Water-in-oil emulsion well fluid, methods of using and preparing same

Claim 1

A STABLE WATER-IN-OIL EMULSION FLUID FOR USE IN WELL OPERATIONS CONSISTING ESSENTIALLY FROM ABOUT 10 TO ABOUT 70 PARTS BY VOLUME OF WATER AND ABOUT 90 TO ABOUT 30 PARTS BY VOLUME OF OIL, FROM 4 TO 30 LBS. PER BAARREL OF VEGETABLE PITCH CONSISTING OF A CRUDE MATERIAL OBTAINED IN THE PROCESSING VEGETABLE OIL, SAID MATERIAL HAVING A HIGHER MOLECULAR WEIGHT THAN SAID VEGETABLE OIL AND CONTAINING PLYMERS OF FATTY AIDS WHICH ACIDS ARE DERIVED FROM SAID VEGETABLE OIL, FROM 1 TO 10 LBS. PER BARREL OF OLEOPHILIC HYDROCARBON SULFONATE, FROM 1 TO 20 LBS. PER BARREL OF A SURFACE-ACTIVE WOOD RESIN EXTRACTED FROM AGED WOOD AND SUBSTANTIALLY INSOLUBLE IN GASOLINE BUT SOLUBLE IN FURFURAL, FROM 2 TO 15 LBS. PER BARRELL OF A WATER SOLUBLE ALKALINE EARTH METAL SALT AND FROM 2 TO 20 LBS. PER BARREL OF AN ALKALINE EARTH METAL BASE.