Page 519 - Practical Well Planning and Drilling Manual

Appendix NEW! revised 11/00/bc 1/30/01 3:30 PM Page 495

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Glossary

Reverse Circulate. The method by which the normal flow of a
drilling fluid is reversed by circulating down the annulus and up and
out the drill string.

Rheology. The science that deals with deformation and flow of fluids.

Rig, Braking Capacity (Performance). The capacity to hold the hook-
load and retard the continuous movement of the hook-load within
reasonable specified limits compatible with specific requirements.

Rock Pressure. A term used for the initial pressure of gas in a well.

Rotary Drilling. The method of drilling wells that depends on the
rotation of a column of drill pipe, to the bottom of which is attached
a bit. A fluid is circulated to remove the cuttings.

Saltwater Muds. A drilling fluid containing dissolved salt (brackish
to saturated). These fluids may also include native solids, oil and/or
such commercial additives as clays, starch, etc.

Samples. Cuttings obtained for geological information from the
drilling fluid as it emerges from the hole. They are washed, dried,
and labeled as to the depth. Also, a portion of well fluid recovered
on a DST.

Seawater Muds. A special class of saltwater muds where seawater is
used as the fluid phase.

Shale Shaker. A vibrating screen that removes coarser cuttings from
the circulating fluid before it flows into the return mud pit.

Shale. Fine-grained clay rock with slate-like cleavage, sometimes
containing an organic oil-yielding substance.

Shear (Shearing Stress). An action, resulting from applied forces,
which causes or tends to cause two contiguous parts of a body to slide
relative to each other in a direction parallel to their plane of contact.

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