Reúso da água produzida na fabricação de fluidos de perfuração base emulsão inversa e sua influência nas propriedades do fluido

Abstract

Oil production plays an important role for the economy and society development. However, the waste generated from the production to exploration need to be minimized, once that toxic waste is produced and cannot be disposed into the environment. The search for treatment and adequate reuse for waste such as drilling fluids and produced water prevent severe damage. In the oil industry, drilling fluid is critical for a good drilling, due to the required pressures and need to clean the well. However, the high volumes of fluids after this drilling stage become waste, just as the water produced in the production phase is a high volume residue. Reducing the environmental liabilities generated in the production of drilling fluids, with the reuse of water produced in the formulation of non-aqueous base fluids containing synthetic olefin, an example that the oil industry can reinvent itself and work to absorb their own waste. Thus, clean water consumption in the new formulations is avoided and reduces the final volume of waste, considering the different stages until oil production. The objective of this work was to formulate drilling fluids using produced water and study its properties. Thus, non-aqueous drilling fluids were formulated and tested in this study, containing between 20- 40% of water produced without treatment. The aqueous phase of these fluids is usually constituted by a brine, due to the required inhibition potential. The same inhibition criterion was applied to the produced water (PW), being the clay swelling analyzed in a Linear Swell Meter, and compared the brines applied to non-aqueous fluids. The PW simulated a residue containing emulsified oil, thus, presenting a high degree of difficulty for its treatment. Through factorial experimental planning 33 it was possible to verify the influence of the residue, and additives such as emulsifier and viscosifying on the rheological parameters and electrical stability. A rheometer was used to obtain rheological data of great quality and a potentiostate was used for corrosion analyses of the produced water and fluids. Comparisons between the fluids already used today and those prepared with the different PW were performed. The tests showed that although the produced water was corrosive, it does not affect the corrosion potential of the drilling fluids because the residue was emulsified. Thus, since the drilling fluid must meet the needs of the drilling operation and develop its function satisfactorily in relation to rheological parameters such as flow limit, plastic viscosity and gels. Commercial software has been applied to simulate the cleaning efficiency of a well with offshore characteristics, in relation to its geometry. According to the directional simulation, the last phase corresponds to the open well and starts in a horizontal stretch of 90°. The fluids formulated with produced water revealed similar corrosion and performance equivalent to those currently applied. For all the flows studied, the simulation showed satisfactory cleaning for the following criteria: relative height of gravels below 15% and solid concentration below 6%. In view of the results the well was considered clean and with heterogeneous cleaning pattern, making it possible to be manufactured and used in addition to a promising alternative in the fluid area.