Improving Injection Efficiency in CCUS Wells: A Comparative Analysis of Different Completion Designs

Abstract

Abstract Global investment has delivered a steadily increasing investment in carbon capture, utilisation, and storage (CCUS) projects for the past years. Such interest moves the petroleum industry from pioneering projects towards multi- and large-scale projects. Industrial-scale CCUS is necessary to meet the demand of climate change initiatives. Numerous subsurface studies have investigated the potential geology for carbon storage and depleted gas reservoirs are considered as appealing targets for carbon dioxide (CO2) sequestration because of their storage capacity, proven sealing capability, reservoir characterization knowledge, existing infrastructure, and potential for enhanced gas recovery. While depleted gas reservoirs are attractive targets for CCUS, the CO2 injection process poses several challenges including extreme cooling due to gas depressurization, a potentially unstable flow regime that has consequences for tubing stress analysis, CO2 deliverability, and reservoir management. Careful well design is critical to answering these challenges. Holistic but practical simulation work is key to ensure that the well is properly designed for all types of operations along its injection lifetime. This paper introduces for the first time, a trifecta of simulation works that links steady-state simulation, transient simulation, and advanced completion stress design. The 1D steady-state and transient analyses would feed into the meshed well-reservoir simulation which enable engineers to investigate the detailed wellbore hydraulics and multiphase flow through advanced completions. These details will be keys as input for analysing the stress and loading simulator. Streamlining these simulations will bridge the communication between the subsurface team and well design team to produce an optimum completion design based on comprehensive analysis. We investigate the behaviour of each of the completion options such as a simple monobore completion, concentric, horizontal wells with inflow control devices and intelligent completion with downhole control valves. The results are then benchmarked to each other with consistency for neutral comparison. Effective CO2 injection entails finding methods for optimising the fluids along the pipeline and the CO2 voidage once the fluids have entered the reservoir drainage. This paper explains a proposed guideline for effective CO2 injection management. We discuss multiple gains and limitations of each completion which cover hydraulics, thermodynamics analysis, material selection, and tubing stress analysis for different scenarios. This paper also discusses phase instability of CO2 transportation within injection systems which can be avoided by maintaining the proposed guidelines.