A new two-phase model to simulate sour gas kicks in MPD operations with Water Based Mud

The simulated results showed that in vertical wells with sour gas and WBM, as the percentage of H2S in total gas increased, the maximum pit gain/casing pressure both decreased while the maximum casing shoe pressure remained almost the same. The peak value of casing pressure appeared later than the moment that gas front migrated to the wellhead. Moreover, the effects of degrees of choke opening on the annular pressure during the MPD well control operations were analysed. The quantitative research has certain guiding significance to improve safety operation of MPD for sour gas reservoir development with lower non-productive time (NPT).