Geological and Engineering Effects on Bottom Water Flow in Volcanic Reservoirs

Volcanic rocks are rich in high-quality oil and gas and represent a key future exploration target. However, bottom water coning in complex reservoirs severely reduces extraction efficiency. This study uses numerical simulation to analyze how permeability, oil layer thickness, interlayers, and horizontal well parameters affect water coning. Results indicate that a permeability ratio of 0.02 delays water breakthrough and increases displacement efficiency by 20%. An oil–water volume ratio of 20 improves displacement efficiency and stabilizes water cut rise. Recovery increases by 15% when the oil layer exceeds 25 m in thickness, with coning expanding significantly at 35 m. A 200 m interlayer can reduce water cut rise by 30%. Optimal well spacing of 300–400 m increases recovery by 10–15%, while a horizontal section of 300–500 m improves reserve recovery. Placing the well 35 m from the top of the layer slows water cut rise.