Abstract

Demjén West is a shallow oil field with unsaturated paraffinic oil in Northern Hungary. Contrary to the long production history the recovery factor is only 13%. Already from the early years of the field number of experiments were completed to enhance production. Recently a new steam generating technology was tested. The objective was to collect information on the usability of the technology in the field and to test the reservoir behaviour for steaming.

First a technology test and demonstration day was organised for international companies in February 2016. After the successful testing an 8-cycle/8-week long pilot project was planned and completed in the summer of 2016. The cycles contained 2 days steam injection half a day soaking period and 5 days production. New heat resistant well equipment were fabricated for the project and a new well completion was applied. However the pilot was planned for an old existing well with the old SRP system what proved key issues for steam injection.

The paper introduces the steaming technology, the results and observations of this exciting cyclic steaming pilot project. A detailed monitoring system was planned and applied in the project. All the parameters of the new steam generating technology and the injection/production process were monitored. The nearby wells were also monitored and the produced fluids were sampled and tested in lab. The project faced to number of technical difficulties. However contrary to the technical problems and to the significantly less injected steam volume the production increased and the reservoir reacted well as it was expected. Observations proved that the injected steam and hot oxygen cleaned the pores of the near wellbore space from paraffin and heavy particles and improved the oil inflow to the well. The condition of the old well proved to be the weakest element of the process. The new steam generator could provide the planned volume of steam with the planned parameters (pressure and temperature). By solving the key technical problems cyclic steaming can be a viable technology to significantly improve the recovery from this old field.

The pilot project served valuable information for future operation. Cyclic steaming can be right solution to enhance recovery from Demjén West and from similar shallow heavy(er) oil fields. Successful and economically viable projects can be completed with new slim-hole wells and suitable lifting technology.

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