Desenvolvimento de fluidos de perfuração com alto grau de inibição ambientalmente corretos.

Abstract

The aim of this work was to develop formulations of water base drilling fluids with high degree of inhibition, ecological and with low toxicity, to be applied in deep perforations with hydrate clays and shale sections. From the Foster swelling it was set up the optimum concentration of inhibitor (16g/350mL of water) and then prepared drilling fluids with three different concentrations of inhibitors of expansive clays without chlorine (potassium sulphate, potassium acetate and potassium citrate). The additives used to prepare the inhibited drilling fluids were: anti-foam, viscosifier, filtrate reducer, pH controller, expansive clay inhibitors (potassium sulphate, acetate and citrate), bactericide, lubricant and sealant. It was developed 57 drilling fluids formulations by using experimental plain. Rheological, filtration and lubricity studies were done after 24 hours of fluids preparation. From 57 formulations it was selected 10 to measure the linear swelling in relation to clays and shale. Also it was estimated the dispersibility and toxicity of the developed fluids. The results were compared with standard fluids with inhibitors of chlorine, typically used in the oil industry. From the results, it was concluded that the drilling fluids were developed with success and with performance close or superior to the standard fluids. Excellent results were obtained in relation to the linear swelling and dispersibility. The toxicity presented by the developed fluids was moderated and indicated that these fluids can be applied in the perforation of oil well without cause excessive damage to the environment. In general, the results indicate that the potassium sulphate, acetate and citrate inhibitors can be used as alternative products in substitution of the well known in the oil industry and do not affect the environment and the perforation.