Coupled Compositional/Geomechanics Reservoir Simulation of Eocene C-Sup VLG3676, Block VII Ceuta Field, Venezuela: A Case Study

Abstract

The Eocene C-Sup VLG3676 reservoir is one of the most important oil reservoirs of Western Venezuela. It has a high lateral sedimentological heterogeneity, some sand production issues due to low sandstone cohesion and high stress gradients, and asphaltene precipitation problems. All these features have created production problems since the beginning of the reservoir production, with a drastic impact on the reservoir potential. This has lead to the construction of a compositional/geomechanical model in order to design a palliative strategy. The proposed modeling methodology includes nine phases: 1) Development of the 3D mechanical earth model (MEM) to simulate reservoir compaction; 2) Quality control of the static model, including the relative permeability values; 3) Development of a fluid model that predicts the onset of asphaltene precipitation; 4) Development of a rock-fluid interaction model; 5) Initialization and calibration of the compositional model; 6) Coupling of the compositional and geomechanics models; 7) History matching; 8) Analytical estimation of the onset of sand production; 9) Implementation of an opportunity index analysis for asphaltene precipitation and sand production. Based on this compositional/geomechanical model it has been possible to map the risk of asphaltene precipitation and sand production in the reservoir, therefore showing that such problems are critical in the Eocene Misoa C-2-Sup and C-3-Sup stratigraphic units, due to the energy depletion caused by the production. This model allowed optimizing the locations of 35 wells to be drilled. The applied methodology enabled engineers to efficiently estimate the bottomhole flowing pressures and the critical drawdown pressures in the reservoir, identify the most prospective areas of the deposit, and design the trajectories of the new wells. It allowed designing the future Asset Development Plan (ADP) to maximize the hydrocarbon recovery and optimize the resources and investments necessary to increase the reservoir productivity. This paper will go through all the nine phases of the workflow, will highlight their most specific features, and will conclude on the value on such an approach.