First Surfactant-Polymer EOR Injectivity Test in the Algyő Field, Hungary
S. Puskas, Á. Vágó, M. Törő, T. Ördög, G.Y. Kálmán, R. Tabajd, I. Dékány, J. Dudás, R. Nagy, L. Bartha, I. Lakatos, A. Thomas and R. Garcia
Event name: IOR 2017 - 19th European Symposium on Improved Oil Recovery
Session: Pilot & Field Cases
Publication date: 24 April 2017
Info: Extended abstract, PDF ( 2.54Mb )
Price: € 20
In the past decades, the primary efforts of R&D activity aimed at developing an efficient EOR method to increase the recovery factor at oil fields depleted with extensive water flooding. Surveying the potential options, a final decision was made to concentrate on chemical EOR using combined surfactant/polymer flooding at the largest Hungarian oil field. The target formation of the stacked multilayer hydrocarbon occurrence was a sandstone reservoir with 70 mD permeability on average and bearing low viscosity oil (0.64 cP at 98 °C and 190 bar). This paper summarizes the workflow and set of experiments that were performed to allow a field injectivity test performed in 2013. The injected chemical solution contained a surfactant mixture developed by MOL and its Hungarian university partners and a sulfonated copolymer. The test started with the injection of 100 m3 of water followed by the chemical cocktail containing 15,000 ppm of surfactant and 1,000 ppm of polymer driven into the reservoir by an additional water volume of 100 m3. The project was precisely monitored measuring the well head pressure, flow rate and viscosity of injected fluids. Although the main criterion of successful job was obtaining good injectivity, other important factors like thermal stability of the surfactant-polymer solution under reservoir conditions was also evaluated by back-flow test. Among others, various laboratory measurements were performed to determine the polymer and surfactant concentration as well as the rheological and interfacial properties of back-flushed solutions in order also to calculate the possible loss of chemicals. In addition, the success of the pilot was also proved by the decreased water-cut and the change of quality of oil in the produced samples, which clearly indicated that the chemical solution mobilized the entrapped oil remaining after water flooding. The current plans and next steps will also be discussed at the end of the paper.