Investigation of Polymer Latex Effects on Cement Mechanical Properties for Improved Wellbore Integrity

Abstract

Cement needs to be designed to prevent short-term and long-term gas migration scenarios. In the short term, the cement must prevent gas flow immediately following cement placement. In the long term, the cement must resist pressure and temperature cycling during drilling and production. Wells are subjected to substantial stresses from pressure and well testing, injection and stimulation treatments, thermal effects, production cycling, and changes in the surrounding formation over years. Due to these stresses, the cement sheath damage can occur during drilling, perforation and stimulation, and subsequent production. Polymer latex has been used to help reduce the fluid loss to minimize gas migration and aid in the mixing ability of cement slurries. However, there are some engineers who believe that polymer latex will improve cement mechanical properties. The objective of this study is to evaluate the effect of polymer latex on cement mechanical properties after curing at elevated temperature and pressures. Experimental work in this study includes formulations at different polymer latex concentrations, densities measurements, rheology measurement, fluid loss testing, thickening time tests, curing for 30 days at elevated temperature and pressure, and finally mechanical properties measurements (Young's modulus, Poisson's ratio and compressive strength). The study shows that polymer latex will improve mechanical properties of cementing which will lead to improved wellbore integrity.