Abstract

An improved cementing technique using thixotropic cement is one method of reducing or eliminating the "fall back" of a cement column after cement is in place. Cement fall back occurs when excessive hydrostatic pressure due to the higher density cement in the annulus breaks down the formation at depth, causing the loss of whole cement to the formation.

The design application and properties of thixotropic cement slurries are discussed. Prejob planning is a necessity and is discussed, emphasizing certain precautionary measures that must be taken into account. Field operation considerations such as additive mixing and blending are covered in detail.

To further enhance the prevention of cement fall back, thixotropic cement can be used in conjunction with a variety of lost circulation materials. Laboratory test results of thixotropic slurries formulated with Indonesian manufactured cement are presented and discussed. The compatibility of various lost circulation materials is discussed. Several case histories of the use of thixotropic cement in Southern Sumatra are presented and discussed.