A novel in-house technique has been developed for infill well production forecasting for brown fields on primary depletion as an alternative method to forecast production when reservoir simulation models are not available. The paper demonstrates the use of an unconventional approach to forecast infill well performance for a complex carbonate reservoir with fractures and vuggy porosity on primary depletion.
The flow equation was used to determine the initial rates of new development wells and to address expected pressure depletion while a new methodology was developed to take into account well interference. The interference equation takes into account five factors classified as main contributors to well production interference: distance to nearby producers, years on production of existing wells and respective initial rates, presence of faults and density of natural fractures. A correlation between these factors and lost oil volume was established based on historical production data and used to predict the interference of new development wells taking into account their locations. The statistical analysis factored all combinations of potential outcomes for new wells based on historical data and built probabilistic cumulative distribution curve to predict performance of new wells, generating a P10/P50/P90 range of production forecast. Also, a methodology was developed to account for gas and water production, which is also described in the paper.