Abstract: A method for drilling with a liner includes: providing a liner string including an upper portion extending towards surface and a lower portion; drilling to a depth with the liner string; disconnecting the upper portion from the lower portion; pulling the upper portion from the well; and leaving the lower portion in the well to line the wellbore. A drilling assembly for drilling a borehole with a borehole liner includes: an upper liner string; a lower liner string including an upper end and a lower end; a releasable connector connecting the lower liner string to the upper liner string; and a drilling assembly connectable at the lower end of the lower liner string.

Abstract: A retrievable bridge plug having an internal bypass passage and external retrieving lugs, and a retrieving tool therefor. When the bypass passage is sealed, both the top and bottom openings of the bypass passage are closed, preventing debris from entering the bypass passage through either opening. A directing shroud is provided adjacent the top opening of the bypass passage, such that when the bypass passage is opened, part of any fluid flowing uphole through the bypass passage is directed over the retrieving lugs, clearing them of any debris and facilitating latching by the retrieving tool. The shroud also prevents debris from packing around the top opening of the bypass passage. A retrieving tool is also provided, which retrieving tool, through cooperation of a sleeve having a “J” shaped slot, and an inner latch sleeve having a straight slot, locks the retrieving tool onto the retrieving lugs.

Abstract: A retrievable bridge plug having an internal bypass passage and external retrieving lugs, and a retrieving tool therefor. When the bypass passage is sealed, both the top and bottom openings of the bypass passage are closed, preventing debris from entering the bypass passage through either opening. A directing shroud is provided adjacent the top opening of the bypass passage, such that when the bypass passage is opened, part of any fluid flowing uphole through the bypass passage is directed over the retrieving lugs, clearing them of any debris and facilitating latching by the retrieving tool. The shroud also prevents debris from packing around the top opening of the bypass passage. A retrieving tool is also provided, which retrieving tool, through cooperation of a sleeve having a “J” shaped slot, and an inner latch sleeve having a straight slot, locks the retrieving tool onto the retrieving lugs.