Sweep Improvement from the Lab to the Field

In the early 1990 s BP pioneered the use of reservoir triggers for in-depth placement of chemical<br>treatments to improve water flood sweep efficiency. It was recognised that the most difficult cases<br>involved injection water thief zones that were in contact with lower permeability zones of high remaining<br>oil saturation. In such cases near well-bore treatments were ineffective and an in- depth block appeared to<br>be required to redistribute the pressures in the reservoir and mobilise the remaining oil. The lessons<br>learned from this work suggested that the most effective treatments would employ single component<br>materials placed deep in the formation. A particulate material was envisaged that was likened to popcorn.<br>It would move freely through the matrix rock until a reservoir trigger caused the particles to increase in<br>size to block thief zone pore throats.