AU624926B2

AU624926B2 - Use of selected low carboxylic acid ester oils in drilling muds

Info

Publication number: AU624926B2
Application number: AU51823/90A
Authority: AU
Inventors: Frank Burbach; Claus-Peter Herold; Heinz Muller; Michael Neuss; Stephan Von Tapavicza
Original assignee: Henkel AG and Co KGaA
Current assignee: BASF Personal Care and Nutrition GmbH
Priority date: 1989-03-08
Filing date: 1990-03-01
Publication date: 1992-06-25
Anticipated expiration: 2010-03-01
Also published as: JP2834319B2; AU5182390A; CA2047697C; WO1990010682A1; NO913239D0; DE59001025D1; NO913239L; EP0386638B2; DK0386638T3; EP0386638A1; EP0386638B1; BR9007192A; ZA901759B; IE900802L; MX174249B; ATE87020T1; EP0462160A1; JPH04503965A; IE63931B1; ES2042101T3

Abstract

The invention describes the use of esters, which are fluid at room temperature and have flashpoints above 80 DEG C, selected from C1-15 monocarboxylic acids and/or mono or multifunctional alcohols as the oil phase or a component thereof in invert drilling muds which are suitable for the environmentally favourable extraction of petroleum or natural gas deposits and, in a closed oil phase, contain a dispersed aqueous phase together with emulsifiers, fillers, fluid loss additives and, if desired, other customary additives. In a further embodiment the invention relates to invert drilling muds of the aforementioned kind in which the oil phase contains esters of C1-15 monocarboxylic acids with mono and/or multifunctional alcohols mixed, if desired, with other components from the class of ecologically acceptable compounds.

Description

0F 1 1 DATE 09/10/90 APPLN. 10 51823 P AOJP DATE 15/11/90 PCT NUMBER PCT/EP90/00342 INTERNATIONALE ANMELDUJNCi VEI{Ul1PEN I LICH I NP&11 VtM VLK I KAU utiSIK VIE INTERNATIONALE ZUSAMMENARI3EIT AUF DEM GEBIET DES PATENTWESENS (PCI1) (51) Intniiaationale Patentklassifikation 5: (11) Internationale Verbffentlichungsnummer: WO 90/10682 C09K 7/06 Al (43) Internationales Veroffentlicliungsdatumn: 20. September 1990 (20.09.90) (21) Internationales Aktenzeichen: (22) Internatioaie Anmeldedatumn: Prioritlitplaten: P 39 07391.2 8. MA PCT/EP9O/00342 1. Miirz 1990 (0 1,03.90) rz 1989 (08.03.89) DEJ (71) Ai'melder (Itir alle Bestirnmungsvtaatien ausser US): HEN- KE KOM MANDITG ESELLSCHA FT AUF AKTIEN [DE/DE]; Henkelstrage 67, D-4000 Dflsseldorf'-Holthausen (DE).

(72) Erfinder; and Ri-finder/Anider ('nur fir US) MOLLER, Heinz [DE/ Golr~egenweg 4, D-4019 Monheimn HElROLD, Claus-Peter Ostpreugenstrage 26, D- 4020 -Mettmann VON TAPAVICZA, Stephan ihbomas-Mann-Strage 12, D-4006 Erkrath 2 NLEUSS, Michael [DE/DE]; Urf'tstrage 115, D-5000 K1,in 50 BURBACH, Frank [DE/DE]; Rdmerstra- Re 29, D-4005 Meerbusch I (DE), (81) Bestimmu ngsstaa ten: AT (europtisehes Patent), AU, BE (europflisches Patent), BR, CA, CH (europiiisches Patent), DE (europtiisches Patent), DK (europ~isches Patent), ES (europflisohes Patent), FR (europiiisches Patent), GB (europflisches Patent), IT (europiisches Patent), JP, LU (europtiisches Patent), NL (europiiisches Patent), NO, SE (europilisches Patent), US.

Vcroffentlicht Mit inlernatianalern Reclzerchenbericht.

L.0'3A (54) Title: USE OF SELECTED LOW CARBOXYLIC ACID ESTER OILS IN DRILLING MUDS (54) Bezeichnung: VERWENDUNG AUSGEWAHLTER ESTER61T,E NIEDERER CARBONSXUREN IN BOHRSPCJLUN-

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(57) Abstract The inwtntion describes the use of' esters, whic 're fluid at room temperature and have flashpoints above 800 C, selected from C 1 -1 5 monocarboxylic acid~s and/or mono or multifunctional alcohols as th'f oil phase or a, comporint thereof in invert drilling muds which are suitable for the enviro- mentally f'avourable extraction of' petroleum or i.1-tural gas deposits and, in a closed oil phase, contain a disper5ed aqueous phase together with emulsifiers, fillers, fluid loss additives and, if' desired, other customary additives. In a further embodiment the invention relates to invert drilling mudi, of the aforementioned kind in which the oil phase contains esters of C 1 15 monocarl.oxylic acids with mnod and/or multif'unctional alcohols mixed, if' desired, with other components from the class of' ecologically acceptable compounds.

(57) Zusgrnenfassung Die Erfindung beschreibt die Verwendung ausgewllhlter, bei Raumtemperatur flie~falhiger und Flammpunkte oberhalb auf'weisender Ester aus C I., 5 -Monodarbonslturen t'nd ein- und/oder mehrf'unktionellen Alkoholen als Olphase oder Ilestandteil der Olphase von Invert-Bohrspilischlllmmen, die f(Ir elne umweltschonende Erschliecung von Erdbl- bzw. Erd.

gasvorkommen geeigne! sind und in einer geschlossenen Olphase elne disperse wtlgrige 'Phase zusammen mit Emulgatoren, lBeschwerungsmitteln, fluid-loss-Additiven and gevinschtenf'alls weiteren iablichen Zusatzstof'f'e e:nthalten. In eintcr weiteren Ausgestaltung betrif'f't die Erfindung Invert. Bohrepillu ngeri der angegebenen Alt, die sich daduufzr kennizeichnen, dall die Olphase Ester von C1.

5 -Monocarbonsilunrn mii I- tind/oder mehrfunktionellen Alkoholen gewilnschtenfalls in Abmischung mit anderen Komponenten aus der Kiasse der 6kologisch vertrllglichen Verbiridungen enthfilt.

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4fr 1" 4 Patent Application D 8606 "The use of selected ester oils of low carboxylic acids in drilling fluids" The invention discloses new drilling fluids based on ester oils and invert drilling muds built up thereon, which are distinguished by high ecological acceptability and at the same time good keeping and application properties. An important area of application for the new drilling fluid systems is in off-shore wells for the development of petroleum and/or natural gas deposits, the aim of the invention being particularly to make available technically usable drilling fluids with high ecological acceptability. The use of the new drilling fluid systems has particular significance in the marine environment, but is not limited thereto. The new mud systems can be put to quite general use even in land-based drilling, for example, in geothermal wells, water boreholes, in the drilling of geoscientific bores and in drilling for the mining industry. Here too it is essentially true that associated ecotoxic problems are substantially simplified by the esturbase drilling oil fluids selected according to the invention.

Oil-base drilling fluids are generally used as so-called invertemulsion muds, which consist of a three-phase system: oil, water and finely particulate solids. These are preparations of the W/O emulsion type, i.e. the aqueous phase is distributed as a heterogeneous fine dispersion in the continuous oil phase. A number of additives can be used to stabilize the system as a whole and to adjust the desired application properties, particularly emulsifiers or emulsifier systems,, weighting agents, fl, j-loss additives, alkali reserves, viscosity regulators and the like. For details, refer, to the publication by P.A. Boyd et al. "New Base Oil Used in Low-Toxic,;ty Oil Muds" Journal of Petroleum Technology, 1985, 137 to 142, and R.B. Bennett, "New Drilling Fluid Technology Mineral Oil Mud" Journal of Petroleum Technology, 1984, 975 to 981 and the literature cited therein.

,f a/ The relevant t -'hnology has for some time recognized the importance of T Wi S- 2 -2ester-base oil phases in reducing the prclems caused by such oil-base muds. For example, US Patent Specifications 4,374,737 and 4,481,121 disclose oil-base drilling fluids in which non-polluting oils are to be used. The following are mentioned as non-polluting oils of equal value mineral oil fractions free from aromatic hydrocarbons and vegetable oils such as groundnut oil, soybean oil, linseed oil, corn oil, rice oil or even oils of animal origin, such as whale oil. Without exception, these named ester oils of vegetable and animal origin are triglycerides of natural fatty acids, which are known to have a high environmental acceptability, and are clearly superior from the ecological viewpoint when compared with hydrocarbon fractions even when these are free from aromatic hydrocarbons.

Interestingly enough, however, none of the examples in the named US Patent Specifications describes the use of such natural ester oils in invert-drilling fluids such as those in question here. In all cases, mineral oil fractions are used as the continuous oil phase. Oils of vegetable and/or animal origin are not considered for reasons of Spracticality. The rheological properties of such oil phases cannot be controlled for the wide temperature range reaching from 0 to 5°C on the 20 one hand up to 250 0 C on the other hand, which is widely required in the industry, In use, ester oils of the type in question do not in fact behave in the same way as the mineral oil fractions based on pure hydrocarbons which were previously used. Ester oils are subject to partial hydrolysis •25 in practical use also and particularly in /O invert drilling muds. Free carboxylic acids are formed as a result. The earlier Australian Patent S" Applications Nos. 46551/89 and 49549/90 corresponding to German Patent Applications P 38 42 659.5 and P 38 42 703.6 ("Verwendung ausgewahlter Esterole in BohrspUlungen and also "Verwendung ausgewahlter Esterole In BohrspUlungen describe the problems caused thereby and give suggestions for their solution.

The subject of these earlier Applications is the use of ester oils based on selected monocarboxylic acids or monocarboxylic acid mixtures and monofunctional alcohols with at least 2, and preferably with at least 4 carbon atoms. The earlier applications show that with the esters and ester mixtures they disclose, monofunctional reactants can not only be TMS/1798R i I A ii

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given satisfactory rheological properties in fresh drilling fluid, but that by using selected known alkali reserves it is possible to work with the drilling fluid and in this way to inhibit undesirable corrosion. For the alkali reserve, one can add calcium hydroxide or lime and/or use zinc 5 oxide or comparable zinc compounds. However, in this case an additional restriction is advisable. If undesired thickening of the oil-base invert-mud system is to be prevented in practical use, the amount of alkalizing additive and in particular the amount of lime must be limited. The maximum amount provided is set at about 2 lb/bbl oil-base mud in the disclosure of the aforementioned earlier Applications.

The teaching of the present invention intends to avoid the problems described above by using in the drilling fluids of the aforementioned type a class of ester oils which forms non-problematical carboxylic acids and carboxylic-acid salts during the limited ester hydrolysis which 15 always occurs. This idea can be technically realized by the selection of ester oils which are based on lower carboxylic acids with 1 to 5 carbon atoms. The corresponding esters from acetic acid are particularly significant here. The acetate salts forming during the partial hydrolysis of the ester oil do not have the emulsifying properties which could substantially disturb the N/O system.

According to a first embodiment of the present invention there is provided a process for preparing an invert drilling fluid which is suitable for environmentally friendly development of petroleum and natural gas deposits, said process comprises mixing together an oil phase comprising esters which are fluid at ambient temperature, have flash points above 80°C and are derived from C 1

-C

5 -monocarboxylic acids and mono- and/or polyfunctional alcohols together with a dispersed aqueous phase, emulsifers, weighting agents, fluid loss additives and optionally other additives.

According to a second embodiment of the present invention there is provided an Invert drilling mud which has been prepared by the process of the first embodiment.

1798R 5/1

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-4- *acids with rznc- and/or polyfunctional alczhols.- The substance properties of the monocarboxylic acid esters of rthe type referred to in the invention can be so controlled by the selection of the alcohol components used for the esterification, that it is possible to use them as described in the invention. Corresponding esters or ester mixtures are preferably used which are fluid and pumpable even in the temperature range of 0 to 5 0 C. It is also preferred to use as the oil phase C 1 _5-monocarboxylic acid esters or their admixtures with ecologically acceptable components from the class of so-called nonpolluting oils, which in the temperature range of 0 to 5 0 C possess a Brookfield (RVT) viscosity of not above 50 mPas and preferably not above 40 mPas. The viscosity of the oil phase is preferably at most about 30 mPas.

The C 1 5 -carboxylic-acid esters used in the drilling mud of the invention usefully have solidification values (pour and setting point) below 0 0 C, preferably below -5 0 C and particularly below -10 0 C. At the same time, particularly for safety reasons, the flash points of these esters 'are to be selected as high as possible so that preferred limit values for the flash point lie at about 90 0 C and preferably above 1000C.

The esters of the lower carboxylic acids suitable according to the invention can be divided into two sub-classes. In a first class the lower monocarboxylic acids are reaction products of monofunctional alcohols. In this case the carbon number of the alcohol is at least 6, but is preferably higher, i.e. at least 8 to 10 carbon atoms. The second sub-class of the ester oils referred to here uses polyfunctional alcohols as the ester-forming component,'. Particularly to be considered here are di- to tetra-hydric alcohols, lower alcohols of this type, preferably with 2 to 6 carbon atoms, being particularly suitable. Typical examples of such poly-hydric alcohols are glycol and/or propanediols. Both ethylene glycol and 1,2-propanediol and/or 1,3-propanediol are particularly important. In the case described here of esters of polyhydric alcohols, completely esterified reaction products are preferred, even though the invention in particular in the case of the polyfunctional alcohols is not limited thereto. In ~t E- 5 the latter case in particular, the use of partial esters of such higher valency polyfunctional alcohols with the lower carboxylic acids mentioned can be considered.

The most important esters for the teaching of the invention are derived from monocarboxylic acids with 2 to 4 carbon atoms, with acetic acid, already mentioned, being of particular importance as the ester-forming component.

When selecting the appropriate alcohols it is important to take account of the following additional considerations: When the ester oil is used in practice, as a rule it is not possible to exclude partial saponification of the ester. Free alcohols form, in addition to the free carboxylic acids thus formed or carboxylic acid salts forming together with the al)ali reserves. They should be selected such that even after partial hydrolysis operational conditions are ensured which are ecologically and toxicologically harmless, with inhalationtoxicological considerations in particular being taken into account.

The alcohols used for the ester formation should in particular possess such a low volatility that in the free state under conditions to be expected in practice, they do not result in any nuisance on the working platform. For the class of ester oils based on very short-chain monocarboxylic acids which are selected in the invention, it is necessary from the outset to use comparatively long-chain monofunctional alcohols, so as to reduce sufficiently the volatility of the ester oil. The considerations discussed here are therefore particularly important in cases in which ester oils of the type defined in the invention are used in blends with other mixture components, in particular other carboxylic acid esters. In the invention it is regarded as particularly important in the preferred embodiment that even after partial hydrolysis in use, the drilling fluids are ecologically and toxicologically harmless, particularly inhalationtocicologically harmless under working conditions.

Suitable alcohols, particularly suitable monofunctional alcohols can be of natural and/or synthetic origin. Straight-chain and/or branched alcohols can be used here. The chain length in the presence of predominantly aliphatic-saturated alcohol is preferably from 8 to A47 6 i carbon atoms. In any case olefin mono- and/or poly-unsaturated alcohol c are also suitable, such as can be obtained, for example, by the sellctive reduction of naturally occurring unsaturated fatty acids or fatty acid mixtures. 01efin-mono- and/or poly-unsaturated alcohols such as this can also have higher carbon numbers in the ester oils according to the Invention, for example, up to 24 carbon atoms.

Ester oils of the type mentioned here can form the whole of the continuous oil phase of the W/O invert mud. On the other hand there is an inddstrial process In the scope of the invention in which the carboxylic-acid esters defined In the invention only constitute a mixture component of the oil phase. Practically any of the oil components previously known and/or previously described in the relevant area of application are suitable as further oil components. Particularly suitable mixture components will be discussed below.

15 The ester oils according to the invention are as a rule 44 S homogeneously miscible with the mixture components in any desired mixture ratios. It is useful in the framework of the invention for at least about 25% and particularly at least about a third of the oil phase to be in the form of the C -5-ester oils. In important embodiments of the 20 invention these ester oils form the main part of the oil phase.

Mixture compQne.ts in the oil pase Suitable oil components for admixture with the monocarboxylic acid esters of the invention are the mineral oils currently used In practice in drilling fluids, and preferably the aliphatic and/or cycloaliphatic 25 hydrocarbon fractions essentially free from aromatic hydrocarbons and with the required rheological properties. Refer here to the prior-art 9 publications cited and the available commercial products.

S Particularly important mixture components are, however, ester oils ee: which are ecologically acceptable when used according to the invention, as described, for example, in the above earlier Australian Patent Applications Nos. 46551/89 and 49549/90. To complete the invention disclosure, essential characteristics of these esters or ester mixtures are briefly summarized below.

TJMS/1798R I f ''il C i I i ii i j i :i j i i i i f iii i:, 1 i i I r m

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ml~c -7 As the oil phase, in a first embodiment, esters are used of monofunctional alcohols with 2 to 12, particularly with 6 to 12 carbon atoms and aliphatic sa.Qturatr monocarboxylic acids with 12 to 16 carbon atoms, which esters are fluid and pumpable in the temperature range of 0 to 5 0 C, or an admixture thereof with at most about the same amounts of other monocarboxylic acids. ester oils are preferred which at least to about 60 by weight referred to the respective carboxylic acid mixture are esters of aliphatic C12- 1 4 -monocarboxylic acids and preferably for the remaining percentage are based on lower amounts of shorter-chain aliphatic and/or longer chain, and in particular olefin mono- or poly-unsaturated monocarboxylic acids.

Esters are preferably used which in the temperature range of 0 to 5 C have a Brookfield (RVT) viscosity of not above 50 mPas, preferably not above 40 mPas and particularly of a maximum of about 30 mPas. The esters used in the drilling mud have solidification values (pour and setting point) below -10 0 C, preferably below -150C and have at the same time flash points above 100C, preferably above 150 0 C. The carboxyllc acids present in the ester or ester mixture are straight-chain and/or branched and are of vegetable and/or synthetic origin. They can be derived from corresponding triglycerides such as coconut oil, palm kernel oil and/or babassu oil. The alcohol radicals of the esters used are derived in particular from straight-chain and/or branched saturated alcohols preferably with 6 to 10 carbon atoms. These alcohol components can also be of vegetable and/or animal origin and can thus be obtained by reductive hydration of corresponding carboxylic acid esters.

A further class of particularly suitable ester oils is derived from olefin mono- and/or poly-unsaturated monocarboxylic acids with 16 to 24 carbon atoms or their admixtures with lower amounts of other particularly saturated monocarboxylic acids and monofunctional alcohols with preferably 6 to 12 carbon atoms. These ester oils are also fluid and pumpable in the temperature range of 0 to 5 0 C. Particularly suitable are such esters derived to more than 70 by weight, preferably to more than 80 by weight and in particular to more than by weight from olefin-unsaturated carboxylic acids with between 16 and 24 carbon atoms.

01 L1% -Uq 4 s r I I i -m -8- S* S 5S .5

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S* S 55 d 0*e lere too the -olidification values (pour and setting point) lie below 10C, preferably below -15°C while.ihe flash points lie above 100 0 C and preferably above 160 0 C. In the temperature range of 0 to the esters used in the drilling mud have a Brookfield (RVT) viscosity of not more than 55 mPas, preferably not more than 45 mPas.

Two subclasses can be defined for the ester oils of the type in question, In the first, the unsaturated C 16 24 -monocarboxylic acid radicals present in the ester are derived to not more than 35% by weight from olefin di- and poly-unsaturated acids, with preferably at least about 60% by weight of the acid radicals being olefin mono-unsaturated.

In the second embodiment the C 16 24 -monocarboxylic acids present in the P ter mixture are derived at more than 45% by weight, preferably at more than 55% by weight from olefin di- and/or poly-unsaturated acids. It is useful if the saturated carboxylic acids with between 16 to 18 carbon 15 atoms which are present in the ester mixture do not amount to more than about 20% by weight and in particular not more than about 10% by weight.

Preferably, saturated carboxylic acid esters, however, have lower carbon numbers In the. acid radicals. The carboxylic acid radicals present can be of vegetable and/or animal origin. Vegetable starting materials are, for example, palm oil, groundnut oil, castor oil and in particular colza oil. The carboxylic acids of animal origin are particularly correspondihg mixtures of fish oils, such as herring oil.

Suitable mixture components are finally however the esters from monocarboxylic acids of synthetic and/or natural origin with 6 to 11 carbon atoms and mono- and/or polyfunctional alcohols, described in the Parallel Australian Patent Application No. 51802/90 which are preferably also fluid and'pumpable in the temperature range of 0 to 5 0 C. For completion-of the invention disclosure, reference is thus made in this regard to the above Parallel Application, the contents of which are hereby also made subject of the present disclosure.

Further mixture components ofthe invert drilling fluid All the usual constituents of mixtures for conditioning and for the practical uses of invert drilling muds can be considered here, that are currently used with mineral oils as the continuous oil phase, In addition to the dispersed aqueous phase, emulsifiers, weighting agents, TMS/1798R 9 fluid-loss additives, viscosifiers and alkali reserves can be considered here.

Use is alsr, made In a particularly important embodiment of the invention, of the further development of these ester oil-base invert drilling fluids which is the subject of the Applicant's earlier K Australian Patent Application No. 49579/90.

The teaching of this earlier Application is based on the concept of Susing a further additive in ester oil-base invert-drilling fluids, which i Is suited to keeping the desired rheological data of the drilling fluid in the required range even when, in use, increasingly large amounts of free carboxylic acids are formed by partial ester hydrolysis. These liberated carboxylic acids should not orly be trapped in a harmless form, it should moreover be possible to reform these free carboxylic acids, preferably into valuable components with stabilizing or emulsifying properties for the whole system. According to this teaching, alkaline amine compounds of marked oleophllic nature and at best limited water solubility, which are capable of forming salts with carboxylic acids, can be used as additives in the oil phase. The oleophilic amine. compounds I can at the same time be used at least in part as alkali reserves in the 20 invert drilling fluid, they can however also be used in combination with Sconventional alkali reserves, particularly together with lime. The use of oleophilic amine compounds which are at least largely free from aromatic constituents is preferred. In particular, optionally olefin unsaturated aliphatic, cycloallphatic and/or heterocyclic oleophillc 25 basic amine compounds, can be considered, which contain one or more 9: N-groups capable of forming salts with carboxylic acids. In a preferred i embodiment the water-solubility of these amine compounds at room temperature is at most about 5% by weight and is usefully below 1% by weight.

TMS/1798R AM,

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10 Typical examples of such amine compounds are primary, secondary and/or tertiary amines, which are at least predominantly water-insoluble, and which can also to a limited extent be alkoxylated and/or substituted particularly with hydroxyl groups. Further examples are corresponding aminoamides and/or heterocycles containing nitrogen as ring constituent. For example, basic amine compounds are suitable which have at least one long-chain hydrocarbon radical with preferably 8 to 36 carbon atoms, particularly with 10 to 24 carbon atoms, which can also be olefin mono- or poly-unsaturated. The oleophilic basic amine compounds can be added to the drillina fluid in amounts of up to about lb/bbl, preferably in amounts up to about 5 lb/bbl and particularly in the range of about 0.1 to 2 lb/bbl.

It has emerged that the use of such oleophilic basic amine compounds can effectively prevent thickening of the mud system, which presumably can be attributed to a disturbance in the W/O invert system and also to the formation of free carboxylic acids by ester hydrolysis.

If in the context of the invention teaching, esters of longer-chain carboxylic acids are used as mixture components, which on hydrolytic cleavage yield fatty acids or fatty-acid salts with a pronounced O/Wemulsifying effect, then in the method according to the invention the measures regarding the alkali reserves should also be taken into y consideration as described in detail in the aforementioned earlier Applications P 38 42 659.5 and P 38 42 703.6 in association with such problems. When such ester mixtures are used the following applies: In a preferred embodiment of the use according to the invention, care is taken not to use considerable amounts of strongly hydrophilic bases of inorganic and/or organic nature in the oil-base mud. In particular the invention refrains from using alkali hydroxides or strongly hydrophilic andines such as diethanolamine and/or triethanolamine. Lime can be also used effectively as an alkali reserve. It is then useful to limit the maximum amount of lime to be used to about 2 lb/bbl, and it may be preferred to work with lime contents in the drilling mud slightly below this, therefore, from about 1 to 1.8 lb/bbl (lime/drilling fluid). Other known alkali reserves can be used in

-II

Saddition to or in place of the lime. The less basic metal oxides, such i as zinc oxide, should particularly be mentioned here. Even when these acid traps are used, care is still taken that the amounts used are not too large, so as to prevent undesired premature ageing of the drilling fluid, associated with an increase in viscosity and therefore a deterioration in the rheological properties. The special features discussed here of the process according to the invention prevent, or at least restrict, the formation of undesirable amounts of highly active O/W-emulsifiers, so that the good rheological properties are maintained for a sufficiently long time in use, even when there is thermal ageing.

The following also applies: SInvert-drilling muds of the type in question here usually contain, together with the continuous oil phase, the finely dispersed aqueous phase in amounts of about 5 to 45 by weight and preferably in armunts of about 5 to 25 by weight. A dispersed aqueous phase from about to 25 by weight can be regarded as pErticularly useful.

The following rheological data apply to the rheology of preferred invert drilling muds according to the invention: Plastic viscosity (PV) from about 10 to 60 nrPas, preferably about 15 to 40 mPas. Yield point (YP) from about 5 to 40 ib/100 ft 2 preferably about 10 to lb/100 f2 each measured at 50°C. For the measurement of these 0 parameters, for the measuring methods used and for the rest of the conventional corposition of the invert drilling fluids described here, refer in detail to the specifications in the prior art which were cited above and are, for example, described fully in the handbook "Manual of Drilling Fluids Technology" of NL-Baroid Co., London, GB, particularly in the chapters "Mud Testing Tools and Techniques" and "Oil Mud Technology", which is freely accessible to interested experts. In summary, for the purposes of completing the invention disclosure the following can be said: The emulsifiers which can be used in practice are systems which are suitable for the formation of the required W/O emulsions. In particular, selected oleophilic fatty acid salts, for example, those t based on amidoamine compounds can be considered. Examples of these are 12 described in the already cited US-PS 4,374,737 and the literature cited there. A particularly suitable type of emulsifier is the p.-duct sold by NL-Baroid Co. under the brand name "EZ-mul".

Emulsifiers of the type in question are sold commercially as highly concentrated active-substance preparations and can, for example, be used in amounts of about 2.5 to 5 by weight, particularly in amounts of about 3 to 4 by weight each referred to the ester oil phase.

In practice, hydrophobied lignite in particular is used as the fluidloss additive and therefore particularly for forming a dense coating on the bore-hole walls of a largely liquid-impermeable film. Suitable amounts are, for example, from about 15 to 20 b/bbl or from about 5 to S7 by weight, referred to the ester oil phase.

The viscosifier conventionally used in drilling fluids of the type in question here, is a cation-modified finely particulate bentonite, which can be used particularly in amounts of about 8 to 10 lb/bbl or from about 2 to 4 by weight, referred to the ester oil phase. The weighting material conventionally used in relevant applications to establish the necessary pressure compensation is oarite, and the amounts added are varied accrvding to the drilling conditions anticipated in each case. It is, for example, possible by adding barite to raise the specific weight of the drilling fluid to values up to 2.5 and preferably from about 1.3 to 1.6.

The dispersed aqueous phase in these irvert drilling fluids, is loaded with soluble salts. Calcium chloride and/or potassium chloride e mainly used here, and saturation of the aqueous phase with the soluble salt at room temperature is preferred.

The aforementioned emulsifiers or emulsifier systems can optionally also be used to improve the oil wettability of the inorganic weighting materials. In addition to the aminoamides already mentioned, further examples are alkylbenzene sulfonates and imidazoline compounds.

Additional information regarding the relevant prior art can be found in the following publications: GB 2 158 437, EP 229 912 and DE 32 47 123.

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13 The drilling fluids synthesized according to the invention using ester oils of the type described are distinguished, in addition to the advantages already described, by a notably improved lubricity. This is particularly important when in very deep wells, for example, the path of the drill rod and therefozr the borehole deviates from the vertical.

The rotating drill rod comes slightly into contact with the borehole wall and when operating buries itself into it. Ester oils of the type used as the oil phase according to the invention have a notably better lubricity than the mineral oils previously used. This is another important advantage of the method according to the invention.

i r 14 Examples In the following examples invert drilling fluids are prepared in the conventional manner using the following basic formulation: 230 ml ester oil 26 ml water 6 g organophilic bentonite (Geltone II of NL Baroid Co.) 12 g organophilic lignite (Duratone of NL Baroid Co,) x g lime (x 1 or 2) 6 g W/O emulsifier (EZ-mul NT of NL Baroid Co.) 346 g barite 9.2 g CaCI 2 x 2 H 2 0 S In this formulation about 1.35 g of lime corresponds to 2 lb/bbl.

After a W/O invert drilling fluid has been prepared in a known manner from the components used, with variation of the ester oil phase, the viscosities of the unaged and then the aged material are determined as follows: Measurement of the viscosity at 50 0 C in a Fann-35-viscosimeter supplied by NL Baroid Co. The plastic viscosity the yield point (YP) and the gel strengths ilb/100 ft 2 are determined in a known manner after sec. and 10 min.

Ageing is carried out by treatment in autoclaves in the so-called roller-oven for a period of 16 hours at 125 0

C,,

Isotridecyl acetate which has the following rheological characteristics is used as the ester oil: viscosity at 20 0 C 5 mPas; viscosity at 50 0

C

2.1 mPas; setting point below -10 0

C.

In Example 1 below, the amount of lime used in the basic formulation is 2 g, in Example 2 this lime amount is reduced to 1 g.

The values determined for the unaged and aged material are listed in the following table.

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-J

15 unaged material aged material plastic viscosity (PV) 31 33 yield point (YP) 11 13 gel strengths (lb/100 ft 2 sec. 6 7 min. 9 9 I Example 2 unaged material aged material plastic viscosity (PV) 24 yield point (YP) 14 12 gel strengths (lb/100 ft 2 sec. 5 min. 8 7 The basic formulation in Examples L and 2 has a value of 90/10 for the oil phase/water weight ratio. In further tests the the ester oil/water ratio is changed to 80/20.

In Examples 3 and 4 below, invert drilling fluids are prepared using the ester oil based on isotridecyl. acetate, according to the following basic formuletion: 210 ml ester oil 48.2 g water 6 g organophilic bentonite (Omnigel) y 13 g organophilic lignite (Duratone of NL Baroid Co.) 2 c( lime 8 g W/O-emulsifier (EZ-mul NT of NL Baroid Co.) 270 g barite g CaC 2 x 2 H 2 0 As in Examples 1 and 2, the viscosities are determined first on the unaged, then on the aged material (16 hours at 125 0 C in the roller oven) (Example 3).

j~j~ i 16 In a further test formulation (Example 2 g of a strongly oleophilic amine is added to the basic formulation given for Example 3 (Applicant's comrercial product "Araphen G2D" the reaction product of an epoxidized C12/1 4 -alpha-olefin and diethanolamine). The viscosity characteristics are then determined as above first on the unaged and then on the aged material.

Exanple 3 unaged material aged material plastic viscosity (PV) yield point (YP) gel strengths (lb/100 ft 2 sec.

min.

Example 4 unaged material aged material i j o plastic viscosity (PV) yield point (YP) gel strengths (lb/100 ft 2 sec.

min.

Example The ester-mixture from acetic acid and a C6_ 10 -alcohol cut (Applicant's commercial product "Lorol technisch"), prepared by the reduction of the corresponding pre-fatty-acid cut of natural origin, is used as the ester oil. The basic formulation for the ester mud corresponds to the formulation given for Example 2.

The viscosity data are determined and the ageing is carried out as indicated in the previous Examples. The following viscosities are

I

determined.

17 unaged material aged material plastic viscosity (PV) 28 29 yield point (YP) 17 gel strengths (lb/100 ft 2 sec. 9 9 min. 24 14 Examples 6 to 8 SIn parallel formulations, three drilling fluids based on isotridecyl acetate are produced according to the basic formulation in Examples 1 and 2 (oil phase/water 90/10). As in the preceding Examples, their rheological data was determined immediately after preparation and after ageing in the roller oven at 125 0 C for a period of 16 hours.

In a first mud, no lime is added (Example in a second mud (Example 7) 2 g of lime is used, while in the parallel third mud (Example 8) 2 g of lime is used together with 1 g of the strongly oleophilic aminle "Araphen G2D".

The rheological data determined in each case are as follows:

I

MO-

-18 Example 6 unaged material aged material plastic viscosity (PV) 28 yield point (YP) 15 9 gel strengths (lb/100 ft 2 sec. 9 7 min. 10 8 Examgje 7 unaged material aged material plastic viscosity (PV) 30 29 yield point (YP) 13 17 gel strengths (lb/100 ft 2 sec. 8 8 min. 10 12 Example 8 unaged material aged material S plastic viscosity (PV" 25 yield point (YP) 12 8 gel strengths (lb/100 ft 2 sec. 8 7 min. 11 9 Examples 9 to 11 In a further comparative series of tests, drilling fluids based on isotridecyl acetate are combined in the basic formulation of Examples 6 to 8 as follows; Example 9 addition of 1 g of lime; Example 10 addition of 2 g of lime; Example 11 addition of 2 g of lime 1 g of "Araphen G2D".

19- These muds are then aged, however, in the roller oven at 125 0 C for a period of 72 hours. The rheological data determined on the unaged and aged material in each case are as follows: Example 9 unaged material aged material plastic viscosity (PV) 30 37 yield point (YP) 15 16 gel strengths (lb/100 ft 2 sec. 7 min. 11 Example unaged material aged material plastic viscosity (PV) 28 34 yield point (YP) 16 13 gel strengths (lb/100 ft 2 sec. 6 6 min. 10 SExample 11 unaged material aged material plastic viscosity (PV) 29 36 yield point (YP) 11 14 gel strengths (lb/100 ft 2 sec. 7 6 min. 10 II r fL

Claims

1. A process for preparing an invert drilling fluid which is suitable-for environmentally friendly development of petroleum and natural gas deposits, said process comprises mixing together an oil phase comprising esters which are fluid at ambent temperature, have flash points above 80 0 C and are derived from C 1 -C 5 -monocarboxylic acids and mono- and/or pblyfunctional alcohols together with a dispersed aqueous phase, emulsifers, weighting agents, fluid loss additives and optionally other additives., 2, A process according to claim 1 characterized in that the said esters are liquid and pumpable at 0 to 5 0 C. 3 A process according to claim 1 or 2 characterized in that said oil phase further compises non-polluting oils. 9 .9 9 0@ 9 9 9 9 9 15 in tha 50 mPa viscos 20 viscos in tha flash

4. A process a.cording to any one of claims 1 to 3 characterized t said oil phase has a Brookfield (RVT) viscosity of less.than .s at 0 to 5, A process according to claim 4 characterized in that said ity is not above 40 mPas.

6. A process according to claim 4 characterized in that said ity is not above 30 mPas.

7. A process according to any one of claims 1 to 6 characterized .t.said esters have solidification values of below 0*C and have points alove 8, A process according to claim 6 characterized in that said 90* 9 0 9 0 0 9 6* 0*99 .9 99 9 9*9* *9*e

9. 0 *9* 25 solidification values are below -5 0 C. 9. A process according to claim 6 characterized in that said solidification values are below 10, A process according to any one of claims 7 to 9 characterized in that said flash points are above 100"C.

11. A process according to any one of claims 1 to 10 characterized in that said esters are derived from monofunctional alcohols with at least 6 carbon atoms and/or di- to tetrahydric alcohols.

12. A process according to claim 11 characterized in that said monofunctional alcohols have at least 8 carbon atoms.

13. A process according to claim 11 characterized in that said di- to tetrahydric alcohols contain from 2 to 6 carbon atoms. S/1798R -s 194 :ylor. 9 r~" i' I t

21- 14. A process according to claim 13 characterized in that said di- to tetrahydric alcohols are glycol and/or propanedlol. A process according to any one of claims 1 to 14 characterized i in that said monocarboxylic acids contain from 2 to 4 carbon atoms. 16. A process according to any one of claims 1 to.15 characterized in that said esters are acetic acid esters. 17. A process according to any one of claims 1 to 16 characterized in that said esters are in admixture with other ester oils and s ad admixture is ecologically and toxicologically harmless even after partial hydrolysis under working conditions. i 18. A process according to claim 17 characterized in that said admixture is Inhalation-toxicologically harmless. 19. :A process according to any one of claims 1 to 18 characterized in that said monofunctioial alcohols are natural and/or synthetic, are predominantly saturated and contain from 8 to 15 carbon atoms. 20.: A process according to any one of claims 1 to 18 characterized S, in that said monofunctional alcohols are olefin mono- and/or polyunsaturated. I 21. A process according to claim 20 characterized in that said 20 unsaturated alcohols contain up to 24 carbon atoms. 22, A process according to any one of claims 17 to;21 characterized in that said ester oils are derived from monofunctional alcohols containing 2 to 12 carbon atoms and olefin mono- and/or poly- unsaturated monocarboxylic acids containing 16 to 24 carbon atoms. 25 23. A process according to claim 22 characterized in that said monofunctional alcohols contain from 6 to 10 carbon atoms. i 24. A process according to claim 22 or 23 characterized in that i G. saie ester oils have solidification values of below -10"C and flash points of above 100 0 C.

25. A process according to claim 24 characterized in that said sol'dification values are below

26. A process according to any one of claims 22 to characterized, in that more than 70% by weight of the ester oils.are derived from olefin-unsaturated carboxylic acids with from 16 to 24 carbon atoms and said ester oIls have a Brookfield (RVT) viscosity of less than 55 mPas at 0* to TMS/1798R w I 22 S27. A process according to claim 26 characterized in that more than 80% by weight of said ester oils are derived from said olefin- unsaturated carboxylic acids.

28. A process according to claim 25 characterized in that more than 90% by weight of said ester oils are derived from said olefin- unsaturated carboxyllc acids.

29. A process according to any one of claims 26 to 28 characterized in that said viscosity is less than 45 mPas. A irocess according to any one of claims 26 to 29 characterized in that said olefin-unsaturated carboxylic acids comprise not more than 35% by weight of olefin di- and poly-unsaturated acids and at least 60% by weight olefin mono-unsaturated acids.

31. A process according to any one of claims 26 to 29 characterized in that said olefin-unsaturated carboxylic acids comprise more than 45% by weight of olefin di- and/or poly-unsaturated acids. S' 32. A process according to claim 31 characterized in that there is more than 55% by weight of said olefin di- and/or poly-unsaturated acids. S" 33. A process according to any one of claims 17 to 21 characterized in that said ester oils are derived from aliphatic 20 saturated monocarboxylic acids with 6 to 16 carbon atoms and mono- and/or polyhydric alcohols.

34. A process for preparing an invert drilling mud substantially as hereinbefore described with reference to the Examples but excluding the Comparative Examples. S. 25 35. An invert drilling mud prepared by the process according to any one of claims 1 to 34.

36. An invert drilling mud according to claim 35 characterized in that said mud further comprises an alkali reserve. A. 37. An invert drilling mud according to claim 36 characterized in that said alkali reserve Is lime.

38. An invert drilling fluid according to any one of claims 35 to 37 further comprising amine compounds of pronounced oleophilic nature and at most limited water solubility and being capable of forming salts with free carboxylic acids.

39. An invert drilling fluid according to any one of claims 35 to 38 characterized in that said fluid further comprises 5 to 45% by weight of a finely-dispersed aqueous phase. S TMS/1798R r r. c i *e 09 0 a a 0* a a *e 0 a a. 00 a *r 0 000 9 23 An invert drilling fluid according to claim 39 characterized in that said fluid comprises 5 to 25% of said aqueous phase.

41. A drilling fluid according to any one of claims 35 to characterized in that said fluid further comprises conventional additives.

42. A drilling fluid according to any one of claims 35 to 41 characterized in that said oil phase comprises at least about 25% by weight of C 1 -C 5 carboxylic acid esters.

43. A drilling fluid according to claim 42 characterized in that said oil phase comprises at least one third of said C 1 -C 5 carboxylic acid esters.

44. A drilling fluid according to claim 42 characterized In that said C1-C 5 carboxylic acid osters comprise the main part of said oil phase. A drilling fluid according to any one of claims 35 to 44 15 characterized in that when said fluid is used as an oil base mud it contains an iakali reserve selected from line, metal oxides, basic amine compounds which are capable of forming salts with carboxylic acids, are of pronounced oleophilic nature and at most limited water-solubility; or mixtures of two or more thereof, 20 46. A drilling fluid according to claim 45 characterized in that said metal oxide is zinc oxide.

47. A drilling fluid according to claims 45 or 46 characterized in that said fluid is free from any considerable amount of strongly hydrophilic bases. 25 48. A drilling fluid according to claim 47 characterized in that said hydrophilic bases are alkali hydroxides.

49. A drilling fluid according to claims 45 or 46 characterized in that said fluid is free from any considerable amount of strongly hydrophilic amines.

50. A drilling fluid according to claim 49 characterized in that said hydrophilic amine is diethanolamine.

51. An Invert drilling fluid according to any one of claims 35 to characterized in that said fluid has a plastic viscosity (PV) of about to about 60 mPas and a yield point (YP) of about 5 to about 40 lb/100 ft 2 each determined at 0S 9 b Q) a .i e g. a TMS/1798R 7Vf UI I 24

52. An invert drilling fluid according to any-one of claims 35 if 51 characterized in that said fluid comprises about 5 to about 45% by weight of a dispersed aqueous phase which contains CaCl 2 and/or KCI salts in solution.

53. An invert drilling fluid according to claim 52 characterized in that said fluid comprises about 10 to about 25% by weight of said dispersed aqueous phase.

54. An invertdrilling fluid according to any one of claims 35 to 53 characterized in that when said fluid is used as a drilling mud the oil phase has a Brookfleld (RVT) viscosity below 50 mPas at 0 to An invert drilling mud according to claim 54 characterized In that said viscosity is below 40 mPas. 6. An inert drilling f'uid substantially as hereinbefore described with reference to any one of Examples 1 to 8.

57. A method of preparilg an invert drilling fluid substantially S "as hereinbefore described with reference to any one of Examples 1 to 8. DATED this THIRD day of APRIL 1992 S Henkel Kommanditgesellschaft auf Aktien Patent Attorneys for the Applicant SPRUSON FERGUSON i 48* TMS/1798R c a ~ifiSX 2 r Abstract "Use of selected ester oils of lower carboxylic acids in drilling fluids" The invention describes the use of selected esters, fluid at room temperature and with flash points above 80 0 C, of Cl_ 5 -monocarboxylic acids and rono- and/or polyfunctional alcohols as the oil phase, or a component of the oil phase of invert drilling muds which are suitable for environume~t-friendly development of petroleum or natural gas deposits and contain in a continuous oil phase a dispersed aqueous phase together with emulsifiers, weighting agents, fluid-loss additives Sand preferably further conventional additives. In a further embodiment the invention relates to invert drilling fluids of the type described, which are characterized in that the oil phase contains esters from C 1 -monocarboxylic acids with mono- and/or polyfunctional alcohols preferably in admixture with other components from the class of ecologically acceptable compounds. M1 INTERNATIONAL SEARCH REPORT International Application No PCT/EP9 0 0 0 34 2 I. CLASSIFICATION OF SUBJECT MATTER (II several classification symbols apply, Indicate all) According to International Patent Classification (IPC) or to both National Classification and IPC C09K 7/06 II. FIELDS SEARCHED Minimum Documentation Searched 7 Classification System Classification Symbols C09K 7/06 Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included In the Fields Searched S III. DOCUMENTS CONSIDERED TO BE RELEVANT' Category Citation of Document, i with indication, where appropriate, of the rlevant passages 12 Relevant to Claim No, 13 i Y US, A, 3728277 T. FOLEY) 1 17 April 1973 see column 4, lines 73-75; column lines 1-13 A Y EP, A, 0009746 (BAYER) 16 April 1980 1 see page 2, lines 21-28; page 3, lines 1-4; page 4, lines 6-34; page 7, lines 5-24; nage 8, lines 5-14 document denng the general state the art which s not or priority date and not n conflict with the application but conidered to be of particular relevance cited to understand the principle or theoi$ under:7!ng the Ii nvention earlier document but published on or after the international document of particular relevance: the claimed Inventovn filing date cannot be ,.onsidered novel or cannot be considered to document which may throw doubts on priority clalm(s) or involve an inventive step which Is cited to establish the publication date of anoter document of particular relevance the claimed nventon citation or other specal reason (as specified) cannot be considered to nvolve an inventive step when the document referring to an oral disclosure, use, exhibition or document Is combined with one or more other such docU- other means ments, such combination being obvious to a person skilled document published prior to the International filing date but In the art. later than the priority date claimed document member of the same patent family IV. CERTIFICATION Date of the Actual Completion of the International Search Date of Mailing of this International Search Report 11 April 1990 (11.04.90) 30 May 1990 (30.05.90) International Searching Authority Signature of Authorized Officer European Patent Office Form PCT/ISAt2io (second sheet) (January i985) *1 .I A ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL PATENT APPLICATION NO. EP 9000342 SA 34875 This annex lists the patent family members relating to the patent documents cited in the abovenmentioned internaional search report. The members are as contained in the European Patebt Office EDP file on 21/05/90 The European Patent Office is iv no way liable for these particulars which are merely given for the purpose of information. atent document Publication Patent family Publication cited in search report date member(s) date US-A- 3728277 17-04-73 BE-A- DE-A- FR-A- GB-A- US-A- 761333 2100302 2075400 1346428 3654177 16-06 -71 22-07-71 08- 10-7 1 13-02-74 04-04-72 EP-A- 0009746 16-04-80 DE-A- 2843473 17-04-80 JP-A- 55058297 30-04-80 US-A- 4362635 07-12-82 ki For more details about this annex wee official Journal of the European Patrnt office, rNo. t7,/;z Ii ii I I I INTERNATI0NALZR RECHERCHENBERICHTI lnternationales Aktenzeichen PCT/ EP 90 /00342 1. KLASSIFI KATION DES ANMELDUNGSGEGENSTANDS Ibeimrnhreren Klassltlkatlanssymbolen sind all, anzugeben) 6 Nach der Internationalen Patentklassifikation (IPC) oder nech der nationalen Kiassifikation und der IPC nt .ci C 09 K 7/06 i 11. RECHERCHIERTE SACHGEBIETE Recherchierter Mindestprdfstoff 7 Klassifikationssystemn K lassifikationssymbole Int.CI C 09 K 7/06 Recherchierte nicht zumn MindestprUfstoff gehorende \/erbffentichungen, sovveit diese unter die recherchierten Sachgebjete fallen 8 III.EINSCHLAGIGE VERO5FFENTLICHUNGEN 9 ArVt Pjennzeichnung der Ver6ffenilichungll,soweit erforderlich unter Angabe der maggeblichen Teile'1 2 Betr. Anspruch Nr, 13 Y US, A, 3728277 T. FOLEY) 1 17. April 1973 siehe Spalte 4, Zeilen 73-75; Spalte Zeilen 1-13 A Y EP, A, 0009746 (BAYER) 1 16. April 1980 siehe Seite 2, Zeilen 21-28; Seite 3, Zeilen 1-4; Seite 4, Zeilen 6-34; Seite 7, Zeilen 5-24; Seite 8, Zeilen 5-14 *Besondere Kategorlen von angegebenen Veroffentlichungen 10 Veroftentlichung, die den aligemelneo Stand der Technik 9pbtere Ver6ffentlichung, die nach dem Internationalen An- definiert. aber nlcht als besonders bed~osamn enzusehen Ist meldedatumn oder dem Prioritarsdatum veroffentlicht wvordY',n alteres Dokument, des jedloch erst am oder nach dem Interna- iSt und mit der Anmeldung nicht kollidlert, tandern nur zuiv! tianalen Anmeldedatumn veroffentlicht warden ist Verst~ndnis des der Erfindung zugrundeliegenden Prinzips "Li' Veroffentlichung, die geeignet ist, einen Priori tatsa nsp ruch oe e h urnelgne hoi neee s ewelfeihaft erscheinen zu lassen, oder durch die des Verf. Veroffentlichung von besonderer Bedeutung; die beanspruch. fentlichungsdatum elner anderen im Recherchenbericht ge- te Erfindlung kann nicht als neu oder auf erfinderitcher Tbtig. namwrln \trbffentlichung belegt wverden soil oder die aus einern keit beruhend betrachtet warden anderen fqesanderen Grund angegeben 1st (wie ausgeftihrt) Veroffentlichung van besonderer Bedeutung: die beanspruch. Ver~ffentlichung, die sich auf elne mtindliche Offenbarung, te Erfindung kann nicht als euf erfinderischer Tatigkeit be. eine Benutzung, elne Aussteilung oder andere Maflnahmen' ruhend betrachtet warden, wenn die Veroffentlichung mit bezieht einer oder mehreren anderen Veraiffentlichungen dieser Kate. gorne In Verbindung gebracht wird und diese Verbindung fur Veroffentlichung, die var demn internatianalen Anmeldeda- einen Fachmann naheliegend it turn, aber nach dem beanspruchten Priritaitsdatumn veroffent. e~feelhndeMtie esle aetaii s llcht warden istVVrfetihndeMlie esle aetaii s IV. BESCHEINIGUNG I LDatur des Aoscniusses oer Internationaien R~echerche Absendedatumn des internationalinn Recherchenberichts 11. April 1990 3 0. Internationale Rechercheni.~.orde Unterschrif t des bevollmachtigi'en Bed Europlisches Patentamtj Farmblaet PCT/ISAI21O0 (Blatt 2) (Januer 1985) ANHANG ZUM IITERNATIONALEN RECHERCHENBERICHT E 004 In dieseni Anhang sind die Mitglieder der Patentfaniilien der im obengenannten internationalen Recherchenbericht angcfdhrten Patentdokumente angeeen. Die Angaben bber die Faniiiienmitglieder entsprechen dem Stand der Datei des Europiiischen Pqtentamts anm 2 1/05/90 Diese Angaben dienen -aur a ur Unterrichtung und erfoigen ohne GewAhr. In' echerchenbericht Datun der Mitglied(er) der Datum der Iangefdhrtes Patentdokument Veroffentlich ung Patentfamilie Veroffentlichung I, .p. US-A- 3728277 17-04-73 BE-A- 761333 16-06-71 OE-A- 2100302 22-07-71 FR-A- 2075400 08-10-71 GB-A- 1346428 13-02-74 US-A- 3654277 04-04-72 EP-A- 0009746 16-04-80 OE-A- 2843473 17-04-80 JP-A- 55058297 30-04-80 US-A- 4362635 07-12-82 Fohr Ns1ieT Eimelbee v~ Amhang 6ebe Amtsbiatt des Europiiisehen Pateutanits, Nr.12/82