Avaliação da aplicação dos métodos indiretos de predição do gradiente de pressão de poros em projetos de poços da Bacia Sergipe-Alagoas

No cenário petrolífero atual, a exploração de petróleo em camadas com grandes profundidades é cada vez mais frequente. Com isso, um estudo mais completo das geopressões se faz necessário, visto que essas são as responsáveis pela manutenção da estabilidade do poço. Na previsão de geopressões são utilizados, geralmente, métodos indiretos, que consistem em correlações empíricas que foram calibradas para uma determinada área. Este trabalho teve como principal objetivo fazer uma análise comparativa e técnica das pressões de poros preditas na Bacia Sergipe-Alagoas, utilizando correlações empíricas calibradas para o Golfo do México. No cálculo dos gradientes de pressão de poros foram utilizados dados de dois poços, X e Y, fornecidos pela empresa Z. Os resultados obtidos através dos métodos indiretos foram comparados com os dados de testes de formação realizados nos poços durante a perfuração. Os resultados obtidos mostraram que, para o poço X, os valores preditos foram conclusivos e coerentes, pois os erros relativos médios dos gradientes de pressão de poros oscilaram entre 2,52 e 11,38%, sendo esses valores próximos dos dados medidos nos testes de formação. Já para o poço Y, os resultados preditos foram representativos apenas no intervalo em que o gradiente de poros medido no teste de formação apresentou valor normal.In the current oil scenario, the exploration of layered oil at great depths is becoming increasingly frequent. Thus, a more complete study of geopressure is necessary, since it is responsible for maintaining the stability of wells. When predicting geopressures, indirect methods are usually used, which consist of empirical correlations that have been calibrated for a certain area. This work’s main objective was to make a comparative and technical analysis of the pore pressures predicted in the Sergipe-Alagoas Basin, using calibrated empirical correlations for the Gulf of Mexico. In the calculation of the pore pressure gradients, data from two wells, X and Y, provided by company Z were used. The results obtained using the indirect methods were compared with the data from formation tests that were performed in the wells during drilling. The results showed that, for well X, the predicted values were conclusive and coherent, as the mean relative errors of the pore pressure gradients ranged from 2.52% to 11.38%, and these values are close to the data measured in the training. As for well Y, the predicted results were representative only in the interval in which the pore gradient measured in the formation test had a normal value

Separation Process by Porous Membranes: A Numerical Investigation

A major problem associated with the membrane separation processes is the permeate flux drop, limiting the widespread of industrial application of this process. This occurs due to the accumulation of solute concentration near the membrane surface. An exact quantification of the concentration polarization as a function of process conditions is essential to estimate the system performance satisfactorily. In this sense, this work aims to predict the behavior of the concentration polarization boundary layer along the length of a permeable tubular membrane, over various operation conditions. The numerical solution of the Navier-Stokes equation, coupled to Darcy's and mass transfer equations, is obtained by the commercial software ANSYS CFX 12, considering a two-dimensional computational domain. The study evaluates the effects of axial Reynolds and Schmidt numbers on the concentration polarization boundary layer thickness during the cross-flow filtration process. Numerical results have shown that the mathematical model is able to predict the formation and growth of the concentration polarization boundary layer along the length of the tubular membrane