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raise the drill pipe up and out of the hole to allow the bit to be
changed. When drilling stops the cuttings suspended in the fluid can
sink to the bottom of the hole and jam the drill. Drilling fluids are
designed to have a very interesting property that takes care of this
problem. The thickness, or viscosity, of the fluid increases as
movement of the fluid slows. When the fluid stops moving it forms a
thick gel that suspends the rock cuttings and keeps them from sinking
to the bottom of the borehole. When the fluid starts moving again it
becomes thinner and reverts to its previous thin, liquid form
There is a popular image of oil gushing from a rig, high into
the sky, while workers rejoice at having found oil. Actually, such
blowouts are rare and no cause for celebration, since the goal is to
extract the oil in a controlled manner. Mud is designed to prevent such
accidents by counteracting the natural pressure of fluids in rock
formations. A proper balance must be achieved in which the pressure
of the drilling fluid against the walls of the borehole is enough to
counter the pressure exerted both by rock formations and by oil or gas
but not so much that it damages the well. If the weight of the drilling
fluid is too great it could cause the rock to fracture and the drilling
fluid would be lost into the ground.

Speaking Section
13 Make up a dialogue on the following situation and talk to your
friend. Let one of your group mates translate the dialogue
consequently.
You are visiting Spindletop with your group. Tell the students
about Spindletop, its informal name, the history of drilling at
Spindletop, who drilled the well and how.

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