Patent attributes
Ported sub openings are controlled by a sliding sleeve assembly. In one variation an external sleeve is pressure actuated with internal pressure to open the ports. After the treatment the ports are closed with a ball landed on an internal sleeve seat and pressure applied from above. In a different arrangement a single internal sleeve is provided that is responsive to tubing pressure to open after breaking a retaining member. After the downhole procedure a ball is landed on a seat on the sleeve and pressure is applied to close the ports with the shifted sleeve and ball moving in tandem. Multiple sliding sleeves can be sequentially operated with sliding sleeves held by retainers that break at sequentially higher pressure moving in an uphole direction.
