| 摘要 |
A wellbore cleaning system provides a relockable shearing swivel tool that can be used in tandem with a lockable weight set circulation tool. Suspended from an upper drill string is an assembly consisting of a landing sub, the lockable weight set circulation tool and relockable shearing swivel tool are located immediately above a liner top and from which is suspended a lower drills string. The lower drill string and production liner are both significantly smaller in diameter than the upper drill string and production casing such than when fluid is pumped at high rates through the entire drill string and reduced cross sectional area of the lower drills string and production liner causes a large pressure drop characterized at surface by a high pump pressure. As part of the method, an operator makes up a drill string assembly that includes an upper drill string, a lower drill string, a landing sub or device, the lockable weight set circulation tool, and the relockable shearing swivel tool. This drill string assembly is lowered into a wellbore until the landing sub is close to a liner top or other shoulder in the wellbore. The drill string is rotated and reciprocated, pumping cleaning chemicals through the entire drill string and through the production liner. The liner top is engaged with the landing sub to open a circulation path from the upper drill string to an upper annulus. The drill string is rotated and reciprocated while pumping cleaning chemicals through the upper annulus to clean the production casing. |
