Inventors:
Edward L. Moses - Houston TX
International Classification:
E21B 2100
Abstract:
A method of inhibiting the occurrence of differential wall sticking in the rotary drilling of hydrocarbon wells is provided. The yield point of the drilling fluid is measured and if necessary increased in a known manner to a minimum value computed from the weight of the drilling fluid so that solid, substantially spherical glass beads having a specific gravity between 2. 4 and 2. 65, a diameter between 9. 84 and 187 mils, and a hardness of 5. 5 Mohs placed therein will not settle, and 10 to 50 ppg of the glass beads are added to a quantity of the drilling fluid. A slug of the glass beads/drilling fluid mixture is then spotted in the well bore adjacent a previously identified zone of possible sticking, so that a substantial number of the glass beads may be deposited in the filter cake lining the well bore adjacent the zone of possible sticking. The presence of the glass beads inhibits the formation of a seal between a drill string, down hole tool or casing and the filter cake, which seal is necessary for the occurrence of differential wall sticking. In an alternative method, the glass beads/drilling fluid mixture is pumped into the well bore without identifying zones of possible sticking.