PSI - Issue 59

Liubov Poberezhna et al. / Procedia Structural Integrity 59 (2024) 739–744 Liubov Poberezhna et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 1. (a) Concentration of corrosive components and (b) corrosion rate of casing tubes in the produced waters of the Karaykoziv field.

The results of the corrosion tests showed an increase in the corrosion rate with increasing temperature in environments 1, 2, 4, and 5. In environments 3 and 6, we see an inverse relationship, namely, a decrease in the corrosion rate with increasing temperature (Fig. 1, b). Most likely, the decrease in the corrosion rate is associated with a decrease in the solubility of CO 2 and the beginning of the decomposition of bicarbonates with their transformation into carbonates (Kontsevoi, 2023). The highest corrosion rates were observed in probes 3 and 6, reaching up to 3.5 mm/year. Considering the casing wall thickness of 6-14 mm, we can assume high risks of penetration damages and leakage of technological fluids after 3-5 years of service. Environmental risk estimation. The main factors that can lead to pollution of surface and underground water during the operation of wells of the Karaykoziv deposit are as follows:  Penetration of surface pollutants due to the violation of the tightness of the column and extra-column space of the wells;  Flows of deep reservoir fluids into aquifers in emergencies at wells. When arranging the existing wells of the deposit, the following measures should be taken to prevent and reduce the negative impact on water bodies:  The descent of the direction to create a binding for circulation and to prevent erosion of the mouths of wells; covering of unstable deposits and isolation of groundwater from contamination by drilling mud filtrate during drilling under the conductor;  The descent of the conductor to cover the upper aquifers and protect them from contamination by drilling mud filtrate;  Cementation of casing columns of wells with the raising of plugging solution to the mouth in order to prevent the migration of groundwater and reservoir fluids;  A collection of associated reservoir waters in a special container with their subsequent return to the reservoir (Price, 2003; Pierce, 2009, Davarpanah, 2022). Protection of surface water from pollution can be achieved by drainage of rainwater from the object due to the relief and drainage organization and installation of hardcover in the mouth part of the wells. According to the proposed methodology map of environmental impact of the petroleum production processes was created (Fig. 2).