17
D.
Example 1.
The drilling fluid sample is mixed and loaded into the cell, then pressurized at 477.5 psi
(3292 kPa) for 10 minutes. The torque plate is seated using the lever and holding for two
minutes. Eight minutes are allowed to pass, then breaking torque is measured in four
breaks, 30 seconds apart, at 36 inch pounds (41.47 kg-cm), 39 inch pounds (44.93 kg-cm),
40 inch pounds (46.08 kg-cm), and 41 inch-pounds (47.23 kg-cm). The drilling fluid sample
has an average .039 Stuck Tendency Coefficient. The pressure is removed and the cell is
opened carefully, leaving the torque plate set in the cake. The cake-torque plate assembly
is washed and the torque plate is turned (not lifted) loose. The diameter of the imprint of the
torque plate impression (smooth domed area) is 1.57 inches (3.95 cm) giving a radius of
0.785 inches (1.98 cm).
Therefore, (using inch dimension) So R=.785; so