TY - JOUR

T1 - Integrated isotope-geochemical and microbiological studies of groundwaters in oilfields (the Southern Part of the West Siberian Basin)

AU - Novikov, D. A.

AU - Khvashchevskaya, A. A.

AU - Pyriaev, A. N.

AU - Nalivaiko, N. G.

AU - Gosteva, I. A.

AU - Chernykh, A. V.

AU - Maksimova, A. A.

AU - Ryzhkova, S. V.

AU - Pavlova, S. A.

AU - Dultsev, F. F.

N1 - The work was supported by the Ministry of Science and Education of the Russian Federation under Projects No. FWZZ-2022-0014 and No.FSWW-2023-0008; by the Novosibirsk State University under the Priority 2030 Program.

PY - 2024/4

Y1 - 2024/4

N2 - The results of integrated isotope-geochemical and microbiological studies of reservoir waters from oilfields under development in the southern part of the West Siberian petroleum province are reported for the first time. The waters have mainly Cl Na chemistry, with salinity 13–72 g/L TDS, pH between 6.9 and 8.5, and reductive geochemical environment with Eh ranging from − 166.3 to − 90.1 mV. Salinity variations are due to the injection of waters from the Aptian–Albian–Cenomanian aquifer to maintain the reservoir pressure early during the development, and subsequent use of closed-cycle produced water, at increased water cutting of the production well stock. The presence of two main genetic types of groundwaters in the hydrogeological section is revealed: the ancient waters of infiltration genesis, and the waters of sediment genesis. In most of the sampled waters, the δD–δ18O pair indicates climate-induced 4–5‰ 16O depletion prior to burial, combined with later 2–3‰ 18O enrichment during prolonged water–rock interaction. In some water samples, dissolved inorganic carbon is of bacterial origin, as suggested by its isotope composition (δ13CDIC). The waters hotter than 90°Cshow an evident positive δ13CDIC shift to a range of − 8 to + 4‰ VPDB, which is common to thermal water values. The analyzed waters are characterized by lower 87Sr/86Sr ratios than those in the present-day seawater. A substantial Sr input from mantle sources is assumed, manifested up to different degrees in the waters of the studied oilfields. Microorganisms involved in the nitrogen, sulfur, iron, and carbon cycles are detected in the studied water samples. The products of the vital activities of nitrifying, thionic, and sulfate-reducing bacteria are nitric and sulfuric acids, and hydrogen sulfide. The joint action of these microbial groups poses large-scale corrosion risks to the oilfield facilities.

AB - The results of integrated isotope-geochemical and microbiological studies of reservoir waters from oilfields under development in the southern part of the West Siberian petroleum province are reported for the first time. The waters have mainly Cl Na chemistry, with salinity 13–72 g/L TDS, pH between 6.9 and 8.5, and reductive geochemical environment with Eh ranging from − 166.3 to − 90.1 mV. Salinity variations are due to the injection of waters from the Aptian–Albian–Cenomanian aquifer to maintain the reservoir pressure early during the development, and subsequent use of closed-cycle produced water, at increased water cutting of the production well stock. The presence of two main genetic types of groundwaters in the hydrogeological section is revealed: the ancient waters of infiltration genesis, and the waters of sediment genesis. In most of the sampled waters, the δD–δ18O pair indicates climate-induced 4–5‰ 16O depletion prior to burial, combined with later 2–3‰ 18O enrichment during prolonged water–rock interaction. In some water samples, dissolved inorganic carbon is of bacterial origin, as suggested by its isotope composition (δ13CDIC). The waters hotter than 90°Cshow an evident positive δ13CDIC shift to a range of − 8 to + 4‰ VPDB, which is common to thermal water values. The analyzed waters are characterized by lower 87Sr/86Sr ratios than those in the present-day seawater. A substantial Sr input from mantle sources is assumed, manifested up to different degrees in the waters of the studied oilfields. Microorganisms involved in the nitrogen, sulfur, iron, and carbon cycles are detected in the studied water samples. The products of the vital activities of nitrifying, thionic, and sulfate-reducing bacteria are nitric and sulfuric acids, and hydrogen sulfide. The joint action of these microbial groups poses large-scale corrosion risks to the oilfield facilities.

KW - Groundwater

KW - Microbial flora

KW - Oilfield development

KW - West Siberia

KW - δ18O, δD, δ13C, 87Sr/86Sr, and 87Rb/86Sr ratios

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85177803153&origin=inward&txGid=ace635707c65050498bce392e62033c4

UR - https://www.mendeley.com/catalogue/ce5fe9a8-9232-3a62-ae11-ab0df0b18046/

U2 - 10.1007/s40808-023-01887-z

DO - 10.1007/s40808-023-01887-z

M3 - Article

VL - 10

SP - 2113

EP - 2131

JO - Modeling Earth Systems and Environment

JF - Modeling Earth Systems and Environment

SN - 2363-6203

IS - 2

ER -