Earth boring – well treating – and oil field chemistry – Earth boring – Contains organic component
Reexamination Certificate
1999-06-01
2001-04-03
Tucker, Philip (Department: 1712)
Earth boring, well treating, and oil field chemistry
Earth boring
Contains organic component
C507S127000, C507S128000, C507S129000, C507S131000, C507S135000, C507S136000, C507S138000, C507S139000, C507S145000
Reexamination Certificate
active
06211119
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a new form of presentation improved in many respects for lubricants and lubricant systems which are added in geological exploration to corresponding water-based drilling fluids and/or other water-based working fluids from this field. In the following, the invention is described with reference to pure water-based drilling fluids and drilling muds based thereon. However, the fluids according to the invention are by no means confined to this particular application. On the contrary, the invention also encompasses corresponding fluids for tackling problems arising out of differential sticking, more particularly spotting fluids and fluids used for workover, stimulation and comparable applications in geological drilling.
2. Discussion of Related Art
In the relevant technology of the geological exploration of, for example, oil and/or gas occurrences, there are three basic types of auxiliary fluids used in practice, more particularly corresponding drilling muds: oil-based systems which generally comprise a continuous oil phase mixed with a disperse water phase in the form of so-called w/o invert muds, water-based oil/water systems in which the aqueous phase with its dissolved and dispersed auxiliaries forms the continuous phase and the oil phase is dispersed therein in the form of a fine emulsion and, finally, pure water-based drilling fluids. So far as the pure water-based drilling fluids in particular are concerned, proposals have recently been taken up again to use purely aqueous systems based on soluble alkali metal silicates which are also known as waterglasses or waterglass-based systems.
The use of components with a pronounced lubricating effect in drilling muds can be extremely important. Thus, the rate of advance can be significantly accelerated so that the time required to drill to predetermined depths can be shortened and problems, for example arising out of differential sticking, are prevented or at least suppressed. General expert knowledge is relevant in this regard, cf. for example the book by George R. Gray and H. C. H. Darley entitled “Composition and Properties of Oil Well Drilling Fluids”, 4th Edition, 1980/81, Gulf Publishing Company, Houston and the extensive scientific and patent literature cited therein and the manual entitled “Applied Drilling Engineering” by Adam T. Borgoyne, Jr. et al., First Printing Society of Petroleum Engineers, Richardson, Tex. (USA).
The use of auxiliary components with a lubricating effect can be of particular importance for water-based working fluids, more particularly corresponding water-based drilling muds. The following specific problem inter alia arises in this regard: auxiliary components with a pronounced lubricating effect which are insoluble in the aqueous system—normally corresponding components of organic origin—should consist of very fine particles and should be uniformly dispersed in the drilling fluid. This applies in particular to their primary incorporation in the drilling mud for periodically or continuously increasing the amount of drilling mud which is increasingly demanded by the rate of advance and by the increasing size of the borehole to be filled with the drilling mud.
The problem addressed by the present invention is in particular to provide a new form of presentation in which organic lubricants or lubricant systems are stably and very finely dispersed in a continuous aqueous phase. The incorporation of such lubricant systems in water-based auxiliary fluids, for example of the drilling mud type, and the immediate very fine homogenization of the organic phase in the water-based system are thus made possible. At the same time, the effect of the organic based lubricants is enhanced, at least in the early stages of their use.
SUMMARY OF THE INVENTION
In a first embodiment, therefore, the present invention relates to multiphase lubricant concentrates with improved properties for use in water-based drilling fluids containing organic components with a lubricating effect which are liquid and/or solid at room temperature (O phase) in conjunction with emulsifiers finely dispersed in a continuous aqueous phase (W phase), these multiphase lubricant concentrates being characterized in that the system of O phase/W phase and emulsifiers has a phase inversion temperature (PIT) above room temperature and has been produced by heating the multiphase system to temperatures equal to or above the PIT and subsequent cooling to temperatures below the PIT. The lower limit to the PIT of the multiphase system is at temperatures of at least 25 to 30° C. and preferably higher, for example at temperatures of or above 40 to 50° C.
In another embodiment, the present invention relates to the use of the multiphase lubricant concentrates as an additive for water-based drilling fluids and borehole servicing fluids. In one important embodiment, the multiphase lubricant concentrates are added to pure water-based drilling fluids and/or emulsion drilling fluids of the o/w type. However, the multiphase lubricant concentrates may also be added to working fluids of which the working temperature in situ within the rock is above the PIT of the multiphase system.
DESCRIPTION OF THE INVENTION
To enable the working principles of the invention as discussed in the following to be understood, the relevant specialist knowledge is briefly reported in the following:
It is well known that, where selected, more particularly at least partly nonionic emulsifiers or emulsifier systems are used, oil-in-water emulsions undergo phase inversion on heating, i.e. the outer aqueous phase can become the inner phase at relatively high temperatures. Extensive prior art literature is concerned with this natural scientific phenomenon of phase inversion, with the characteristics and the adaptation of selected emulsifiers for developing this capacity for phase inversion and with potential practical applications for utilizing this special effect. Hitherto, this technology has been of particular significance in connection with the production of cosmetic formulations, cf. for example the disclosures of EP 0 354 586 and EP 0 521 981 which describe the production of stable low-viscosity oil-in-water emulsions of polar oil components and the production of oil-in-water creams.
Applicants' earlier application U.S. Ser. No. 08/933,188, now U.S. Pat. No. 6,022,833, incorporated herein by reference relates to the application of this natural scientific principle of phase inversion in multiphase mixtures of water and oil to water-based drilling fluids and/or borehole servicing fluids. The disclosure of this earlier application goes in detail into the natural scientific and technical parameters and their acknowledgement in the application of the known principle of phase inversion or rather the phase inversion temperature (PIT) range. The disclosure of this earlier application is hereby specifically included as part of the disclosure of the present invention so that only a brief summary of important aspects of established expert knowledge to be taken into account in the teaching of the present invention is given in the following.
The establishment of the particular phase inversion temperature range (PIT or middle phase) during the temperature-dependent formation of the particular stable system in the o/w-middle phase-w/o phase equilibrium is influenced by a number of specific parameters: chemical nature of the oil phase; character of the emulsifiers/emulsifier systems; loading of the aqueous phase. The phase inversion temperature range of the particular multicomponent system can be experimentally determined by measuring the electrical conductivity as a function of the temperature of the multicomponent system. The continuous aqueous phase in the o/w system ensures high electrical conductivity. The continuous oil phase in the w/o system allows the electrical conductivity to fall to substantially zero. The temperature range between these two limits is characteristic of the middle inversion phase.
In addition, the mor
Claas Marcus
Foerster Thomas
Herold Claus-Peter
Mueller Heinz
von Tapavicza Stephan
Drach John E.
Henkel Kommanditgesellschaft auf Aktien
Millson, Jr. Henry E.
Murphy Glenn E. J.
Tucker Philip
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