The consistency of the cross-linked plug will range from a solid plug to a rubbery plug that will move and flex with the pump rates. Penetration into the thief zone will not be hindered with any concentrations. (Professional Fluid Services, LLC)

An operator working in Argentina wanted to eliminate running 20" surface casing by drilling with casing while isolating the shallowest thief zone. The operator drilled an 870 ft section to reach section TD at 20.5 ft/hr through clay and soft sandstone, successfully isolating the trouble zone with 17 1/2" EZCase technology on 13 3/8" casing. (Baker Hughes Incorporated)

Significant challenges exist when drilling through and below salt formations. The thief zone at the base of the salt can introduce severe lost circulation and well control problems, often resulting in loss of the interval or the entire well. (CBS Interactive Inc.)