| 摘要 |
A method of removing debris from a well is disclosed, comprising RIH to required depth with coiled tubing having at least one closed check valve, moving a sleeve through the check valve to hold it open, opening a flow control valve located on the coiled tubing below the check valve; then reverse circulating a fluid to entrain debris in the wellbore and bring it to surface through the coiled tubing, before releasing the sleeve from the check valve; and POOH with the at least one check valve returned to the closed configuration. By holding the check valves open, reverse circulation can be performed in the well using coiled tubing, so sufficient lift can be achieved to bring the debris to surface even in underbalanced or low pressure wells. Safety measures can be maintained by having at least one check valve in the conventional closed configuration on RIH and POOH. The flow control valve allows the check valve to be opened or closed without pumping any fluid into the well and thus the sleeve can be moved to hold the check valve open with a relatively low pressure. |
