Evaluation of mechanical properties of cement slurries containing SBR latex subjected to high temperatures

Abstract

The oil and gas industry uses different techniques to increase the productivity index of a reservoir, and steam injection is one of the most widely used in the world. In this technique, heated water vapor at high temperatures (between 300 and 400 °C) is injected under pressure into the reservoir, increasing the pressure in situ and reducing the oil viscosity present in the rock. Notwithstanding this, another physical consequence is the expansion and contraction of the casing column, an effect that can affect the cement sheath and lead to failure. In this context, SBR latex is used to improve the flexibility of the cement matrix by reducing the amount of fatigue failure, besides what, the mechanical behavior should be carefully adjusted to the well conditions. Therefore, this work aims to study the mechanical behavior of cement slurry systems additivated with SBR latex and applied to oil wells cementing that are subject to steam injection. Through a central composite factorial design, the authors studied the compressive strength behavior by varying the slurry density from 1.75 g/cm³ (14.6 ppg) to 1.89 g/cm³ (15.8 ppg), curing time between 4 days and 28 days and concentration of SBR latex between 0 L/m³ and 534.722 L/m³ (0 gal/ft³ and 4 gal/ft³). The results showed that increasing the SBR latex concentration, within the given ranges, decreased the compressive strength of the specimens. Through the study it was possible verified the potential of statistical tool in the aid of determination of the best systems.