Research on conversion technology for gas-based fluid drilling

Gas-based fluid drilling methods are primarily comprised of gas drilling,atomized drilling,foam drilling as well as aerated mud drilling.For different method,gas-fluid flowrate,gas fluid ratio,annular flow pattern and formation compatibility are to-tally different.So the treatment and effect are also different in case of operation failure.Based on theoretical analysis,referring to field practices,gas-based fluid drilling conversion technology is systematically analyzed in case of downhole troublesome conditions.And relevant technologic measures and methods for field problems have been prepared.This paper introduces the gas-based fluid drilling conversion technology for Iranian well TABNAK-3,which is believed to offer reference to similar operations.