Managed Pressure Drilling (MPD), with the installation of Rotating Control Device (RCD) and MPD Choke has been identified as an time saving value added technology to two different operators in Vietnam when mitigating well control situations.
Conventional well control approach is to shut in the annular BOP and circulate out influx by using either the Driller's or Weight & Wait methods. However, these methods can only be used when the bit is on bottom and circulation is possible. In cases when it is unsuitable to use the standard well control methods, alternative such as: stripping to maintain BHP constant plus Volumetric to control gas migration to surface is considered.
Referencing two HPHT wells drilled in offshore Vietnam with MPD equipment; both influxes were encountered when the bit was completely out of the hole and the other when the bit was halfway from bottom of the well. The operators used the RCD bearing assembly and the MPD Choke Manifold to strip the drillstring back to total depth and performed standard well control procedures. The MPD stripping technique allowed the operators to regain well control, enhanced operational safety and significant time savings.
This paper will discuss the methodology of MPD well control techniques based on the experience from the two HPHT wells in Vietnam. The main objectives of the paper is to define, document, and develop workflows to successfully implement well control procedures using MPD in future HPHT wells.