CA2152778A1

CA2152778A1 - Rheology-controlled flowable and pumpable aqueous preparations, for example for use as water-based drilling muds

Info

Publication number: CA2152778A1
Application number: CA002152778A
Authority: CA
Inventors: Heinz Mueller; Claus-Peter Herold; Stephan Von Tapavicza; Wolfgang Breuer
Original assignee: Individual
Current assignee: Henkel AG and Co KGaA
Priority date: 1992-12-28
Filing date: 1993-12-20
Publication date: 1994-07-07
Also published as: EP0675937A1; AU5813494A; WO1994014918A1; NO951618L; NO951618D0; AU677815B2

Abstract

The invention concerns the use of lower all alkoxylates, which are boundary-layer-soluble in water at room temperature, of water-insoluble alcohols of natural and/or synthetic origin to control the rheological properties, even at high temperatures, of pumpable, fluid aqueous preparations of fine particulate mineral substances of natural and/or synthetic origin, the aqueous preparations being suitable for use in particular as working fluids in the disintegration zone in soil and/or geological formations, e.g. as water-based drilling fluids.

Description

~ 52 7 78 Translation Rheology-controlled flowable and pumpable aqueous preparations, for example for use a~ water-based drilling muds This invention relates generally to the rheology control of aqueous liquid phases using viscosity genera-tors based on fine-particle swellable or even non-swell-able minerals of natural and/or synthetic origin, the choice of new controllers providing for reliable rheology control from ambient temperature to high temperatures, for example up to 300C or even higher. The teaching according to the invention is based on an interaction between the fine-particle minerals on the one hand and the controllers according to the invention described hereinafter. The teaching according to the invention enables the rheological properties and, more particular-ly, the thixotropic properties of such water-based preparations to be effectively precision-controlled over lS a wide temperature range, so that flowable and pumpable aqueous thixotropic preparations improved in various respects can be prepared using the auxiliaries described hereinafter.
The thickening of water-based systems using fine-particle swellable or even non-swellable clays and/or other layer compounds of natural and/or synthetic origin is widely practised. The possibility of thickening, more particularly thixotropically thickening, aqueous or water-based liquid phases is utilized in various applica-tions. Without any claim to completeness, such applica-tions include the treatment of solid materials, more par-ticularly metals, the field of fire extinguishing prepar-ations, the use of thixotropically thickened liquid phases in water-based paints and coating systems, hy-draulic fluids and the like.

~ 21~i2778r Thixotropically thickened water-based auxiliary liquids are being widely used to an increasing extent in the technology of geological land-supported drilling and also for other purposes, for example as soil supports in excavating operations, more particularly in channel wall construction, in the sinking of shafts, wells and cais-sons, in pipe laying and the like. A literature refer-ence which deals with the corresponding application of thixotropic liquid systems is, for example, F. Weiss "Die Standfestigkeit flussigkeitsgestutzter Erdwande" in Bauingenieur-Praxis, Heft 70 (1967), Verlag W. Ernst &
Sohn, Berlin-Munchen. Water-based drilling fluids which are sufficiently thickened by the addition of mineral viscosity generators (normally using suitable polymer compounds at the same time) without losing any of their flowability and pumpability under shear stressing and which - depending on the particular situation - contain additional dissolved, emulsified and/or suspended auxili-aries are used on a wide scale. However, many other liquid auxiliaries in the field of application in ques-tion - known for example by the technical terms of stim-ulation, fracturing, spotting, milling or simply cleaning - are water-based liquid phases which have been thickened with inorganic and/or organic viscosity generators; see, for example, MANUAL OF DRILLING FLUIDS TECHNOLOGY, 1985, NL Baroid/NL Industries, Inc. and A.T. Bourgoyne Jr. et al. "Applied Drilling Engineering", Society of Petroleum Engineers, Richardson, Tx, 1986. Relevant information can also be found in the book by George R. Gray and O.C.H. Darley entitled "Composition and Properties of Oil Well Drilling Fluids", 4th Edition 1980/81, Gulf Publish-ing Company, Houston and the extensive patent and specia-list literature cited therein.
The present invention is largely described in the following with reference to such auxiliary liquids for "- 215277~

use in the field of geological drilling, although it is by no means limited in its application to this particular field. The term "earth boring" is also meant to be broadly interpreted, encompassing both the development of geological occurrences, such as oil and/or gas, and technical auxiliary drilling, for example undertunneling, so-called river crossing, the development of waste dis-posal sites, water drilling and the like.
The mineral viscosity generators used for the rheology control of water-based drilling fluids are typically swellable clays of natural and/or synthetic origin, although fine-particle non-swelling minerals may also be used for thixotropic thickening. Corresponding smectites, such as montmorillonite, bentonite, beidel-lite, hectorite, saponite and stevensite, are mentionedas examples. Attapulgite is another important auxiliary of the type in question, see for example US-A 4,664,843, more particularly columns 5 and 6. Several other propo-sals are concerned with the synthetic production and use of fine-particle clay-like minerals, more particularly corresponding compounds of the hectorite and/or saponite type, see DE-A 16 67 502 and in particular EP-B 0 260 538. The disclosure of the second of these two docu-ments, which describes one of applicants' developments, is hereby included as part of the disclosure of the present invention.
By selecting suitable natural or synthetic, usually swellable minerals, in conjunction with water-soluble and/or swellable polymer compounds, optionally diluents and the like, it is possible very largely to control the particular rheological properties required, as reflected in particular in suitable figures for plastic viscosity (PV), yield point (YP) and gel strength - determined both before and after ageing under standard conditions.
Relevant particulars can be found, for example, in the above-cited publication "MANUAL OF DRILLING FLUIDS
TECHNOLOGY" of NL Baroid.
An important further development in the rheological control of mineral-thickened aqueous preparations is the subject of applicant's earlier German patent application P 42 24 537.0 which describes the use of mixed hydroxide compounds of divalent and trivalent metals with a 3-dimensional space lattice structure of the garnet type for regulating the thixotropic thickening of aqueous preparations by means of swellable clays and/or other swellable layer silicate compounds of natural and/or synthetic origin. Water-swelling layer silicates known per se, such as clays of the sodium bentonite type or even synthetic mineral compounds of the type described in EP-B 0 260 538, are used in conjunction with the selected mixed hydroxide compounds of garnet structure mentioned in the disclosure of that earlier application. The teaching of the earlier application, of which the dis-closure is hereby specifically included as part of the disclosure of the present invention, is based on the surprising observation that these fine-particle mineral auxiliaries of garnet structure with a space-filling 3-dimensional space lattice structure are effective rheol-ogy control auxiliaries and, so far as the property spectrum of the thickened aqueous liquid phases is concerned, can lead to a hitherto unknown combination of desirable properties.
Further documents relating to the rheology control of aqueous liquid phases using sodium bentonite, for ex-ample, as viscosity generator are EP-A 0 207 810 and US-A 4,664,843. According to these documents, layer sili-cates known per se, such as clays of the sodium bentonite or attapulgite type, are used with selected synthetic mineral mixed oxides which are distinguished by a crys-talline monolayer structure of the mixed metal hydroxides ~` 2~ 52778 per unit cell. These layer crystals are said to be "monodispersed" in a liquid carrier so that the individu-al crystals form separate layers of the mixed metal hydroxide compounds. Particulars of the quality and mode of action of these mineral auxiliaries of synthetic origin known as "mixed metal layered hydroxide compounds (MMLHC)" can be found in the above-cited patents and in the article by J.L. Burba III et al. "Laboratory and Field Evaluation of Novel Inorganic Drilling Fluid Additives", IADC/SPE 17198, pages 179 to 186.
In the practical application of water-based drilling fluids, however, selected water-soluble or at least water-swellable polymer compounds have hitherto played a predominant part. The drilling fluids used here to illustrate the problems involved are liquid phases which are expected to perform a considerable number of dif-ficult functions at one and the same time. The drilling fluid cools and lubricates the bit and, at the same time, is expected to transport the drilled cuttings upwards.
The deeper the borehole, the higher the temperatures to which the drilling fluid pumped through the borehole is exposed. Particulars of the various requirements can be found, for example, in the above-cited US-A 4,664,843.
Another factor to be taken into consideration in this regard is that sodium bentonite - the most widely used viscosity generator in water-based drilling fluids - is sensitive not only to the effect of heat, but also to the effect of polyvalent cations, more particularly calcium ions. Hitherto, the result of this in practice has been that so-called diluents and rheology-controlling polymer compounds of correspondingly adapted thermal stability are widely used in working fluids of the type under discussion here.
The problem addressed by the present invention was to provide rheology-controlling additives of organic 2 1 ~ ~ 7 7 8 origin which would enable auxiliaries of the type men-tioned above, more particularly based on thickening organic polymer compounds, to be partly or completely replaced. Rheology control would be both possible and effective at high temperatures. However, by using certain selected organic auxiliary components, it would also be possible to retain the possibility of favorably influencing other important properties of drilling fluids independent of rheology, for example their lubricity, their pH control and, in particular, their "inertization"
to polyvalent cations.
The teaching according to the invention is based on the observation that selected lower alkoxylates of water-insoluble alcohols which show limited solubility in water, particularly at room temperature, appear to interact with the mineral particles very finely dispersed in the aqueous phase. This interaction enables the rheological properties of the system to be controllably influenced. More particularly, this controllable thick-ening is effective over the entire range of temperaturesencountered in practice without unreasonably impeding the reduction in viscosity under shear stressing. In addi-tion, this interaction between very fine-particle miner-als suspended in the aqueous phase on the one hand and the viscosity controllers selected in accordance with the invention on the other hand makes even those mineral viscosity generators inert to polyvalent metal ions, for example calcium ions, which would be sensitive to such components in the absence of the viscosity controllers according to the invention. Water-swollen sodium ben-tonite is a typical example of such a viscosity con-troller.

Subject of the invention In a first embodiment, therefore, the present ~1~2778 invention relates to the use of lower alkoxylates of water-insoluble alcohols of natural and/or synthetic origin (hereinafter also referred to as "controllers") showing limited solubility in water at room temperature for effectively thickening and controlling the rheologi-cal properties of flowable and pumpable aqueous prepara-tions of fine-particle minerals, even at high tempera-tures, which may be used in particular as working fluids in the development of geological formations and/or for land development, for example for liquid-aided excavating operations.
In another embodiment, the invention relates to flowable and pumpable aqueous preparations rheologically controlled by addition of fine-particle minerals of natural and/or synthetic origin which are additionally thickened by addition of organic additives (controllers) and which may be used in particular as water-based aux-iliary liquids in the fields of application mentioned above. In this embodiment, the teaching according to the invention is characterized in that they contain lower alkoxylates of water-insoluble alcohols of natural and/or synthetic origin of the type described hereinafter to stabilize their rheological properties, even at elevated temperatures.
In the context of the present invention, lower alkoxylates of water-insoluble alcohols are understood in the broadest sense - for both of the embodiments men-tioned above - to be corresponding lower ethoxylates and/or lower propoxylates and/or lower butoxylates.
Corresponding lower ethoxylates and/or lower propoxylates are preferred for the purposes of the invention, lower ethoxylates being particularly preferred.
Finally, in another embodiment, the invention relates to the complete or partial replacement of hither-to typical water-soluble or at least water-swellable polymer compounds in water-based flowable preparations which are thickened with swellable or even non-swellable mineral fine-particle solids, but which may be used for example as water-based drilling fluids for other com-parable applications.

Particulars of the teachinq according to the invention Water-insoluble alcohols of natural and/or synthetic origin containing a relatively large number of carbon atoms are known starting materials for the production of various classes of surfactant compounds, more particular-ly anionic and nonionic surfactants. Nonionic surfac-tants are obtained from these water-insoluble fatty alcohols in particular by alkoxylation with ethylene oxide and/or propylene oxide, the necessary equilibrium between hydrophobic and hydrophilic parts of the molecule structure being established by the introduction of an adequate number of EO units, more particularly highly hydrophilic EO units. Conventional surfactants of this type are o/w surfactant compounds with sufficiently highly pronounced hydrophilic molecule components which ensure that the surfactant components are largely soluble in aqueous phase at room temperature. Any increase in the temperature of the aqueous surfactant solution leads to visible clouding of the aqueous solution, depending on the cloud point of the particular nonionic surfactant.
This clouding is caused by separation into two liquid phases of which one is poorer in surfactant and the other richer in surfactant than the starting solution. The clouding temperature is dependent on the particular size of the hydrophobic and hydrophilic groups attached to one another in the molecule. The temperature at which separation and hence clouding begins for a given concen-tration is called the "cloud point". The cloud point is normally expressed as the cloud point of a 1~ aqueous .- 21S2778 solution. For a predetermined size of the hydrophobic part of the mo ecule, the cloud point is a measure of the degree of alkoxylation and, hence, is an important performance characteristic. Further particulars can be found in the relevant specialist literature, see for example applicants' book entitled "Fettalkohole, Roh-stoffe, Verfahren und Verwendung", more particularly the subchapter by H. Lange and M.J. Schwuger entitled "Physi-kalisch-chemische Eigenschaften von Fettalkoholen und Folgeprodukten", subchapter 3.5 "Entmischung; Trubungs-punkt; Verteilungscoeffizient" and J. Glasl "Anwendung der Fettalkohole und Folgeprodukte", more particularly subchapter 3.1 "Fettalkohol-Polyglykolether".
The lower alkoxylates of water-insoluble alcohols used as controllers in accordance with the invention are distinguished by such a low degree of alkoxylation and hence by the introduction of hydrophilic groups into the molecule as a whole that they are regarded as so-called limited solubility compounds at room temperature, i.e. do not form clear solutions in water. Fatty alcohol alkoxy-lates of this type, which are substituted on a statisti-cal average by 2 to 4 EO groups, for example at a C1218 hydrocarbon radical, are known commercial products for a variety of different applications. They are marketed by applicants, for example under the registered names of "DEHYDOL LS 2", "DEHYDOL LS 3" or "DEHYDOL LS 4", for various industrial applications, for example for the leather industry, the textile industry and also in connection with cold cleaning preparations, car cleaning preparations and the like.
One of applicants' more recent publications is concerned with the use inter alia of the class of limited solubility fatty alcohol ethoxylate compounds under discussion herein as new N-free thickeners for surfactant formulations, cf. the article of the same name in "Seif-en-Ole-Fette-Wachse", No. 2/1990, pages 60 to 68, more particularly subchapter 3~2 "Fettalkohol-Ethoxylate" and 3.3 "Fettalkohol-Ethoxylate mit eingeengter E0-Homologen-verteilung" (author A. Behler et al.). This article describes the effect of lightly ethoxylated fatty alco-hols on the viscosity of cosmetic formulations (shampoos, bath and shower preparations). The cosmetic formulations in question contain anionic surfactants of the alkyl ether sulfate type as primary surfactant component. The article in question shows that the aqueous surfactant preparation can be thickened by the use of selected nonionic fatty alcohol ethoxylates with a limited degree of ethoxylation. The objective of mixtures such as these is to influence the surfactant micelle structure. More particularly, isometric spherical micelles are said to be converted into anisometric rodlet or disk micelles.
Macroscopically, this is reflected in an increase in the viscosity of the surfactant solution. This mechanism clearly has no connection with the interaction underlying the teaching according to the invention between suspended and, preferably, water-swollen mineral particles and the controllers selected in accordance with the invention based on lower alkoxylates of water-insoluble alcohols showing limited solubility in water at room temperature.
25An article published at the end of the forties relates to the use of typical o/w detergents as auxili-aries for suspending clays in high concentrations in water-based drilling muds (T.M. Doscher, "CHARACTERISTICS
OF DETERGENT-SUSPENDED CLAYS", Journ. of Phys. and 30Colloid Chem. 53 (1949), 1362). The article in question is concerned solely with highly concentrated suspensions of clays in an aqueous phase which are distinguished by the following test parameters: the swellable parts of natural clay are flocculated out by reaction with large quantities of calcium chloride, so that suspensions of - 21~2778 non-swelling solids are said to be produced. The clay solids content of these suspensions is very high, more particularly in the range from about 20 to 60% by weight, based on the aqueous suspension. Drilling fluids of this type cannot be compared with the low-solids water-based drilling fluids with which the present invention is concerned. Modern systems of this type use the struc-ture- and rheology-determining, more particularly swell-able clays in far smaller amounts - typically well below 10 to 15% by weight and, preferably, at most about 5% by weight, based on the system as a whole. Understandably, controlling the rheological properties of such low-solids liquid phases and eliminating any problems arising in this regard cannot be compared in any way with the technical problems of water-based systems containing non-swelling clay compounds in very much higher concentra-tions. In low-clay systems, the swellability of the clay is crucial to the development of the required rheology.
In their case, the difficulties to be overcome lie on the one hand in the establishment of adequate temperature stability of the system, so that the desired rheological properties can be adjusted and maintained, even at temperatures above about 100C, for example up to around 250C. On the other hand, swellable clays have to be protected against the effect of polyvalent cations, particularly calcium.
It has surprisingly been found that the use of small quantities of the lower alkoxylates of water-insoluble alcohols of natural and/or synthetic origin showing limited solubility in water at room temperature, which are referred to in accordance with the invention as "controllers", is capable of optimally solving the problems discussed in the foregoing. In addition, the aqueous flowable and pumpable preparations thickened in accordance with the invention, more particularly aqueous preparations of swellable fine-particle minerals of the ~odium bentonite and/or ~ynthetic swellable layer sili-cate type, can be further-controlled and optimized.
One preferred embodiment of the invention is charac-terized by the use of limited solubility controllers ofthe type mentioned above which are present in liquid form at temperatures of up to about 100C and which in par-ticular have pour points and flow points below about 80C. Particularly important auxiliaries of the type defined in accordance with the invention have pour points and flow points below 50C, preferably below 25C and more preferably below 10C. The most important auxili-aries of the type defined in accordance with the inven-tion are distinguished by pour points and flow points below 0C. Accordingly, in the temperature ranges which normally prevail in practice, they are present as liquids which may readily be processed in situ or added, for example, to the water-based drilling fluid in operation, even under offshore conditions.
The controllers used in accordance with the inven-tion, which are liquid at room temperature, may be further defined by their preferred cloud points, as measured on a 1% by weight mixture in water. Their cloud points are preferably below 25C, best below 20C and generally below 10C. Limited solubility controllers of the type mentioned with cloud points below 0C can be particularly interesting representatives for the teaching according to the invention.
Important representatives of controllers according to the invention are lower alkoxylates of aliphatic and/or ethylenically unsaturated alcohols containing at least 6 carbon atoms and preferably at least 8 to 10 carbon atoms. Particularly suitable thickeners are derived from monohydric C1024 and preferably Cl218 alcohols of natural and/or synthetic origin. The alcohol mole-21~2778 cules may be linear, branched and/or cyclic. They may bealiphatically saturated or monoolefinically or even poly-olefinically unsaturated. Aromatic systems are less suitable for ecological reasons alone and, accordingly, are not preferred.
The limited solubility controllers defined in accordance with the invention are obtained from these water-insoluble alcoholic components by ethoxylation and/
or propoxylation and/or butoxylation. For example, fatty alcohols can be reacted with ethylene oxide (EO) and/or propylene oxide (P0) and/or butylene oxide (B0) in the presence of catalysts to form polyglycol ethers. The hydrophilicity or water solubility of the fatty alcohol derivatives increases while their oil solubility decreas-es with increasing degree of addition. Accordingly, thehydrophilic E0 chain and/or P0 chain and/or B0 chain has to be correctly adapted to the oleophilic nature of the alcohol radical for the limited solubility thickeners of the type in question used in accordance with the inven-tion. For example, depending on the chain length of thestarting alcohol, surfactants which form clear solutions in water at 20~C are obtained with 3 moles of E0 (in the case of n-octanol) to 7 moles of E0 (in the case of tallow alcohol). In the two cases mentioned, the limited solubility condition is exceeded in the direction of water-soluble nonionic surfactant compounds. According-ly, controllers according to the invention should have relatively short oligo-E0 chains.
A particularly important class of controllers in the context of the teaching according to the invention are the lower alkoxylates, more particularly the lower ethoxylates, of fatty alcohols containing 12 to 18 carbon atoms. In their case, both technical mixtures in the Cl2_l8 range and much narrower-range starting materials, for example fatty alcohols in the Cl2/l4 or Cl2/l6 range~ may be used as the fatty alcohol starting material for pro-ducing the thickeners. Limited solubility ethoxylates of these starting materials and hence optimized con-trollers in the context of the invention are obtained by the addition of 1 to 3 EO groups and, more particularly, 2 to 3 EO groups (on a statistical average) onto fatty alcohols of the type just mentioned. PO or BO groups introduced are known to be less hydrophilic than corre-sponding EO groups, so that the number of PO chain links or BO chain links can be slightly shifted upwards. The use of PO groups and, in particular, the combination of EO/PO groups can be useful for other reasons, for example for suppressing any tendency towards foaming. The same applies to the use of BO groups. The general knowledge of the expert on corresponding surface-active compounds may again be applied in this regard. The relevant literature is represented, for example, by applicants' above-mentioned book entitled "Fettalkohole, Rohstoffe, Verfahren und Verwendung", cf. in particular the subchap-ter by J. Glasl "Anwendung der Fettalkohole und Folge-produkte", loc. cit., pages 132 to 143 and in particular the Tables on pages 133 to 138 with their data on ethoxy-lates based on C12l4 coconut oil fatty alcohol, on C1216 coconut oil fatty alcohol, on C1218 coconut oil fatty alcohol and on oleyl and cetyl alcohol.
The controllers according to the invention are used in aqueous suspensions of fine-particle minerals which, in one preferred embodiment, are swellable in water although they may even be non-swellable. The minerals may be of natural and/or synthetic origin. The general knowledge of the relevant expert, as derived for example from the literature cited at the beginning, is the determining factor for the most important application of the rheology-controlled aqueous preparations according to the invention, i.e. flowable and pumpable auxiliaries for ~ 2152778 use in soil excavating operations and/or as geological borehole servicing fluids. According to the invention, natural and/or synthetic clays, such as bentonite, attapulgite, hectorite and/or saponite or even mixtures thereof with mineral controllers, such as katoite or the mixed metal layered hydroxide compounds (MMLHC) mentioned above, are preferably used as mineral component(s), sodium bentonite being particularly preferred.
In addition to the literature references cited above in connection with expert knowledge of mineral solids to be thickened, more particularly of the sodium bentonite type, reference is made here to applicants' earlier German patent application P 42 24 537.0, of which the disclosure is hereby specifically included as part of the disclosure of the present invention.
The viscosity generators based on mineral fine-particle solids, preferably-swellable or even non-swell-able clays, are typically used in quantities of at most about 15% by weight and, in particular, in quantities below about 10% by weight. Suitable quantities are, for example, in the range from about 1.5 to 9% by weight and preferably in the range from about 2 to 8% by weight.
For the water-based drilling fluids based on sodium bentonite typically used in practice, the bentonite is normally used in quantities of, for example, about 2 to 6% by weight, based on the aqueous phase.
Highly effective mineral thickeners of synthetic origin, which may even be used in much smaller quan-tities, are described for example in the above-cited EP-30B 0 260 538 which has been included in the disclosure of the present invention.
In another preferred embodiment of the invention, the quantity in which the particular limited solubility controller as defined in the description of the invention is used is adapted to the particular quantity of mineral ` 2152778 fine-particle thickening components used. According to the invention, the organic controller component(s) is/are used in at most substantially equivalent quantities to the fine-particle clays. The organic controllers are preferably used in smaller quantities than the clays, mixing ratios (by weight) of controller to clay of 0.01:1 to 0.8:1 and preferably of the order of 0.05:1 to 0.5:1 being particularly preferred.
Accordingly, taking into account the limited quanti-ties in which mineral thickening components are presently used in water-based systems of the type in question, the organic controllers according to the invention are often used in quantities of up to about 5% by weight, based on the water-based system, and preferably in quantities of up to about 3% by weight. It has actually been found that even very small quantities of the controller com-ponents according to the invention are sufficient to initiate permanent rheology-stabilizing effects. Thus, upper limits of about 1.5 to 2% by weight (again based on the flowable and pumpable aqueous preparation) are often sufficient in practice for the quantity of organic con-troller to be used. The following Examples illustrating the teaching according to the invention show the extreme effectiveness of even very small additions of the con-troller components, for example of the order of 0.2 to 1%by weight and preferably of the order of 0.5 to 1% by weight of the aqueous preparation. Despite these small amounts of controller components, for example of the order of 0.3 to 0.8% by weight, the clay phase, more particularly the water-swollen clay phase, is permanently stabilized, so that predetermined rheological values in regard to plastic viscosity, yield point and gel strength are maintained over wide temperature ranges in which the particular systems tested would show significant changes in their rheological properties without the addition of the controllers according to the invention. Such changes include on the one hand the known tendency of sodium bentonite to gel at relatively high temperatures and the collapse of rheology at relatively high temperatures. By using the controller components according to the inven-tion, the particular system is stabilized in both direc-tions.
In this connection, it may be useful in some cases to allow even the systems stabilized in accordance with the invention a limited time for stabilization of the rheological properties. The freshly prepared water-based mixture may lead to a - normally limited - change in the rheological properties on initial exposure to relatively high temperatures. However, once this incipient ageing process has been controlled in accordance with the invention, the now existing level of rheological proper-ties is maintained over prolonged periods and/or wide temperature ranges.
Another advantage is again emphasized at this juncture. The thickened aqueous systems are stabilized not only against variations in the temperatures to which they are exposed. More particularly, the susceptibility of water-swelling clays of the sodium bentonite type to the effect of polyvalent cations is also eliminated or at least limited to a very considerable extent. Calcium is known to be an element of particular significance in this regard in the field of drilling muds insofar as it is regularly introduced into the drilling mud system in the form of its water-soluble salts during the penetration of corresponding water-containing layers.
The use in accordance with the invention of the controllers or stabilizers based on limited solubility lower alkoxylates of water-insoluble alcohols, preferably based on limited solubility fatty alcohol ethoxylates, leads to another important possibility: the polymer ~-`; 2152778 compounds hitherto almost always required in mixtures of the type in question here are now completely or at least partly unnecessary. The importance of using polymer compounds of natural and/or synthetic origin is discussed in the literature cited at the beginning. In general, the polymer compounds are said to arrest weaknesses in the mineral-thickened system occurring in practice as a result of variations in the working conditions. Stabili-zation of the mineral thickener system by using con-trollers of the described type in accordance with theinvention is so thorough that it may be regarded as an at least equivalent replacement of the polymer compounds.
Of crucial significance in this regard is the well-known high thermal stability of nonionic fatty alcohol alkoxy-lates which enable the stabilizing principle according tothe invention to be applied over the wide temperature range occurring in practice, for example up to 300~C or even higher. The use of limited quantities of selected polymer compounds does of course fall within the scope of the teaching according to the invention.
Knowledge of the production of nonionic surfactants may be used in connection with the production and charac-teristics of the controllers according to the invention.
It may be briefly summarized as follows: suitable alkoxy-lates are those which have been conventionally equippedwith a comparatively broad statistical distribution of the chain lengths of the E0, P0 and/or B0 groups. How-ever, alkoxylates of the so-called "NRE (narrow-range ethoxylate)" type produced by more modern methods are also suitable. The following observations should be interpreted in this sense: preferred alcohol alkoxylates are provided with up to 7 alkoxy groups and preferably with up to 4 alkoxy groups (statistical mean values) while particularly preferred controllers or thickeners are Cl2-18 fatty alcohol-E0x compounds where x is a number of 1 to 3.
In one important e~bodiment, the teaching according to the invention is of particular significance in connec-tion with the production of water-based borehole servic-ing fluids, more particularly drilling muds, which to-gether with the thickened aqueous phase contain a dis-persed organic oil phase - flowable in particular at working temperatures - in finely emulsified form.
Drilling muds of this type are known to be o/w emulsions which, so far as their performance properties are con-cerned, occupy the middle ground between purely aqueous systems and oil-based invert muds. Detailed information can be found, for example, in the above-cited book by George R. Gray and O.C.H. Darley entitled "Composition and Properties of Oil Well Drilling Fluids", 4th Edition, 1980/81, Gulf Publishing Company, Houston and the exten-sive specialist and patent literature cited therein. O/w drilling muds of this type are typically 3-phase systems of oil, water and fine-particle solids.
O/w emulsions such as these are of particular significance in the context of the invention. Preferred embodiments are characterized by the use of ecologically safe dispersed oil phases which are based in particular on at least substantially water-insoluble alcohols, correspondingly water-insoluble ethers and esters of mono- and/or polycarboxylic acids and comparable carbonic acid esters. Further information on this subject can be found in relevant publications and patent applications in applicants' name (DE-A 39 15 875, DE-A 39 15 876, DE-A 39 16 550, DE-A 40 18 228 and DE-A 40 19 266). The subject matter of these documents is hereby specifically included as part of the disclosure of the present inven-tion in connection with the particular embodiment in question.
In connection with water-based borehole servicing 21~2778 fluids, more particularly drilling muds, the addition of auxiliaries to inhibit drilled rock showing high sensi-tivity to water can be of particular significance. For example, the water-soluble salts known from the prior art as additives for water-based drilling fluids may be used for this purpose. The water-soluble salts in question are in particular halides of the alkali and/or alkaline earth metals, among which corresponding potassium salts, particularly in combination with lime, can be of particu-lar significance. Recent developments in this field arebased inter alia on the use of water-soluble polyalco-hols, such as polyglycols, the use of glycerol, cross-linked and/or uncrosslinked oligoglycerols and/or poly-glycerols and comparable compounds, see for example EP-A
0 293 191 (glycerol and/or polyglycerols), US-A 4,830,765 (polyhydric alcohols, glycol, glycol ethers, polypropy-lene glycols, polyethylene glycols, ethylene oxide/propy-lene oxide copolymers, alcohol-initiated EO-PO copolymers and mixtures thereof), M.E. Chenevert "Glycerol Additive Provides Shale Stability" in Oil & Gas Journal, July, 1989, 60-64 and D. Green et al. "Glycerol-Based Mud System Resolves Hole Sloughing Problems" in WORLD OIL, September 1989, 50/51. The regulation and adjustment of viscosity by the measures proposed in accordance with the invention is also of importance in connection with water-based borehole servicing fluids modified in this way.
In the particular embodiment of the invention in question here, the viscosity-controlled water-based drilling auxiliaries may contain any of the additives typically used for comparable drilling fluids. These additives may be water-soluble, oil-soluble and/or water-or oil-dispersible. Known additives for water-based drilling fluids, more particularly o/w drilling emul-sions, are for example emulsifiers, fluid loss additives, alkali reserves, weighting agents, agents for inhibiting 21~2778 the unwanted exchange of water between drilled formations and the water-based drilling fluid, wetting agents to improve the adsorption of the emulsified oil phase onto solid surfaces, disinfectants and the like. Further information on this subject can be found in the relevant prior art as represented, for example, by the above-cited book by Gray/Darley. Further detailed information on o/w-based drilling emulsions can also be found in appli-cants' above-cited patent applications.
For safely controlling and developing the interac-tion between the fine-particle layer silicate compounds on the one hand and the controllers based on lower, limited solubility alkoxide compounds of water-insoluble alcohols on the other hand, it may be advisable in the preparation of drilling systems from a number of com-ponents to ensure that the interaction between these two principal components is not affected by other possible constituents. Accordingly, it may be desirable for example to combine an aqueous sodium bentonite suspension adjusted with NaOH to typical pH values in the range from about 7.5 to 12 and more particularly in the range from about 8 to 10.5-11 with controllers according to the invention in the absence of substantial quantities of polyvalent cations, particularly calcium ions, and to initiate the suspension/controller interaction. Inten-slve mixing of the components, if desired under the effect of raised temperatures, may be useful for this purpose. The developing structures are thus optimally suitable for further mixing with any required and/or desired additional constituents of the ready-to-use water-based auxiliary and working fluids.
In one embodiment of the invention, the controllers are used together with defoamers or foam inhibitors.
This embodiment can be of particular significance in cases where the water-based aqueous preparations are exposed to intensive mechanical forces under conditions which can lead to foaming. Although basically any defoamers or foam inhibitors known to the expert may be used, one particular component has proved to be particu-larly useful in the context of the teaching according tothe invention. The component in question is a Guerbet alcohol, i.e. a fatty alcohol condensation product branched in the 2-position to the hydroxyl group.
Particulars of this class of alcohols can be found, for example, in applicants' book entitled "Fettalkohole, Rohstoffe, Verfahren und Verwendung", pages 168/169. The foam inhibitors are used together with the controllers according to the invention generally in small quantities, based on the particular quantity of controller used.
Thus, the foam inhibitor may be used in quantities of from about 1 to 50% by weight and preferably in quanti-ties of from about 5 to 30% by weight, based on the quantity of controller according to the invention.

E x a m p 1 e s In the following Examples, the rheological behavior of aqueous alkaline sodium bentonite suspensions is tested and numerically determined, the particular test suspensions being defined in the individual Examples.
Unless otherwise specifically stated, the following procedure is adopted for testing the products produced:
Using commercial fine-particle sodium bentonite, an aqueous suspension containing the particular quantity of bentonite indicated is prepared by intensively stirring the powder-form mineral into the water (tapwater) phase.
A pH value of 11 is adjusted with 30% sodium hydroxide.
The bentonite suspension thus prepared is left standing overnight at room temperature.
The following values which have been introduced into the technology of auxiliary fluids for geological dril-~152778 ling (particularly for identifying the rheologicalproperties of drilling muds) are determined as the rheological characteristics:

Plastic viscosity (PV) in cP
Yield point (YP) in lb/100 ft2 Gel strength - 10 secs. and 10 mins. - in lb/100 ft2 Unless otherwise stated, the particular suspensions are tested before and after ageing. Ageing is carried out in a so-called roller oven over a period of 16 hours at 250F (121C), again unless otherwise specifically stated.
The following Examples describe the combination of materials on which the particular measurements were based. The test results obtained are then set out in tabular form.

Example 1 A 3.5% by weight sodium bentonite suspension (12 lbs/bbl, pH 11) is initially prepared as the blank value in the manner described above. Its rheological data are determined before and after ageing.
In a second stage, the Cl2/14 ethoxylate marketed by 2S applicants under the trade name of "Dehydol LS2" (normal statistical E0 distribution; mean E0 value = 2) is added to and intensively incorporated in the bentonite suspen-sion as a controller according to the invention. The controller is used in a quantity of 0.5% by weight (1.5 lb/bbl). The rheological data of this suspension are determined before and after ageing. The test results obtained with the blank sample and with the material formulated in accordance with the invention are set out in Table 1 below.

Table 1 PV YP Gel strength 10 secs. 10 mins.
Blank value (BV) 5 Before ageing 5 3 2 6 BV after ageing 5 4 1 7 + 0.5% by weight LS2 Before ageing 12 42 25 23 After ageing 12 84 37 33 Example 2 An aqueous suspension is initially prepared as described above using 2.9% by weight of sodium bentonite (pH 11). In comparative tests, samples of this suspen-sion are added in a quantity of 1.5% by weight to and intensively incorporated in a commercial polymer compound from the field of drilling fluids based on carboxymethyl cellulose (commercial product "CMC U 300 S9"). The rheological data of the drilling fluid are determined before and after ageing.
For comparison, the controller of Example 1 ("Dehy-dol LS2") is added in a quantity of 0.5% by weight to and incorporated as described in the same sodium bentonite suspension instead of the polymer compound. In this case, too, the rheological data of the material are determined before and after ageing. The results obtained are set out in Table 2.

- 21527~

Table 2 PV YP Gel strength 10 secs. 10 mins.
+ 1.5% by weight CMC
Before ageing 25 17 3 20 After ageing 16 11 2 7 + 0.5% by weight LS2 Before ageing 8 32 16 10 After ageing 7 39 17 12 The temperature-stable control of the rheological values by the auxiliary according to the invention by comparison with the known polymer compounds used in a far larger quantity is clearly apparent.

Example 3 In a series of comparative tests, the two test suspensions of Example 2 are tested for their stability to the addition of increasing quantities of calcium chloride. In a first step, quantities of 0.125% by weight, 0.25% by weight and finally 0.5% by weight CaCl2 are added to three separate batches of the CMC-containing bentonite suspension which of course had been originally prepared using tapwater. All the suspensions are aged.
The plastic viscosity (PV) and yield point (YP) of the aged suspensions are determined. The results are set out in Table 3a below.
In a series of comparative tests, calcium chloride is again added to separate samples of a bentonite suspen-sion prepared in accordance with the invention and controlled with "Dehydol LS2", followed by ageing. The following quantities of calcium chloride are used: 0.25%
by weight, 0.5% by weight and 1.0% by weight. The rheological data (PV and YP) of the suspensions before - ` ~152778 and after ageing are set out in Table 3b below.

Table 3a PV YP
S No addition of CaCl2 16 11 + 0.125% by weight of CaCl2 16 9 + 0.25 % by weight of CaCl2 14 8 + 0.5 % by weight of CaCl2 12 9 Table 3b PV YP
No addition of CaCl2 7 39 + 0.25% by weight of CaCl2 4 44 + 0.5 % by weight of CaCl2 3 42 + 1.0 % by weight of CaCl2 4 34 The stability of the yield point (YP) to the addi-tion of considerable quantities of divalent calcium is clearly apparent.
Example 4 The effect of the degree of ethoxylation of the controllers used in accordance with the invention is determined in a series of comparative tests. All the 25measurements are carried out with a 2.9% by weight suspension of sodium bentonite (pH 11) prepared as described with tapwater, to which the alcohol ethoxylates are added on the one hand in a quantity of 0.5% by weight and on the other hand in a quantity of 2.0% by weight.
30All the results set out in Table 4 below relate to aged test specimens (ageing carried out as described above in the roller oven for 16 hours at 250~F (121C)).
In addition to the data of Table 4, the following observation is crucial: the drilling fluids prepared with 35 the limited solubility regulators according to the ~ 2152778 invention of the "LS2" and "LS3" type show no tendency to separate, even after ageing. The drilling fluids pre-pared with the nonionic surfactant "Dehydol LS7" show a pronounced tendency to separate after ageing. In addi-5 tion to the thickened aqueous bentonite phase, free wateris formed as a separate phase. The same tendency also exists, but is not as pronounced, even where "Dehydol LS4 " is used.
The collapse of the yield point under the relatively high dosage of the "LS7" component is also interesting.

Table 4 PV YP Gel strength 10 secs. 10 mins.
+0.5% by weightLS2 10 2817 22 +2.0% by weightLS2 7 1912 8 +0.5% by weightLS3 7 3016 14 +2.0% by weightLS3 15 2218 12 +0.5% by weightLS4 5 3617 12 +0.5% by weightLS7 9 3415 12 +2.0% by weightLS7 8 4 18 20 Example 5 The tests of this Example investigate the influence and effect of using limited quantities of the mineral 30 controller described in earlier German patent application P 42 24 537.0 based on mixed hydroxide compounds of divalent and trivalent metals with a 3-dimensional space lattice structure of the garnet type - in addition to the controllers according to the invention based on fatty 3 5 alkoxylates.

A dry powder is used as the inorganic controller mixture in accordance with the earlier German patent application cited above. It consists of the following mixture:

90% by weight of a very lightly silicate-modified katoite - sio4 content, based on the silicate-free katoite unit Ca3Al2(0H)12, less than 0.1 sio4 units.

10% by weight of a highly swellable synthetic hectorite according to EP-B 0 260 538.

Two variants are investigated in connection with the production of the controller-stabilized bentonite suspen-sion:

Variant A: The controller according to the inventionbased on the fatty alcohol ethoxylate is first added to and intensively mixed with the bentonite suspension (12 lb/bbl sodium bentonite, pH 11). The commercial product "Dehydol LS3" (Henkel KGaA) is used as the controller.
The mineral controller mixture according to the earlier application is then thoroughly mixed with the suspension now present. The rheology data are then determined before and after ageing.

Variant B: The procedure is as described for variant A
except that, on this occasion, the mineral controller according to the earlier application is first incor-porated in the aqueous bentonite suspension and only after it has been intensively mixed is the controller according to the invention based on fatty alcohol ethoxy-late (LS3) incorporated. In this case, too, the rheolog-ical data are determined before and after ageing.
In both cases, 0.5 lb/bbl of the mineral controller mixture and 0.9 lb/bbl of the controller based on fatty alcohol thoxylate were added to the basic bentonite suspension (12 lb/bbl, pH 11).
In another version of variant B, applicants' commer-cial product "LS2" is used as the controller based onfatty alcohol ethoxylate.
The rheological data determined are set out in Table 5 below.

Table 5 PV YP Gel strength 10 secs. 10 mins.
Variant A
Before ageing 13 96 23 26 After ageing 9 37 19 19 Variant B
Before ageing 20 177 55 51 After ageing 11 78 25 37 Variant B + LS2 After ageing 11 63 32 44 It can clearly be seen that the order of variant B
leads to a distinctly greater increase in the rheological data than variant A.

Example 6 A bentonite suspension is prepared in the same way as in Example 5, variant B, but with an increased quan-tity of controller based on fatty alcohol ethoxylate.
The final suspension contains the following constituents:

12 lb/bbl bentonite, pH 11; 0.5 lb/bbl of the mineral controller mixture and 1.3 lb/bbl of the controller 21S2~78 according to the invention ("Dehydol LS2").

The rheological data are measured both before and after ageing at 250F (121C) and for 16 hours at 350F
(177C). The results obtained are set out in Table 6 below.

Table 6 PV YP Gel strength 10 secs. 10 mins.

Before ageing 19 161 73 60 After ageing (250F) 11 54 19 23 After ageing (350F) 14 45 30 28 Example 7 On the one hand, 0.5~ by weight of "Dehydol LS2" is added to a 3.5% by weight bentonite suspension (pH 11);
on the other hand, a corresponding narrow-range material is used instead of this thickener. The commercial product "Arlypon F" is used as controller.
The rheological data measured on the unaged samples are set out in Table 7 below, suspension A. The figures shown in brackets in the yield point column are deter-25mined after ageing at 250F (121C).
In a second series of tests, the mineral controller mixture according to Example 5 (0.2% by weight) is first added to the aqueous bentonite suspension. The rheologi-cal data measured on the unaged samples are set out in Table 7 as "suspension B".

- . 2152778 Table 7 PV YP Gel strength 10 secs. 10 mins.

Suspension A
+ LS2 12 42(81) 25 23 + Arlypon F 10 43(82) 18 19 Suspension B
+ LS2 10 161 73 60 + Arlypon F 20 125 42 38 Example 8 Bentonite suspensions containing Dehydol LS 2 according to Example 1 as controller were tested for foam inhibition. Various organic compounds were used as the foam inhibitors. 3.5% by weight sodium bentonite suspen-sions adjusted to pH 11 were again used for the tests.
The following mixtures were tested:
8.1) 80% by weight of Dehydol LS 2 20~ by weight of C16 Guerbet alcohol (2-hexyldecan-l-ol) 8.2) 90% by weight of Dehydol LS 2 10% by weight of a mixture of CglO oxo alcohols and C12-18 fatty alcohols + 5 EO + 13 PO (ratio 1:1) 8.3) 90% by weight of Dehydol LS 2 10% by weight of a mixture of C8l8 fatty alcohols and mineral oil (ratio 1:1) + approximately 2% by weight of aluminium stearate 8.4) 90% by weight of Dehydol LS 2 10% by weight of C12l4 fatty alcohol + 2 EO + 4 P0 2 1 ~2778 8.5) In addition, the foam inhibitor according to 8.4j -Cl2l4 fatty alcohol + 2 EO + 4 PO - was tested on its own, i.e. without the Dehydol LS 2, for comparison.

(EO = ethylene oxide units, PO = propylene oxide units) Quantities of 2 g of mixtures/compounds 8.1) to 8.5) were mixed with 400 g of the bentonite suspensions de-scribed above and the resulting mixtures were subjected to mechanical stressing, i.e. treated for 1 minute with a Multimixer.
To evaluate the foaming of the mixtures, their specific densities were then determined at 25C (D25). In addition, the gel strengths of the mixtures were deter-mined after ageing for 16 hours at around 120C (the measurements were carried out in a Fann 35 viscosimeter).
The specific densities of the pure bentonite suspen-sions, i.e. with no additives, were determined as blank values:
8.6) Blank value I: specific density of the deaerated bentonite suspension before the Multimixer treatment 8.7) Blank value II: specific density of the bentonite suspension after the Multimixer treatment (as . described above) The results obtained - specific densities D25 and gel strengths - are set out in Table 8 below:

- ` 215277~

Table 8 Example D25 Gel st-ength 10 secs. 10 mi~s.
8.1 0.9310 42 37 8.2 0.8950 47 40 8.3 0.8812 44 38 8.4 0.9033 43 36 8.5 0.8401 42 37 8.6 (Blv. I) 1.0212 - -8.7 (Blv. II 0.775 The above results show that a particularly good foam-inhibiting effect is developed in particular by the C16 Guerbet alcohol (Example 8.1) and by the adduct of E0 and P0 with C1214 fatty alcohols (Example 8.4).

Claims

1. The use of lower alkoxylates of water-insoluble alcohols of natural and/or synthetic origin (controllers) showing limited solubility in water at room temperature for effectively controlling the rheological properties -even at high temperatures - of flowable and pumpable aqueous preparations of fine-particle minerals which may be used in particular as working fluids in the develop-ment of land and/or geological formations.

2. The use claimed in claim 1, characterized in that the lower alkoxylates of water-insoluble alcohols are corresponding lower ethoxylates and/or lower propoxylates and/or butoxylates, preferably corresponding lower ethoxylates and/or lower propoxylates and in particular lower ethoxylates.

3. The use claimed in claims 1 and 2, characterized in that the controllers used preferably have pour and flow points below 80°C, preferably below 25°C and more prefer-ably below 10°C and cloud points (1% by weight mixture in water) below 25°C, preferably below 10°C and more prefer-ably below 0°C.

4. The use claimed in claims 1 to 3, characterized in that the controllers used are lower alkoxylates of aliphatic and/or ethylenically unsaturated alcohols containing at least 6 carbon atoms and preferably at least 8 carbon atoms, lower ethoxylates of alcohols of natural and/or synthetic origin in the C10-24 range and above all in the C12-18 range being particularly preferred.

5. The use claimed in claims 1 to 4, characterized in that alcohol alkoxylates containing up to 7 alkoxy groups and preferably up to 4 alkoxy groups (statistical mean values) are used as controllers, C12-18 fatty alcohol-EOx-compounds where x has a value of 1 to 3 being particular-ly preferred.

6. The use claimed in claims 1 to 5, characterized in that the controllers are used in aqueous suspensions of fine-particle swellable or even non-swellable clays of natural and/or synthetic origin which are used in the field of flowable and pumpable geological borehole servicing fluids or in soil excavating operations, quantities of the mineral thickening solids of up to at most about 15% by weight, more particularly below 10% by weight, for example in the range from 2 to 8% by weight, being preferred.

7. The use claimed in claims 1 to 6, characterized in that the controllers are used in at most substantially the same quantities as the fine-particle clays, but preferably in smaller quantities, mixing ratios (by weight) of controller to clay of 0.01:1 to 0.8:1 and preferably 0.05:1 to 0.5:1 being particularly preferred.

8. The use claimed in claims 1 to 7, characterized in that the controllers are used in quantities of up to about 5% by weight, preferably in quantities of up to about 3% by weight and, more particularly, in quantities of not more than about 1.5 to 2% by weight, for example in quantities of 0.2 to 1% by weight (percentages by weight based on the flowable and pumpable aqueous prepa-ration).

9. The use claimed in claims 1 to 8, characterized in that, even where swellable clays are used, water-soluble salts of polyvalent cations, more particularly salts of calcium, are used as a possible mixture component in the aqueous phase.

10. The use claimed in claims 1 to 9, characterized in that the controllers based on limited solubility alcohol alkoxylates, more particularly on limited solubility fatty alcohol ethoxylates, are used in addition to or preferably instead of water-soluble and/or water-swell-able polymer compounds for controlling the rheological properties of the aqueous mixtures.

11. The use claimed in claims 1 to 10, characterized in that the controllers are used in combination with the fine-particle minerals, more particularly swellable layer silicate compounds of natural and/or synthetic origin, for controlling the rheological properties of thickened, more particularly thixotropic, aqueous preparations of the water-based drilling fluid type or other auxiliary fluids used in the development of land or geological occurrences by excavation and/or rock drilling, their controlling effect being at least substantially indepen-dent of temperature.

12. The use claimed in claims 1 to 11, characterized in that natural and/or synthetic clays, such as bentonite, attapulgite, hectorite and/or saponite or even mixtures thereof with mineral controllers, such as katoite or MMLHC, are used as mineral component(s).

13. The use claimed in claims 1 to 12, characterized in that the controllers are used in alkalized aqueous borehole servicing fluids thickened with swellable clays, more particularly sodium bentonite.

14. The use claimed in claims 1 to 13, characterized in that the controllers are used together with foam in-hibitors.

15. Flowable and pumpable aqueous preparations rheology-controlled by addition of fine-particle minerals of natural and/or synthetic origin and additionally thick-ened by addition of organic additives (controllers), more particularly for use as water-based auxiliary fluids in the development of geological formations and/or in soil excavating operations, characterized in that they contain lower alkoxylates of water-insoluble alcohols of natural and/or synthetic origin as controllers and for simul-taneously stabilizing their rheological properties, even at elevated temperatures.

16. Flowable and pumpable preparations as claimed in claim 15, characterized in that they contain lower ethoxylates and/or lower propoxylates and/or lower butoxylates of water-insoluble alcohols, preferably corresponding lower ethoxylates and/or lower propoxylates and in particular corresponding lower ethoxylates as controllers.

17. Flowable and pumpable preparations as claimed in claims 15 and 16, characterized in that they contain lower alkoxylates of aliphatic and/or ethylenically unsaturated alcohols containing at least 6 carbon atoms and preferably at least 8 to 10 carbon atoms as con-trollers.

18. Flowable and pumpable preparations as claimed in claims 15 to 17, characterized in that the controllers are present in liquid form at room temperature or at least at elevated temperatures up to preferably about 100°C and have cloud points (1% by weight in water) of at most 25°C, preferably below 10°C and more preferably below 0°C.

19. Flowable and pumpable preparations as claimed in claims 15 to 18, characterized in that lower alkoxylates of fatty alcohols of natural and/or synthetic origin preferably containing 10 to 24 carbon atoms and more preferably 12 to 18 carbon atoms and at most up to 7 alkoxide groups (statistical mean value) in the molecule and preferably showing limited solubility in water at room temperature are used as controllers, fatty alcohol alkoxylates containing up to 4 alkoxide groups (statis-tical mean value) being preferred.

20. Flowable and pumpable preparations as claimed in claims 15 to 19, characterized in that they contain alcohol ethoxylates selected in particular from compounds showing limited solubility in water at room temperature.

21. Flowable and pumpable preparations as claimed in claims 15 to 20, characterized in that the controllers are fatty alcohol ethoxylates of C12-18 fatty alcohols containing up to 4 and preferably 1 to 3 EO groups.

22. Flowable and pumpable preparations as claimed in claims 15 to 21, characterized in that they contain the controllers together with water-swellable and water-swollen layer silicates of natural and/or synthetic origin.

23. Flowable and pumpable preparations as claimed in claims 15 to 22, characterized in that they are alkal-ized, preferably by addition of alkali metal hydroxides, and have preferred pH values of about 7.5 to 12 and, more particularly, 8 to 11.

24. Flowable and pumpable preparations as claimed in claims 15 to 23, characterized in that they contain other typical additives of water-based borehole servicing fluids, more particularly weighting agents, fluid loss additives, inhibitors against rock swelling, such as water-soluble salts and/or water-soluble organic com-ponents, such as polyhydric alcohols, oligomers and/or polymers thereof.

25. Flowable and pumpable preparations as claimed in claims 15 to 24, characterized in that they are formu-lated as water-based drilling fluids of the o/w emulsion type which contain in particular ecologically safe oils -preferably from the classes of oleophilic alcohols, ethers, esters of mono- and/or polycarboxylic acids and/or carbonic acid esters - as the dispersed oil phase.