Integrated wellbore cleaning, near-wellbore stimulation, and water–air injection for restoring productivity and enhancing oil recovery in mature oil fields
M.M. Asadov, E.N. Aliyev
https://doi.org/10.65294/gpogc.2026.33
Mature oil fields are commonly characterized by declining production rates, increasing water production, formation damage, near-wellbore plugging, sand accumulation, and decreasing efficiency of conventional reservoir-displacement processes. These factors act at different spatial scales, from the wellbore to the near-wellbore zone and the reservoir, and therefore require complementary technological solutions. This paper presents an integrated technological approach based on three complementary developments: a structured washing fluid for sand-plug removal and wellbore restoration; a piston-pump-driven impact-wave device for near-wellbore stimulation; and an ejector system for generating a water–air mixture without an external gas-supply system. The technologies are considered as sequential components of a unified production-restoration and oil-recovery concept. The first technology restores wellbore accessibility by improving the suspension and transport of sand particles. The second restores reservoir-to-well connectivity by generating pressure waves directed toward the perforated productive interval. The third extends the stimulation effect to the reservoir scale by injecting a water–air mixture to improve oil displacement. Laboratory studies associated with the ejector technology demonstrated final oil-displacement factors of 0.50 for formation water, 0.46 for air, and 0.62 for the water–air mixture. A field test of the impact-wave device increased oil production from 0.4 to 1.0 t/day while water production remained at 6 t/day. The washing-fluid technology was implemented in several production wells affected by sand-plug formation; quantitative production indicators are to be incorporated from the original field records. The integrated concept provides a basis for combining wellbore cleaning, near-wellbore stimulation, and reservoir-scale displacement improvement within a unified strategy for mature oil-field development.