Page 28 - Drilling Technology in Nontechnical Language

Chapter 1 – DRILLING GEOLOGY 19

Apart from the predicted lithology, there are two other critical bits of
information that the geologist needs to evaluate: how the pore pressure and
fracture pressure vary with depth.

Pore and fracture pressure prediction

The geologists on the project will examine all available information to
predict how pore pressure (the pressure of the fluid within the rock pores)

and fracture pressure (the pressure inside the well that would fracture the
hole) vary with depth. The information will be passed to the drilling team,
normally as a graph and also as a table showing estimated pressures at

various depths (fig. 1–12).

Fig. 1–12. Graph of pore and fracture pressures

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