Method of providing a high permittivity fluid
The present invention provides for an electrically insulating fluid or material of high relative permittivity or dielectric constant. The fluid has a low conductivity and high relative strength and is applicable to pulsed power drilling applications.
1. An electrocrushing drilling fluid comprising:
a first, carbon-based material comprising one or more oils and having a dielectric constant equal to or greater than approximately 2.6;
a second, carbon-based material, different from said first material, having a dielectric constant greater than approximately 10.0;
said first material in a concentration in said formulation of from between approximately 75.0 and 85.0 percent by volume;
said second material comprising one or more alkylene carbonates, said second material in a concentration in said formulation of from between approximately 15.0 and 25.0 percent by volume;
said first material miscible with said second material, said first material thus not forming an emulsion with said second material;
one or more additives useful for electrocrushing drilling; and
said electrocrushing drilling fluid having an electrical conductivity less than approximately 10 −6 mho/cm;
wherein none of said one or more additives prevents the miscibility of said first material with said second material.
2. The electrocrushing drilling fluid of claim 1 wherein said first material and said second material are substantially non-aqueous.
3. The electrocrushing drilling fluid of claim 1 wherein said first material and said second material are non-aqueous.
4. The electrocrushing drilling fluid of claim 1 wherein said second material comprises butylene carbonate.
5. The electrocrushing drilling fluid of claim 1 wherein said first material comprises castor oil.
6. The electrocrushing drilling fluid of claim 1 wherein said first material comprises a synthetic oil.
7. The electrocrushing drilling fluid of claim 1 wherein one of said additives is a gel-forming additive which increases a viscosity of said electrocrushing drilling fluid when the fluid is under low shear conditions and decreases the viscosity when the fluid is under shear stress.
8. The electrocrushing drilling fluid of claim 1 having an ability to absorb water up to 2,000 ppm, without apparent effect on the dielectric performance.
9. The electrocrushing drilling fluid of claim 1 comprising a dielectric strength of at least approximately 300 kV/cm (1 μsec).
10. The electrocrushing drilling fluid of claim 1 wherein one of said additives increases the density of the fluid.
11. The electrocrushing drilling fluid of claim 10 wherein said additive comprises barite.
12. The electrocrushing drilling fluid of claim 10 wherein said additive is selected from the group consisting of barite, calcium carbonate, dolomite, ilmenite, iron ore, olivine, siderite, strontium sulfate and a mixture thereof.
13. The electrocrushing drilling fluid of claim 1 useful in combination with pulsed power electric applications.
14. The electrocrushing drilling fluid of claim 1 limited to pulsed power electric applications.