In this paper, we analyze the environment and the dynamics of the Black-Scholes model starting from a stochastic differential equation that explains the evolution of the future prices of an asset. With these defined guidelines, the data obtained by the daily closing prices between June 2013 and June 2016 of the shares of Ecopetrol and Pacific Exploration are normalized, by means of a Box-Cox transformation, to determine the volatility of each of them and apply this model to calculate the value of the asset with fixed time, and thus determine which of the two oil companies have a lower risk at the time of investing.