Uso do Poli(álcool vinílico) reticulado para mitigação da perda de circulação em poços de petróleo

Abstract

In the oil and gas industry, one of the most critical and common problems during the well drilling process is the circulation loss. This problem is associated with the occurrence of fractured rocks or highly permeability fields and leads to economic, operational and safety hazards, making them a central issue for well planning and construction. Different materials have been used to treat the problem and seal the cracks. The process demands materials with high mechanical resistance, thermal stability and physical characteristics for efficient use in the wide ranges of temperatures and porosity found in a well. The present work focused on the development of high mechanical strength materials based on crosslinked PVA for control of circulation loss. The research was carried out with aid of statistical design of experiments in order to determine how the reaction conditions affect the mechanical properties of the formed hydrogels. To evaluate the efficiency of crack sealing using hydrogels, a laboratory equipment that simulates the conditions of the porosity of oil wells and allows materials to be subjected to pressures up to 1000 psi was developed. It was observed that the hydrogels with better mechanical properties for application as crack-sealing fluids were those that presented greater elastic deformation capacity before the fracture. Regarding the results of the plugging tests, it was observed that the obtained hydrogels are highly efficient, supporting pressures up to 380 psi without any leakage of fluid.