INORGANIC GELS
FOR ENHANCED OIL RECOVERY
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INORGANIC GELS FOR ENHANCED OIL RECOVERY |
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A novel physico-chemical method has been developed to enhance oil recovery. The method is based on the capacity of inorganic GALKA system to generate inorganic gel and CO2 in situ. Gelation causes rearrangement of the filtration patterns, modifies water injection profile in the injection wells and decreases water cut in the production wells.
Three component solutions constitute gel-forming GALKA systems. Small amounts of additives are used to increase the effect. Gel-forming GALKA systems are low-viscous solutions with pH of 2.5 - 3.0. They are capable to dissolve carbonate minerals of reservoir rocks and to suppress the swelling of clays. One can use water of any salinity to prepare the solutions. Standard equipment is employed to inject GALKA systems via the injection wells into the reservoir. Under reservoir conditions GALKA systems are converted into gels due to reservoir heat energy or that of the injected heat-carrier. The time required for gelation depends on the temperature and component ratio of the gel-forming system. Gelation significantly reduces water permeability of reservoir rock by the factor of 4 - 35. The higher is the initial water saturation and reservoir rock permeability, the greater is the decrease in water permeability.
Pilot tests of gel-forming GALKA systems were carried out in oil fields of West Siberia. They proved economic and technological efficiency of the systems. Thus, the injection of gel-forming GALKA systems into the injection wells in Nivagalskoye, Las-Yeganskoye and Ershovoye oil fields (formation Yu1 with the temperature of 75-95 oC) decreased the water cut in production wells by 10-50%.
Jointly with Stock Companies “AURAT” and “KHIMEKO-GANG” Institute of Petroleum Chemistry RAS organised commercial production of the following solid marketable forms of GALKA system:
GALKA-thermogel-C for reservoir temperature above 70 oC;
GALKA-thermogel-U for reservoir temperature ranging from 40 to 70 oC;
GALKA-thermogel-NT for reservoir temperature ranging from 20 to 40 oC.
Technologies employing GALKA system are industrially used in oil fields of West Siberia; about 200-300 wells are annually treated. Additional oil recovery ranges from 400 to 10, 000 tons per one well treatment. Period of payback is one year.
Prof. Lyubov K. Altunina, Director of the Institute
Dr. Vladimir A. Kuvshinov
Institute of Petroleum Chemistry
3, Akademichesky Avenue, 634021,Tomsk, Russia
Phone: 7(382-2) 491623, 491146, 492411, 491621
Fax: 7(382-2) 491457 E-mail: alk@ipc.tsc.ru & canc@ipc.tsc.ru Internet: http://www.ipc.tsc.ru