min.
High Alumina -
8 Gel -
3 NaCI
1 hr . 19 min.
High Alumina -
12 Gel
- 3 NaCl 3 hr .
35
min.
Based on t he se dat a an actual
cementing
treatment in
Southern
Alberta was performed utilizing
this te chnique. On this
job
7 feet
of
8
inch
diameter
cas ing was
set
using
15.6 lbs. pe r
gallon
slurry
containing 2 calcium
chloride
acce ler ator . Sur fa ce
temperature
was
26°F., wat er t empera tu re was
32°F.,
and
th e
slurry temperature
wa s
38°F.
Dur ing thi s
cementing
operation 700 lbs. of caustic was
mixed in 5 barrels of water and
neutralized with 200 gallons
of
28
hydrochloric acid. Two pump trucks
were used to pump these solutions
which
were
mixed
immediately
prior
to injection down
the
casing.
Figttre 11
shows
comparative
tem
perature surveys run
on
this
well
ti c
solution
was
prepared and pump·
ed down
th e
casing.
Even without
neutralization considerable benefi
cial
heating
of
th e
cement
slurry in
the annulus occurred.
TechnologYr Summer
962
algary
69
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-
_
- .
-
_
...
o
·
J ~
_ e l t ~
SURFACE)
160
u..
0
VICAT
FINAL
UJ
a:::
SET
>
I
80
-
::
O l
a:::
.
.
•
. - .
UJ
a...
40
. -
UJ
I
TIME
HOURS
Figure
1 0 . ~ L a b o r a t o r y temperature tests
on
cement s lu rr ies dur ing
setting,
ut il izing chemical heating, in
sim
ulated format ion.
from freezing,
even
though
th e
tem
perature may be
many
degrees
below
th e
freezing point. This prop
erty of
high Alumina
cement slur
ries recommends
i t for
low tempera
ture use, in
spite
of its p remium
price. Ano th er a dv an ta ge o f
this
material
is that it enables consid
erable l ightening of th e
slurry,
a
definite
advantage
in
surface
pipe
cementing,
w ith resultant
lower
costs
pe r
cubic foot
of
slurry_
Various m ixture s of high Alum
i na cemen t s lu rr ie s wer e
laboratory
tested
at
40°F., th e borderline
tem
perature
fo r
normal
cements. The
cement,
additives,
water an d moulds
were
al l
precooled at
·10
F. fo r 2·
hours. Mixing an d poring proce
dures
wer e car ri ed out al controlled
temperatures of ·10 >F. The
resulls
of these tests ar e shown
in
Tn hI
IV.
Th e favorable results
of thesl
tests, which showed
adequatf
I
-.J
I .
I I A F T E R
\ • CEMENT
If
J
BEFORE
C E M E N T
O - - ~ ~ - I ~ - - . - - , - - - r - - - - ,
., •.-. ,
k
HRS_ LATER
I
r
.........
\
I
-
/ /
{ : .
vi
v Vf HRS
LATER
1 5 0 0 0 ; 5 ~ 0 ~ ~ 1 0 ~ 0 : 1 : : . 5 0
TEMPERA TURE _ OF
0 . . . .
---PRE-CEMENT
3 0 0 3 ~ 0 - - - - - - - - - - = 5 : : - 0 - - - - - - = 7 : : - 0 - - ~ 9 ; : - 0
- - ~ 1 l 0
TEMPERATURE
OF
>-
w
w
500
..
w
w
u
I
>-
0
W
200
:r:
0
0
W
Cl
1000
Figw e H.-Subsurface
temperature surveys
on a
well in
Southern
Alberta
following surface casing
cementing operat ions,
ut il izing chemical heating.
Figure 12.-Subsurface temperature surveys
on 1
well in Southern Alber ta following
casing
cement
in g ope ra ti ons, u ti li zi ng chemica l hea ti ng .
70
Journal of Canadian
Petroleum
-
8/20/2019 Low Temperatur Cementing
8/8
Temperature
of cement
returns
No.1 42°
No.2
43
0
Temperature at top
of
cement
7 hours
after
plug down: 55°
Top
of
cement found to
be quite
hard.
TABLE
VII.
Surface Casing Cementing
Job Done on
Dome
al Winter
Harbour
No 1
September
30th,
1961.
Conductor pipe: 20 to 77'
Hole size: 7: 4
to 1048'
Casing size: 13 355
54,5Ib,
Outside temperature:
3°
above
zero
Wind:
N.N.W. at
12 m,p.h,
Temperature of
dry
cement:
8
0
Temperature
of
salt
water
gel: go
Temperature
of
mix
water
(lst 25 bbls.) :45
0
Temperature
o f remaining mix
water
(125
bbls.):
60
0
Started
mixing:
6:00
a.m.
September
30th,
1961
Temperature
of slurry
at mixing tub:
No.1 300 (Mix water at 45°)
No.2 40° (changing
temperature
of mix
water)
No.3 500 (mix
water at
60
0
)
No.4
50°
m ix
water
at
60
0
)
No.5
51
0
(mix water at 600)
End mixing: 8:00
a,m.
September
30th,
1961
Total
mix:
600
Ciment Fondu w/12 salt water
gel.
75
neat Ciment
Fondu
mixing
water:
Ocean
at 3 salt
Plug released:
8:08 a.m.
Plug
down: 8:30 a.m. Pumped by
rig
pump,
Temperature of mud returns while displacing plug.
No, 1 45
0
No.2 44°
No,
3 45
0
strength, resulted in s im ilar
tests
under more s tr ingent t empe ra tu re
conditions.
These
latter
t es ts were
conducted
at
temperatures as
low
as 10°F in an effort to
solve
th e
problems of extended
W.O.C. time
on normal
surface
cas ing j ob s
in
WesteTIl
Canada and in th e Perma-
frost
zones.
In
these
tests, aU
cem
ent, additives, moulds
and
cover
plates were
brought
to constant
temperature at
10°F.,
w ith the
ex
ception of the
mix
water whi ch was
maintained
at 40°F.
Tests were
mixed i n a Cold Room at
lOGF.
an d
placed
under
water
containing anti
freeze.
Thickening
t imes were de
t ermined by
AP I
Schedule I modi
fied
to
70°F,
an d
500
psi.
Th e
reo
sultant thickening
times
an d com
pressive strengths ar e
shown
in
Tables
V
an d
VI,
respectively.
The
d ata a re
no t
fully
developed
on
these tes ts due
to their severity
.
Many
samples
were spoiled by con
taminat ion with antifreeze. Sodium
chloride was used as
a
retarder
to
offset th e acceleration effect
of ben
tonite
on t he h igh Alumina
cement.
Thickening
t ime of 12 ge l
cement
at 70°F.
was onl y 12
minutes.
Based on
th e encouraging
results
obtained
dur in g t he se l abo ra to ry
tests,
a cementing
job util izing high
Alumina
cement slurry
was
per
formed . Deta ils
of this
treatment
are shown in Table
VII. In
spite
of
th e
extremely
r igorous temper
ature
conditions
under which this
cementing
t reatment was conduct
ed,
the job
proved
highly
success
ful
CONCLUSIONS
Evaluation of laboratory tests
an d
field
cementing
treatments
in
dicates
that
in most cases surface
cas ing can be successfully an d sec
urely cemented, even
a t extremely
low
temperatures.
Apparently. i f
th e mixing water
can
be
hea ted to
a temperature
of
70 to 80
o
F. , th e
additional heat of
hydration
of th e
h igh Alumina cemen t
will
prevent
freezing from
occurring
before th e
final
set.
Additional modification
an d
improvement o f
heating tech
niques should a ssur e the successful
performance
of
surface casing cem
enting jobs, even
under
rigorous
low
temperature
conditions.
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