Core Drilling With Air Containing Polymer in Oil (Patent No: 949739)

Inventor: Amoco Canada Petroleum Company Ltd.

Location: Calgary

Comments: N/A

Description: THE EMBODIMENTS OF THE INVENTION IN WHICH .AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CIAIMED ARE DEFINED AS FOLLOWS:

1. In a process for drilling a well and obtaining cores in a core barrel at the bottom of the well while circulating a gas in said well, in which process oil is added at the top of the well to the gas flowing down the well, the improvement comprising adding polyisobutylene to said oil before the oil is added to the gas, said polyisobutylene having an average molecular weight between about 0.1 million ani about 15 million as determined by the intrinsic viscosity measure, the concentration of polyisobutylene in said oil being from about 0.00025 to about 0.0015 pound of polymer per U. S. gallon of oil, and from about one to about ten gallons of the polymer solution in oil being added to each 1,000 cubic feet of circulated gas, the gas volume being measured at the pressure at which it enters the well.

2. The method of claim 1 in which the direction of circulation of the gas is down the annular space outside the drill pipe and up inside the drill pipe.

3. The method of claim 1 in which the polymer has a molecular weight of about 250 thousand.