Hamdeen's ported relief sub is used to obtain increased downhole flow capacity to provide improved annular velocities. During normal operations the flow ports are isolated and flow is maintained to the drill bit only. To activate the drop-ball shears pins thereby shifting a piston allowing additional flow rate to the annular ports. The tool facilitates flow splitting by retaining a percentage of flow to the bit once the ports are opened.
Hamdeen's 2 ball-drop circulation sub is used in applications where the operator wishes to pump to annular ports and then have the option to reinstate flow to the bit. In the running position the annular ports are isolated and the flow path is to the drill bit only. Once the first ball has landed, pressure is applied, a shear ring is activated and a piston shifts opening flow to the annular ports. Once the displacement is complete the second ball can be dropped reinstating flow to the bit and isolating flow to the annular ports.