Study of Using Natural Rubber Latex as a Filtrate Loss Prevention Additive for API Class G Cement

Abstract

The main objective of this research is to study the probability of using natural rubber latex (NRL), inexpensive and ecological friendly biopolymer and easily affordable in Thailand, as a fluid loss prevention additive for the API Class G Cement. In this study the API class G cement had been prepared as cement slurry at water/cement ratio (W/C) of 0.5 wt.% and were mixed with natural rubber latex (60% concentrated Latex - High Ammonia) at polymer (NRL) /cement ratio (P/C) of 0.05, 0.10, 0.15, 0.20 and 0.25 The cement slurry samples were casted in the cylindrical mold, moist cured for 7 days, and air cured for 28 days at room temperature, respectively.
The porosity and permeability test were conducted under the Overburden poro-perm cell unit, and results of the tests showed that the porosity and permeability values of the cement samples decreased until the P/C ratio reach 10 wt.% and then they increased steadily. This is because if the P/C ratio is greater than 10 wt.%, the hydration reaction of the mixed cement will take place rather than the polymer coalescence reaction and resulted in the higher polymer flocculant and dispersion. Therefore, the optimal P/C ratio for using the natural rubber latex as a fluid loss prevention additive for the API Class G Cement is 10 wt.%.