Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 9 r)
D 9243 Mar. 04, 1991
USE OF SURFACE-ACTIV~ ESTER SU~FONATE S~LTS
IN WATER- AND OIL-BASED D~ILLING FrUIDS
AND OTHrR DRILL-HOLE TREATME~T AGENTS
The invention relates to the use of selected
emulsifiers having an increased ecological compatibility
for the production of fluid dispersed systems which are
present either as W/O inverted emulsions comprising a
continuous oil phase or as aqueous emulsions containing
a dispersed oil phase and which are suitable for the
technical application within the field of use of fluid
drill-hole treatment agents. Referring to a character-
istic example for agents of this kind, the invention is
described hereinbelow by way of oil-based and water-
based drilling fluids, respectively, and drilling muds
formed therewith. Ho~lever, the field of application or
the modification according to the invention of auxiliary
liquids of the Xind involved here is not limited there-
to, while it also includes in particular the areas of
spotting fluids, spacers, auxiliary liguids for wor~over
and stimulation and for fracturing.
It is one particular object of the invention to
substantially in~luence the ecological compatibili~y of
said auxiliary a~ents which are beinq worldwide used
today by employing selected and, more specifically,
.
7, ~3 `~ 3 3
D 9243 - 2 - Mar. 04, l991
ecologically acceptable types of e~ulsifiers. In its
preferred embodiment the invention intends to use said
biologically acceptable emulsifiers simultaneously in
combination with oil phases having an increased environ-
mental compatibility and especially a biological degrad-
ability.
Re ~eneral prior art
In the area of liquid sweeping systems for rock-
drilling to bring-up the removed drill cuttings, the
so-called inverted drilling muds are of excellent
importance which, based on W/O e~.uls-ons, contain a
dispersed aqueous phase in the continuous phase. The
content of the dispersed aqueous phase usually is within
the range of from about 5 to 50~ by weigh~.
However, also known are water-based drilling fluids
comprising an emulsified dispersed oil phase (O/W type),
the oil content of which may range f.om some percent to
about 50% by weight. O/W emulsion fluids of this kind
exhibit a number of considerable advantages over merely
water-based fluid systems.
The stabilization of each of the selected dispers-
ion forms requires the use of appropriate emulsifiers
either of the W/O type (inverted fluids) or of the O/W
type (emulsion fluids), respectively. Hereto, reference
is made to the pertinent literatur2, for example, G. R.
Gray, H. C. H. Darley, "Composition and Properties of
Oil Well Drilling Fluids", 4th Edition, Gulf Pu~lishing
Cp., Houston, London 1981, especially pages 51, 64 and
320 et seq..
.
. . . .
2 ~ 9 ~
D 9243 - 3 - Mar. 04, 1991
Today the oil phases of drilling fluids of the type
described here and comparably composed other drill-hole
treat~ent agents in practice are almost exclusively
formed by mineral oil fractions. This involves a con-
siderable environmental pollution, if, for example, the
drilling muds directly or via the drilled rock will
infiltrate the environment. Mineral oils are only
difficult to decompose and are virtually not anerobic-
ally degradable at all and, thus, to ~e rated as long-
term pollutants. ~evertheless, even i^ these oil phases
as the main constituent or at le~st a substantial
portion of the drilling fluid make a significant start-
ing point for ecological consideraticrs, an equivalent
attention will have to be paid also ~o the other com-
ponents of such multi-component sys~ems. Here, the
emulsifiers are of specific i~portance. Compounds of
this type, in accordance with the intended use thereof,
are highly active substances already at a low concen-
tration which are ~nown to be capable of an intense
interaction with ~he vegetable or ani~al organism.
Obiect of the invention
It is the object of the present invention to sub-
stantially improve the working agents of the described
type based on continuous or disparsed oil phases in
admixture with aqueous phases, in ap~reciation of the
ecological compatability thereof, over the working
agents of this kind as co~on to-day. More specific-
ally, it is the object of the invention, for the field
o~ use as involved here, to provide e~ulsifiers and/or
emulsifier combinations which have been per se ~nown and
have been described to be environmentally compatible to
a high degree, while they have not been put into use in
:. :
,. , : .
g~, ~
D 9243 - 4 - Mar. 04, 1991
the field of use involved here. In the preferred
embodiment of the invention, these environmentally
compatible emulsifiers of the W/O type or of the O/W
type are to be employed in combination with oil/water
phases, where the oil phases themselves have an in-
creased ecological compatibility and, more specifically,
are capable of being decomposed by natural degradation
mechanisms doing little harm to the environment.
On how to attain the object of the invention
The invention, in order to attain the first partial
object thereof, provides the use of per se ~nown
surface-active ester sulfonate salts as ecologically
compatible or acceptable compounds which, depending on
their constitution and kind of interaction with the
surrounding system are to be classified as W/O emulsi-
fiers or as O/W emulsifiers.
Thus, in a first embodiment, the invention relates
to the use of surface-active salts of esters from mono-
and/or polyolefinically unsaturated carboxylic aci s
having at least 8 carbon atoms and lower mono- and/or
polyhydric alcohols, which esters have been sulfonated
in (an) inner position(s) and comprise sulfur that has
been organically bonded to an at least predominant
degree, (briefly: ester sulfonate salts) as ecologically
compatible emulsifiers of the W/O type and/or o/W type
in fluid and pumpable drilling fluids and other fluid
drilling-hole treatment agen~s which comprise a con-
tinuous or a dispersed oil phase toge~her with an
aqueous phase and which are suitable for an environ-
mentally acceptable exploitation of geological
~ resources, for example oil or natural gas deposits.
: .
2 0 ~ 5
D 9243 - 5 - Mar. 04, 1991
Of particular importance in this context are the
corresponding inverted drilling fluids which in
continuous oil phase contain a dispersed aqueous phase
together with emulsifiers and further conventional
auxiliary agents such as thickeners, fluid-loss
additives, weighting agents, soluble salts and/or alkali
reserve. In this embodiment according to the inventlon
there is provided the use of selected surface-active
ester sulfonate salts as emulsifier or at least as a
component on an ecolcgically compatible emulsifier
system.
Preferred is the use of emu!sifiers based on
surface-active ester sulfonate salts in combination with
environmentally compatible ester oils, oleophilic
alcohols and/or corresponding ethers as continuous or
dispersed oil phase. Here particular reference is to oe
made to pertinent developments by applicant describir.g,
in a greater number older patent applications, proposals
for substituting the previously co~mon mineral oil
fractions with ecologically compatible readily degradab-
le oil phases. Thereby, various types of substituti-.g
oils h~ve been presented which may also be used as
mixtures. They include selected oleophilic monocarb-
oxylic acid esters, selected polycarboxylic acid esters,
at least largely water-insoluble alcohols which are
fluid under the operation conditions, corresponding
ethers and selected carbonic acid esters. In summary,
reference is made here to the older applications
P 38 42 659.5 (D 8523), P 38 42 703.6 (D 8524),
P 39 07 391.2 (D 8506), P 39 07 392.0 (D 8607),
p 39 03 785.1 (D 8543), P 39 03 784.3 (D 8549),
P 39 11 238.1 (D 8511), P 39 11 299.3 ~D 8539),
P 40 18 228.2 (D 9167) and P 40 19 266.0 (D 9185). All
... ~
.
.~ .
.
20~91)9~ ~
D 9243 - 6 - Mar. 04, 1991
of the older applications mentioned here relate to the
field of oil-based drilling fluid systems, especially of
the W/O inverted type. Water-based emulsion fluids
using these oil phases of an increased degradability
have been described in the older German applications
P 39 15 876.4 (D 8704), P 39 15 875.6 tD 8705),
P 39 16 550 7 (D 8714) and the applicatlons
P 40 18 228.2 (D 9167) and P 40 19 266.0 (D 9185) as
already mentioned.
The invention, in its most important embodiment,
comprises the use, in combination, of the a_ove-
described e~ulsifiers of the class of the surface-active
ester sulfonate salts toyether with dispersed or con-
tinuous oil phases of the type described last. ~he
disclosure of said older applications is hereby expli-
citly incorporated by reference.
Details of the teachinq accordinq to the invention
before the backqround of a special technical knowled~e
The sulfation of unsaturated ~arboxylic acids o~
natural or synthetic origin and of the esters thereof
with mono- and/or polyfunctional alcohols has been Xnown
for long. Here the term sulfation to be classified as a
superordinate term, in its precise chemical definition,
comprises two different possible subjects with respect
to the reactions occurring or the reac~ion products
being formed, both of which subjects may as well be
simultaneously involved. The first of these subjects,
in its chemical definition, is to be described 25 a
sulfat~ formation ("sulfation" in a narrower sense)
wherein sulfuric acid ester groups are formed which
contain the sulfur bonded to carbon through an oxygen
.
,
D 9243 - 7 - Uar. 04, 1991
atom. Such sulfation products are formed, for example,
by the addition of a sulfuric acid residue to the
olefinic double bond of unsaturated carboxylic acid
molecules or by esterification of free hydroxyl groups
present on the carbon backbone.
To be distinguished therefrom is the sulfonation.
Typical for this reaction is the attachment of organic-
ally bonded sulfur to the carbon backbone to for~ direct
C-S bonds. The te~ching of the invention deals with
emulsifiers of the described type which at least pre-
dominantly are true sulfonates within the last-described
.eaning, that is with directly organically bonded sulfur
in the molecule thereof.
In spite of these clear differences in constitution
which are also manifest in the chemical behavior, e.g.
in the respective stabilities to hydrolysis of both
classes of co~pounds, the :Language used in practice is
ambiguous. Thus, in the pertinent litera~ure the term
sulfonate is frequently used when, in reality, sulfates
are intended to be described. Thus, for example, there
is reported of sulfonation products which are relatively
poorly stable to acids and alkalis, if, besides the
formation of true sulfonic acids, above all unstable
sulfuric acid esters are formed; hereto cf., for
example, DE 12 46 71~ and the summarizing treatise by
H.L~ Sanders "Sulfoils - The Resurgent Surfactants",
SOAP/COSMETICS~C~E~ICAL SPECIALTIES, May 1975, 39/40.
Also in the field of drilling fluid systems which the
invention relates tol and more particularly of the
so-called inverted fluids, this definition in unprecise
language is frequently used; hereto cf., for example,
the U.S. Patent Specification No. 3,642,623, column 6
:. :
i
~ ,
J ~
D 92~3 - 8 - Mar. 04, 1991
lines 26 to 28. The preparation of true sulfonates com-
prising predominantly organically bonded sulfur from
esters of unsaturated carboxylic acids, and especially
unsaturated fatty acids, with mono- or polyhydric
alcohols has been known since long. Reference may be
made, for example, to the DE 12 46 717 as already quoted
and to the DE-A1-3~ 37 443. Thus, for exa~,ple, true
sulfonates may be obtained under compara~ly mild wor~ing
conditions from unsaturated oils of vegetable and/or
animal origin, highly diluted sulfur trio~ide/air
mixtures are employed for sulfation. Upon subsequent
neutralization, well electrolyte-resistant water-soluble
compounds are obtained which have been described as
storage-stable acid-resistant and alkali-resistant
emulsifiers. Fields of technical use include, for
example, leather oiling agents, greasing agents for the
textile industry, the manufacture of metal processing
oils and the production of electrolyte-resistant
emulsions for the most ~arious intended uses. As to
details, cf. the literature already quoted.
Ester sulfonates confor~ing to the definition
according to the invention, and more specifically the
combination thereof with ecologically compatible oil
phases o~ an increased degradability have so far not
been proposed for the field of use of the drilling hole
treatment agents which the instant invention relates to.
The class of the so called fatty acid sulfonates
within the wide meaning of the term as explained herein~
above indeed plays an important role in practice and in
the literature as an emulsifier component for building
O/W a~d W/O emulsions for the field of drilling hole
~luids and for drilling hole treatment agents. However,
2 i~
D 9243 - 9 - Mar. 04, 1991
here in the first place the corresponding sulfation
products of unsaturated carboxylic products have been
described, but not so the esters within the definition
according to the invention. Moreover, sulfonates having
a dif~erent constitution play an important role, in
which sulfonates especially the sulfo grouping has been
introduced into the emulsifier molecule via aromatic
molecular moieties. Compounds of this type are not
compatible with the goal according to the invention o~
an increased ecological compatibility. Reference may be
made, by way of an extract from the voluminous prior art
printed literature, to DE 12 ~ 289 and to the U.S.
?atent Specifications ~os. 3,476,912, ~,012,329,
3,89~,431, 3,340,188, 3,878,111 and, as already quoted,
3,642,623. In these printed publications there have
been mentioned, inter alia, petroleum sulfonates, tall
oil pitch sulfonates, combinations of sodium oleic acid
sulfonate and titanates and further combination systems.
In the practice of, more particularly, water-based
fluid systems and comparable liquid phases the so-called
Turkey-red oil plays a remarXable role as an emulsifier
component. Said material is ~nown to be a sulfated,
castor oil-based oil; hereto cf. in detail, for example,
Rompp Chemie-Lexikon, 7th Edition (1977), 3707.
In contrast thereto, the teaching of the invention
provides the use of sur~ace-active salts of esters from
mono- and/or polyolefinically unsaturated carboxylic
acids having at least g carbon atoms and lower mono-
and/or polyhydric alcohols, which esters have been
sulfonate~ in (an) inner position(sj and comprise sulfur
that has been organically bonded to an at least pre-
dominant degree, as ecologically compatible emulsifiers
,
....
.~ ' .
. . .
2 o ~
D 9243 - 10 - Mar. 04, 1991
of the W/O type and/or o/w type. In comparison to the
salts of unsaturated carboxylic acids or salts thereof
which have been correspondingly sulfonated in (an) inner
position(s) to form C-S bonds, the substance class
proposed according to the invention is distinguished by
the additional ester bond and, hence, the alcohol moiety
included in the molecule. The free carboxylic group,
thus, has been prevented from undergoing an immediate
salt formation. At the same time the respective pre-
deter~ined alcohol moiety allows a wide variation of the
base molecule. -hus, mn C5m bination with the deliberate
control of the degree of sulfonation which will in
greater detail be described hereinbelow, hereby the
possibility is created of synthesizing emulsifier
molecules exhibiting a distribution as wide as possible
of the ratio of lipophilic to hydrophilic properties of
the material. Hence, in combination with further
possibilities o~ variation to be discussed hereinbelo~,
this implies the chance of taking an improved technical
action without havlng to compromise the ecological
advantages of _he emulsifie3r class as involved here.
There~ore, the teach~ng of the invention makes il
possible to tho_oughly and persistently stabilize oil~
based W/O inverted emulsions without using the
N-containing emulsifier systems as widely used today,
the ecological compatibility of which, especially in the
highly sensitive marine eco-system, is no~ undisputed.
The ester sulfonate salts to be emplox~d accordinq to
the invention
Ester sulfcnate salts preferred for a use according
to the invention are derived from unsaturated monocarb-
oxylic acids of natural and/or synthetic origin which
~ ~ 3 ~
D 9243 - ll - Mar. 04, l991
comprise from lO to 40 carbon atoms and preferably are
within the range of Cl2_32.
Starting materials which are inexpensive and
available in large amounts may be the respective fatty
acid glyceride esters of natural origin. The prevailing
portion of the carboxylic acid moieties as here con-
templated is within the range of appropriate fatty acids
having from 16 to 24 carbon atoms and from l to 5 double
bonds. Examples for such ester oils of natural origin
are fatty acid glycerol esters, and especially the
~espective triglycerides based on coriander oil,
chaulmoogra oil, sunflower oil, cottonseed oil, olive
oil, peanut oil, linseed oil, lard ol, meadow foam oil,
hog's lard or fish oil. Of particular importance as a
starting material for the production of the sulfonated
fatty acid esters to be used according to the invention
is fresh rapeseed oil which is rich in oleic acid.
Certain selected tri~lycerides may be employed as well
as any optional mixture of various origins. Admixtures
of natural and synthetic esters are as well usable.
The term o~ the fatty acid glycerol esters includes
the mono-, di- and tri-esters and the mixtures thereof,
as may be obtained by esterification of one mole of
glycerol with from one to three moles of fatty acids
and/or fatty acid mixture or by the transesterification
of unsaturated triglycerides with, more specifically,
from 0.3 to 2 moles of glycerol. The term of the
unsaturated fatty acid esters and the sulfonates obtain-
ed therefrom, respectively, expressly includes also
those native and/or synthetic esters and ester mixtures,
the fatty acid component of which is not completely, but
only partially composed of unsaturated fatty acids.
"
.
... .
2~3 `3 0 `9 i ; `F
D 9243 - 12 - Mar. 04, 19~'
Further included is the range of mixtures, and more
particularly of those commercial mixtures ob~ained in
practice, of various unsaturated or largely unsaturated
fatty acid glycerol esters with each other. In all of
these cases it is preferred that in the ester or ester
mixture, respectively, the portion of the mono- and/or
polyunsaturated carboxylic acids comprises at leat about
50% by mole - relative to the mixture of carboxylic
acids. The use in combination of saturated fatty acids
in minor or at most equal amounts is expressly included
in the teaching of the invention.
The ester-forming alcohol component especiall~
comprises the moieties of mono- to tetrahydric alcohols
comprising preferably up to 5 carbon atoms. Thus,
important esters may be derived from methanol, ethanol
and, if desired, also hiqher alcohols. Thus, under the
aspect of the use of sulfonated esters of monofunctional
alcohols, it may be expedient for reasons to be discuss-
ed hereinafter, to employ sufficiently lo~-volatile
alcohcl components so that a potential ester cleavage
during practical use will induce no inhalation-toxico-
logical danger. Nevertheless, said aspect which will be
discussed hereinbelow in the context of ester oils is or
minor importance in connection with the emulsifiers.
These emulsifier components anyway ar~ employed only in
comparably restricted amounts so that the respective
endangerment is a priori of minor significance. The
aspect of a potèntial inhalation-toxicological danger is
in fact irrelevant in the case of use of esters derived
from polyfunctional alcohols due to the low volatilities
thereof. Thus, here diols such as ethylene glycol, 1,2-
and 1,3-propanediol or the respective butanediols are to
be considered. Nevertheless, of particular importance
:
.~, , ~.
"
~i~ 3~ jJ~ i i
D 3243 - 13 - Mar. 04, 1991
is glycerol, already quoted as an ester-forming poly-
functional alcohol component.
More specifically, such esters derived from poly-
functional alcohol provide the options of modifying, by
introducing the sulfo group, only one or several or all
of the carboxylic acid moieties present in combination
with the alcohol .olecule. In a per se known manner the
hydrophilic character will be the more pronounced, the
higher the number of sulfonate groups per ester molecule
will be. This is to be taken into special consideration
also if esters of polyunsaturated carboxylic acids will
be employed which are basically accessible to a multiple
sulfonation reaction.
Under this aspect of the facts it is preferred
according to the invention to use ester sulfonate salts
having a molar ratio of sulfonate/carboxylic acid moiety
of a maximum value of about 1 (statistical mean value).
Nevertheless it r~ay be particularly preferred here to
employ lower values of said molar ratio. In the way as
intimated here t:-e lipophilic por~ion of the ester
molecule will be strengthened. This fact may be de-
liberately utilized for the formation of particularly
suitable W/O emulsifiers. Thus, for example, molar
ratios of sulfonate/carboxylic acid moiety within the
ranqe of from 0.25 to 0.7 may be preferred. In the case
of the triglyceride-based ester sulfonate salts the
preferred molar ratios of the kind indicated are within
the range of from about 0.3 to 1 (statistical mean
value), i.e. within the range of from about 1 sulfonate
group per molecule to a degree of conversion allowing
one sulfonate group at each carboxylic acid moiety.
.
': ;;
-.
:
.
~'~J ~ ) J ') ,~, `''
D 9243 - 14 - Mar. 04, 1991
The preparation of the substance group as especial-
ly important according to the invention of the ester
sulfonate salts based on unsaturated mono-, di- and/or
triglycerides derived from fatty acids having from 16
to 24 carbon atoms and from 1 to 5 double bonds at a
proportion of unsaturated fatty acids of more than 50%
by weight, in an improved embodiment, is the subject
matter of applicants older German patent application
P 39 36 001.6 (D 8902). The disclosure of said older
patent application is incorporated herein by reference.
Ester sulfonates of this kind, in preferred -mbodiments
~ay be derived to a degree of more than 50~ by weight
from oleic acid and/or linoleic acid and especially
ori~inate from rapeseed oil which is rich in oleic acid.
In the manner described in said older application -
hereto also cf. J. Falbe (Ed.) "Surfactants in Consumer
Products", Springer Verlag, Berlin-Heidelberg 1987, page
61 - a largely selective introduction of sulfonate
groups is successfully achieved with a s~multaneous
significant suppression of the introduction of sulfate
groups into the ester molecule, the partial occurrence
of which is inevitable.
The emulsifiers based on ester sulfonate salts as
praferred according to the invention comprise a ratio of
sulfonate groups to sulfate groups of at least 60/40.
Higher sulfonation ratios, especially those in excess of
70/30, are preferred. In the prac~ice of the technical
process, upon the use of the described ester oils of
natural and/or synthetic origin, ratios of sulfonate
groups to sulfate groups within the range of from about
75/25 ~o 85/15 are achievable at a reasonable technical
expense. Ester sulfona~es of this ~ind are especially
2ag~0.~
D 9243 - 1~ - Mar. 04, 1991
suitable materials for the use on a commercial large
scale within the scope of the invention.
One important possibility for modifying the
emulsifier properties and, more specifically, for
influencing the .iLB value of ;he respective ester
sulfonate salts is constituted by the choice of the
salt-forming cations. Thereby also the water and oil
solubilities may be especially affected. Generally
there is ap~licable that water-scluble salts of
monovalent cations, more specifically the al.`~ali metal
and/or ammoniu~ salts, will result in favoring the
hydrophilic properties, ~hereas the ~se of ?oly~alent
cations may reduce the water-solubility. Then in
compounds of this kind the lipophilic character may
become more pronounced, so that compounds of this kind
are particularly suitable fOL^ a use in the field of the
W/O inverted emulsions. Polyvalent cations a-e derived
especially from the al~aline earth metals and aluminum.
In the class of the polyvalent cations, calcium is of
special importance, whereas sodium and a~monium are of
predo~inant im?ortance as mor.ovalent cations. It ~
~e apparent that the structure of the ester sulfonate
salts selected according to the invention cc-.prises a
multiplicity of parameters to be purposefully influenced
such as to allow controlling the emulsifier action and,
thus, an optimization of the desired effec.s. Under
this aspect, ester sulfonate sal~s within the scope of
the invention, are much more flexibly modifiable than
the corresponding sulfonate salts of unsaturated mono-
carboxylic acids of natural and/or synthetic origin
which have been sulfonated in the inner positions.
.
''
, ,
2~J~
D 9243 - 16 ~ Mar. 04, 1991
In the practical operation there is the further
possibility of utilizing an in situ formation of such
ester sulfonate salts of pol~alent cations. This may
be illustrated by way of the following example:
The aqueous dispersed phase in oil-based drilling
fluids of the inverted type is generally loaded ~ith
dissolved salts, especially calcium salts such as
calcium chlorid, in practical use. If such aqueous
phases containing dissolved alkaline earth metal salts
are used in forming 'che inverted emulsion, then the
corresponding alkaline earth metal salts of tne ester
sulfonates will be formed even if said e~ulsifier
components are initially employed in the form of their
sodium salts. Not only does this allow a particularly
economical realization of the teaching according to the
invention, but it has also heen shown that rheologically
highly stable inverted emulsions are accessible by such
an in situ formation of the alkaline earth metal salts
which are especially active as ~/0 emulsifiers. It will
be right apparent in the case of such a salt-exchange
reaction as shown here that also the ootassium salts may
have particularly importance as feedstock material: In
the reaction with the meaning as described last, there
is formed potassium chloride besides the calcium salts
that are active as W/O emulsifiers, which potassium 5
chloride transits in the aqueous dispersed phase and
here is a known preferred constituent for ~he inhibition
of water-swellable clays within the exploitation of
geological resources.
The ester sulfonate salt-based emulsifiers, in a
preferred embodiment, are employed as the essential
components forming the type of emulsion and stabilizing
:
D 9243 - 17 - Mar. 04, 1991
the emulsion. Nevertheless the teaching according to
the invention also includes mixed systems in which ester
sulfonate salts are used together with other emulsifier
components. It is preferred that these other emulsifier
components on their own are ecologically compatible; in
this context reference may be made to applicant's older
application P 40 03 028.8 (D 8158) wherein selected
ether-based emulsifiers for oil-based inverted emulsions
have been described. Another example for suitable
co-emulsifiers is provided by the surface-active alpha-
sulfofatty acid derivatives and al~yl glycoside com-
pounds described in the parallel pending Ger~an Patent
Applicatlons P 40 24 659.0 and P 40 24 658.2 (D 9222 and
D 9223).
Salts - and more specifically corresponding alXali
metal or alkaline earth metal salts - of sulfonated
and/or unsulfonated unsaturated and/or saturated fatty
acids of natural and/or syr~thetic orgin can be especial-
ly suitable co-emulsifiers. Thus, the invention in-
cludes admixing any optional fatty acids or fatty acid
salts as co-emulsifiers to the respective compositions
of active ingredients, in which case, more specifically,
it has been shown that no problems are caused by a use,
in combinatioll, of unsatured straight-chain and/or
branched fatty acids.
If such emulsifier mixtures are used, then in
preferred embodiments of the invention the ester sulfon-
ate salts constitute at least 10% by weight, and prefer-
ably at least 50% by weight, of the respective emulsi-
fier system.
''
.
.
:~ 2 ~ 3 ~j
D 9243 - 18 - Mar. 04, 1991
The ester sulfonate salts may be used in amounts of
from about 0.1 to 10% by weight, relative to ths sum of
the liquid phases water and oil. Preferred amounts are
within the range of from about 0.5 to 5% by weight of
the emulsifier components, while the range of from about
1 to 3% by weight of the emulsifier - again relative to
the sum of water + oil - is of particular importance.
The economical production of the emulsifiers
according to the invention is significantly facilitated
by omitting the step of bleaching the reaction products
as primarily o~tained, which step in prior art as
evidenced by the pertinent printed publications is
considered as an essential process step. Thus, the
production process for compositions of active substances
containing ester sulfonate salts within the scope of the
invention may be restrictecl to the process steps of
sulfonation and salt-formation. The cruda reaction
product may be directly put into a commercial use.
In the preferred embodil~ents as especially ~eatured
in the introduction, the appropriate oil phases are
constituted by the ecologically compatible ester oils,
oleophilic alcohols and/or ethers described in appli-
cant's older applications as quoted. When said agents
are used, the invention relates to the drill-hole treat-
ment agents which are fluid and pumpable within the
temperature range of from 5 C to 20 C, and more
specifically drilling fluids based on
~ either a continuous oil phase, especially in
admixture with a dispersed aqueous phase (W/O
inverted type)
- or a dispersed oil phase in a continuous aqueous
phase (O/W emulsion type).
:
2 ~ 3 ~
D 9243 - 19 - Mar. 04, 1991
The ecologically compatible oils and oil phases,
with respect to the possible physical properties there-
of, covers a wide range. The invention comprises, on
the one hand, oil phases which are fluid and pumpable
also at low temperatures. These, more particularly,
include representatives suitable for the preparation of
W/O emulsions. However, on the other hand, highly
viscous to solid oil phases and materials of this type
may also be included in the use within the scope of the
teaching according to the invention. This may be
exemplified by the following deliberations:
For water-based 0/~ emulsion fluids a high mobility
of the dispersed oil phase is not required and, as the
case may be, not even desirable. For example, to ensure
good lubricating properties, oil phases adjusted such as
to be comparably viscous may be advantageous. Another
possible use of highly visc:ous or even solid ecological-
ly compatible oil phases may be constituted, if the
respective oil phase involved in the final product is
only partially formed by said highly viscous to solid
representatives of degradable esters, alcohols and/or
ethers which themselves have been admixed with comparab-
ly highly liquid oils of this kind.
.
Nevertheless, there is consistently applicable to
all oil phases or mixed oil phases to be used according
` to the invention that ~lash points of at least about
100 C and preferably flash points of above about 135 'C
are demanded for reasons of safety in operations.
Values that are distinctly higher, particularly those
above 150 ~C, may be especially expedient. rurthermore~
there is consistently applicable ~o the oil phases as
potentially susceptible to hydxolysis that may be used
. ` `" - .
. .
D 92~3 - 20 - Mar. 04, 1991
within the scope of the invention not onLy that the
requirement of the ecological compatibility will have to
be met by the compound put into use, i.e., for example,
the respectively selected ester oil or ester oil mix-
ture, but also that no toxicological and especially no
inhalation-toxicological danger will be induced upon a
partial saponification in practical use. Within the
scope of the mentioned older applications there has been
described in great detail that here, more particularly,
the various representatives of ester oils are referred
to, with the monofunctional alcohols from the esters
formed being again of particular significance here. In
comparison to ?olyfunctional alcohols, the lo~er members
of the monofunctional alcohols are highly volatile, so
that here a partial hydrolysis may cause exposure to
secondary danger. Accordingly, in the classes of the
various ester oils those monofunctional alcoholâ
included in the use, or the moieties of such alcohols,
have been chosen so that they have at least 6 carbon
atoms, and preferably at least 8 carbon atoms, in t~.e
molecule thereof.
The inverted drilling fluids of the ~ind involve
according to the invention, irrespectively of a definite
property of the continuous oil phase, in preferred
embodiments have a plastic viscosity (PV) wi~hin t~.e
range of from 10 to 60 mPa.s and a flow limit (yield
~oint, YP) within the range of from 5 to 40 lb/100 ft
each determined at 50 C.
As an oil phase which is ecologically compatible
and well fluid at low temperature, there have proven to
be useful, more specifcally, ester oils o~ monocarboxyl-
ic acids which then, in a preferred embodiment of the
;'
~ , ;
n ~
D 9243 - 21 - Mar. 04, l991
invention, are derived from at least one of the follow-
ing subclasses:
a) Esters of Cl 5-monocarboxylic acids and mono-
and/or polyfunctional alcohols, whereof the
moieties of monohydric alcohols comprlse at least 5
carbon atoms and preferably at least 8 carbon atoms
and the polyhydric alcohols preferably have from 2
to 6 carbon atoms in the ~olecule,
b) Esters of monocarboxylic acids of synthetic and/or
natural origin co~prising from 6 to 16 carbcn
atoms, and ~ore specifically esters of aliphatic
saturated monocarboxylic acids and ~.ono- and/cr
polyfunctional alcohols of the kind .~.entioned
a),
c) Esters of olefinically mono- and/or polyunsaturated
monocarboxylic acids having at least 16, and
especially 16 to 24 carbon atoms and es?eciall~
monofunctiona} straight-chain and/or branched
alcohols.
Starting materials for recovering numerous .~.ono-
carboxylic acids falling under these subclasses,
especially those having a higher number of carbcn atoms,
are vegetable and/or animal oils. There may be -.ention-
ed coconut oil, palm kernel oil and/or babassu oil,
` especially as feedstock for ~he recovery of .~nocarb-
oxylic acids of the prevailing range up to Cl3 and of
essentially saturated components. Ester oils of
vegetable origin based on olefinically mono- and option-
ally poly-unsaturated carboxylic acids of the range of
Cl6 24 are, for ex~mple, palm kernel oil, peanut oil,
:~ :
~3 9 ~ j ~
D 9243 - 22 - Mar. 04, 1991
castor oil, sunflower oil, and especially rapeseed oil.
sut also components synthetically recovered are import-
ant structural elements for ecologically compatible oil
phases on the side of the carboxylic acids as well as on
the side of the alcohols.
Additives to the oil-based and/or water-based fluid
Inverted drilling muds conventionally contain,
together with the continuous oil phase, the finely
dispersed aqueous phase in a~ounts of from ~ to 50% by
weight. In water-based emulsion fluids the dispersed
oil phase is usually present in amounts of f-om at least
about 1 to 2~ by weight, frequently in amounts of from
at least about 5% by weight with an upper limit of the
oil portion of about from 40 to 50% by weight - the
percentage by weight in all cases being based on the sum
of the unloaded liquid portions of oil/water.
Besides the water content, there are to be taken
into consideration all of the additives provided for
comparable types of fluids. Said additives may be
wa~er-soluble, oil-soluble and/or water-dispersible
and/or oil-dispersible.
Conventional additives, besides the emulsifiers
defined according to the invention, include, for
example, fluid-loss additives, soluble and/or insoluble
materials to build-up structural viscosity, alkali
reserve, agents for inhibiting an undesirable water
exchange between drilled formations - e.g. water-swell-
able clays and/or salt layers - and the, e.g., water-
based drilling fluid, wetting agents for an improved
~trike of the emulsified oil phase on solid surfaces,
e.g. for improving the lubricating effect, but also for
D 9243 - 23 - Mar. 0~, 1991
improving the oleophilic closure of exposed rock
formations, e.g. rock surfaces, biocides, for example
for inhibiting bacterial onset and growth of o/w
emulsions and the like. In detail, reference is here to
be made to pertinent prior art such as described, for
example, in the technical literature as initially
quoted; cf., more specifically, Gray and Darley, loc.
cit., Chapter 11, "Drilling Fluid Components". Just by
way of an excerpt, there may be quoted:
Finely dispersed additives for increasi..g the
der.sity of the fluid: ~idely used is barium sulfate
(baryte), but also calcium carbonate (calcite) or the
mixed carbonate of calcium and magnesium (dolomite) are
used.
Agents for a build-up of structural viscosity which
simultaneously will act as fluid-loss additives': Here,
bentonite of hydrophobized bentonite are to be mentioned
in the first place. For salt water fluids, other com-
parable clays, and more specifically attapulgite and
sepiolite are of considerable importance in prac-ice.
Also the use in combination of organic polymer
~o~pounds of naturàl and/or synthetic origin may be of
considerable importance in this connection. There may
be especially mentioned starch or chemically -.odified
starches, cellulose derivatives such as carboxymethyl-
cellulose, guar gum, xanthan gum, or also merely
synthetic water-soluble and/or water-dispersible polymer
compounds, especially of the type of the high .~.olecular
weight polyacryl amide components with or without an-
ionic or cation modifications, respectively.
' '' ~ . : ''
, . ~ .
~'`'`' ~ ' .
2033~
D 9243 - 24 - ~ar. 04, l991
Diluents for regulatlng the viscosity: The so-
called diluents (thinners) may be organic or inorganic
in n~ture. Examples for organic thinners are tannin
and/or quebracho extract. Further examples are lignite
and lignite derivatives, especially lignosulfonates.
However, as has been set forth hereinabove, in a pre-
ferred embodiment, just here no toxic compounds will be
included in the use, among which in the first place the
respective salts with toxic heavy metals such as
chromium and copper are to be mentioned. ~olyphosphate
compowlds constitute an exa-?le of inorganic thinners.
Additives inhibiting the undesirable ~ter-exchange
with, for example, clays: Here to be consi~ered are the
additives known from prior art for oil- an~ water-based
drilling fluids. These include halides and/or
carbonates of the alkali and/or alkaline earth metals,
whereof the potassium salts, optionally in combination
with lime, may be of particular importance.
R~ference may be made, for example, to the relevant
publications in "Petroleum Engineer In~ernational",
September 1987, 32-40, and "World Oil", November 1983,
93-97.
Alkali reserves: Here to be taken into consider-
ation are inorganic and/or organic bases adjusted to
match the total behavior of the fluid, and more part-
icularly basic salts or hydroxides of alkali and/or
alkaline earth metals as well as organic bases. Kind
and amount of these basic components will have been
selected and mutually adjus~ad in a known manner so that
the drilling hole treating agen~s will be adjusted to a
pH value within the range of from about neutral to
. .
.
~ .
;. , , ~ ,
;~ ~ $ ~
D 9243 - 25 - Mar. 04, 1991
moderately basic, especially to the range of from about
7.5 to 11.
3asically, the amounts of each of the auxiliary
materials and additives is within the conventional range
and, thus, may be learnt from the relevant literature as
quoted.
E X A M P L E S
In the following Examples 1 ar.d 2, by observation
of a standard formulation for oil-based drilling fluid
systems of the W/o type there are set forth appropriate
drilling fluid systems, wherein each continuous oil
phase is formed by a selected oleophilic carboxylic acid
ester of the following definition:
An ester mixture comprising substantially saturated
fatty acids based on palm kernel and 2-ethylhexanol
which to the by far predominating part is derived from
C12/14-carboxylic acids and confor.-..s to the following
specification:
C8: from 3.5 to 4.5% by weight
C10: from 3.5 to 4.5% by weight
C12: from 65 to 70 ~ by weisht
C14: from 20 to 24 % by weight
C16 about 2 % by weight
C18: from 0.3 to 1 % by weight
The ester mixture is a bright yellow liquid which
has a flash point in excess of 165 C and a viscosity
(Brookfield, 20 C) of from 7 to 9 cP.
~, ~
., .
. .
.J J3 9 ~ ;
~ . . ..
D 9243 - 26 - Mar. 04, 1~91
The viscosity characteristics are determined with
unaged and aged material as follows:
Measurement of the viscosity at 50 C in a Fann-35-
viscosimeter from the company Baroid Drilling Fluids,
Inc.. In a ~ se known manner there have been deter-
mined the plastic viscosity (PV), the yield point (YP)
and the gel strength (lb/100 ft2) after 10 seconds and
after 10 minutes. In Example 1 there is further deter-
mined the fluid loss value (HTHP).
Ageing of the respective drilling fluid is effected
by way of a treatment at 125 'C in an autoclave - in a
so-called roller oven - for 16 hours.
', The drilling fluid systems are composed in a per seknown manner in accordance with the following basic
formulation:
230 ml of carboxylic acid ester oil
26 ml of water
6 g of organophilic ~entonite (GELTONE from
the company Baroid Drilling Fluids,
Inc . )
12 g of organophilic lignite (DURATONE from the
company Baroid Drilling Fluids, Inc.)
2 g of lime
12 g of emulsifier based on ester sulfonate sal.s
346 g of baryte
g.a g of CaC12 . 2 H2O
;
.
;.
,
. . .
:, , .
9.j
D 9243 - 27 - Mar. 04, l991
Example 1
An unsaturated C16 24-triglyceride obtained from
rapeseed oil is allowed to react with gaseous S03 (about
5% by weight of 5O3 in nitrogen or air~ within a
temperature interval of from 70 C to 80 C at a feed
~olar ratio of triglyceride ester to SO3 of 1 : 1.2.
This is followed by an alkaline hydrolysis to a constant
pH value. Then the products are adjusted to a pH value
of from 6.5 to 8.5. There is obtained an aqueous con-
centrate of the low-sulfonated rapeseed esters which has
the following characteristic values:
Active substance: 39.7 % by weight
Unsaturated portions: 27.1 % by weight
Water: 58.9 % by weight
Na2S04: 1.4 % by weight
This reaction product is employed as the "emulsi-
fier based on ester sulfonate salts" in the basic form-
ulation quoted above.
The characteristic values determined of the unaged
and of the aged r.~aterials - as indicated above - are
summarized in the following Table.
Unaged Aged
Material Material
Plastic viscosity (PV) ~1 ;8
Yield point (YP) 4 23
Gel strength (lb/100 ft2)
lO seconds 3 17
10 minutes 5 36
HTHP 6 ml
.
. .
. .
....
2 0 3 ~
D 9243 - 28 - Mar. 04, 1991
Example 2
As the emulsifier there is employed a rapeseed oil
which now has been sulfonated to a higher degree. The
following data apply to the sulfonation step: Ratio of
triglyceride ester to SO3 of 1 : 3; process temperature
80 'C to 90 'C. The aqueous sulfonate salt product
employed as "emulsifier" in the basic formulation quoted
above has the following cha~acteristic values:
~ctive substance: 53.9 % by weight
Unsaturated portions: 1,.6 -O by weight
Water: 44.4 % by weight
Na25O4: 1.7 % by weight
The values determined of the unaged and of the aged
materials are as follows.
Unaged Aged
Material Material
Plastic viscosity (PV) 45 52
Yield point (YP) 8 22
Gel strength tlb/100 ft2)
10 seconds 6 19
10 minutes 14 33
HTHP 18 ml
Examples 3 and 4
.
With the use of the ester sulfonate salt-based
emulsifiers of the Examples 1 and 2, W/o inverted fluid
systems were prepared based on pure mineral oil as
common in practice (commercial product BP 83 HF) in a
~ se known manner according to the following form-
; ulation:
.
:
:
. .
~ .
3 ',~
D 92~3 - 29 - Mar. 04, 1991
204 ml of mineral oil
7.2 g of emulsifier based on ester sulfonate salts
3.6 g of lime
6 g of organophilic lignite (DURATONE from the
company Baroid Drilling Fluids, Inc.)
3.6 g of co-emulsifier based on C18-fatty acid
105.6 g of aqueous calcium chloride solution
(9-2 g of CaC12 . 2 H2O)
4.8 g of organophilic bentonite (GELTONE from
the company Baroid Drilling Fluids,
Inc.)
216 g of baryte
In the Example 3, there is used the comparably
lower-sulfonated emulsifier based on sulfonated rapeseed
; oil according to Example 1, while Example 4 employs the
corresponding higher-sulfonated emulsifier based on
sulfonated rapeseed oil according to Example 2.
~ he characteristic values determined of the unaged
and of the aged fluid systems are as follows:
Example 3
:
Unaged Aged
MaterialMaterial
Plastic viscosity (PV)37 47
Yield point (YP) 19 10
Gel strength (lb/100 ft2)
~ 10 seconds 9 2
:, 10 minutes 11 3
.
HTHP 7 ml
. - .
.
: ' ~'` ' ;: i : , ";
.
2 ~
D 9243 - 30 - Mar. 04, l991
Example 4
UnagedAged
Material Material
Plastic viscosity (PV) 40 82
Yield point (YP) 29 60
Gel strength (lb/lO0 ft2)
10 seconds 13 18
lO minutes 29 61
HTHP 6 ml
The values determined of the unaged and of ~he aged
materials are as follows.
Unaged Aged
Material Material
Plastic viscosity (PV) 38 35
Yield point (YP) 13 10
Gel strength (lb/lO0 ft2)
10 seconds 7
lO minutes 14 9
Example 5
In the following Example 5 a water-based emulsion
fluid using a complex oleophilic polycarboxylic acid
ester having a lubricant character as the dispersed oil
phase is prepared according to the following procedure:
First, a homogenized slurry containing 6% by weight
of bentonite is produced from a commercially available
`, :
,
.~ ~
D 9243 - 31 - Mar. 04, l991
bentonite (non-hydrophobized) and tap water and the pH
value thereof is adjusted to from 9.2 to 9.3 with
caustic soda solution.
This pre-swollen bentonite phase is charged and, in
subsequent process steps - each with thorough mixing - ,
the individual components of the water-based ester-oil
emulsion are incorporated in accordance with the ~ollow-
ing formulation:
350 g of 6% by weight bentonite solution
l.S g of co~ercial carboxymethylcellulose
(of lo~ viscosity) (~elatin U 300 S 9
g of sodium chloride
g of complex ester
6 g of emulsifier of ~xample 2
219 g of baryte
As an oleophilic ester oil phase there is employed
the reaction product of trimethylolpropane (14% by
weight), a co~mercially available dimer fa'ty acid
mixture (24% by weight) and oleic acid as the balance.
The dimer fatty acid mixture contains 77% by ~eight of
dimer acids and tri- and higher polycarboxylic acids as
the balance - here % by weight relative to the dimer
fatty acid mixture.
The viscosity of the OJW emulsion fluid thus
prepared is determined as follows:
.
First the plastic viscosity (PV), the yieId point
, (YP) and the gel strength after 10 seconds and
lO minutes of the unaged emulsion fluid are determined
at room temperature.
~ ~ 3 ~
D 9243 - 32 - Mar. 04, 1991
Then the emulsion fluid is aged under static
conditions at 90 C for 16 hours in order to test the
influence of the tPmperature on the stability of the
emulsion. Then the viscosity values are once more
determined at room temperature.
Unaged Aged
Material Material
.
Plastic viscosity (PV) 19 18
Yield point (YP) 99 110
Gel strength (lb/100 ft )
10 seconds 49 ~3
10 minutes 50 ;6
.
. .
:
:,
.. :
