Low solids salt water drilling fluids

Claim 1

A LOW SOLIDS SALT WATER DRILLING FLUID CONTAINING A SMALL BUT EFFECTIVE AMOUNT OF PREHYDRATED MONTMORILLONITIC CLAY NOT TO EXCEED ABOUT 17 LBS. PER BARREL OF SAID FLUID, A SELECTIVE WATER SOLUBLE BENEFICIATING AGENT FOR SAID CLAY PRESENT IN A CONCENTRATION OF FROM ABOUT 0.075 TO ABOUT 3 LBS. PER BARREL OF SAID FLUID, SAID BENEFICIATING AGENT BEING SELECTED FROM THE CLASS CONSISTING OF A VINYLMALEIC COPOLYMER HAVING FROM 1 TO ABOUT 1 1/2 TIMES AS MANY VINYL RADICALS AS MALEIC RADICALS AND A WATER SOLUBLE SALT OF AN ARCYLIC ACID-ACRYLAMIDE COPOLYMER, WHEREIN THE RATIO OF CARBOXYLIC ACID SALT GROUPS TO AMIDE GROUPS RANGES FROM ABOUT 12:88 TO ABOUT 70:30, SAID COPOLYMER BEING POLYMERIZED TO A DEGREE SUCH THAT A 1 PERCENT BY WEIGHT SOLUTION IN DISTILLED WATER HAS A VISCOSITY OF BETWEEN ABOUT 2,000 AND ABOUT 20,000 CPS., AS MEASURED WITH A BROOKFIELD VISCOSIMETER AT 20*C., ROTATING AT 6 R.P.M., USING A NO. 2 SPINDLE FOR VISCOSITIES UP TO 5,000, A NO. 3 SPINDLE BETWEEN 5,000 AND 20,000, AND A NO. 4 SPINDLE FOR VISCOSITIES ABOVE 20,000 CPS., AND FROM ABOUT 1.5 TO ABOUT 6 LBS. PER BARREL OF FLAX MEAL, EXCLUSIVE OF HULLS, HAVING AN AVERAGE PARTICLE SIZE RANGING FROM ABOUT -12 TO ABOUT+30 MESH.