| 摘要 |
<p>A method of drilling and cleaning a wellbore whilst rotating the drill string after full drilling depth is reached without running the drill string out the bore to install a clean up work string is disclosed wherein a drill string having a drill bit at one end includes at least one near bit selectively activatable cleaning tool (10, 11, 12) mounted within the length of the drill string, said cleaning tool having a cleaning member (18) adapted to be moved from a close fitting stowed configuration within a recess (17) to a deployed configuration upon a body of the tool, wherein the cleaning member has magnets (19, 43) for use in positioning thereof, and compact tools for scraping, milling and brushing with improved resistance to ingress of detritus, debris and formation particulates are disclosed.</p> |
