This paper presents the industry's first application ofbalanced pressure drilling to drill a difficult well sectionwith continuous circulation using jointed pipe. Previousattempts to drill the section in 2004 failed and balancepressure drilling was identified as the only safe andpractical drilling technique to use.The paper will present the reasons for employing a newdrilling technique, together with the associated changesto conventional drilling and well control procedures.In the Port Fouad Marine Deep-1 (PFMD-1) well below4000m, there exists a critical pressure gradient zonewith pore pressures exceeding 2.0 sg EMW, with thedifference between pore and fracture pressure gradientsas low as 0.10 sg EMW. The dynamic hydrostaticpressure difference between the Equivalent CirculatingDensity (ECD) and the mud weight was equivalent toabout 0.07 sg during drilling operations. The well was reenteredin June 2005 using the Continuous CirculationSystem (CCS?) and the problem zone drilledmaintaining constant ECD. Drilling difficulties resulting inthe earlier suspension were successfully overcome.Balance Pressure Drilling (BPD) with uninterruptedcirculation and revised drilling and well controlprocedures significantly improved drilling performanceand operational safety in the critical gradient zone. Thisresulted in adding significant new hydrocarbon reservesthat could not previously be drilled.
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