Page 266 - Drilling Technology in Nontechnical Language

Chapter 11 – WELL CONTROL 257

Figure 11–1 shows the situation after closing the blowout preventer.

Fluid influx has entered the well, the blowout preventer is closed, and the

pressures have stabilized. Notice that the influx is in the annulus. The

density of all the fluids in the annulus is not known. However, the drillpipe
is full of clean mud of known density.

Fig. 11–1. BOP closed on in ux

As the mud hydrostatic pressure in the drillpipe and surface pressure
are both known, the pressure at the bottom of the well can be calculated.

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