Qualificação de sistemas para operações de tamponamento em abandono de poços de petróleo

Abstract

The main objective of this work is to qualify the plugging systems for the abandonment of wells according to the Oil & Gas Guidelines. Four class G portland cement pastes and an epoxy resin system were studied. The conventional, expandable and expandable and flexible pastes were studied to be used in scenarios of coiled tubing abandonment wells operations. The composite of class G portland cement with resin and the resin only system were evaluated for conventional plugging operations. This research was divided into two stages. In the first stage the characterization of the systems was performed. The tests were carried out to determine the rheological properties of the pastes, fluid loss, free fluid, static sedimentation, thickening time, development of compressive strength with ultrasonic pulse, adhesion, shrinkage / expansion and isothermal calorimetry. The second step consisted in evaluating the medium term integrity of the systems under bottom-hole temperature simulated and in contact with well completion fluid. The ageing process was carried out for 60 days with the samples immersed in in thermal bath at the bottom-Hole static temperature of the well (BHST). Mechanical, physical, thermal and dimensional variation were evaluated for plugging systems before and after the ageing process. Finally, the influence of the brine solution on the degradation of the Portland cement matrix and resin, during the aging process, was evaluated supported by X-ray, thermograpimetric and scanning electron microscopy.