Release:
2024. Vol. 10. № 4 (40)About the authors:
Maxim I. Zagidullin, Chief Specialist, Tyumen Petroleum Research Center, Tyumen, Russia; mizagidullin2@tnnc.rosneft.ru, https://orcid.org/0009-0009-7854-9320Abstract:
Numerous bitumen occurrences are widely developed on the territory of the Siberian platform, some of which are not infrequently associated with oil and gas condensate deposits. Bitumen accumulations from small inclusions to large zones in reservoirs negatively affect the filtration-capacitance properties of the rock and have low productivity during well testing. This paper studies the selection of optimal solvent and extraction time for removal of mobile oil hydrocarbons and maximum possible preservation of bitumen in the pore space, as well as the estimation of bitumen content in core samples by pyrolytic method before and after extraction. The object of research is rocks of oil-saturated formation B1 of one of the fields of Eastern Siberia. Using the pyrolytic method and visual inspection, core pieces with preserved saturation were selected from the maximum bituminous-saturated zone. Extraction was carried out on crushed rock in 8 different solvents from 1 to 72 hours. Based on the results of the extraction of crushed rock, 2 solvents were chosen for gentle extraction of samples — hexane and petroleum ether — and 2 solvents for complete extraction of samples — toluene and chloroform. The next step involved the extraction of samples: 2 bitumen-saturated samples and 10 plugs (the sample and plugs were taken from the same sampling site) of the B1 formation, represented by bitumen-saturated dolomite. Studies on core samples were carried out by pyrolytic method, nuclear magnetic resonance (NMR), and gas-volumetric method at preserved saturation and after extraction from 1 hour to 28 days. A full extraction is not necessary to determine the total porosity of bituminised core samples. Porosity can be determined at any time of extraction, even if extraction is not yet complete or only a gentle extraction with bitumen preservation has been carried out.Keywords:
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