Avaliação da perda de carga e do fator de atrito no escoamento de fluidos de perfuração em geometrias circular e anulares concêntricos

Abstract

The constant search for new technologies of drilling oil wells has reinforced the research and development of drilling fluids and the specific study of their disposal, particularly with regard to the load loss caused by the different geometries. Within this context, this study focused on the load loss and friction factor in the disposal of the drilling fluids A, B and C in circular and concentric annular pipelines, simulating a real system. The data were obtained in a pilot plant consisting of a system operating in a closed circuit of 6 m long horizontal tubes of galvanized iron, arranged in three independent parallel flow lines, which allowed the evaluation of load loss in a circular tube of 1 " diameter and two ratios of concentric rings (annular tubes consisting of 2" and ¾ "and 1 ¼" and ½ "). The system consisted of a 500 l tank with a mechanical stirrer (3HP), coupled with a positive displacement pump with a helical rotor (25HP), operating at flow rates of up to 20 m3/h. The pilot plant was equipped with a set of three pressure transducers, to collect a wide range of experimental data recording the pressure loss. The flow volume was determined by a gravimetric technique and the fluid rheology was measured by a FANN viscometer, model 35A. Data of load loss and friction factor in relation to the above experimental geometries were recorded for water and the fluids A, B e C. The rheological models power-law and Casson were used to evaluate the correlations of hydraulic diameter and friction factor for laminar and turbulent regimes. Correlations proposed in the literature were evaluated, based on the experimental data of friction factor and loss.