Integrated Assessment of Mud Volcano–Oil Field Interaction and Production Optimization in Lokbatan Oil Field

The Lokbatan field, located in the Absheron Peninsula, represents an important example of the spatial and genetic association between hydrocarbon reservoirs and active mud volcanism. This study investigates the long-term evolution of Horizon VIII of the Lokbatan field and examines the relationship between reservoir development, production dynamics, and mud volcano activity. Historical production and reservoir data covering 1934–2024 were integrated with documented eruptive events. The dynamics of oil production, water production, liquid production, and gas production, together with gas factor and water cut, were evaluated using Shewhart statistical control charts to identify long-term shifts in the production regime and deviations from established control ranges. The results reveal a pronounced transition from an early stage of intensive hydrocarbon production to a mature stage characterized by strongly depleted production conditions. Oil production reached exceptionally high values during the initial development period but subsequently declined and remained close to or below the lower control limit during the later decades. Liquid and water production also showed a long-term reduction, whereas water cut evolved toward a persistently high, water-dominated production regime, reaching a maximum of 94.9% in 1993 and remaining above 80% during most of the recent development period. Gas production and gas factor exhibited an overall decline, although the gas factor showed an exceptional increase during 1995–1997, reaching 871 m3/t in 1996. The analysis further indicates that intensive hydrocarbon extraction was associated with changes in the frequency and character of mud volcanic eruptions, whereas available monitoring data show no clear short-term abrupt effect of individual eruptions on reservoir pressure or well productivity. The novelty of this study lies in integrating long-term reservoir performance indicators with Shewhart statistical process control and historical mud-volcano activity within a single analytical framework. This approach makes it possible to identify major transitions in the development regime of a mature hydrocarbon field while assessing its interaction with an active mud-volcanic system. The Lokbatan field thus provides a valuable case study of long-term reservoir depletion, increasing water dominance, changing gas behavior, and reservoir–mud volcano interaction in a tectonically active petroleum system.