| Summary: | Failure to adequately equipping the wellhead with appropriate well control
equipment may result in a high pressure in the gas drilling when it reaches
a high-yield gas layer. This would require the execution of a well killing
operation to facilitate follow-up drilling and well completion. An empty
well of gas-phase brings implementation of a gas-liquid two-phase transient
flow, filling with killing mud. The operation may also entail coupling of
the transient seepage from the formation with the gas-liquid two-phase
transient flow through the wellbore. In this study, a mathematical model and
a numerical method for coupling the transient gas flow through the formation
with the gas-liquid two-phase transient flow in the wellbore were developed.
The numerical simulation results showed that successful killing of an empty
gas-drilled well required proper co-ordination of several key parameters
among which the wellhead backpressure is particularly crucial to the
operation. The findings of this study promise to facilitate the pro-cess
design and parameter optimization for the killing of empty gas-drilled
wells.
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