CA1131404A - Synergistic microbicidal mixtures of 4-isothiazolin-3-ones and quaternary ammonium salts for use in oil field injection water - Google Patents

Abstract

Abstract of the Disclosure This invention relates to the use of 4-isothiazolin-3-ones and quaternary ammonium salts for use in inhibiting the growth and activity of sulfide-generating bacteria and/or the activity of aerobic micro-organisms.

Description

4~

ONES AND QUATBRNARY AMMONIUM SALTS FOR USE IN OIL FIELD
IMJECTION WATER

BACKGROUND OF THE INVENTION
5The effectiveness of the biocide in controlling the microbial aspects of corrosion will depend on its ability to inhibit the growth and activity of sulfide-generating bacteria and/or the activity of aerobic micro-organisms.
These later organisms while not being corrosive produce the energy substrates required for the growth of the sulfide-generating bacteria. Sulfide can be produced from partially oxidized forms of sulfur as well as sulfate. Some bacteria cannot use sulfate as an electron acceptor and therefore if it is used as the sole electron acceptor many sulfide generating bacteria would be overlooked. The total sulfide generating capacity of any environmental microbial population therefore would be the sum of the activities of all organisms capable of producing sulfide from all forms of oxidized sulfur. Any medium used for the detection of these organisms should contain both sulfate and a reduced form such as sulfite.
United Kingdom Patent Mo. 1,488,891 granted February 8, 1978 discloses that mixtures of 4-isothiazolin 3-ones and quaternary amines exhibit synergistic bactericidal activity in the presence of organic matter.

.
: - .

.: - . . : : ~ :: ,, .
., : .
.
: .

Such compositions are disclosed to be especially effective in controlling microbial activity on such solled surfaces as in dairies, barns, stie5, chicken co~ps, swimming pools and the like.
SUMMARY OF THE INVENTION
A
The present invention relates to the biocidal effects of 4-isothiazolin-3-ones and quaternary ammonium mixtures on the total aerobic and sulfide generating bacterial populations of ~enriched" oil well injection water for use in secondary oil recovery.
m is ~nvention prov~des a ~ethod for controlli~g aer~bic and sulfide-generating bacteria ~n a sea~ndary recovery o:E oil frc)m oil fields which oo~prises the addition to oil well aqueous injection fluids of compositions containlng a mixture of (1) 4-isothiazolin-3-ones of the ~orm~la R O

2~ ~ / \ y S
R' wherein Y is a hydrogen atom, an alkyl group, preferably having 1 to 18 carbon atoms, an alkenyl or alkynyl group, prefera~ly having 2 to 18 carbon atoms, and most preferably 2 to 4 carbon atoms, a cycloalkyl group~ preferably having 3 to 12 carbon atoms, and a single 3 to 8 carbon atom ring, an aralkyl group, preferably having up to 10 carbon atoms, or an aryl group, preferably having up to 10 carbon atoms;
R is a hydrogen atom, a halogen atom, preferably chlorine or bromine, or an alkyl group, prefer~bly having 1 to 4 carbon atoms; and R' is a hydrogen atom, a halogen atom, pre~erably chlorine or bromine, or an alkyl group, preferably having 1 to 4 carbon atoms;
salts of 4-isothiazolin-3-ones of Formula I with a .

, _ 3 v strong acid, such as hydrochloric acid, hydrobromic acid, perchloric acid, nitric acid, sulfuric acid, oxalic acid, trichloroacetic acid, ~-toluenesulfonic acid, or the lik-e, and metal salt complexes of the formula R O

~ j (MXn) (II) lU S
R' wherein Y, R, and R' are as defined above, M is a ~ation of a metal, such as barium, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, mercury, nickel, sodiumr silver, strontium, tin, zinc, or the like;
X is an anion forming a compound with the ca~ion M, wherein the compound has sufficient ~olubility to form a metal salt complex;
a is the integer 1 or 2; and n is an integer which for the anion X satisfies the valence of the cation M; an~ 12) a bactericidal ~uaternary ammonium salt or m~xture of ~uaternary ~nium salts; at a level fr~m about 1 to about 100 ppm by weight of the injection water, and Ln which the ratio of the 4-isothiazolin-3-one to quaternary ~nium sal~ is from about 5:1 to about 1:50.
As used in the specification and claims, the term alkyl group is in~ended to ~nclude unsubstituted alkyl groups as well as substituted alkyl groups in which one or more of the hydrogen atoms are replaced by a - substituent group other than aryl group. Examples of the substituted alkyl groups which characterize 4-isothiazolin-3-ones and the metal salt complexes of Formulas I and II include hydroxyalkyl, haloalkyl, cyanoalkyll alkylaminoalkyl, dialkylaminoalkyl, arylaminoalkyl, carboxyalkyl, carbalkoxyalkyl/

~.
.
' .
i .

,~
`, : !

3L~ O~

alkoxyalkyl, aryloxyalkyl, alkylthioalkyl, arylthioalkyl, isothiazolonylalkyl, haloalkoxyalkyl, carbamoxyalkyl, az wycloalkylalkyl, such as morpholinoalkyl, piperidinoalkyl, and pyrrolidonylalkyl, and the like.
The terms alkenyl group and alkynyl group are intended to include unsubstituted alkenyl and alkynyl groups as well as substituted groups such as haloalkenyl, haloalkynyl, and the like.
The term aralkyl group is intended to include unsubstituted aralkyl groups, such as benzyl, phenethyl, methylbenzyl, and the like, such aralkyl groups having one or more of the hydrogen atoms on either the aryl ring or the alkyl chain replaced by another substituent group. Examples of the substituted aralkyl ~roups which characterize 4-isothiaæolin-3-ones and the metal salt complexes of Formulas I and II include halogen-, nitro-, (Cl-C4)alkyl-, or (Cl-C4)alkoxy-substituted aralkyl groups, and the like.
The term aryl group is intended to include unsubstituted aryl groups, such as phenyl, naphthyl, or pyridyl, as well as such aryl groups having one or more of the hydro~en atoms on the aryl ring replaced by another substituent group. Examples of such substituent groups include halogen, cyano, nitro, (Cl-C4)alkyl, (Cl-C4~alkoxy, (Cl-C4)alkylacylamino, (Cl-C4)carbalkoxy, sulfamyl, and the like.
Representative Y substituents include hydrogen, methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, decyl,`pentadecyl, octadecyl, cyclopropyl, cyclohexyl, benzyl, 3,4-dichlorobenzyl, 4-methoxybenzyl, 4-chlorobenzyl, phenyl, 3,4-dichlorophenyl, 4-methoxyphenyl, naphthyl, hydroxymethyl, chloromethyl, chloropropyl, diethylaminoethyl, cyanoethyl, carbomethoxyethyl, ethoxyethyl, 2-metho~y-1-bromoethyl,

3,3,5-trimethylcyclohexyl, phenoxyethyl, .,.
, ~ ,J

~chloroanilinomethyl, phenylcarbamoxymethyl, hydroxybutyl, allyl, propynyl, vinyl carboxyethyl, l-isothiazolonylethyl, 1,2,2,-trichlorovinyl, and the like. Representative R and R' substituents include hydrogen, bromine, chlorine, iodine, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, and the like. The alkyl substituents represented by Y, R, and R' can have either branched- or straight-chain spatial configuration.
Among the anions which X can rPpresent are chloride, bromide, iodide, sulfate, nitrate, nitrite, acetate, chlorate, perchlorate, bisulfate, bicarbonate, oxalate, maleate, ~-tol~enesulfonate, carbonate, phosphate, and the like. The preferred metals from which M is derived are calcium, copper, magnesium, manganese, nickel, and zinc. Among the metal cations embraced by M are cationic complexes of the metal ions, including complexes with ammonia, simple organic amines, and various heterocyclic organic amines such as pyridines, pyrimidines, and the like.
i!0 The preparation and properties of the 4-isothiazolin-3-ones and metal salt complexes of the composition of the invention are described in Canadian Patent No.
941,828, granted February 12, 1974 to Sheldon N. Lewis et al.; and in United States Patents Nos. 3,517,02 of George A. Miller et al~, granted June 23, 1970;
3,544,480 of Sheldon N. Lewis et al., granted December 1, 1970; 3,761,4~8 of Sheldon N. Lewis et al., granted September 24, 1973; and 4,150,042 of George A. Miller et alO, granted April 17, 1979.
In the compositions of the present invention, a particularly useful group of 4-isothiazolin-3-ones are those in which R is a hydrogen atom, a methyl group, or a halogen atom, preferably a bromine or chlorine atom; and ~ . .
~".

R' is a hydrogen atom, or a halogen atom, preferably a bromine or chlorine atom. In this gro~p, those compounds in which Y is a hydrogen atom or a substituent having one to seven carbon atoms, such as a methyl group, a hexyl group, a cyclohexyl qroup, a phenyl group, a halophenyl qroup, a nitrophenyl group, a benzyl group, or a halobenzyl group, are generally most active, especially in providing good residual activity.
The quaternary ammonium salts which can be used in the microbicidal compositions of the invention are well known compound~, and include dilower alkyl higher alkyl benzyl ammonium halides, such as dimethyldodecylbenzyl-ammonium chloride, diethyldodecylbenzylammonium chloride, ~-diisobutylphenoxyethoxyethyldimethylbenzylammonium chloride, ~imeth~loctadec~l-dimethylbenzyl ammonium chloride, and the like, alkyldimethylethylbenzylammonium halides, dilower alkyl dihigher alkyl ammonium halides and trilower alkyl higher alkyl ammonium halides, such as dimethyldidecylammonium chloride, dimethyldidodecylammon~u~ chlor~de, trimethyltetradecylammonium chloride, methyldiethyl-decyloxyethyl ammonium bromide, methyldodecylbenzyl-trimethylammonium chloride, methyldodecylxylylenebis-(trimethyl)ammonium chloride, and the like, N-trimethyl-N-chlors-N'-benzyl-N'-dodecyl-cinnamide, N-higher alkyl heterocyclics such as cetylpyridinium chloride, 2-tridecylpyridinium 3ulfate, l-hexadecyl-pyridinium chloride, 2-dedecylisoquinolinium bromide, 2-octyl-1-(2-hydroxyethyl)imidazolinium chloride, 6-dodecyloxybenzylquinolinium chloride, and benzyldecylpiperidinium chloride, and the like. Mixtures of these quaternary ammonium salts can also be used. The preferred quaternary ammonium salts are those having at , ~'', .

least one hydrophobic chain of 8 to 18 carbon ato~s, most particularly the n-alkyldimethylbenzyl ammonium halides, including mixtures of Cl2-, C14- and Cl6- alkyl dimethylbenzyl ammonium halides and substituted-benzyl ammonium halides.
The ratio of 4-isothiazolin-3-one to quaternary ammonium salt in the compositions of the invention and the use levels of the compositions can be varied greatly depending on the degree of total activity desired, the degree of bacterial contamination to be eradicated, the quaternary ammonium salt and isothiazolone involved, and related factors. Generally, the weight ratio of

4-isothiazolin-3-one to quaternary ammonium salt will be from about 5:1 to about 1:50, preferably about 20l to 15 about 1:200 The upper limits for each of the active components of the microbicidal compositions of the invention are usually related to purely economic considerations.
The compositions of the invention can be formulated in any convenient fashion using appropriate solvents such as water, alcohols, glycols, and the like, or mixtures of solvents. For various use applications, it may be advantageous to add suitable surfactants, as well as other conventional additives such as synthetic liquid or solid detergents, stabilizers, anticorrosive agents, extenders and the like. The compositions can be formulated at any desired concentration, the choice of concentration generally being dependent on the particular use conditions which may be anticlpated. In general, the compositions will be utilized at a formulated concentration of about 1 to about 100 parts per million by weight of quaternary ammonium compound and about 0.2 to about 20 parts per million by weight of 4-isothiazolin-3-one.
As noted above, the microbicidal compositions of the invention are synergistic -~ that is, the activity of the .. . . .

compositions is greater than would be expected from the combined individ~al activity of the 4-isothiazolin-3-one an~_quaternary amine.
The microbicidal compositions of the present inv~ntion are effective in controlling the total aerobic and sulfide generating bacterial populations found in oil field injection water when utilized at a concentration of from about 0.5 to about 50 ppm. The microbicidal compositions of the present invention possess ~he ability to not only produce a rapid ~peed of kill of the aerobic and sulfide generating bacteria but also possess the ability to maintain a sustained kill and inhibit the regrowth of bacteria which is a common problem in the quaternary ammonium mi~robicides.
The following examples are provided in order to illustrate the synergistic combination of the microbicidal composition of the present invention and its use in oil field iniection water. These examples are provided merely to illustrate the use of the present invention and are not intended to be interpreted in any way as limitations upon the breadth and scope thereof.
Monitoring Levels of Bacteria (a) Aerobes The effect of these biocides on aerobic bacteria present in injection water was measured using the spread plate count technique. One-tenth of a ml of original solution or a suitable dilution was spread in quintuplicate on Petri plates containing Plate Count Agar ~manufactured by Difco Laboratorles, ~etroit, Mich.).
All dilutions were prepared in sterile 3mM
phosphate buffer (p~ 7.2). All plates were incubated for 3 days at 30~C prior to counting colony forming unit~.
The mean and standard deviation was determined for each treatment if there was between 30 and 300 colonies per plate. Plates with counts out~ide of these values were reported as being lesser or greater than the count after taking into consideration tbe dilution used.

(b) Sulfide-generating bacteria A most probable number (M.P.N.) procedure was used foE-monitoring the level of sulfide-generating bacteria which would grow in Butlin's medium (N~4Cl-l.0 gm;
Na2S4-2 gm; MgSO4 7H20-0~02 gm; sodium lactate-60% solution-1.5 mls; yeast extract~l.0 gm;
K2~PO4-0.5 gm and 1000 ml of distilled water). The pH of this medi~m was 7.2 to 7O3. Two iron finishing nails were added to each tube prior to autoclaving.
Three drops of a sterile 10~ solution of Na2SO3 were added to each tube prior to inoculation. Dilutions of samples were prepared in 3mM phosphate buffer (pH 7.2) to which 1 ml of a sterile 10% solution of sodium thioglycollate was added prior to the use of the dilution bank. Five tubes of medium were inoculated with 0.1, 1.0 and 10.0 mls from each of 0, 10 2, 10 4 and 10 6 dilutions of injection water with and without biocides.
Tubes which received 10 mls of inoculum contained double strength medium. ~11 tubes were incubated at room temperature. The presence of growth (turbidity) and the development of a black precipitate (particularly on the finishing nails) which was characteristic of the activity of sulfide-generating bacteria was determined after 1, 3, 7, 14 and 21 days incubation. Growth without the development of a black precipitate was attributed to the presence and multiplication of non-sulfide generating bacteria.
Results and Discussion The effect of isothiazolinones, quaternary ammonium compounds and mixtures of these two biocides on the aerobic bacterial plate count is presented in Table 1 and that obtained via the M.P.N. procedure in Table 2. The pattern of action of the biocides observed in both media is similar. The isothiazolinone (Il) alone require a longer contact time to be effective where the quaternary ammonium compound (Ql) acts quickly. Re-growth r~

~: ' , ' ;

.
;

:: '~

is observed at low concentrations of the quaternar~
ammonium compound but not for the isothiazolinones.
Mixtures of the biocides were effective in controlling aerobic bacterial growth at low concentrations. As can be seen from the 96 hours data the isothiazolinone and quaternary ammonium mixture produces a total kill at total concentrations much lower than those needed for the isothiazolinone (Il) or QUAT (Ql) alone.
The effect of Il, Ql and mixtures of the two biocides on the incidence of sulfide-generating bacteria are presented in Tables 3, 4 and 5. An even greater synergistic effect is noted on the biocidal effect of these compounds on sulfide-generating bacteria than for the aerobes. Mixtures of the two biocides are very effective in inhibiting growth of these bacteria at lower total concentrations and at shorter term intervals than those needed for either biocide alone. It is to be noted that low levels of sulfide-generating bacteria were always detectable in experiments with Il. These were not detected with Ql or when mixtures of the biocides were used.
TABLE 1 EFFECT OF BIOCIDES - ISOTHIAZOLINONE (Il), QUAT
(Ql) AND THEIR MIXTURES ON AEROBIC BACTERIAL
PLATE COUNTS OF INJECTION WATER
.
Contact Time Concentration Bacterial Counta Biocide (hours) (ppm) #/ml . .
Ile 0 0 1.54 ~o 2.15 x 107 1.4 9.68 to 16.7 x 106 ~0 2.8 1.4 to 11.0 x 106 4.2 3.0 to 8.5 x 106

5.6 4.3 to 11.0 x 106 7.0 1.0 to 5.~ x 106 8.4 2.3 to 6~6 x 106 Il 3 0 2.4 to 2.7 x 107 Contact TimeConcentrationBacterial Counta Biocide (hours)(ppm) #/ml ... .. . .. . . . .. . ..

1.4 3 to 30x 10 2.8 3 to 30x 105 4.2 3 to 30x 105 5.6 3 to 30x 105 8.4 3 to 30x 105 ~ 3 105 Il 24 0 1.7 to 2.4 x 107 1.4 3.1 to 16 x 104 2.8 1.8 to 7.2 x 104 ~4.2 3 to 30x 103 5.6 3 to 30x 103 7.0 3 to 30x 103 8.4 6.5 to 12 x 102 Il 48 0 1.2 to 1.5 x 107 1.4 3 to 30 3 2.8 3 to 30x 10 4.~ < 3 102 5.6 <3 102 7.0 <3 102 8.4 <3 102 ~l g6 0 1.~ to 1.7 x 107 1.4 <3x 102 2.8 ~3x 102 4.2 <3x 102 5.6 ~3x 102 7.0 <10x 10 .. . .. . ..

- . . ... ~: . , : , 1~3~04 Contact Time Concentration Bacterial Counta Biocide (hour~) (ppm) #/ml 8.4 ~ 10x 10 S Qlf 0 0 1.5 to 2.1x 107 3 4.6 to 5.7x 106

6 3 to 30x 105 9 ~.7 to 16x 1044 18 2.4 to 3.3x 10 36 < 3104 72 ~3 104 Ql 3 0 2.1 to 3.0x 107 3 <3 106 6 3.3 to 4.3x 106 9 <3 104 18 <3 10~
36 <3 104 72 < 3102 Ql 24 0 1.5 to 1.6x 1075 3 ~ 3 10 6 ~3x 105 9 3.4 to 5.6x 104 18 1.6 to 2.1x 103 36 < 3x 102 72 ~10x 10 Ql 48 0 1.1 to 1.8x 107 3 > 3x 105 6 ~ 3~ 105 9 8.1 to 17x 104 18 3 to 30x 103 36 <3x 102 72 <10x 10 : -. . , ~, , , , : . , , . ;, :

~ 3 Contact TimeConcentration Bacterial Counta Biocide(hours)(ppm) ~/ml .

Ql 96 0 1.9 to 3.1 x 107 3 > 3 x 10 6 ~ 3 x 105 9 1.87 to 3.10 x 105 18 3 to 30 x 103 36 < 3 x 1o22 72 ~ 3 x 10 Il + Ql 0 0 1.9 to 2.4 x 10 1.4 + 6 3 to 30 x 10 1.4 + 9 1.4 to 1.9 x 10 2.8 + 6 1.5 to 4.1 x 10 2.8 + 9 1.2 to 1.5 x 106 4.2 + 9 1.0 to 1.3 x 105 4.2 + 18 < 3 x 104 Il + Ql 3 0 1.5 to 2.8 x 107 1.4 + 6 < 3 x 104 1.4 + 9 ~ 3 x 104 2.8 + 6 < 3 x 104 2.8 + 9 ~ 3 x 104 4.2 + 9 ~ 3 x 104 4.2 + 18 <3 x 102 Il + Ql 24 0 1.4 to 1.8 x 107 1.4 + 6 2.6 to 3.5 x 10 1.4 + 6 ~ 3 x 12 2.8 + 6 ~ 3 x 10 2.8 ~ 9 < 3 x 10 4.2 + 9 ~3 x 12 4.2 + 18 ~3 x 10 Il + Ql 48 0 1.0 to 1.4 x 107 1.4 + 6 < 3 x 10 1.4 + 9 ~ 3 x 102 . . . : ., . : . ~ . . . --, ... .
, : : - . , , :. . . . : ~: , :

~l13~

Contact TimeConcentration Bacterial Counta Biocide(hours)(ppm) #/ml 2.8 + 6 <3 x 102 2.8 + 9 ~3 x 102 4.2 + 6 <3 x 102 4.2 + 18 <3 x 102 Il + Ql 96 0 9.9to 14 x 106 1.4 + 6 <3 x 102 1.4 + 9 ~3 x 102 2.8 + 6 <3 x 102 2.8 + 9 <10 x 10 4.2 + 9 <10 x 10 4O2 + 18 <10 x 10 .
a = + 1 standard deviation from mean of 5 plates b = ~ 300x103 but ~30x105 c = ~ 300xlOl but ~30x103 d = no colonies on plates of 10 dilution e = The isothiazolinone used was a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-iso-thiazolin-3-one at approximately a 3.5 to 1 ratio.

f = The quaternary ammonium compound was a mixture of C12 (40~) - C14 (50%) - C16 (10~) n-alkyldi-methylbenzylammonium chloride.

:, s : , :

, :

o~

-- ~`J ~1 ~ N ~1 ~1~0 1` 1-- 1S Irl O ~`
O O O O O O C:)O O o o O O o O O O O
X X X X X X X X X X X X X X X X X X
(T~ ~ ~ ~ ~ ~ ~r ~r ~) ~ N r~ ~ ~ o N O O .
H Al Al Al /~l O
_ ~ C~
~ u~ r~ u~ 9 ~ ~ O O ~ ~ ~ O
Et ~ o o o o o o oo o o o o o o o o o o C~ ~ ~ ~ ~1 ~1 ~1 ~ ~J~ ~ ~ ~ ~ ~ ~ ~1 ~ ~ ~
~: ~ ~ X X X X X X X X X X X X X X X X X X
~r c~ er ~ ~r ~ ~ e~ In ~ 1-- ~ ~ ~ ~
H N ~r r~ N ~--1 ~7 N ~) ~ ~--1 0 0 N u~ N co ~ ~3 .~ ~
w æ JJ t~ ~ ~ 0 O ,~
æ~; ~ o 0OOOO 0 0 0O 0O 0 0O 0 0 0O
W W ~ ~ ~ ~ ~ ~ ~, Y~ ~ X X X X X X X X X X X X X X X X X X
a o ~ ~ r ~ ~ ~ ~ ~ w ~ ~r ~ N
H Z N 1~ r~ L~) ~ N t~ l O O N r-i ~ N
~I H ~\1 ,.~ ~ J\
I ~ r~ r ~ ~ o r~ er æ~ 0OOOO 0 0 Oo 0O o 0O o O 0O
W O Z ~ ~1 ~ ~J ~ ~ ~1 ~ ~ ~ ~ ~ ~ ~ ~J ~J ~ ~
~ Z H ~ X X X X X X X X X X ~C X X X X X X X
E~ e~
p:~ H ~1 N ~ r-l C~ r~l ~1 N 1-- il r~l ~) r~l ~ N r-l 11 3 ~ ~I/~I /\l ~l Al ,. ,~
ii~ H ~~ I~ I~ I~ r~ I~ r r~ D ~ er ~ ~ ~1 1-- w ~ r~
ooooo o o oo oo ~ oo o o oo ,~ ,~ ,~ ,~ ~ ~ ~ ~ ~ ~ ~ ,i ,~ ,~ ~ ~ ,~
O H O X X X X X X X X X X X X X X X X X X
u~ eJ~ o ~r ~r Ll o ":P
~W ~ cS~ ~ N N
H /\I/\IA!Al/\l /\1 Al Al H O ~ ~ 1~0 m .~ + ~ +
O ~ _ ~ co ~ ~9 0 ep ~ ~ O ...... . O ~ ~ ~ ~ O -E~ C Q ,~ ~ ~ u~ ~ co ~ ~ ~ ,~
~) a) Q
E~ O--~4 o +
w t~
~ ,~
.,~ ~ w -~
.,~
~ H 01 H
111 o In o ~ ~ ~ .

' :, .

;, ; ' ~, `

ooo V
o C~ o ~D
~ X X X
r~
. . . ,~
ooo v~
H C
_ Q t) ~ ~n o ~ o a) ~
E~ ~ o o o ~ 4~ C
_I ~ ~ .
O CO L~
a: s ~r x x x ~ ~ .,, _ ~ ~
~D
z a) ~. ,~
H E~ U~ ~`I ~ ~) E-l ~1 ._~ ~-I
~ E~ ~ Q
W ~z: ~ ~ ~1 0 ~ _1 ~
Z ~ 14 t~ O O o ~) LI h ~ W ~ (~ ~ i r-l (1~
t~ ~ ~ ~r ~ c 3 I ~ ~ ~ :~ X X
3 o ~ ~
a ~ ~ ~ ~ aJ u~ ~, H Z. . . 8~
O~1 _1 0 I ~ S
1 ~ a~ o 3 C~ ~~ .Q ~
I ~~ ~ o ~ a~ v Z 1~O O O
OOZ ~ ~ ~
.)Z H ~ U~ 3 X X X Z
~ ~o~ ~ ~o o~

m w H tr) ~ ~ .o S3 E~
0~ ~ ~U
E~ ~ ~ u~ ~ ~r ~ v ~O oo o s~
,~ ~
O H O X X X ~ Z 3 tn el~ (V ~-~
E'l . . .
H t~ o Eo~
~ ~I Ll lV r~
O C ~ ~1 ~ 1 Q ,a H O C~ l ~ ~ t~ ~a m .~, ~ u~ v E~ E~
v + + ~ u~ a) O ~ _ a~ ~3 ~ ~ O _ _ ~ ~ . . . ~
E~ :: ~ ~ ~r ~ ~ ~ o_:
O ~ '~ ~1 3 ~_ ~
O I~V
V o C C
E3 4~ v o o ~ O ~ O O
11~ U~ O
~ C C:
.,.
o O E~
m ~ o a .~ . .
.
.
. . ~ . .
.

.
.

~3~

~ ~o ~o o ~ o~
ô â~ o ~ ~

~ V
~ o ~ x ~ x x Ei ~ 'O N o ~::
O s.l ~0 d'o ~1 x_ a ~ ~ ~X 'X~ ~1 X a~
U If~ _ _ X~ ' _~
~ a~ ~ ~ I O ~ @ ~
~ ~ - ~ V oo $ ~3 .~ ~ X ~ ~
_ x x x . ~ ~ ~r ~ I ~ tn ~1 ~ ~ ~ ~ o ~ ~ ~o o ~ u~, o E~ ~ u~ oo ~ X ~x ~ ~x ~ ~ ~
~ ~ ~ ô ^~ ô ~^ û~ a) r~a ~ ~ ~

H . el~ ~ X X X X iU ~ ~D
_i ~ . ~ W

_ _ ~ ~

H O X X ~ X ~: _ ~ ~
~i Lr~ t~) o ~ L,O~ - 7~'w~
.. c~ 1 0 ~ 1 l~
J ~ I O I 3 ~
~3~ w~ ~

o ~ ~ Q C~
u~ o ' , :.

C~

o o o o o ~ ~ ~ X X X
V V V \/ V

~o ~
.-~ o ~ o o o $
H V VV V ~1 O O O
X ~Xô ~X ~
~ ~ ~ l O
~~D ~ ~ O ~ S~ ~
~)~r~ oo o o o C
Q Oo o~3 \~ ~ CJ
E~ .,., O o o o o ~ ~ ~ c~ ~x -XI ~X X _ X ~ ' H ~ ~ E~; ~ ~ ,, t~ .0 ~ ~ Q)~ In o Ll') o ~, ~1 !~ ~ ~ ~ ,, v ~
!Z: C :5 o o ~ u~
E~ O li U~ ~ o~ ,o~ o~o~
~ ~l ~ u~ X X x x X
F~ H ~ ^ aJ
~ O er I ~ P I ~ ~

X X X X X

-i V N
æ O x ~ X ~x x ~

~ --1 0 N C~ ~1 W ~
8~ o ~
. I o 0 Ln ~ ~1 1~

~ . :
~: . ' :

v~

~ o o l9Qo~ ~ X

~r ~o~ O O o ,V V V \/ V' în x x ~ ~ x 8 r~ ~ o o o er ~\~ V ~ /
"oO O O O o a) ~x ~ ~ ~X o CO~D V V \/ V

H ~ .H ~9X W X ~ X
~ ~ ~ a:~ ~_ I o o o o .~
~ ~ ~ ~ ~V V V V 'C
:5 + C~ U~
~ ,i ~IV \/ V V a)-8l~

H l~j o o t_ o o o~ ~ ~ ~
~ ~ X Xo x x x ~
H ~ el~ ~ I O O O O O 1~
-1 ~ / V V L~

~C ~ ~ X X ~
o ,o~ _ o o o 8 ~ o ~1 ~
~ ta ~ o o ~

~3~

These experiments were carried out using injection waters containing high levels of both aerobic and sulfide generating bacteria. Both biocides were effective at different but relatively low concentrations. However, they acted in a different manner in inhibiting growth of these diverse bacterial populations. The isothiazolinone took longer to inhibit the bacteria whereas the quaternary amine acted very quickly. The growth was only noted when low concentrations of quaternary ammonium compound were used. The microbicidal action of mixtures of these compounds was greater than either of the compounds used alone.

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for controlling aerobic and sulphide-generating bacteria in a secondary recovery of oil from oil fields which comprises the addition to oil well aqueous injec-tion fluids of compositions containing a mixture of (a) a 4-isothiazolin-3-one of the formula wherein Y is a hydrogen atom, a (C1-C18) alkyl group, a (C2-C18) alkenyl or alkynyl group, a (C3-C8) cycloalkyl group, or a phenyl group which is either unsubstituted or is substituted with halogen, cyano, nitro, (C1-C4) alkyl, (C1-C4) alkoxy, (C1-C4) alkylacylamino, (C1-C4) carbalkoxy, or sulfamyl, or a naphthyl group;
R is a hydrogen atom, a halogen atom, or a (C1-C4) alkyl group; and R' is a hydrogen atom, a halogen atom, or a (C1-C4) alkyl group; or the acid addition salts or metal salt complexes thereof, at a level from about 0.2 to about 20 ppm by weight of the aqueous injection fluid; and (b) a bactericidal quaternary ammonium salt or mixture of quaternary ammonium salts, at a level from about 1 to about 100 ppm by weight of the injection water, and in which the ratio of the 4-isothiazolin-3-one to quaternary ammonium salt is from about 5 to 1 to about 1 to 50.

2. A method according to claim 1 wherein the ratio of the 4-isothiazolin-3-one to quaternary ammonium salt is from 0.05 to 2.

3. A method according to claim 2 wherein the quaternary ammonium salt is a substituted dimethylbenzylammonium halide.

4. A method according to claim 3 wherein the quaternary ammonium salt is an n-(C8-C18)alkyl dimethylbenzylammonium halide or a mixture of n-(C8-C18)alkyl dimethylbenzylammonium halides.

5. A method according to claim 1 wherein Y is (C1-C8) alkyl, (C2-C8) alkenyl or alkynyl, (C3-C8) cycloalkyl, or phenyl, R is a methyl group, a hydrogen atom or a halogen atom, and R' is a hydrogen atom or halogen atom.

6. A method according to claim 5 wherein the 4-isothiazolin-3-one is 5-chloro-2-methyl-4-isothiazolin-3-one or 2-methyl-4-isothiazolin-3-one and the quaternary ammonium salt is alkyl (C12-40%, C14-50%, C16-10%) dimethylbenzyl ammonium chloride,in a weight ratio of from about 2 to 1 to about 1 to 20.

7. A method according to claim 6 wherein the microbicidal composition is added to the oil field injection water at a concentration of from about 0.5 to about 50 ppm.

8. A method according to claim 7 wherein the 4-iso-thiazolin 3-one is a mixture of approximately 3.5 to 1 weight ratio of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one and the quaternary amine is a mixture of C14 (40%) C16 (50%), C16 (10%) n-alkyl dimethyl benzylammonium chloride.

9. The method of claim 1 wherein Y is a (C1 -C18) alkyl group, a (C2-C18) alkenyl group, a (C2-C18) alkynyl group, a (C3-C8) cycloalkyl group, an aralkyl group consisting of a phenyl group substituted with a (C1-C4) alkyl group, or a phenyl or naphthyl group;
R is a hydrogen, chlorine or bromine atom, or a (C1-C4) alkyl group; and R' is a hydrogen, chlorine or bromine atom, or a (C1-C4) alkyl group.

10. The method according to claim 9 wherein Y is a (C2-C3) alkenyl or (C2-C4) alkynyl group.