Characterization and CO2 storage capacity analysis of the “lU” reservoir in the oriente basin

Abstract

The objective of this work is to determine the CO2 storage capacity of the Lower “U” reservoir and identify a sealing formation that does not compromise the integrity of the PRH field in the Oriente Basin. Information obtained from drilled wells in the field, such as core analyses, logs, thin sections analyses, and pressure-transient analyses, were utilized to evaluate the petrophysical properties, the reservoir quality, and the reservoir fluids. Also, petrophysical properties were determined by different methods to address the uncertainty in the measurements. All these properties were utilized in the static and dynamic model to understand the behavior of the Lower “U” reservoir under CO2 injection as a mechanism to increase the recovery factor (i.e., enhanced oil recovery (EOR) through CO2 injection). The continuity and adequate CO2 storage capacity of the Lower “U” reservoir were demonstrated. The presence of a sealing formation of ultra-low permeability/porosity (shale, limestone) above the Lower “U” reservoir provides a safe geological storage system for greenhouse gases (GHG). The central area of PRH field has the best characteristics for CO2 injection due to low reservoir pressures. Additionally, the azimuth providing greater stability for the CO2 injection process was determined, preventing the generation of micro-fractures in the Lower “U” and the communication of the sandstone with other formations. The study incorporated existing information from the oil exploration of the PRH field, and various methodologies were applied to determine petrophysical parameters. Characterizing the Lower “U” provided crucial details about the reservoir, fluids, and lithology. The theoretical storage volume for the Lower “U” reservoir was 9.13 million tons of CO2. This work is one the very first to assess the carbon capture and storage (CCS) in the Oriente Basin to reduce the environmental impact of GHG emissions.