OPC has completed a geochemical study to evaluate the subsurface risk relating to the evolution of CO2 rich fluids through the long term injection and storage of CO2 in the Miocene Sandstone saline aquifers of Texas and Louisiana, Gulf of Mexico.

Image source: Roberts-Ashby et al., 2012

The OPC technical team consisted of a PVT and geochemical specialist, a reservoir simulation engineer and geologist. They performed an integrated project to assess the development and migration of CO2 rich fluids in the Miocene sandstone saline aquifers in the Gulf of Mexico.

The objective of the study was to examine the evolution of reservoir fluid pH in the presence of injected CO2, and how they will evolve interacting with the reservoir mineralogy, and ultimately how the lithology will affect / buffer the pH spatially and temporally away from CO2 injectors. The pH being a critical factor that will dictate well design, as wells are required to be designed to resist the corrosion attributed by low pH fluids.

While it is a given that class VI wells require enhanced metallurgy to ensure integrity over time, near-by monitoring and stratigraphic Class V wells do not have such a requirement. Therefore, being able to reasonably predict the fluid pH in these areas laterally enabled the client to take a view on the level of enhanced well protection. The avoidance of utilising chrome enhanced steel in well design represents a significant cost saving, and therefore the results of the study aided well design and placement, ultimately leading to cost savings in the millions of dollars.

OPC developed a bespoke reservoir simulation-geochemical work flow that integrated multiple simulation technologies to work seamlessly between CMG GEM and T-Navigator. Geochemical analysis was performed in-house using a bespoke geochemical thermodynamic database.

KeyFacts Energy Industry Directory: OPC