CO2 Injection Well Design Considerations: Completion Design to Injectivity Analysis

Abstract Carbon Capture and Underground Storage (CCUS) has been identified as a viable method for reducing industrially sourced greenhouse gases. In this paper, the methodology and workflow were developed to provide insight on the feasibility of CO2 injection and storage potential in proposed injection well to sustain the target injection rates with proper designed well construction under operating conditions. Inflow Performance Relationships (IPR) and Vertical Lift Performance curves (VLP) were developed for predicting the temperature and pressure profiles from the wellhead to sandface under well operating conditions (injection pressure and temperature, injection rate). CO2 phase envelope was developed by using proposed CO2 stream composition and plugged-in well modeling. Dynamic multiphase transient analysis software was used for wellbore dynamics to predict pressure and temperature of CO2 at the wellhead, as well as CO2 phase behavior in the wellbore during well transient operations. Proper well construction was applied to ensure that CO2 was safely injected into and contained within the targeted injection zone for the protection of drinking water zones by considering well integrity must be maintained during CO2 injection. Developed pressure and temperature profiles from well modeling were superimposed on the CO2 phase envelope for designed CO2 injection rates to evaluate CO2 phase changes within the wellbore during CO2 injection. Understanding the steady-state and transient multiphase flow behavior of CO2 within the wellbore is crucial for appropriate well design and operational risk assessment. In transient analysis, well models were developed to represent start-up, shutdown, and re-start of the CO2 injection during life of the well. Casing and tubing stress analysis was performed on the suitability of the proposed casing and tubing under the injection conditions required and with a given set of safety factors using industry recognized software. This analysis enabled to predict how the well construction will respond to various operational conditions, thus ensuring its reliability over the course of the CCUS project. In this paper, CO2 phase envelope development, well modeling for steady-state and transient analysis in CO2 injection methodologies were combined with proper well construction for designing the wells in CCUS project.