Rotary drilling & mud circulation

Rotate the string, circulate the mud, and drill ahead.

Mast / derrick Hoisting block / hook Rotary table BOP (shown open) Casing + cement Drill pipe Drill collars Drill bit Mud pump Shale shaker Mud tank Blue: down inside pipe · Brown: up in annulusStandpipe / rotary hoseReturn lineSchematic · independent scales
Clean mud → inside pipe → bitMud + cuttings → annulus → shaker
Assumptions and reference

Circulation sequence: tank → pump → standpipe / rotary hose → drill string → bit nozzles → annulus → shale shaker → tank. Source: OSHA · Mud Circulation System. The shaker and mud tank sit above ground; shaker supports extend to ground level. Cone motion is a projected visual cue for axial bit rotation, not a rigid-body engineering model. The diagram combines simplified surface equipment and a cutaway well. Casing shoe depth is a fixed visual reference; not a design value.

Geometry assumptions: drill pipe inside diameter 4 in; pipe outside diameter 5 in; hole diameter 8.5 in. Bulk velocities follow Q/A; compressibility, mud rheology, pressure losses and solids slip are omitted. The control sets an illustrative ROP, not a prediction from RPM or flow. Drill-ahead is allowed only when rotation and circulation are both enabled in this teaching model. Below-ground depth and time are compressed. The rotation visual is slowed by 4 times to avoid flicker; displayed RPM is the input value. This is not a well-control or operational simulator. BOP remains open; no kick simulation.