A Critical Tool for Oil Well Cementing
Gas migration through hydrating cement slurry is a major reason for well completion failures which require costly remedial well treatments. Chandler Engineering developed the Model 7200 Cement Hydration Analyzer (CHA) to realistically simulate gas migration scenarios of varying severity.
The Model 7200 Cement Hydration Analyzer is a precision instrument that measures four key aspects of oil-well cement: (a) its susceptibility to gas migration, (b) its degree of hydration, (c) its shrinkage during curing and (d) the gas permeability of the cement.
Description of the Instrument
The Model 7200 is a closed system in which nitrogen gas is injected into the bottom of a cement slurry at any time during its hydration (setting). The cement’s susceptibility to gas migration is determined by whether or not the nitrogen gas injection pressure is transmitted up through the column of cement to the opposite (top) side of the cement sample where the pore pressure is measured.
Gas migration will result in the pore pressure of the sample rising and possibly becoming and/or remaining equal to the gas injection pressure. If no gas migration occurs, the pore pressure will continue to drop (due to the shrinkage and loss of fluid communication through the sample) during hydration, possibly continuing to reach a vacuum.
Operational Simplicity
The Model 7200 is designed to be as easy to use as possible. The instrument’s software controls, records and displays all test measurements in real time.
Test conditions, including the static gel strength profile of the cement, are easily programmed and controlled through this system. As the system is designed to avoid line plugging, clean-up after testing is both quick and easy.
