Estudo do aquecimento geral indireto como método de recuperação avançada de petróleo

Abstract

The rise in world oil prices has been becoming viable ventures with previously considered high expenditures, such as ultra-deep water depth oils or unconventional oils (ultra-heavy). As for reservoirs with greater depths, those considered shallow ones have shown disadvantages due to the pressures and low temperatures. Furthermore, the direct impediments to the recovery of oil have been not ensuring effective isolation training, thereby allowing evaporation or consumption of light fractions by bactéria. The greater weight, remaining components have characterized oils of high density and reduced mobility, providing additional challenges for recovery at acceptable cost. Oil has its viscosity substantially reduced by being heated, which makes thermal methods the choice of reference in heavy oil recovery. Blanket Heating is a method included in this category, which has been especially designed for shallow deposits and ultra-shallow ones, although studies need to clarify its applicability in the field. In this technique, steam is inserted into conduits which act as heat exchangers, mediating the transfer of heat from the heated fluid to the oil, and preventing the direct introduction of steam into the formation. The study was developed from a commercial simuiator STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) of CMG (Computer Modelling Group), and discussed alternative configurations for the Blanket Heating, as the application of vertically inserted conduits into the reservoir and integration with waterflood, comparing them to conventional pattern and investigating the possibility of in situ steam generation (resulting from the association between methods). Individual analyzes were also promoted in order to determine the existence of an optimum temperature and consider the benefits of method for ultra-heavy oils, as well as the relevance of heat losses involved. Finally, the previous results were weighted by a techno-economic analysis. A better use was proven for horizontal conduits, but the waterflood demonstrated ability to balance the lower recoveries of vertical mode, in addition to expanding the already satisfactory results from traditional configuration, due to the confirmation ofthe generation ofsteam within the formation. Above 400 °F, no obvious changes were observed in the recovery, and below that value occurred late peak oil flow. The Blanket Heating - studied in two modes - resulted in higher recoveries for extremely viscous oil reservoirs, and heat losses along the conduits produced evident variations in the production of oil. Blanket Heating with vertical conduits (not associated with waterflood) presented the lowest Net Present Value (NPV), the other cases (horizontal conduits applied with and without waterflood and vertical conduits associated with waterflood) achieved high rates of return. The cases alternating temperatures presented NPV higher than the model that fixed the maximum temperature.