Characterization of Reservoir Properties Calibrating with Production Data for Carbon Capture and Storage in the Depleted Gas Reservoirs - An Integrated Assisted History Matching Approach for Reservoir Simulation

Abstract

Abstract One of a key responsibility for oil and gas industry is to ensure the balance between energy sustainability and minimizing the net carbon footprint to the environment. PTTEP, Thai national oil and gas company, has aligned this goal to achieve net zero greenhouse gas emission in 2050. Therefore, the scope of this project is to utilize carbon capture and storage (CCS) technology by injecting CO2 into the depleted reservoirs in the Gulf of Thailand. To evaluate the feasibility of the project, the simulation model was required to mimic the physics behaviors, including free gas structural storage, residual trapping, soluble gas in water and mineralization, when the CO2 was injected into many layers of depleted reservoirs. This is to obtain the optimized scenario for CO2 injection. However, the key step for reservoir simulation is the history matching by calibrating the model with production data. First, the static model was built by integrating geological understanding, well data, logging data and petrophysical interpretation, core data, and quantitative interpretation (QI) from seismic data. Then, the subsurface uncertainties were captured and transferred to dynamic model for history matching step. The sensitivity analysis was performed to understand causes and effects and determine the significant uncertain parameters. Then, the assisted history matching was performed to explore the possible solutions using evolutionary algorithm. Lastly, multiple realizations of history matching solutions were obtained. From sensitivity analysis, the key parameters to be calibrated with production data and routine shut-in bottomhole surveys are gas-water contacts, porosity and permeability correlation and relative permeability endpoint parameters. From history matching solutions, we narrowed down the range of uncertainty of uncertain parameters during history matching. The pressure, gas and water production could be matched. Obtaining the calibrated model from history matching is the critical step because this will determine the feasibility of the project in terms of injection strategy and CO2 storage volume. This study was the first history matching task performed for Thailand CCS project. The practical and robust history matching workflow used in this CCS project could be set as a milestone and provides the guideline how to implement assisted history matching technique for any future CCS projects.