Study on Application of Arps Decline Curves for Gas Production Forecasting in Senegal

Abstract

The purpose of this study is to evaluate the feasibility of using methods for predicting the flow rates of gas wells in fields in Senegal. Accurate forecasting of natural gas production allows you to correctly set the operating mode of wells and design onshore infrastructure. One of the gas fields of Senegal was chosen as the object of study, where deposits were discovered within the exploitation perimeters in the Campanian and Santonian sandstone horizons. Gas formations have high porosity and permeability values, as well as high formation temperatures. Gas well flow rates can be predicted using hydrodynamic models, mathematical models (hyperbolic, etc.) and other methods. This study assessed the possibility of using Arps curves for long-term forecasting of gas flow rate and comparing the forecasting results with actual data. Comparison of Arps curves and actual gas flow rates for wells made it possible to note a discrepancy in the forecast results and actual values of more than 20%. These differences arose for two reasons. Deviations at the initial stage of well operation (6 months), which is associated with the adjustment of the technological operating mode of the well and the establishment of constant parameters of rocks near the wellbore. The second reason is well repairs, which change the properties of rocks near the wellbore. In general, Arps curves of exponential type showed high convergence between predicted and actual values, which makes it possible to use them in predicting the flow rate of gas wells in Senegal.