Oil production is a strategic business, important investments in infrastructure are performed in order to assure the reliability, quality and safety of the associated electric power system. This issue requires making an accurate forecast of power demand in the medium and long term, to avoid over- or under-investments that would produce economic effects. Conventional methods of forecasting demand for industrial sectors do not consider the variables involved in the process of oil extraction. For that reason, the present article, proposes a comprehensive method to forecast the electric power demand for an oil field in the medium-term. The key drivers of the demand, are parameters related to oil production process, which are directly obtained through field measurements, e.g. oil, gas, and water production volumes. A multiple linear regression method is applicated to forecast the future electricity demand, and it is validated by comparing the results of applying a conventional regression model. Satisfactory results are obtained.