Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
.LL COMPLETION FLUID COMPOSITIONS
This invention relates to well completion and -~orkover
fluid compositions and more particularly to a high density
well completion and workover fluid composition that may be
employed in petroleum recovery operations without excessive
corrosion to ferrous metal tubing and pipe with which the
composition may come into contact.
Current practice when completing wells, such as oil and
gas wells, is to have drilling fluid, such as mud, salt
water, water, or oil, in the well casing and to perforate
the _asing with a bullet shaped charge, or chemical or punch-
type perforator. When the pressure of the formation traversed
by the well exceeds the hydrostatic pressure of the column of
oil or water at the completion depth, it is customary to use
a composition with a density great enough to exceed the for-
mation pressure in order to control the well while perforat-
ing the casing in performing other routine completion and
workover operations. These compositions are prepared by dis-
solving certain inorganic salts in water.
These compositions, which have been employed during
completion and workover operations, have certain undesirable
consequences. For example, these compositions are usually
somewhat corrosive and, thereore, cause corrosion to the
ferrous metal conduits with which the composition comes in
contact. This problem is particularly acute in petroleum
"
82
recovery operations which require a high density composition
as the increased concentration ofsa~sin the fluid composi-
tion result in greater corrosion damage to the ferrous con-
duits.
For various reasons, it has become the practice in the
petroleum industry to drill deeper and deeper wells and very
often also to complete these wells at a plurality of zonesA
This, of course, has presented additional new unique prob-
lems in the art of completing and producing wells. Also,
the closely related problems of workover on wells has been
greatly magnified by the advent of and specifically in mul-
tiple completion wells which is at least in part due to
prior completion factors. For example, after completing
operations on an oil well to place it into production, a
campletion fluid again is employed to fill the annular
space between the casing and the tubing above packers ard
left there throughout the life of the well or until rework
ing is required.
The purpose of using such annulus or filled-up fluids
to fill the annulus space between tubing and casing above
the packer after a well is completed and producing is to
maintain a hydrostatic pressure at the top of the packer.
A pressure desired at such poin-ts is one slightly greater
than the highest pressure of all the producing formations.
In this way, the hydrocarbons being produced exert only a
slightly lesser pressure on the bottom side of the packer than
the completion fluid exerts on the top side of the packer.
Thus, by reducing the differential pressure between the top
and bottom of the packer, the crude oil or other fluids exit-
ing from the formation will not leak or bleed around the
packer and/or control of the well will not be lost. The dis-
advantages and deleterious consequences of bleeding around
packers by such fluids are well known to those skilled in
the art. The consequences of losing control of the well are
stlll better known. Similarly and especially with regard to
multiple completion wells, the consequences of a completion
fluid which is corrosive to ferrous metals is well known and
appreciated by those skilled in the art.
In drilling deeper and deeper wells in search for petro-
leum producing formations, the temperatures encountered have
increased to an extent that difficulties nonexistent thereto-
fore have been encountered. Temperatures in the order of
200 to 250F or even higher may be encountered in oil and
gas wells. At these temperatures, the completion fluids
may form corrosive fluids which will damage ferrous metal
tubing and pipe with which it may come into contact. It is,
therefore, desirable to provide a well completion fluid
which will be noncorrosive to ferrous metal conduits wi-th
which i-t may come in contact.
Tempera-ture, as a rule, increases literally with depth.
2~
~anv factors affecting temperature may vary in subterranean
locations and the subterranean temperatures even in comparably
close locations may vary considerably. The occurence of such
and the reasons, therefore, are well known in the art. Thus,
despite the general rule that temperature increases with
depth, comparably high temperatures are sometimes encountered
at relatively shallow depths, for example, at 3,000 feet.
At depths beginning at about 15,000 feet, high temperatures
are encountered without exception regardless of location.
High tempexa-tures, then, may be encountered at a depth
below 3,000 feet. These temperatures, when encountered
regardless of depth, extenuate or accelerate the disadvan-
tages of prior art completion and packer fluids
In an effort to overcome the foregoing problems, high
density salt solutions for use as well completion fluid
compositions has been proposed. For instance, United States
Patent 3,126,950 discloses a completion packer fluid made
up of a water solution of calcium chloride and zinc chloride
and optionally a corrosion inhibitor. United States Patent
4,292,183 discloses a high density fluid composition consist-
ing of zinc bromide and calcium bromide in water having a
density in the range of about 14.5 up to 18.0 pounds per
gallon and a pH in the range of 3.5 up to 6Ø
These high density fluid compositions have had limited
utility. Severe downhole corrosion problems and corrosion
l of 1~3
to above ground equipmen-t has been encountered with their
use.
the present invention provides a solution for, or at
least mitigates the above described problem. The present
invention provides a new well completion composition and a
method for use of said composi-tion. Thus, in accordance
with the broad aspect of the concept of the invention, there
is provided a composition for use as a well completion, pack-
ing and perforation medium comprising water; a salt selected
from the group consisting of aluminum chloride, aluminum
bromide, aluminum iodide, ammonium chloride, ammonium bro-
mide, ammonium iodide, sodium chloride, sodium bromide,
sodium iodide, potassium chloride, potassium bromide, potas-
sium iodide, calcil~m chloride, calcium bromide, calcium
iodide, zinc chloride, zinc bromide and zinc iodide and mix
tures thereof; and, a compound selected from the group con-
sisting o.f acetylenic alcohols having the general formula:
H - C - C - C - OH
P'
wherein R is H, alkyl, phenyl, substituted phenyl, or hydroxy-
alkyl radical wherein said composition has a density of about
9.0 pounds to abou-t 21.5 pounds per gallon of composition.
Optionally other ingredien-ts may be added to the above de-
scribed compos1tion. For instance, an organic amine selected
~3~2~2
from the group consisting of mono, di and tri-alkyl amines
having from about two to about six carbon atoms in each
al.~yl moiety, six membered N-heterocyclic amines, quinolines
and quaternized derivatives of quinolines, quaternized pyri-
dines, alkyl pyridines having from one to five nuclear alkyl
substituents per pyridine moiety wherein said alkyl substi-
tuents have from one to 12 carbon atoms and mixtures thereof
may be added.
When desixed, an acid selected from the group consist-
ing of formic acid, acetic acid, proprionic acid, butyric, glycolic
acid and mixtures thereof may be added to the above described
composition. The method of the invention comprises contacting
the well at sufficient hydrostatic pressure with the composi-
tion of the invention.
When the above described method of completion of work-
over of wells is employed, the composition is relatively non-
corrosive to the ferrous metal conduits with which it comes
in contact.
The salts, which may be used in the practice of the
present invention, function as weighting agents and increase
corrosion inhibition. These salts are presented in the follow-
ing Table.
TAsLE I
Salts Suitable as Weighting Agents
_ tame FormulaSpecific Gravity
Aluminum Bromide AlBr3 3.01
Aluminum Chloride AlCl3 2.44
Aluminum Iodide AlI3 3.98
Ammonium Bromide NH4Br 2.33
Ammonium Chloride NH~Cl 1.53
Ammonium Iodide MH4I 2.51
Calcium Bromide 2
Calcium Chloride CaC12 2.15
Calcium Iodide CaI2 3.96
Potassium Bromide KBr 2.75
Potassium Chloride XC1 1.98
Potassium Iodide KI 3.13
Sodium Bromide NaBr 3.20
Sodium Chloride NaC1 2.16
Sodium Iodide NaI 3.67
Zinc Bromide ZnBr2 2.56
Zinc Chloride ZnC12 2.91
Zinc Iodide ZnI2 4.66
The preferred salts and combinations of salts for use in the
present invention are sodium chloride, calcium chloride,
calcium bromide and the following combinations oE salts:
sodium chloride and calcium chloride, calcium chloride and
or tr
calcium bromide, calcium chloride and zinc chloride, calcium
bromide and zinc bromide, calcium bromide, zinc bromide and
zinc chloride, and zinc chloride and zinc bromide.
The most preferred salts and combinations of salts for
5 use in the invention are calcium chloride, calcium chloride
and calcium bromide, calcium bromide and zinc chloride, and
calcium bromide and zinc bromide.
The amount of these sal-ts used in the composition of
the invention will be the amount necessary to achieve a
composition having a density of about 9.0 pounds -to abou-t
21.5 pounds per gallon of composition.
The acetylenic alcohols which inhibit corrosion of
ferrous metal and which may be employed in accordance with
the present invention have the general formula:
R
H - C - C - C - Ox
R
wherein R is H, alkyl, phenyl, substituted phenyl, or hydroxy-
alkyl radical. Examples of suitable acetylenic compounds
include methylbutynol, ethyloctynol, methylpentynol, 3, 4 di-
hydroxy 1-butyne, 1 ethynylcyclohexanol, 3-methyl-1-nonyn-3-ol,
2-methyl-3-butyn-2-ol, also 1-propyn-3-ol, 1-butyn-3-ol, 1-
pentyn-3-ol, 1-heptyn-3-ol, 1-octyn-3-ol, 1-nonyl-3-ol, 1-
decyn-3-ol, 3-~2, 4, 6-trimethyl-3-cyclohexenyl)-1-propyne-
3-ol~
-- 8
In many instances, the corrcsion protection of the com-
position of the invention may be increased by adding an
organic amine to the above described acetylenic alcohol.
mines that are suitable for this puxpose include an organic
amine selected from the group consisting of mono,di and tri-
alkyl amines having from ahout two to abou-t six carbon atoms
in each alkyl moiety, six membered N-heterocyclic amines,
quinolines and quaternized derivatives of quinolines, alkyl
pyridines having from zero to six nuclear alkyl substituents
per pyridine moiety wherein said alkyl substituents have
from one to 12 carbon atoms and mixtures thereof Examples
of these amines include ethylamine, diethylamine, triethyl-
amine, propylamine, dipropylamine, tripropylamine, mono, di,
tributylamine, mono, di and tripentylamine, mono, di and
trihexylamine and isomers of these such as isopropylamine,
tertiarybutylamine, aniline, dehydroabiethylamine, pyridine,
quaternized derivativesof pyridine, nitro picoline, methyl
quinoline alkyl pyridines such as alkyl
pyridines having from 1 to 5 nuclear alkyl substituents per
pyridine moiety, quinolines, quaternized derivatives of
quinolines alkyl quinolines and mixtures.
In some instances, it may be desirable -to include an acid
in the composition of the inven-tion. The acid, when present
in the composition of the invention will remove acid soluble
scales in the well bore or open perforations in the well
bore. when an acid is desired, suitable acids which may be
employed include formic acid, glycolic acid, acetic acid,
proprionic acid, butvric acid and mixtures thereof.
As stated earlier, the acetylenic alcohol maY be used
alone with the composition of the invention or an organic
amine may be combined with an acetylenic alcohol. The
relative proportions of acetylenic alcohol and organic amine
may vary over a wide range. Furthermore, it has been found
that the concentration of acetylenic alcohol and the concen-
tration of the organic amine are not interdependent and thus
significant improvement in corrosion protection can be ob-
tained by varying the concentration of one of the components
without varying that of the other. In general, the acety-
lenic alcohol concentration will vary from about 0.2 to
about 5.0 percent by volume of the composition. However,
lower or higher concentrations will still be effective when
an organic amine is added to the composition of the inven-
tion. Thus, the amine concentration will vary over a wide
range with really no upper or lower limitations. General,
the organic amine concentration when desired will vary from
about 0.05 to 3.0 volume percent of the composition of the
invention.
A particularly affective blend containing an amine and
acetylenic alcohol is set forth below.
- 10 -
~'3~
slend I
Chemical: Percent by vol.
Pure propargyl alcohol_ _ _ _ _ _ _ _ _ _ _ _ _ 33.94
Crude propargyl alcohol _ _ _ _ _ _ _ _ _ _ _ 11.31
Ethyl octynol _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 16.97
High alkyl pyridines_ _ _ _ _ _ _ _ _ _ _ _ _ _ 3.85
Formladehyde (55%) in methanol_ _ _ _ _ _ _ _ _ 33.94
Another efective composition containing an amine and
acetylenic alcohol is yiven below.
Blend II
Chemical: Percent by vol.
Pure pro~argyl alcohol_ _ _ _ _ _ _ _ _ _ _ _ _ 33.94
Crude propargyl alcohol _ _ _ _ _ _ _ _ _ _ _ 11.31
Ethyl octynol _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 16.97
~l~yl pyridines _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3.85
Diacetone alcohol 33.94
.. _ _ _
Another effective blend containing an amine and acety-
lenic alcohol is given below. This blend is very effective
when the denslty of the composition of the invention is
20 from about 15.0 pounds per gallon to about 16.5 pounds per
gallon and the salts utilized are calcium bromide and zinc
chloride and when the density is from about 16.5 pounds per
gallon to about 19.2 pounds per gallon and the salts uti.lized
are calcium bromide and zinc bromide.
Blend III
Chemical: Percent by vol.
Cnlde quaternized quinoline _ _ _ _ _ _ _ _ _ _ 56.G0
Propargyl alcohol _ 21.00_ _ _ _ _ _ _ _ _ _ _ _ _
Ethyl Octynol _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 13.00
15 moles of ethylene oxide adduct of nonyl
phenol _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 10.00
Cu2I2 _ _ _ _ 0.024 grams per milliter of composition
The preferred density of the composition of the inven-
tion is from about 16.5 to about 21.5 pounds per gallon of
composition.
The concentration of the acid, when employed in the
composition of the invention will vary over a great range.
Generally the range of acid is from .2 percent to about 40
volume percent of the composition. The most preferred acid
concentration is from abou-t 3 to about 17 volume percent
of the composition.
The following examples will serve to more comprehensively
illustrate the principles of the invention but in being directed
to certain specific compounds in process steps and conditions
are not intended to limit the bounds of the invention.
EXAMPLE I
In order to compare -the corrosion inhibiting ability of
the composition of -the invention, various samples containing
10 percent by volume of formic acid or acetic acid were pre-
- 12 -
~30~
pared with various amounts of calcium chloride. Tests 1
through 5 contained slend I as an inhibitor. slend I, as
disclosed earlier, contains the rollowing inyredients: pure
propargyl alcohol, crude propargyl alcohol, ethyl octynol,
high alXyl pyridines and formaldehyde (55%~ in methanol.
Tests 6 through 10 contained, as an inhibitor, Blend
III. Blend III was made up of crude quaternized quinoline,
propargyl alcohol, ethyl octynol, and 15 moles of ethylene
oxide adduct of nonyl phenol and Cu2I2.
A coupon of A~I Type N-80 steel was placed in the acid
composition for a period of eight hours at 200Fo All tests
were carried out under atmospheric conditions.
The loss of weight in pounds per square foot was cal-
culated as follows:
144
Corrosion Loss lbs/ft
_ _
455 lg X Surface Area of Coupon in
Results of these tests are shown in Table II.
13
TABLE II
Volume - Surfaco Area Ratio - 25 cc./in.
Corrosion Loss lbs/ft
Test InhibitorCaCl~Formic A id Acetlc Acid
1 Blend I - 0.287 0.296
2 Blend I9.5 lhs/gal 0.052 0.029
3 Blend I10.0 lbs/gal 0.023 0.025
4 lend I10.5 lbs/gal 0.005 0.005
Blend I11.0 lbs/gal 0.005 0.004
6 Blend III - 0.029 0.019
7 Blend III 9.5 lbs/gal 0.009 0.013
8 Blend III 10.0 lbs/gal 0.003 0.009
9 Blend III 10.5 lbs~gal 0.003 0.002
Blend III 11.0 lbs/gal 0.002 0.002
Table II shows that the composition of the invention
effectively reduced iron corrosion.
EXAMPLE II
In order to demonstrate the corrosion inhibiting ability
of the composition of the invention, various samples of a
10 percent by volume acetic acid were prepared with various
salts. The density of the samples was ten pounds per gallon
of sample. Tests 4 through 6 and 8 contained Blend I as an
inhibitor. The composition of this Blend is the same as dis-
closed in Example I. Tests 1 through 3 and 7 utilized MBA
29 as an inhibitor. MBA 29 contained, as ingredients, 50
percent by volume crude quaternized quinoline and S0 percent
by volume methyl butynol.
A coupon of API rrype ~-80 steel was placed in the acidic
- 14 -
f
composition for a period of six hours at 200F. All tests
were carried out under atmospheric conditions. The corro-
sion loss was calculated as in Example I.
The results of these tests are shown in Tahle III.
TABLE III
Volume - Surface Area Ratio - 25 cc./in.
___
Inhibitor Corrosion Loss
Test Salt 1% v/v _ lbs/ft _
1 AlC13 MBA29 0.004
2 NaBr MBA29 0.004
3 NH4I MBA29 0.003
4 AlC13 Blend I 0.009
NaBr Blend I 0.018
6 N~I Blend I 0.005
7 - MBA29 0.150
8 - Blend I 0.287
Table III shows that the composition of the invention
reduced iron corrosion.
EXAMPLE III
In order to compare the corrosion inhibiting ability
of the composition of the invention, a composition which had
a density of 19.2 pounds per gallon was prepared. The salt
u-tilized in preparing the composition was a mixture of zinc
brcmide and calcium bromlde. A coupon of API Type N-80 steel
was placed in the composition for a period of seven days at
26~F. All tests were carried out under atmospheric condi-
tions.
Blend III was made up of the same componen-ts as de-
scribed in Example I. Blend II was made up of pure
g
propargyl alcohol, crude propargyl alcohol, ethyl oc-tynol,
alkyl pyridines and diacetone alcohol.
Test 9 could not be accurately calculated due to con-
tamination of the sample during the test.
Results of these tests are shown in Table IV.
TABLE IV
~Jolume - Surface Area Ratio 25 cc./in.
Inhibitor Corrosion2Loss
Test l V/V lbs/ft
1 - 0.102
2 Propargyl alcohol 0.058
3 Methyl butynol 0.019
4 Me-thyl pentynol 0.056
50 percent by volume hexynol0.026
6 Ethyloctynol and 10 percent by volume 0.098
of lS moles of ethylene oxide adduct
of nonyl phenol
7 50 percent by volume propargyl alcohol 0.013
& 50 percent by volume quaternary
quinollne
8 50 percent by volume methyl butynol 0.011
50 percent by volume quaternary
quinoline
9 50 percent by volume methyl pentynol 0.105
& 50 percent by volume quaternary
quinoline
50 percent by volume propargyl alcohol 0.044
& 50 percent by volume pyridine
11 mixture of acetylenic alcohol, cyclic 0.052
amine and linear amines
12 mixture of acetylenic alcohol, cyclic 0.050
amine and llnear amines
13 mixture of acetylenic alcohol, cylcic 0.048
amine and linear amines
14 mixture of acetylenic alcohol, cylcic 0.048
amine and linear amines
31end II 0.005
16 Blend II~ 0.007
- 16 -
Table IV shows that tne composition of the invention
effectively reduced iron corrosion.
While certain embodiments of the invention have been
described for illustrative purposes, the invention is not
limited thereto. Various other modifications or embodiments
of the invention will be apparent to those skilled in the
art in view of this disclosure. Such modifications or embodi-
ments are within the spirit and scope of the disclosure.
hat is claimed is:
- 17 -