Virgilio Go Boncan

Characterization of the initial, transitional and set properties of oilwell cement

Upon hydration, Portland cement-based materials vary in physical and mechanical properties as a function of time, temperature, and pressure. A new laboratory instrument, which determines the dynamic modulus of a substance, has been developed to measure the properties of a Portland cement as it solidifies. This information serves to improve the understanding of the various physical and mechanical phenomenon that occur within a setting cement. Measurable properties include: (1) the duration of the cement`s hydraulic phase; (2) beginning and end of a static gel period; (3) time of transition into initial compressive strength; (4) current compressive strength; and (5) cement expansion/shrinkage as a function of time. As such, this laboratory device can be used to characterize the conversion of a cement from a fully hydraulic fluid, through its static gel stage, into a solid mass. With this information, a more complete understanding of the interrelationship of fluid-state, gel-state, and solid-state phenomenon, as they relate to cement shrinkage and compressive strength development, can be obtained.