Dan T. Mueller

Portland Cement - Blast Furnace Slag Blends in Oilwell Cementing Applications

Recent investigations of blast furnace slag cementing technologies have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a long history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends in field applications are also included.

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.