Analysis of Riser Gas Pressure from Full-Scale Gas-in-Riser Experiments with Instrumentation

As the use of adaptive drilling process like Managed Pressure Drilling (MPD) facilitates drilling of otherwise non-drillable wells with faster corrective action, the drilling industry should review some of the misconceptions to produce more efficient well control methods. This paper discusses results from full-scale experiments recently conducted in an extensively instrumented test well at Louisiana State University (LSU) and demonstrate that common expectations regarding the potential for high/damaging internal riser pressures resulting from upward transport or aggregation of riser gas are unfounded, particularly when compressibility of riser and its contents are considered. This research also demonstrates the minimal fluid bleed volumes required to reduce pressure build-up consequences of free gas migration in a fully closed riser.