Drilling and Completion Engineering
Pressure and the mud window
Pore pressure, fracture gradient, and overburden define the safe mud-weight window. Hydrostatic pressure = 0.052 × mud weight (ppg) × TVD (ft). Distinguish measured depth from true vertical depth; all pressure calculations use TVD. Equivalent circulating density (ECD) adds annular friction pressure to the static mud weight.
Well control
Kick indicators, shut-in drillpipe pressure (SIDPP), shut-in casing pressure (SICP), kill mud weight, and the U-tube model. Slow-circulating-rate pressure converts surface pressures into equivalent mud weights. Know kick tolerance and the difference between the driller's method and the wait-and-weight method.
Casing, cement, and completion
Casing seat selection, burst/collapse/tension design, cement placement, and shoe tests (FIT/LOT). Completion types include openhole, cased and perforated, gravel pack, frac pack, and multistage fracturing. Understand perforating, sand control, packers, and tubing movement.
Traps
Using MD instead of TVD, omitting the 0.052 factor, adding SIDPP to SICP, mixing ppg with psi/ft, and confusing leak-off test pressure with fracture gradient. In completion questions, ask whether zonal isolation is required; openhole completions cannot selectively isolate.
Worked example
Kill mud weight = current MW + SIDPP ÷ (0.052 × TVD). With MW = 10.0 ppg, SIDPP = 500 psi, TVD = 10,000 ft: 500 ÷ (0.052 × 10,000) = 500 ÷ 520 ≈ 0.96 ppg, so kill weight ≈ 10.96 ppg.