Isolation assembly for coiled tubing

A method of treating a downhole well formation, comprising:

• connecting a downhole tool to a coiled tubing string via an isolation assembly, the isolation assembly including a housing having a hollow inner diameter and a housing port through the housing;
• biasing a check valve to a closed position preventing fluid flow through the isolation assembly, the check valve pivotably attached to a shuttle slidably disposed within the housing;
• positioning the downhole tool at a desired location in the well formation;
• pumping fluid down the coiled tubing to increase the pressure in the coiled tubing to move the flapper check valve to an open position allowing fluid flow through the isolation assembly to the downhole tool;
• biasing the shuttle within the housing such that a shuttle port through the shuttle is out of alignment with the housing port;
• and
• selectively providing fluid communication through a shuttle port in the shuttle of the isolation assembly, the shuttle adapted to move upwardly with respect to the housing having the housing port of the isolation assembly, when an upward force on the check valve exceeds a downward force of a shuttle spring the shuttle moving upwardly within the housing until the port in the shuttle at least partially aligns with the port in the housing.

A method of bleeding off the pressure of a downhole tool connected to a coiled tubing string via an isolation assembly, the method comprising:

• biasing a shuttle slidably disposed within the isolation assembly so that a hydraulic port through the shuttle is not aligned with a hydraulic port through the isolation assembly;
• biasing a flapper check valve pivotably connected to the shuttle, the flapper checked valve being biased to a position that prevents fluid flow through the isolation assembly;
• pumping fluid through the coiled tubing string to move the flapper check valve to a position that permits fluid flow through the isolation assembly;
• reducing the pressure in the coiled tubing string to move the flapper check valve to the position that prevents fluid flow through the isolation assembly;
• moving the shuttle until the hydraulic port through the shuttle is at least partially aligned with the hydraulic port through the isolation tool;
• bleeding of pressure from the downhole tool to an annulus through the at least partially aligned hydraulic ports.