Initialize and Drill

At Rest Before Flow

Before the first timestep, the model is equilibrated: each phase pressure climbs with depth along its own gradient, and the saturation grades from connate water at the crest, down through a transition zone, to the water leg below the contact. Getting this initial state right keeps the first volumes and pressures physical.

Drill the Wells

Then the wells go in. Here an injector sits on one flank and a producer on the other, the simplest waterflood pattern. Their placement, relative to the structure and the good rock, will shape how cleanly the flood sweeps.

Complete the Wells, Layer by Layer

A well injects or produces only where it is perforated, so choosing which layers to open is the completion decision, and it sets the vertical sweep. Injection splits among the open layers in proportion to their flow capacity, permeability times thickness, so a high-permeability streak takes most of the water.

That streak is a thief zone: it floods and breaks through early while the oil-rich but tighter layers are barely swept and left behind. Seal the thief at the injector and the same water spreads into the bypassed pay, lifting recovery and cutting the water cut. Because the reservoir is nearly incompressible, every barrel injected replaces a barrel produced, the voidage that also holds the reservoir pressure up.

Ready to Flood

Equilibrated and drilled, the model is finally complete: a faithful grid, filled with rock and properties, initialized and connected to wells. One thing remains, to run it.