Abstract
Maintaining wellbore integrity throughout the life of a well has become a major concern for production optimization. Corrosion logs are mainly run to investigate and inspect the casing integrity and corrosion severity. In this paper, we will discuss a case study for well integrity monitoring for a specific case, where the focus of monitoring integrity was on a miscible CO2-EOR pilot to evaluate and understand the effect of miscible supercritical CO2 flood on the down-hole well equipment, the effect of CO2 on various designed materials, the Impacts of corrosion inhibitor on well metallurgy in a CO2 environment, Integration of differently data sourced in forecasting and therefore designing mitigation plans of zones that could be potentially negatively impacted, perforation design and optimizing for well performance, and down-hole completion accessories and logging portfolio selection.
The case study comprises three wells drilled vertically; a number of mechanical and electromagnetic wire-line logging tools were deployed to investigate the integrity of the wells.
Cement bond integrity was evaluated prior to injection of supercritical CO2 into the reservoir in order to ensure correct cement placement and protection was in place for adequate mechanical support for the casing, to safeguard against fluid corrosion, and to isolate permeable zones at different pressures to avoid hydraulic communication.
Another approach was targeted to better understand the area presumed to be affected early by the flood by assessing the open hole data conventional logging technologies to determine the permeability contrast of the reservoir in order to predict the CO2 flow path and entry points.
The paper will expound some important lessons learnt were derived from this case study and the critical data needed to provide understanding of the EOR flood behavior that can be used as indicators for mitigation plans and robust design of CO2 impacted wells.
