Clara Mata, Senior Product Development Specialist, 3M
Cementing across highly depleted zones and weaker formations requires low density cement systems capable of reducing the hydrostatic pressure of the fluid column during cement placement. If wellbores encounter weak or depleted zones, standard cement cannot be used because the bottom-hole pressure will exceed the pressure gradient and cement will get lost to the formation. Service companies offer cement solutions made light enough to circulate in such situations while retaining the ability to withstand down-hole conditions and maintaining adequate compressive strength to meet regulatory guidelines. Lightweight cements can be achieved using water extension, foamed cement or lightweight microspheres. The seminar focuses on the use of lightweight microspheres as density reducing agent. Selected experimental data comparing different types of hollow microspheres and guidelines on the selection of the appropriate microsphere grade will be discussed.