Production and Facilities Engineering
Inflow and outflow
Productivity index, inflow performance relationships (IPR), Vogel's equation for solution-gas drive, and vertical lift performance (VLP). Nodal analysis finds the operating point where inflow equals outflow. Know how skin, water cut, GOR, and tubing size shift the curves.
Artificial lift
Gas lift (valve spacing, injection gas rate), ESP (free gas handling, viscosity, pump curves), rod pump (pump fillage, gas interference), and plunger lift. Match the lift method to rate, depth, deviation, and solids production.
Surface facilities
Two- and three-phase separators, residence time, mist extractors, TEG dehydration, compression, and metering. Flow assurance covers hydrates, wax, scale, corrosion, and slugging, along with mitigation methods such as methanol or glycol injection, insulation, and chemical inhibitors.
Traps
PI units (STB/d/psi), applying Vogel to undersaturated or waterflood cases, confusing GOR with gas rate, sizing separators on pressure alone, and mixing hydrate formation temperature with hydrocarbon dew point. Watch for standard versus actual gas volumes in compression questions.
Worked example
Vogel: q/qmax = 1 − 0.2(Pwf/Pr) − 0.8(Pwf/Pr)². With Pr = 3,000 psi and Pwf = 2,000 psi: ratio = 0.667; q/qmax = 1 − 0.133 − 0.356 = 0.511, so the well produces about 51% of qmax.