Geophysical processes and biosphere: article

Аnnotation: In the paper, on the example of the long-term developed offshore oil and gas field Neft Dashlari in the South Caspian Basin (SCB), the influence of seismicity on well flow rate is considered (taking into account the world experience in studying this problem). The analysis is based on field data from 27 wells located in different parts of the structure and exploiting different stratigraphic intervals of the Productive series (PS, Lower Pliocene). Fluid dynamics was studied in connection with the local earthquake on November 25, 2000 (М = 6.7) with the epicenter in the sea, south of the Absheron Peninsula, and the distant Iranian earthquake (М = 6.3), with the epicenter near the southwestern margin of the SCB. Limited data are also provided for other fields of the SCB. The most characteristic feature of fluid dynamics in the period of earthquake preparation is high-contrast and stable fluctuations with extreme maximum and/or minimum values observed for several years before the main shock. In the period immediately before, during and/or after a seismic event (lasting several months) in oil production, as a rule, there is a positive anomaly of different contrast. In general, the studied wells have different sensitivity to the seismotectonic processes occurring in the depths, which is largely due to the spatial heterogeneity of the geological environment (the presence of tectonic faults and block structure of the reservoir, lithofacies variability of rocks, etc.), as well as the properties of the fluids contained in the reservoir (oil, gas and water). An analysis is given of the applied aspect of the problem – the effectiveness of wave methods of reservoir stimulation with purpose to increase oil recovery.