Análise da coinjeção cíclica de vapor e solvente em reservatório do nordeste brasileiro

Abstract

One of the main challenges facing the oil industry today is improving land field recovery. Of the hydrocarbon land reserves, a significant portion is made up of heavy and extraheavy oils. Thermal and miscible methods help to increase hydrocarbon production by reducing viscosity, capillary forces and interfacial tension. They can be combined by steam and solvent stimulation. One of the most versatile solutions for heavy oil recovery is cyclic steam and solvent stimulation, as it delivers sizable volumes and returns on a short time. Therefore, this work aims to technically and economically evaluate the cyclic steam and solvent coinjection process in a heavy oil reservoir with characteristics of Brazilian northeastern. The simulations were performed in a commercial oil reservoir modeling program. For this analysis, a complete 2x34 experimental design and a 3 5 design were performed, varying factors such as: solvent type, molar solvent percentage, injection temperature, fluid injection flow rate, rock compressibility, injection time, soaking time and duration of cycles. A study of the behavior of the temperature along the well (in the blocks) and the energy losses was performed. The accumulated volume of oil produced was analyzed. The results show that the analyzed variables that had the greatest influence on the accumulated oil production were formation compressibility, injection flow rate, solvent percentage, cycle interval and injection phase duration. The compressibility was the variable that influenced the most. And among the three solvents used (pentane, heptane and diesel), heptane presented superior performance and the other two presented similar performances. The temperature along the well was more influenced by the injection flow rate. The temperature along the well was more influenced by the injection flow, higher flow rates provided greater heat losses. The temperature along the well was different, with the upper part warmer and changes occurred when analyzing equivalent periods of different cycles. Economic analysis has shown that higher amounts of steam and solvent make the project economically unviable.