Well completion and workover fluid

Claim 1

A WELL COMPLETION AND WORKOVER FLUID CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION SUBSTANTIALLY FREE FROM SUSPENDED AND COLLOIDAL SOLIDS, SAID AQUEOUS SOLUTION BEING SUBSTANTIALLY SATURATED WITH CALCIUM HYDROXIDE AND CONTAINING DISSOLVED THEREIN A WATER-SOLUBLE CALCIUM SALT HAVING A SOLUBILITY IN WATER GREATER THAN THAT OF CALCIUM HYDROXIDE IN AN AMOUNT SUFFICIENT TO YIELD A TOTAL CALCIUM ION CONCENTRATION IN EXCESS OF 200 BUT BELOW 2,000 PARTS PER MILLION BY WEIGHT, AND HAVING DISSOLVED THEREIN A SUBSTANTIAL AMOUNT UP TO THE POINT OF SATURATION OF A WATER-SOLUBLE ALKALI METAL COMPOUND COMPATIBLE AND NON-REACTIVE WITH SAID AQUEOUS PHASE TO MATERIALLY INCREASE THE SPECIFIC GRAVITY OF SAID AQUEOUS SOLUTION, SAID COMPOUND BEING SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL NITRATES, NITRITES, CHLORATES, ACETATES, CITRATES, POTASSIUM CHLORIDE AND LITHIUM CHLORIDE, SAID SOLUTION HAVING A PH IN THE RANGE OF 10.2 TO 12.6 AND AN ALKALINITY ABOVE 0.70 CC. OF N/50 SULPHURIC ACID PER CC. OF SOLUTION TO PHENOLPHTHALEIN END POINT, THE SAID FLUID BEING EFFECTIVE TO SOLIDIFY AND HARDEN SHALEY AND BENTONITIC TYPE MATERIAL IN CONTACT THEREWITH IN SPITE OF THE HIGH ALKALI METAL ION CONCENTRATION THEREOF.