The Llancanelo Field is located in the northern sector of the Neuquen basin, in the province of Mendoza, 37 km south of the city of Malargüe. Due to the characteristics of reservoirs and reservoir production conditions, it was decided to use oil geochemistry to observe areal and vertical variations of the fluids and quantify the amount of oil that each reservoir contributes to the total production and to correlate this data with the quality and quantity of the reservoirs contacted. For this reason, a selection and geochemical characterization of the samples taken from wells that produce of a single formation was carried out, to compare with the mixtures produced by the rest of the wells. Through the integration of data from reservoirs and geochemistry, we concluded that oil geochemistry is a tool that contributes to the development of reservoirs since it allows to understand the areal and vertical oils characteristics and to know the contribution of each of the zones to the joint production of the wells.