Drilling fluids containing novel compositions of matter

Claim 1

An aqueous clay-free drilling fluid containing water and from about one to about 25 weight percent of a new composition of matter resulting from the reaction of (1) substantially water-insoluble polycyclic, polycarboxylic acids obtained as a result of the nitric acid oxidation of coal, said oxidation comprising subjecting a slurry containing coal to reaction with aqueous nitric acid having a concentration of about one to about 90 percent at a temperature of about 15° to about 200° C. for about five minutes to about 15 hours, with (2) a base, said base being a hydroxide of an element of Group IA of the Periodic Table or a hydroxide of an element of Group IIA of the Periodic Table, a basic salt of an element of Group IA or IIA of the Periodic Table whose aqueous solutions exhibit a pH in the basic region, or ammonium hydroxide, the amount of said base, said basic salt or ammonium hydroxide, being at last an amount stoichiometrically required to react with at least about 50 percent of the carboxyl groups in said acids, the reaction between said acids and said base, said basic salt or ammonium hydroxide being in the range of about 5° to about 150° C.