Drilling Operations and Parameters
Domain focus
This domain tests drilling parameters and operational decisions: weight on bit (WOB), rotary speed, torque, standpipe pressure (SPP), flow rate, rate of penetration (ROP), bit hydraulics, connections, tripping, casing, and cementing. Questions often present a trend and ask for the safe response.
Core rules
- Establish a baseline for each parameter and watch trends, not isolated values. A change in ROP, torque, drag, SPP, or pit level can signal a formation change, bit wear, hole cleaning problem, or influx.
- Optimize ROP within limits: excessive WOB can cause bit balling, stick-slip, or damaged components; too little WOB polishes the bit.
- SPP reflects pump rate, mud weight, bit nozzles, and restrictions. Do not chase pressure by increasing pump speed before finding the cause.
- During connections and trips, monitor flow, fill-up, and drag; record volumes and abnormal trends.
- Follow the drilling program for casing and cementing; verify displacement and pressure test before continuing.
Worked example
SPP rises from 2,500 to 2,900 psi while SPM and mud weight are unchanged. The reasoning is: something has increased resistance, such as a plugged bit nozzle, a partially closed valve, or a line restriction. Stop and check the standpipe, manifolds, and bit nozzles; do not simply raise pump speed, which adds pressure and may damage the pump or open a formation.
Traps
Chasing ROP with excessive WOB; treating a drilling break as a good sign without a flow check; ignoring torque and drag trends; using measured depth instead of TVD for pressure calculations.