Controls on Production in the Chicontepec Oil-Bearing Reservoirs, Mexico

The siliciclastic, oil-bearing Chicontepec reservoirs contain 33% of Mexico’s total reserves, representing the largest oil accumulation in Mexico associated with a single producing play. Oil production from these typically describes low-rates and high-declination profiles, resulting in poor-recovery efficiencies. Despite these reservoirs have been subjected to unprecedented financial inversions and an intense operative strategy, their total crude-oil output is underperforming compared to the estimated production projections. Total cumulative production (oil and gas) of Chicontepec reservoirs has only reached 0.4% of its oil originally in place (OOIP). The principle aim of this thesis is to provide with experimental evidence and tools to increase the level of understanding of the Chicontepec reservoirs with a particular focus on their oil productivity. A study area within the Chicontepec basin was selected. This consisted of two oilfields with sufficient information to allow a comprehensive investigation. The objective has been addressed by combining descriptive, analytical, experimental and numerical approaches. The controls on oil production in the Chicontepec reservoirs have been analysed in this work by integrating: 1) descriptive studies of the reservoir rock to try to understand the origin of their low-permeability; 2) measured-rock attributes and well-log analysis to evaluate their petrophysical properties; 3) experimental tests to examine rock-fluid interactions and existence of formation damage; 4) reservoir modelling to assess heterogeneity; and 5) simulation case studies to investigate oil recovery efficiencies. Exploiting the Chicontepec reservoirs has been challenging, particularly for their extreme-heterogeneity, their low-transmissivity capacity and the poor-recovery potential of its drive mechanism. The analytical information and experimental results reported in this work intends to contribute in improving the understanding of the variables that control the oil productivity in these reservoirs.