EP0457774A1

EP0457774A1 - Oleophilic basic amine compounds as additives in invert mineral oil muds

Info

Publication number: EP0457774A1
Application number: EP90902197A
Authority: EP
Inventors: Heinz Müller; Claus-Peter Herold; Stephan Von Tapavicza
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1989-02-09
Filing date: 1990-01-31
Publication date: 1991-11-27
Also published as: CA2009689C; ES2059843T3; ZA90951B; EP0382070B1; CA2009689A1; NO179487C; ATE96160T1; DK0382070T3; AU4957990A; SG28389G; DE59003100D1; EP0382070A1; TR25112A; NO179487B; NO913041D0; WO1990009417A1; BR9007113A; NO913041L; DE3903785A1; JPH04503367A

Abstract

A first embodiment of the invention concerns the use of basic amine compounds capable of forming salts with carboxylic acids and having a pronounced oleophilic character and minimal solubility in water, as additives in water-oil invert mineral oil muds. These compounds contain, in the closed oil phase, ester oils and, together with the disperse aqueous phase, emulsifiers, inert fillers, fluid-loss additives and, if desired, other additives to protect them from undesirable thickening in use and/or to improve their pourability. Another embodiment concerns water-oil invert mineral oil muds which are suitable for improved off-shore development of crude oil and natural gas deposits and the concomitant use of basic amine compounds which are capable of forming salts with carboxylic acids and are characterized by a pronounced oleophilic character.

Description

- 1 -

"Oleophilic basic amine compounds as an additive in Irivert drilling muds"

The invention describes new drilling fluid based on ester oils and invert drilling muds based thereon, which are characterized by high ecological compatibility and, at the same time, good standing and usage properties. On . An important area of application for the new drilling fluid systems is offshore drilling for the development of petroleum and / or natural gas, whereby the invention is particularly concerned with providing technically usable drilling fluids with high ecological compatibility . The use of the new drilling fluid systems is particularly important in the marine area, but is not limited to this. The new systems can Spül¬ very general use found in _'landge¬ assisted drilling, for example in geothermal drilling, water drilling, geoscientific drilling and mine drilling. In principle, it also applies here that the ester-based drilling oil fluids selected according to the invention substantially simplify the δcotoxic problem area.

Liquid flushing systems for drilling rock holes while applying the detached cuttings are known to be restricted, flowable, water-based or oil-based systems. These last-mentioned oil-based systems are of increasing importance in practice and here in particular in the area of offshore drilling or when intersecting water-sensitive layers. Oil-based drilling fluids are generally used as so-called invert emulsion slurries, which consist of a three-phase system: oil, water and finely divided solids. These are preparations of the type of W / O emulsions, i.e. H . the aqueous phase is heterogeneously finely dispersed in the closed oil phase. A plurality of additives are provided to stabilize the overall system and to set the desired performance properties, in particular emulsifiers or emulsifier systems, weighting agents, fluid loss additives, alkali reserves, viscosity regulators and the like. For details, reference is made, for example, to the publication PA Boyd et al. "New Base Oil Used in Low-Toxicity Oil Muds" Journal of Petroleum Technology, 1985, 137 to 142 and R. B. Bennett "New Drilling Fluid Technology - Mineral Oi l Mud" Journal of Petroleum Technology, 1984, 975 to 981 and the literature cited therein.

Oil-based drilling fluids were initially based on diesel oil fractions containing aromatics. In order to detoxify and reduce the ecological problems created thereby, it has been proposed to use largely aromatic-free hydrocarbon fractions - now also referred to as "nonpolluting oils" - as a closed oil phase - see the literature cited above. If, in this way, certain progress has also been achieved by excluding the aromatic compounds, a further reduction in the environmental problem - triggered by drilling fluid of the type concerned here - appears to be urgently required. This is particularly valid when drilling offshore bores to develop oil or natural gas deposits, because the marine ecosystem is particularly sensitive to the introduction of toxic and difficult-to-decompose substances. The relevant technology has been around for some time. Importance of oil phases based on esters to solve this problem. US Pat. Nos. 4,374,737 and 4,481,121 describe oil-based drilling fluids in which nonpolluting oils are to be used. As nonpolluting oils, side by side and equivalent, aromatic-free mineral oil fractions and vegetable oils of the type peanut oil, soybean oil, linseed oil, corn oil, rice oil or oils of animal origin such as whale oil are mentioned. All of the ester oils of vegetable and animal origin mentioned here are triglycerides of natural fatty acids which are known to have a high level of environmental compatibility and, from ecological considerations, are clearly superior to hydrocarbon fractions - even if they are free from aromatics.

Interestingly, however, no example of the above-mentioned US patents describes the use of such natural ester oils in invert drilling fluids of the type concerned here. Mineral oil fractions are used throughout as a closed oil phase.

The studies on which the invention is based have shown that the _Ein_5_3 ± z of readily degradable oils of plant and / or animal origin considered in the prior art cannot be considered for practical reasons. The theological properties of such oil phases cannot be mastered for the wide temperature range of 0 to 5 C required on the one hand and up to 250 C and above on the other hand.

In practice, ester oils of the type concerned do not behave in the same way as the mineral oil fractions based on pure hydrocarbons used to date. Ester oils of any constitution are subject to practical use in the W / O invert drilling muds of a partial hydrolysis. This forms free carboxylic acids. These in turn react with the alkaline constituents that are always present in drilling fluid systems of the type affected here - for example. B. with the alkali reserve used for corrosion protection - to the corresponding salts. However, salts of strongly hydrophilic bases and the acids in the range from about C 12 to 24 predominantly found in oils of natural origin are known to be compounds with comparatively high H LB values, in particular for adjusting and stabilizing O / W emulsions to lead . The washing and cleaning technology makes known use of this to the greatest extent. The formation of already limited amounts of such O / W emulsifier systems must, however, interfere with the W / O emulsions required in the sense of the objective according to the invention and thus lead to disturbances.

Subject of previous registrations. , , (D 8523 "Use of selected ester oils in drilling fluids (I)" and D 8524 "Use of selected ester oils in drilling fluids (II)") is the use of ester oils based on selected monocarboxylic acids or. Monocarboxylic acid mixtures and associated monofunctional alcohols. The older applications describe that with the esters or ester mixtures of mono-functional reactants disclosed therein, satisfactory rheological properties can be set not only in the fresh drilling fluid, but that it is also possible to use selected known alkali reserves in the drilling fluid work and in this way retain undesirable corrosion. According to the teaching of these older applications with regard to the alkali reserve, it is essential that the use of strongly hydrophilic bases such as alkali hydroxide and / or diethanamine be avoided. The addition of lime (calcium hydroxide or lime) and / or the concomitant use of zinc oxide or comparable zinc compounds is provided as the alkali reserve. However, an additional restriction is also required here. If the undesired thickening of the oil-based invert rinsing system is to be prevented in practical operation, the amount of the alkalizing additive and in particular the amount of lime must be limited. According to the disclosure of the older applications mentioned, the maximum amount envisaged is about 2 lb / bbl oil rinse.

The teaching of the present invention, on the other hand, is based on further considerations and findings which are unknown in the field of invert drilling fluids with a closed oil phase which are concerned here. The teaching according to the invention takes into account the fact that drilling fluids containing ester oils of the type concerned here are subject to limited partial hydrolysis in practical operation, so that inevitably increasingly free carboxylic acids form as a hydrolysis product and sooner or later reach a critical or - at least endangered state of aging , which forms as an undesirable thickening of the drilling fluid. The teaching according to the invention is based on the concept of using an additional additive in invert drilling fluids of the type concerned here, which is suitable for keeping the desired theological data of the drilling fluid in the required range, even if increasingly more or more or even excessive amounts of free carboxylic acid are formed by partial ester hydrolysis. The teaching of the invention not only wants to trap the free carboxylic acids formed in a harmless form, but also, if desired, convert them into valuable components with stabilizing or emulsifying properties for the overall system.

The invention accordingly relates to the use of basic and for in a first embodiment Salt formation with carboxylic acids enabled amine compounds of pronounced oleophilic nature and at most limited solubility in water as an additive in W / O invert drilling oil slurries, the ester oils in the closed oil phase and, together with the disperse aqueous phase, emulsifiers, weighting agents, fluid loss additives and, if desired, further additives contain, to protect the drilling oil sludge against unwanted thickening in use and / or to improve their flowability.

In a further embodiment, the invention relates to W / OI invert drilling fluids which are suitable for the offshore development of petroleum or natural gas deposits and which, in a closed oil phase containing ester oils, comprise a disperse aqueous phase together with emulsifiers, weighting agents, fluid Loss additives and, if desired, further conventional additives, the invention in this embodiment being characterized in that the drilling fluids contain, as an additional additive, basic amine compounds which are capable of salt formation with carboxylic acids, are of a pronounced oleophilic nature and have a maximum solubility in water. The addition of the additives according to the invention gives the drilling muds protection against undesired thickening in use and is generally suitable for improving their flowability.

Finally, in a further embodiment, the invention is directed to additive mixtures which are suitable for the stated purpose in drilling fluids containing ester oils and which contain the basic amine compounds which are capable of salt formation with carboxylic acids and which are distinctly oleophilic in nature and at most limited in water solubility in a solvent miscible with the oil phase. So-called nonpolluting oils are preferred as solvents, the ester oils in particular being of particular importance here. In mixtures of the type mentioned last, the anti-aging agents based on the oleophilic basic amine compounds are expedient in concentrations of at least about 20% by weight. -%, preferably in amounts of at least about 50 wt. -% in front .

The core of the teaching according to the invention in all of its embodiments is the knowledge that the carboxylic acids which are inevitably liberated in practical operation by partial hydrolysis of the ester oils are intercepted when the anti-aging agents based on oleophilic basic amine compounds are also used, without resulting in any Disruption of the theological properties of invert mud. By selecting suitable amine compounds, it is even possible to form valuable stabilizing and / or emulsifying mixture components in situ by means of the salt formation now occurring. The oleophilic basic _t amine compounds can be added to the drilling fluid systems from the start and / or they can be added to them during use. It has been shown that by adding or. With the use of the basic oleophilic amine compounds according to the invention it is even possible to refresh aged and undesirably thickened drilling fluid systems of the type concerned here in such a way that their rheology is reduced in the range required for pumpability and flowability even at low temperatures.

In connection with the use of the additives defined according to the invention, a further important relief has been shown in the construction of W / O drilling fluids: the alkaliization of the drilling fluid required to prevent corrosion and, in particular, the provision of a sufficient alkali reserve, in particular against the ingress of acid gases like CO- and / or H_S becomes unproblematic. The markedly oleophilic basic additives proposed according to the invention Amine compounds form a basicity buffer which can be used as an alkali reserve. What is more important is the surprising finding that the use of conventional alkali reserves, and here in particular the use of the particularly inexpensive lime, is at least largely unproblematic if the anti-aging additives according to the invention are simultaneously present in the drilling fluid. The aforementioned limit value of about 2 Ib / bbl (lime / oil rinse) for rinse systems based on ester oils, which is disclosed in the earlier applications mentioned, can generally be exceeded without thinking if the pronounced oleophilic basic amine compounds in the sense of the invention present in the oil rinse. Even if undesired thickenings have formed when using conventional highly hydrophilic alkali reserves, this thickening state can be eliminated again by incorporating the additive component according to the invention into the overall system.

In the following, more detailed information on the basic amine compounds of pronounced oleophilic nature selected according to the invention is summarized.

Basic amine compounds with shorter carbon wedges are known to be to a considerable extent water-soluble and, if appropriate, water-miscible in any proportions. In contrast, the amine compounds selected according to the invention are characterized by markedly limited solubility in water with simultaneous formation of their oleophilic character. Their water solubility at room temperature is generally below about 10% by weight and in the preferred embodiment does not exceed about 5% by weight. Of particular importance are those oleophilic amine compounds which have very low limit values for their water solubility at room temperature. An important limit is around 1% by weight, preferably less than about 0.1 wt. -%. Basic amines which are particularly important for the invention can be mentioned as being practically water-insoluble.

Oleophilic amines of the type described can generally be used insofar as they are capable of salt formation with the carboxylic acids released during the ester hydrolysis and are preferably soluble in the oil phase. Within the scope of the intention according to the invention of causing the lowest possible toxic environmental pollution, preference is given in this large range of objectively suitable amine compounds to ecologically comparatively harmless compounds. Aromatic amines are generally less suitable on the basis of these considerations, so that in a further preferred embodiment of the invention oleophilic amine compounds are used which are at least predominantly free of aromatic constituents. Suitable compounds for carrying out the teaching according to the invention can generally be assigned to the groups of aliphatic, cycloaliphatic and / or heterocyclic amines. The respective representatives can contain one or more N groups which are capable of forming salts with carboxylic acids. Amine compounds of the type described can be nitrogen-containing saturated hydrocarbon compounds, but amine hydrocarbons which contain one or more olefinically unsaturated groups in at least one of their hydrocarbon members are also suitable.

There is great freedom in the selection of the particular constitution of the amine components used according to the invention. Economic considerations here largely determine the selection of the particular components. In general, representatives who are particularly suitable for practice can be assigned to the following classes: At least largely water-insoluble primary, secondary and / or tertiary amines, corresponding aminoamides and / or nitrogen-containing heterocycles as ring constituents. A bases which have at least one long-chain hydrocarbon radical with preferably about 8 to 36 C atoms and in particular with about 10 to 24 C atoms in the molecule can be particularly suitable. Such hydrocarbon residues can attack directly on the nitrogen atom. However, they can also - for example in the case of aminoamides - be bonded via a functional group to an N-containing part of the molecule, it then being necessary to ensure that there is at least one basic N atom in the total molecule which is used for salt formation with those caused by ester hydrolysis lysis-free carboxylic acids is capable. Typical examples for the different classes addressed here are described in more detail below.

A first group includes primary, secondary and tertiary amines with one or more N atoms, the ratio of hydrocarbon groups to amine groups in the respective compound being chosen so that the conditions given above for limited water solubility and pronounced oleophilicity are met . In simple unsubstituted compounds of the type concerned here, the number ratio C / N is at least about 5 or better 6, but is preferably above this. In amines of the type affected here, which are readily available industrially, there are often 1 or 2 comparatively long-chain hydrocarbon radicals on the amino nitrogen and - if present - the methyl radicals on the remainder. Typical examples of the type concerned here contain 1 nitrogen atom per molecule. However, comparable compounds which are derived from polyfunctional amines, in particular from lower diamines, for example from ethylenediamine or propylene diamine, are also easily accessible from an industrial point of view. Lower polyamines of the type affected here are highly water-soluble. However, one or more become in their molecule If long-chain hydrocarbon radicals of the type previously described are introduced, then suitable additives are produced in the sense of the invention, provided that at least one nitrogen atom is capable of salt formation with the carboxylic acids. Suitable representatives of this type are, for example, compounds of the general formula R-NH- (CH-) -N H_. Here, R means, for example, a hydrocarbon radical having about 8 to 22 carbon atoms and n a lower number to about 6, in particular 2 to 4.

Primary and possibly also secondary amines with strongly oleophilic molecular constituents can still be useful in the sense of the invention if the N H groups present are alkoxylated with, for example, ethylene oxide and / or propylene oxide or. higher homologues, e.g. B. Butylene oxide, oligo-alkoxide groups are introduced. For example, long-chain primary and / or secondary amines are sufficiently oleophilic even when introducing up to about 8 to 10 EO and / or PO groups that they can be considered for use in the sense of the invention.

Technically easily accessible amine compounds for use in the context of the invention are derived from the epoxidation of olefinically unsaturated hydrocarbon compounds. with subsequent introduction of the N function by adding “to the epoxy group. The implementation of the epoxidized intermediate components with primary uηd / or secondary amines with the formation of the corresponding alkanolamines is of particular importance. Also suitable for opening the epoxy ring are polyamines, in particular lower polyamines of the type corresponding to alkylene diamines.

Another important class of oleophilic amine compounds for the purpose according to the invention are aminoamides, which are composed of preferably long-chain carboxylic acids and polyfunctional, derive in particular lower amines of the aforementioned type. It is important here that at least one of the amino functions is not bound in the amide form, but is retained as a potentially acid-forming basic amino group. Both here and in all the cases described above, the basic amino groups, when they are formed as secondary or tertiary amino groups, can contain, in addition to the oleophilic part of the molecule, hydroxyalkyl substituents and here in particular lower hydroxyalkyl substituents with up to 5, preferably with up to 3, carbon atoms exhibit . Suitable N-basic starting components for the production of such addition products with long-chain oleophilic molecule constituents are monoethanolamine and / or diethanolamine. Thus, in a preferred embodiment, suitable additives for the purposes of the invention are reaction products from the epoxidation of long-chain olefins having, for example, 8 to 36, in particular about 10 to 18, carbon atoms and mono- and / or diethanolamine. Alpha-standing olefins of the type mentioned can be of particular importance as a starting material for the epoxidation and the subsequent conversion to the secondary and / or tertiary amine with hydroxyalkyl groups on the N atom.

An important class for heterocyclic additives for regulating the flow properties of drilling muds in the sense of the invention are the imidazoline compounds. Alkylpyridines can also be significant from this heterocyclic group.

The additives based on oleophilic basic amine compounds for the purposes of the invention are preferably added to the drilling fluids in amounts not exceeding about 10 Ib / bbI and preferably in amounts not exceeding 5 Ib / bbI. The amount used can be determined, inter alia, by the shape of the use intended in practice. Different variants are possible here, which can also be connected to each other. In a first embodiment, the rheology ^* regulating additive is added to the drilling mud in a substantial amount from the beginning. It can then take on a double function. On the one hand, it forms the alkali reserve of the drilling fluid to intercept any ingress of acidic constituents such as CO_ and / or H_S, on the other hand the basic amine compound, which may be in a large excess, absorbs the carboxylic acid fractions formed by hydrolysis to the extent of their formation and converts them into the corresponding oil-soluble salts. In the opposite limit, the invention initially works with the ester oil-based mud without ^" addition of the additives according to the invention - for example in the sense of the teaching of the earlier patent applications mentioned at the outset.... [D 8523 and D 8524) by the beginning of increasing the viscosity values, the additive according to the invention is used to regulate the

Rheology metered batchwise or continuously to the drilling fluid. This can be done easily during the drilling process. It is obvious that any combination of the metering of the additive according to the invention before and during the operation of the drilling or the use of the drilling fluid are possible between these two extremes. If suitable amine compounds which form effective emu igators systems are selected, it is even possible to save emulsifier parts in the oil portion to be replenished and instead to use the amine salts with emulsifier action which arise in situ to stabilize the overall system.

The amine compounds can be added to the invert drilling muds directly or indirectly. For example, they can be incorporated into the oil phase containing ester oil beforehand, or they can be added to the overall system as such. In a particularly suitable embodiment, additive concentrates are prepared, which are then used in particular during operation Drilling mud can be added. These are solutions of the oleophilic amine compounds in suitable solvents at preferred concentrations of the additive of at least about 20% by weight, but preferably of at least about 50% by weight. Suitable solvents are nonpolluting oils that can be homogeneously incorporated into the drilling mud. Ester oils are particularly suitable here, for example those of the type described in the two older applications mentioned.

As already stated, it is an important advantage of the invention that the use of the additives according to the invention for regulating the flow and pumpability of the drilling muds now also makes it possible to use conventional alkali reserves in quantities of oil phases based on ester oil, as was previously the case for drilling oil muds Base of mineral oils are common as an oil phase. For example, lime can be used in quantities of up to 5 Ib / bbI without fear of sustained damage to the drilling fluid during operation. The same applies to the zinc compounds mentioned in the earlier applications, such as zinc oxide, zinc complex compounds and the like. Surprisingly, however, even strongly hydrophilic bases from the previous practice of alkalizing drilling fluids can also be used. If the alkali reserve in the manner described is ensured by conventional means, for example by using not inconsiderable amounts of lime, the amount of the amine-based additives selected according to the invention can be reduced to the range required by the ester hydrolysis in the continuous process. In an important embodiment, only a slight excess of the oleophilic amine base is used, and the portion consumed by salt formation is metered in batches or continuously during the drilling process. In such embodiments, the addition of amine base can, for example, in the range from 0.1 to 2 Ib / bbI (amine base / drilling fluid) or even less.

Particularly suitable ester oils are esters of monofunctional carboxylic acids or carboxylic acid mixtures and monofunctional alcohols, in particular the ester types described in detail in the older applications mentioned. To complete the disclosure of the invention, essential characteristics of such esters or ester mixtures are briefly summarized here.

In a first embodiment, flowable and pumpable esters of monofunctional alcohols with 2 to 12, in particular with 4 to 12 C atoms and aliphatic saturated monocarboxylic acids with 12 to 16 C atoms or their mixture with at most approximately in the temperature range from 0 to 5 C. equal amounts of other monocarboxylic acids used as the oil phase. Preference is given to ester oils which are at least about 60% by weight, based on the carboxylic acid mixture, of esters of aliphatic C ... monocarboxylic acids and, if desired, the rest, to a lesser extent, of minor amounts of shorter-chain aliphatic and / or longer-chain, then in particular 1- and / or poly-unsaturated monocarboxylic acids. Esters einge¬ is preferred in the temperature range of 0 to ^"5 C a Brookfield (RVT) viscosity in the range not above 50 mPas, preferably not above 40 mPas vor¬ and have, in particular of at most about 30 mPas. The in Esters used in drilling mud show solidification values (pour point and pour point) below - 10 C, preferably below - 15 C and in particular have flash points above 100 C, preferably above 150 C. The carboxylic acids present in the ester or ester mixture are at least predominantly straight-chain and They are preferably of vegetable origin and can be derived from appropriate triglycerides such as coconut oil, palm kernel oil and / or baseball oil. The alcohol residues of the esters used conduct in particular from straight-chain and / or branched saturated alcohols with preferably 4 to 10 carbon atoms. These alcohol components can also be of vegetable and / or animal origin and have been obtained by reductive hydrogenation of corresponding carboxylic acid esters.

The other class of particularly suitable ester oils is derived from olefinically 1- and / or polyunsaturated monocarboxylic acids with 16 to 24 carbon atoms or their mixtures with subordinate amounts of other, in particular saturated monocarboxylic acids and monofunctional alcohols with 2 to 12 carbon atoms. These ester oils are also flowable and pumpable in the temperature range from 0 to 5 ° C. Are particularly useful ester of this type, which has become more than 70 wt .-%, preferably more than 80 wt .-% and in particular more than 90 wt -.% Of olefinically _ß ungesät¬ saturated carboxylic acids the range of _ C. derive _ü .

Here, too, the solidification values (pour point and pour point) are below - 10 ° C, preferably below - 15 C, while the flash points are above 100 C and preferably above 160 ° C. The esters used in the drilling mud show a Brookfield (RVT) viscosity of not more than 55 mPas, preferably not more than 45 mPas, in the temperature range from 0 to 5 C.

In the case of ester oils of the type concerned here, two subclasses can be defined. In the first, the unsaturated C_ present in the ester is derived. g__ _ü monocarboxylic acid residues from not more than 35% by weight of 2- and poly-olefinically unsaturated acids, preferably at least about 60% by weight of the acid residues being simply olefinically unsaturated. In the second embodiment, the C. - - ^ - monocarboxylic acids present in the ester mixture are derived to more than 45% by weight. -%, preferably more than 55 wt. -% of 2- and / or multiple olefinic unsaturated acids. Saturated carboxylic acids in the Ci _c / ig range present in the ester mixture advantageously do not make more than about 20% by weight. -% and in particular not more than about 10 parts by weight. Saturated carboxylic acid esters, however, are preferably in the range of lower C numbers for the acid residues. Here too, the present carboxylic acid residues are at least predominantly straight-chain and are preferably of vegetable and / or animal origin. Vegetable starting materials are, for example, palm oil, peanut oil, castor oil and in particular rape oil. Carbonic acids of animal origin are, in particular, corresponding mixtures of fish oils such as herring oil.

Invert drilling muds of the type concerned here usually contain, together with the closed oil phase, the finely disperse aqueous phase in amounts of about 5 to 45% by weight and preferably in amounts of about 5 to 25% by weight. The range from about 10 to 25% by weight of disperse aqueous phase can be of particular importance.

The following theological data apply to the rheology of preferred invert drilling fluids in the sense of the invention: plastic viscosity (PV) in the range from about 10 to 60 mPas, preferably from about 15 to 40 mPas, yield point (YP) in the range from about 5 to 40 lb / 100 ft, preferably from about 10 to 25 lb / 100 ft - each determined at 50 ° C. For the determination of these parameters, for the measurement methods used and for the otherwise usual composition of the invert drilling fluids described here, the details of the prior art apply, which were cited at the beginning and are described in detail, for example, in the manual " Manual Of Drilling Fluids Technology "from NL-Baroid, London, GB, there in particular under" Mud Testing - Tools and Techniques "and" Oil Mud Technology ", which is freely accessible to interested professionals. In summary, here to For the purpose of completing the disclosure of the invention, the following can be said:

Emulsifiers that can be used in practice are systems that are suitable for forming the required W / O emulsions. Selected oleophilic fatty acid salts, for example those based on amidoamine compounds, are particularly suitable. Examples of this are described in the already cited US Pat. Nos. 4,374,737 and the literature cited therein. A particularly suitable type of emulsifier is the product sold by NL Baroid, London, under the trade name "EZ-mul".

Emulsifiers of the type concerned here are sold commercially as highly concentrated active ingredient preparations and can be used, for example, in amounts of about 2.5 to 5% by weight, in particular in amounts of about 3 to 4% by weight. -% - each based on ester oil phase - are used.

In practice, hydrophobicized lignite is used in particular as a fluid loss additive and thus in particular to form a dense covering of the drilling walls with a largely liquid-impermeable film. Suitable amounts are, for example, in the range from about 15 to 20 Ib / bbI or in the range from about 5 to 7% by weight, based on the ester oil phase.

In . Drilling fluids of the type concerned here are the viscosity formers commonly used, a cationically modified, finely divided bentonite which can be used in particular in amounts of about 8 to 10 lb / bbl or in the range of about 2 to 4% by weight, based on the ester oil phase. The weighting agent usually used in the relevant practice for setting the required pressure equalization is barite, the additional amounts of which are adapted to the respectively expected conditions of the bore. For example, it is possible to Adding barite increases the specific weight of the drilling fluid to values in the range up to approximately 2.5 and preferably in the range from approximately 1.3 to 1.6.

The disperse aqueous phase is loaded with soluble salts in invert drilling fluids of the type concerned here. Calcium chloride and / or potassium chloride are predominantly used here, the saturation of the aqueous phase at room temperature with the soluble salt being preferred.

The previously mentioned emulsifiers or. Emulsifier systems may also serve to improve the oil wettability of the inorganic weighting agents. In addition to the aminoamides already mentioned, alkylbenzenesulfonates and imidazoline compounds are further examples. Additional information on the relevant prior art can be found in the following literature references: GB 2 158 437, EP 229 912 and DE 32 47 123.

In addition to the advantages already described, the drilling fluids based on the use of ester oils of the type described are also distinguished by a significantly improved lubricity. This is particularly important if the passage of the drill pipe, and thus also the borehole, deviate from the vertical in bores, for example at greater depths. The rotating drill pipe easily comes into contact with the drill hole and digs into it during operation. Ester oils of the type used according to the invention as an oil phase have a significantly better lubricating effect than the mineral oils previously used. This is another important advantage for the action according to the invention. Examples

In the following examples, two typical ester oils are used as the oil phase of the invert drilling fluids. In both cases, monocarboxylic acids / monoalcohol esters can be characterized as follows:

Examples 1 to 3: Distilled n-hexyl-lauric acid ester with the following key figures

Flash point above 165 C, pour point below - 5 ° C, density (20 ° C) from 0.857 to 0.861, iodine number and acid number each below 1, water content below 0.3% and the following viscosity data (Brookfield mPas) in the low temperature range:

- 5 ° C 22.5 to 25.5; + 2 ° C 15 to 18; + 5 ° C 15 to 18; + 10 ° C approx. 15; 20 ° C 12 to 14.

Examples 4 to 10: isobutyl rapeseed oil esters based on a mixture of predominantly unsaturated straight-chain carboxylic acids, which correspond approximately to the following distribution: 60% oleic acid, 20% linoleic acid, 9 to 10% linoienic acid, olefinically unsaturated C ₂ O / 22 ~ monocarboxylic acids, for example 4%, the rest saturated monocarboxylic acids predominantly in the range C_. _{fi /} _. ".

The rapeseed oil ester used also has the following characteristics: density (20 ° C.) 0.872 g / cm; Pour point below

- 15 ° C; Flash point (DIN 51584) above 180 ° C; Acid number (DGF-C-V 2) 1.2; Viscosity at 0 ° C 32 mPas, viscosity at 5 ° C 24 mPas.

An invert drilling fluid is made in a conventional manner using the following ingredients: -21 -

230 ml ester oil

26 ml water

6 g organophilic bentonite (Geltone I I from NL Baroid)

12 g organophilic lignite (Duratone from NL Baroid) x g lime

6 g W / O emulsifier (EZ-mul NT from NL Baroid) ,,

346 g barite ^'

9.2 g CaCI x 2 H O y g oleophi les basic amine

First of all the plastic viscosity (PV), the pour limit (YP) and the gel strength after 10 sec. And 10 min. certainly.

The invert drilling fluid is then aged for 16 hours at 125 ° C. in an autoclave in a so-called "roller oven" in order to check the influence of temperature on the stability of the emulsion. Then the viscosity values at 50 ° C are determined again.

example 1

It works with the lauric acid / n-hexyl ester as an oil phase. Lime is added in an amount of 2 g of the specified framework recipe. The process is carried out without the addition of a basic amine with a pronounced oleophilic character in the sense of the definition according to the invention. The following values are determined on the unleaved and aged material.

Already aging for only 16 hours at 125 ° C causes a considerable thickening of the drilling fluid. The amount of lime used is above the threshold of 2 Ib / bbl.

Example 2

The invert drilling fluid of Example 1 is now additionally mixed with 0.5 g of a pronounced oleophilic basic amine. The basic amine is the reaction product of an epoxidized C_. _ _{/ 1 ü} -alpha-olefins and diethanolamine ("Araphen G2D" of the applicant) are used.

The theological data determined on the unaged and aged material are now the following:

Example 3

The approach of Example 2 is repeated, but ^" is the

Invert drilling fluid added the oleophilic basic amine ("Araphen G2D") in an amount of 1 g. The values determined on the unaged and aged material are the following:

unaged aged

Material material

Plastic viscosity (PV) 20 21

Yield value (YP) 8 6 Gel strength (lb / 1 00 ft ² )

10 sec. 5 4

10 min. 6 5

The comparison of Examples 1 to 3 against each other clearly shows the stabilizing effect of the addition of an oleophilic basic amine in the sense of the definition according to the invention.

Example 4

In this and the following Examples 5 to 9, the previously defined isobutyl rapeseed oil ester is used as a closed oil phase.

In the present example 4, work is initially carried out without the addition of lime but with the addition of 2 g of the previously defined oleophilic basic amine (“araphene G2D”). The values determined on the unaged and aged material are the following:

The approach of Example 4 is repeated, but here the oleophilic basic amine stearylamine is used in an amount of 2 g. The values determined on the unaged and aged material are the following:

For comparison, the isobutyl rapeseed oil ester is mixed with 1 g of lime, but without the use of oleophilic basic amine compounds. The amount of 1 g of lime used in the general formulation is below the threshold value of 2 Ib / bbl, which corresponds to the addition of approximately 1.35 g lime for the formulation used here. The theological values determined on the unaged and aged material are as follows:

The formulation of Example 6 are now in addition 2 g of the oleophilic basic amine compound len "Araphen G2D" _ι added. The theological values determined on the drilling fluid are the following:

An isobutyl rapeseed oil ester is again investigated without the use of the oleophilic basic amine, but with the addition of 2 g of lime to the framework recipe. The measured rheology data are as follows:

The comparison of this example 8 with example 6 shows the serious thickening effect which occurs when increasing the

Lime amount above the threshold of about 2 Ib / bbI is triggered during aging.

Example 9

An invert drilling fluid according to Example 8 is now additionally added with 2 g "Araphen G2D". The rheology values determined on the unaged and aged material are the following:

The comparison with the rheology data of Example 8 shows the influence of the oleophilic basic amine compound added according to the invention. Example 10

An invert drilling fluid according to Example 8 is additionally initially treated with 2 g of diethylenetriamine, ie. H. with a pronounced hydrophilic base. Then the rheological data are first determined on the unaged material.

This invert rinse is then aged at 125 ° C. for 16 hours, as previously indicated. It turns out that the rinse is so thickened that it is not possible to record the rheological data.

2 g each of the oleophilic basic amine compound "Araphen G2D" are added to the thickened mass and this substance mixture is aged again for 16 hours at 125 ° C. in a roller oven. A liquefaction of the thickened mass occurs, which enables the rheological data to be measured.

Overall, the following values are determined:

Claims

Patent claims

1 . Use of basic amine compounds capable of salt formation with carboxylic acids, of a pronounced oleophilic nature and at most limited water solubility as an additive in W / O invert drilling oil slurries, the ester oils in the closed oil phase and emulsifiers and weighting agents together with the disperse aqueous phase , fluid-loss additives and, if desired, further additives, to protect them against undesired thickening in use and / or to improve their flowability.

2. Embodiment according to claim 1, characterized in that the basic and at the same time oleophilic amine compounds are used at least partially as an alkali reserve of the invert drilling fluid.

3. Embodiment according to claims 1 and 2, characterized ge indicates that the oleophilic basic amines are used together with conventional alkali reserves, in particular together with lime.

4. Embodiment according to claims 1 to 3, characterized ge indicates that oleophilic amine compounds are used which are at least predominantly free of aromatic constituents.

5. Embodiment according to claims 1 to 4, characterized ge indicates that optionally olefinically unsaturated aliphatic, cycloaliphatic and / or heterocyclic oleophilic basic amine compounds are used which contain one or more N-groups capable of salt formation with carboxylic acids.

6. Embodiment according to claims 1 to 5, characterized in that basic amine compounds are used whose water solubility at room temperature is at most about 5% by weight and preferably below 1% by weight and in particular below 0.1% by weight. lies.

7. Embodiment according to claims 1 to 6, characterized in that at least largely water-insoluble primary, secondary and / or tertiary amines, which can also be alkoxylated to a limited extent and / or substituted with, in particular, hydroxyl groups, corresponding aminoamides and / or N heterocycles containing ring component can be used.

8. Embodiment according to claims 1 to 7, characterized ge indicates that work is carried out with basic amine compounds which have at least one long-chain hydrocarbon radical having preferably 8 to 36 carbon atoms, in particular 10 to 24 carbon atoms , which can also be mono- or poly-olefinically unsaturated.

9. Embodiment according to claims 1 to 8, characterized in that the oleophilic basic amine compounds of the drilling fluid in amounts up to about 10 Ib / bbI, preferably in amounts up to about 5 Ib / bbI and in particular in the range of about 0, 1 to 2 Ib / bbI can be added.

10. Embodiment according to claims 1 to 9, characterized ge indicates that the oleophi len basic amine compounds are used in drilling muds, the at least partially ester oils from monofunctional alcohols and monofunctional carboxylic acids and preferably at least partially ester oils of natural origin, in particular Contain esters of monocarboxylic acids with about 8 to 24 carbon atoms and monofunctional alcohols.

11. W / O invert drilling fluids which are suitable for the off-shore supply of petroleum or natural gas deposits and which, in a closed oil phase containing ester oils, contain a disperse aqueous phase together with emulsifiers, weighting agents contain additives and, if desired, further customary additives, characterized in that they additionally contain basic amine compounds which are capable of salt formation with carboxylic acids and are characterized by oleophilic nature and at most limited water solubility as an additive to protect against unwanted thickening in use and / or included to improve their fluidity.

12. Drilling fluid according to claim 11, characterized in that the oleophilic basic amine compounds make up at least the predominant proportion of the alkali reserve of the drilling fluid or are present in a mixture with conventional alkali reserves, in particular together with lime.

13. Drilling fluid according to claims 1 1 and 12, characterized gekenn¬ characterized in that the rheology of the drilling fluid protective additive optionally olefinically unsaturated aiiphatic, cycloaliphatic and / or heteroeyclic basic amine compounds with oieophilic character are present, one or more with carboxylic acids Have N groups capable of salt formation.

14. Drilling fluid according to claims 1 1 to 13, characterized gekenn¬ characterized in that basic amine compounds with a -31 -

Water solubility at room temperature of at most about 5% by weight, preferably below about 1% by weight.

15. drilling fluid according to claims 11 to 14, characterized gekenn¬ characterized in that as a rheology-protecting additive at least largely water-insoluble primary, secondary and / or tertiary amines, which can also be alkoxylated to a limited extent and / or substituted with in particular hydroxyl groups, corresponding aminoamides and / or N are heterocycles containing ring constituents.

16. Drilling fluid according to claims 1 1 to 15, characterized gekenn¬ characterized in that basic amine compounds are present as an additive, which have at least one long-chain hydrocarbon residue with preferably 8 to 36 carbon atoms, in particular with about 10 to 24 carbon atoms , where these residues can also be mono- and / or poly-olefinically unsaturated.

17. Drilling fluid according to claims 11 to 16, characterized gekenn¬ characterized in that the oleophilic basic amine compounds are present in the drilling fluid in amounts up to about 10 Ib / bbI, preferably not above about 5 Ib / bbI.

18. Drilling fluid according to claims 1 1 to 17, characterized gekenn¬ characterized in that the ester oil phase contains at least partially esters of monofunctional carboxylic acids with in particular about 6 to 24 carbon atoms and monofunctional alcohols.

19. Additive for the improvement and in particular the aging protection of the flow properties of W / O invert drilling fluids based on a closed oil phase containing ester oils, which together with the disperse aqueous phase emulsifiers, weighting agents, fluid loss - Contains additives and, if desired, further additives. characterized in that it contains the basic amine compounds which are capable of salt formation with carboxylic acids and which are distinctly oleophilic in nature and at most have limited solubility in water in a solvent miscible with the oil phase, preferably based on non-polluting oils, in particular based on ester oil.