Well Control and Kick Detection
Domain focus
This domain tests kick detection and well control: primary and secondary barriers, kick indicators, shut-in procedure, pressures, kill mud, MAASP, and BOP use. Expect questions on what to do first and which pressure or depth to use.
Core rules
- Primary barrier is the mud column; secondary barrier is the BOP stack and related equipment. Both must be verified.
- Kick indicators include flow with pumps off, pit gain, decreasing SPP, gas-cut mud, a drilling break, and unexplained fill or trip tank changes.
- On a kick: stop rotary, stop pumps, close the BOP, then record stabilized shut-in drillpipe pressure (SIDPP), shut-in casing pressure (SIRPP), and pit gain.
- Kill mud weight in ppg equals current mud weight plus SIDPP ÷ (0.052 × TVD in ft). Use true vertical depth, not measured depth.
- MAASP is the maximum casing pressure that can be held without exceeding formation fracture pressure at the shoe.
Worked example
Current mud is 10.0 ppg, TVD is 6,000 ft, and SIDPP is 300 psi. Kill weight = 10.0 + 300 ÷ (0.052 × 6,000) = 10.0 + 0.96 = 10.96 ppg. The reasoning is: SIDPP represents the underbalance at the bit; converting it to mud weight uses the vertical column to the bit.
Traps
Reading SIDPP before pressure stabilizes; using measured depth; opening the BOP before a kill plan is agreed; confusing SIDPP with SIRPP; ignoring pit gain after shut-in.