Model 640 & 640CC Instruction Manual
D01206676
Revision A February 2016
6
1
Introduction
Cements are a critical element in the drilling, completion, workover, and
abandonment of wells. For each application, cement slurry is designed with specific
properties and is given additives that provide predictable slurry density, volume,
viscosity, compressive strength, fluid loss, gas migration, and thickening time.
Slurry thickening time, or the time a slurry remains pumpable in a well, is one of
the most critical properties in designing cement slurry. A predictable thickening
time is desired, while maintaining the other specific properties of the cement slurry.
The thickening time can be measured in a laboratory by testing a sample of the
cement slurry in a pressurized consistometer. The elapsed time between initial
application of pressure and temperature on the slurry sample and occurrence of a
predetermined value of consistency (usually 100 Bearden Units, Bc) is the
thickening time for the sample at the particular specification test schedule. The
typical test schedules are listed in API Specification 10 on oilwell cements.
The Model 640 & 640CC Pressurized Consistometers are able to test cement
slurries at temperatures up to 600 F/316 C and pressures as high as 40,000 psig/276
MPa.
