Effects of Additives and Conditioning Time on Compressive and Shear Bond Strengths of Geothermal Well Cement

Abstract

Waiting on cement in the cementing operation of geothermal wells is usually conducted from 8 hours to 24 hours after displacement of cement into an annulus of casing. After that, the quality of cement is evaluated using the CBL (Cement Bond Log) test. Evaluation results of the compressive strength and shear bond strength that is interpreted at 24 hours does not reflect the final strength of the cement.
The laboratory experiment for 7-day measurement indicated that extending additives to API class G cement could increase the compressive strength and shear bond strength of cement immediately for about 3 days. After that the compressive strength slightly changed or stable until the seventh day, whereas the shear bond strength still increased in lower level.
The experiment was carried out at a temperature of 150oC dan pressure 2000 psi in a curing chamber that was contaminated with formation fluid of the Kamojang Field.