WO1991016391A1

WO1991016391A1 - Use of hydrated castor oil as a viscosity promoter in oil-based drilling muds

Info

Publication number: WO1991016391A1
Application number: PCT/EP1991/000645
Authority: WO
Inventors: Heinz Müller; Claus-Peter Herold; Stephan Von Tapavicza
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1990-04-14
Filing date: 1991-04-05
Publication date: 1991-10-31
Also published as: EP0524995A1; DE4012105A1; CA2080484A1

Abstract

The description relates to the use of hydrated castor oil instead of organophilic quaternised clays to control and especially to increase the viscosity spontaneously in oil-based drilling muds for opening geological processes. The object of the invention also includes oil-based drilling muds of this kind which contain hydrated castor oil, together, if desired, with further known N-free viscosity promoters as oil soluble viscosity promoters and are free from oil-dispersible, finely dispersed solids containing quaternised N compounds, especially correspondingly fortified clays.

Description

"Use of hydrogenated castor oil as a viscosity builder in oil-based drilling fluid systems"

The invention relates to a further development in the field of oil-based drilling fluids for the development of geological occurrences and relates in particular to oil-based, conventional weighting agents such as baryta-containing drilling shafts which are free from the oleophilic compounds used today on a large scale and equipped with quaternary N compounds Tone.

As is known, the practice of tapping geological deposits through land and / or sea-based drilling distinguishes between the two systems of water-based drilling fluid systems on the one hand and oil-based drilling fluids or drilling fluid systems on the other hand. The invention relates to the last-mentioned class of substances and relates to rinses of the type mentioned, which - at least at the start of their use - can be practically water-free or are designed as invert rinses of the W / O emulsions type.

Drilling fluid systems of the type concerned here contain, dissolved and / or dispersed in flowable oil phases of selected rheology, a large number of additives, the presence of which only ensures the usability of the respective system under practical conditions. Reference is made to the relevant specialist literature, for example the publication Adam T. Bourgoyne Jr. et al. APLIED DRILLING ENGINEERING, SPE TEXTBOOK SERIES, VOL. 2, SOCIETY OF PETROLEUM ENGINERS, Richardson, TX 1986, there in particular the subchapter 2.5 Oil Muds, loc. Cit. Pages 75 to 81.

An essential component of such oil-based flushing systems is the viscosity generator. Its selection and control largely determine the rheological properties of the rinse in practical use, which in turn affect a number of parameters. Without any claim to completeness, the following are enumerated: the operating costs for pumping the drilling fluid, the need to keep the applied weighting agents, in particular barite, in suspension, and to carry the drilled rock safely to the surface, here but to ensure timely the rapid separation of drilled rock and possibly gaseous fractions on the one hand and drilling fluid phase to be returned on the other.

The following fact is to be considered as a particular difficulty for the practical usability of the viscosity-forming additives: The progressive drilling requires the constant replenishment and metering of additional portions of the drilling fluid. In practice, the required additional portions are freshly prepared on site and fed into the system. In this context, the viscosity-building additive has the requirement of the practically spontaneously building higher viscosity in the oil-based liquid phase. Only when such a spontaneous viscosity build-up is guaranteed, even under the ambient conditions, can other mandatory components of the drilling fluid system, in particular the weighting means, be safely incorporated. A delayed increase in viscosity, as is the case with a whole series of known ones Viscosity formers can be determined leads to an unacceptable phase separation in the freshly prepared portions of the drilling fluid and thus prevents their trouble-free use in ongoing operation.

In the practice of the drilling fluid systems based on oil-based active ingredient mixtures, which are used on a large scale today, the hydrophobized clays, in particular oleophilic bentonite, are of paramount importance. A loading of the swellable layered silicate with quaternary ammonium compounds is provided as the oleophilic finish, which convert the originally hydrophilic mineral feedstock to an oleophilic active substance. Hydrophobicized clays of this type optimally meet the diverse requirements for the viscosity former in oil-based flushing systems, as is currently thought. Due to their rapid and uniform distributability in the closed oil phase, they ensure the required spontaneous formation of the desired degree of viscosity, especially when freshly prepared.

Findings from the recent past, however, make a restriction of the use of such quaternized clays in large quantities appear desirable. In the area of sea-borne drilling in particular, it can be assumed that considerable portions of this thickener end up in the marine environment and then enter into a secondary interaction with the marine ecosystem. Quaternary ammonium compounds are now considered to be not harmless components for the undisturbed Regarding the metabolism in the marine ecosystem, so that there is an increasing need to avoid the use of viscosity formers based on quaternary nitrogen compounds. However, the hydrophobicized oleophilic clays of the prior art can also lead to difficulties for purely practical reasons. When interacting the Drilling mud with the rock to be drilled occasionally gives rise to precipitation reactions which lead to flocculation of the viscosity formers of the type discussed here. In these cases, too, the use of the oleophilic clays for the stated purpose is eliminated for purely practical reasons.

The invention is concerned with the exchange of the viscosity formers in oil-based rinsing systems of the type described here and in particular with the use of N-free alternative viscosity formers. In particular, the invention aims to solve the subtask of the spontaneous training of sufficient viscosity required by practice when freshly preparing drilling fluids, and especially under practical conditions.

The teaching according to the invention is based on the knowledge that the use of hydrogenated castor oil - and in particular a selected specific quality of the hydrogenated castor oil - alone or together with other N-free viscosity formers known per se for adjusting the viscosity in the oil phase of the oil-based flushing system that meets all practical requirements. Not only is it possible to adjust and control the viscosity in continuous operation, but in particular the use of the hydrogenated castor oil as an exchange material for the previously used hydrophobic bentonites also enables the desired viscosity to be formed spontaneously when freshly prepared. The hydrogenated castor oil used according to the invention thus differs from the previously known viscosity formers, for example based on N-free waxes, higher fatty acids and / or their salts. The teaching according to the invention

Accordingly, the invention relates in a first embodiment to the use of hydrogenated castor oil instead of organophilic quaternized clays for viscosity control and in particular for spontaneously building up viscosity in oil-based drilling fluids for the development of geological deposits.

In a further embodiment, the invention relates to oil-based drilling fluids for the development of geological deposits, containing viscosity formers dissolved in the oil phase, dispersing weighting agents, fluid loss additives and, if desired, further additives such as emulsifiers, alkalis and dissolved salts, these drilling fluids are characterized in that, if desired, they contain hydrogenated castor oil as oil-soluble viscosity formers together with other known N-free viscosity formers and are free of oil-dispersible, finely dispersed solids containing quaternized N compounds, in particular appropriately treated clays.

Finally, the invention also relates to the process for the fresh preparation of oil-based drilling fluids under ambient conditions, these drilling fluids containing viscosity formers, weighting agents, fluid loss additives and, if desired, further additives. The process is characterized in that viscosity formers based on hydrogenated castor oil are used in the absence of oil-dispersible and finely divided solids which are equipped with quaternary N-compounds oleophilically.

Hydrogenated castor oil is known as a commercial product on the market. It is usually offered as a solid with melting points above 80 ° C, especially above 85 ° C. For the purposes of the invention Particularly suitable are materials which are not only particularly finely divided, for example by fine grinding, but which also have a comparatively high hydroxyl number. Powdery, finely divided hydrogenated castor oil types with a 0H number of at least 150 are particularly suitable according to the invention, with particular importance being given to the types whose OH number exceeds 154. It has been shown that for practical usability in the spontaneous formation of the desired viscosity when freshly prepared, the swelling and dissolving behavior of the types of hydrogenated castor oil defined here leads to optimal technical action.

Details of the teaching according to the invention

Hydrogenated castor oil dissolves in the oil phases used in practice from drilling fluid systems of the type concerned here. Nevertheless, the desired effect of the viscosity build-up in the sense of the hydrophobized bentonite to be replaced is achieved. The hydrogenated castor oil can be used alone as a viscosity generator, but in a preferred embodiment it is used as a mixture component in a mixture with other viscosity-increasing additives. These further mixture components can in turn also be oil-soluble, but optionally also oil-dispersible. The same applies to them that, like the hydrogenated castor oil, they are free of undesired N compounds and in particular quaternary nitrogen compounds.

Examples of such additional components are waxes and wax-like compounds such as montan wax and tall pitch, higher fatty acids and / or their salts, in particular those which are solid at ambient temperature. In the area of such salts, particular preference is given to corresponding compounds with polyvalent cations, with two and / or trivalent cations of the type of magnesium, calcium and / or aluminum are of particular importance.

In mixed systems of hydrogenated castor oil with such additional viscosity-forming components, the proportion of hydrogenated castor oil is usually at least about 20% by weight and in particular is at least about 25 to 45% by weight, based in each case on the Viscosity-forming mixture of active ingredients.

In addition to or instead of such oil-soluble mixture components, the hydrogenated castor oil can also be used together with oil-dispersible solid components which contribute to the viscosity build-up of the oil-based flushing system. Here, organophilically hydrophobicized very finely divided solids come into consideration, but in the sense of the teaching according to the invention, oleophilic equipment based on quaternary nitrogen compounds is now dispensed with. Here, for example, very finely divided silicas come into consideration which have oleophilic finishes on their surface by means of silyl radicals containing hydrocarbon groups. Such products are known, for example, under the name "Hydrophobic AEROSIL ( ^R )" and can be obtained by treating the surface of finely divided silicas with halogen silanes, alkoxysilanes, silazanes, siloxanes and the like. Another example of such oleophilic ultrafine materials which have been given an ecologically harmless finish are the polycationic layered compounds based on the applicant, which are described in the earlier patent application P 39 14916.1 (D 8636 "Means for increasing viscosity in non-aqueous liquid phases, processes for their preparation and their use") 2-dimensional inorganic polycations and 1- and / or polybasic acid anions of pronounced oleophilic character. Also apply when using such insoluble mixture components the numerical ranges given above for the minimum content of the hydrogenated castor oil in the mixture of substances for the viscosity build-up.

The additives used to increase viscosity based on hydrogenated castor oil are usually used in amounts of about 1 to 10% by weight, based on the weight of the oil phase from the oil-based rinse. Additional amounts in the range from about 2 to 5% by weight can be particularly suitable.

The oil-based rinsing systems used are both suitable mixtures based on practically water-free oils or oil fractions of suitable rheology and oil-based rinsing systems based on W / O invert emulsions, in particular with contents of the dispersed aqueous phase of up to about 40 to 45% by weight. , into consideration. Reference is made to the relevant state of the art for the structure, the nature and the requirements profile of such oil-based drilling fluid systems. As is well known, drilling fluids of this type consist of a multiphase system which has oil, optionally water and finely divided solids. A number of additives are provided for stabilizing the finely dispersed aqueous phase distributed in the closed oil phase and for stabilizing the overall system and for setting the desired performance properties. Particularly worth mentioning here are the weighting agents, in particular barite, for regulating the density of the drilling fluid, emulsifiers, fluid loss additives, alkali reserves and the like. In addition to the literature already cited, 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 RB Bennett "New Drilling Fluid Technology - Mineral Oil Mud" Journal of Petroleum Technology, 1984, 975 to 981 and the literature cited therein . Selected diesel oil fractions and, in particular, in recent times, at least largely aroma-free pure paraffin oils have been used as the oil phase. The relevant technology has recognized the importance of the environmental problems caused by these oil phases for some time. This explains the increasing importance of oil rinsing based on so-called nonpolluting oils. In addition to the aromatic-free mineral oil fractions, oil phases based on ester are also included in the class of nonpolluting oils. Usable ester oils or invert drilling fluid systems based on ester oils, which are significantly improved from the point of view of environmental protection, are the subject of a number of earlier applications by the applicant. Reference is made here in particular to applications P 3842 659.5 and P 3842 703.6, the older patent applications P 3907 391.2 and P 3907 392.0 and to the related further development of such invert drilling fluids based on ester oil from the earlier application P 39 03 785.1 of the applicant. The disclosure of all these older applications is in principle also valid for the modification described in the context of the present application with regard to the viscosity-building additives.

Finally, in this context, the older applications P 39 11 238.1 and P 39 11 299.3 must also be taken into account, which likewise relate to novel W / 0-based systems for the purpose of drilling fluids, which are characterized by increased environmental compatibility and which Describe the use of selected oleophilic alcohols and / or ethers as the oil phase. Within the scope of the invention, any restrictions from the oil types listed above also fall.

The same applies to all these possibilities of oil-based drilling fluid systems, that by using the teaching according to the invention practically under any environmental and working conditions spontaneous viscosity formation when starting the oil rinse is made possible. The good solubility and high swellability of the hydrogenated castor oil selected according to the invention, which in particular can be mixed with the oil phase as a finely divided solid and quickly dissolves in it, ensures that a reliable suspension of even high proportions of weighting agents is immediate when freshly prepared is guaranteed. According to the invention, this enables problem-free working even at low temperatures, for example in permafrost areas, so that a full substitute for the oleophilic bentonites equipped with quaternary ammonium compounds is also ensured.

The following also applies:

Invert drilling muds of the type concerned here are either water-free or practically water-free (water content in the oil phase at a maximum of about 5% by weight) or, together with the closed oil phase, they usually contain the finely dispersed aqueous phase in amounts of about 5 to 50% by weight .-% and preferably in amounts of about 5 to 25 wt .-%. The following rheological data apply to the rheology of preferred invert drilling fluids: plastic viscosity (PV) in the range from approximately 10 to 60 mPas, preferably from approximately 15 to 40 Pas, yield point (YP) in the range from approximately 5 to 40 lb / 100 ft ² , preferably from about 10 to 25 lb / 100 ft ² - each determined at 50 ° C. For the determination of these parameters, for the measuring 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 also described in detail, for example, in the manual "Manual Of Drilling Fluids Technology" from NL-Baroid, GB, there in particular under chapters "Mud Testing - Tools and Techniques" and "Oil Mud Technology", which the interested professionals is freely accessible. In summary, the following can be said here for the purpose of completing the disclosure of the invention:

Emulsifiers which can be used in practice are systems which are suitable for forming the required W / O emulsions. Selected oleophilic fatty acid salts, for example those based on idoamine compounds, are particularly suitable.

Examples of this are described in US Pat. No. 4,374,737 and the literature cited therein. A particularly suitable type of emulsifier is the product sold by NL-Baroid 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, based in each case on the Oil phase - find use.

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 lb / bbl or in the range from about 5 to 7% by weight, based on the oil phase.

The amount of the weighting agent - in practice usually barite - to adjust the necessary pressure compensation is adapted to the expected conditions of the bore. It is possible, for example, to add the specific by adding barite Increase the weight of the drilling fluid to values in the range up to approximately 2.5 and preferably to values in the range from approximately 1.3 to 1.6.

The disperse aqueous phase is usually 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 aforementioned emulsifiers or emulsifier systems also serve, if appropriate, to improve the oil wettability of the inorganic weighting materials. In addition to the aminoamides already mentioned, further examples are alkylbenzenesulfonates and imidazoline compounds. Nitrogen-free emulsifier systems and their use in oil-based drilling muds are described in the applicant's earlier patent application P 4003028.8 (D 8158 "Use of selected ether-based emulsifiers for oil-based invert emulsions").

B e i s p i e l e

Examples 1 and 2

A water-free, barite-weighted pure oil rinse based on a commercially available mineral oil (BP 83 HF) is produced and tested in accordance with the following recipe:

340 ml mineral oil

266 g barite

20.g organophilic lignite ("DURATONE" from NL-Baroid)

3 g Turkish red oil as emulsifier x g hydrogenated castor oil ("Thixcin" from Kronos Titan)

Example 1 contains 8 g of hydrogenated castor oil in the recipe given, in Example 2 this viscosity former is used in the amount of 5.4 g.

The following test parameters were measured: plastic viscosity (PV) in cP and yield point (YP) in lb / 100 ft ² as well as the gel strength (GS) in lb / 100 ft ² for 10 see. and 10 min., the first information in the table referring to the value after the rinse was made and the second information to the value after aging (16 hours at 250 ° F). The specific values are summarized in the table below.

Example No. PV YP GS

1 18/25 14/65 7; 15/32; 34 2 15/17 6/44 2; 6/18; 25 Examples 3 to 6

Oil-based, barite-weighted drilling fluid systems based on diesel oil are produced according to the following recipe by stirring in at room temperature:

300 ml diesel oil

5 ml sea water

220 g barite

2 g organophilic lignite (OPX from Hughes Drilling

Fluids) 8 g of lime x g of hydrogenated castor oil ("Rilanit spec. Micro" from the applicant) y g of stearic acid z g of a powdered active ingredient mixture of montan wax (40

% By weight), lime (30% by weight), aluminum stearate (10% by weight),

Stearic acid (20% by weight)

The following apply to the additional quantities according to x, y and z

Information.

Example 3: x = 1.7; y = 1.7; z = 4.6

Example 4: x = 2.1; y = 2.1; z = 5.7

Example 5: x = 2.6; y = 2.6; z = 6.9

Example 6: x = 3.4; y = 3.4; z = 9.1

As in Examples 1 and 2, the plastic viscosity (PV), the yield point (YP) and the gel strength (GS) for 10 see. and 10 min. certainly. The parameters determined in the temperature range from 29 to 32 ° C in the sense of the information given in Examples 1 and 2 before and after the aging at 250 ° F for an hour are the following:

Example 7

An oil-based invert rinse based on an ester oil (predominantly ethylhexyl ester of CIO / Ci2-carboxylic acids) is put together in accordance with the following recipe and tested in the fresh state and after aging for 16 hours at 250 ° C.

239 ml ester oil

20 g of saturated aqueous calcium chloride solution

150 g barite

20 g oleophilic lignite (0PX from Hughes Drilling Fluids)

4 g of lime

2 g hydrogenated castor oil (according to Example 6)

5 g tall pitch

The values for plastic viscosity, yield point and gel strength (10 seconds and 10 minutes) determined before and after aging are as follows:

Ex.

No. PV YP GS

7 25/39 11/15 5; 8/3; 30

Claims

Patent claims

1. Use of hydrogenated castor oil instead of organophilic quaternized clays for viscosity control and in particular for spontaneous viscosity build-up in oil-based drilling fluids for the development of geological deposits.

2. Embodiment according to claim 1, characterized in that hydrogenated castor oil with an OH number of at least 150, preferably above 154, is used, which is expediently present as a very finely ground material.

3. Embodiment according to claim 1 and 2, characterized in that the hydrogenated castor oil is used together with other known N-free viscosity formers such as waxes, higher fatty acids and / or their salts, the proportion of the hydrogenated castor oil in the viscosity-forming active ingredient mixture makes up at least about 20 wt .-% and is preferably at least about 25 to 45 wt .-% - based on the mixture of active ingredients.

4. Embodiment according to Claims 1 to 3, characterized in that the viscosity formers based on the hydrogenated castor oil are used in oil-based drilling fluids containing weighting agents, such as barite, and are used in particular in the fresh preparation of the fluids.

5. Embodiment according to claims 1 to 4, characterized gekennzeich¬ net that the N-free viscosity former in practically water-free oil rinses and / or invert rinsing systems of the W / O type are used.

6. Embodiment according to claims 1 to 5, characterized gekennzeich¬ net that the N-free viscosity formers based on hydrogenated castor oil to build up viscosity at ambient temperatures or only moderately elevated temperatures, especially in per afro areas, are used.

7. Embodiment according to claims 1 to 6, characterized gekennzeich¬ net that the viscosity-forming additive based on the hydrogenated castor oil in amounts of about 1 to 10 wt .-%, in particular in amounts of about 2 to 5 wt .-% is used.

8. Embodiment according to claims 1 to 7, characterized gekennzeich¬ net that the viscosity formers based on hydrogenated castor oil are used together with N-free hydrophobic finely divided solids.

9. Oil-based drilling fluids for tapping geological deposits, containing viscosity formers dissolved in the oil phase, dispersed weighting agents, fluid loss additives and, if desired, further additives such as emulsifiers, and optionally a disperse aqueous phase, alkalis and dissolved salts, characterized in that that they contain hydrogenated castor oil with an OH number of at least 150, if desired together with other known N-free viscosity formers, as oil-soluble viscosity formers and free from oil-dispersible, finely dispersed solids containing quaternized N compounds, in particular appropriately equipped clays are.

10. Oil-based drilling fluids according to claim 9, characterized in that they contain the viscosity formers based on hydrogenated castor oil (OH number above 154) in amounts of about 1 to 10 % By weight, preferably in amounts of about 2 to 5% by weight, based on the oil phase.

11. Oil-based drilling fluids according to claims 9 and 10, characterized ge indicates that, together with the hydrogenated castor oil, waxes such as montan wax or tall pitch, oil-soluble and, at ambient temperature, in particular solid fatty acids and / or their salts with in particular polyvalent cations as viscosity formers contain.

12. Oil-based drilling fluids according to claims 9 to 11, characterized in that the hydrogenated castor oil in the viscosity-forming system makes up at least about 20% by weight, preferably at least about 25 to 45% by weight.

13. Oil-based drilling fluids according to claims 9 to 12, characterized ge indicates that they are based on diesel oil, naphthenic and / or paraffinic mineral oil, paraffin oil, ester oils, oleophilic alcohols and / or oleophilic ethers as an oil phase.

14. Process for fresh preparation under ambient conditions of oil-based drilling fluids containing viscosity formers, weighting agents, fluid loss additives and, if desired, further additives, characterized in that for spontaneous viscosity formation even at low temperatures, for. B. in permafrost areas, uses viscosity formers based on hydrogenated castor oil in the absence of oil-dispersible and with quaternary N-oleophilic finely divided solids.