Use of Cement As Lost Circulation Material - Field Case Studies

摘要

Cement is one of the most common lost circulation materials (LCMs). Various types of cement have been used as LCMs in the past. Recent developments in cement technology and the understanding of lost circulation have produced custom- designed applications utilizing effective cement types and compositions. Applications also vary depending on the drilling fluid type and its properties. Custom-designed applications include thixotropic and ultrathixotropic cement slurries; slurries containing cello flakes, mica, and CaCO3 for mechanical bridging; unique spacers and surfactant packages; and foamed cement for controlling loss. Selection of proper cement type and injection procedure calls for specific information such as formation properties, wellbore conditions, and thief zone characteristics. Laboratory experiments are recommended in this process. Field observations are also critical in making the final decision for selecting the optimum treatment fluid train and application strategy. This paper discusses the process designs and application of various cement types as LCMs. Solutions to four problematic field cases are provided. The conditions that require cement as an LCM and the criteria for selecting the best cement compositions are outlined along with optimal strategies.