Predicting Oilfield Productivity Under Two-Phase Flow Conditions in Fishbone Wells

The seepage mechanism of fishbone wells is complex and it is difficult to accurately predict productvity. Most of the existing productivity prediction models are based on single-phase seepage theory and have limited applicable conditions. In order to accurately predict fishbone well productivity under oil-water two phase seepaging conditions, this paper first deduces the calculation method of oil-water distribution in the near-wellbore region of fishbone wells based on the tubing method combined with the micro-unit idea and the principle of potential superposition. Then, the mathematical models of reservoir seepage and wellbore flow are established. By considering the varying mass flow in the wellbore and the interference between different producing segments of branched wells, semi-analytical models for coupling reservoir seepage and wellbore flow are constructed to predict oil-water two phase productivity of fishbone wells. The calculation results of the established model are compared with numerical simulation results using field parameters from an actual block, and the error is within 10%.