Bullheading has its reasons when applied to bring back the well under control and one of them is circulation is not possible to be achieved. If kill fluid is under displace first, I cannot see where is the benefit. The goal is to have the well killed ASAP, safely and efficient. Maybe I am missing something from your question. I never under displaced just make sure I am pumping at a sufficient rate to avoid gas migration to surface (Rate of gas migration = Change in SICP in 1 hour multiplied with Fluid gradient - ft/h, psi and psi/ft; Pumping pressure is not increasing)
Hope this helps you.
Dan Antonescu -
Posted from Romania - 2019-06-21 08:32:34replyResponse