Abstract
A methodology was implemented to produce and transport heavy oil (12° API) from Basal Tena Formation in Libertador and Atacapi Fields, in a profitable way.
Before implementing the pilot project in January 2015, not a single well was producing from Basal Tena Formation in the southern part of Libertador and Atacapi Fields. Furthermore, commingled production is not allowed by the authorities unless reliable production allocation is guaranteed. The pilot project consists in mixing oil from two formations with different fluid characteristics in the wellbore. The heavier oil is combined with lighter oil, which works as a diluent; this process renders a blend suitable for production by submersible pump system and transport through pipelines. Both formations were tested and their fluids were characterized independently before starting commingled production.
Oil from Basal Tena Formation has an API gravity of 12° and a viscosity of 260 cP at reservoir conditions. The pilot shows that it is possible to produce, transport and quantify it after dilution; in this case 35° API oil diluent is produced from Napo T formation. Almost seven months after implementing the pilot, oil from both formations is still being produced, despite the fact that diluent contribution rate is not constant, as the production of the Napo T formation is declining because of water breakthrough. The key variable observed to quantify the production from each formation is the specific gravity of the produced blend.
Because of its success, this pilot is the first step towards the future development of these accumulations of oil in the Basal Tena Formation, not feasible without implementing a more expensive method, until now. This simple approach can be repeated in other areas in Oriente Basin.
