Screening and ranking carbon storage sites in Western Egypt

Using advanced proprietary data analysis for fast and accurate screening and ranking, SLB identified potential carbon storage sites for Cherion and its partners, Capricorn Energy and BAPETCO, in Egypt's Western Desert. This solution seeks to reduce the carbon footprint stemming from oil and gas assets by capturing and sequestering 350,000 metric tons of CO₂ and utilizing another 15,000 metric tons annually.

With the vision of being net zero by 2040, it was essential to identify reservoir candidates for CO₂ sequestration within the Western Desert of Egypt. Typically, these formations consist of shallow, gently dipping saline aquifers or depleted hydrocarbon reservoirs under low pressure. However, in this study, none of the reservoirs were depleted of hydrocarbons, and the shallow saline aquifers below 800 m were too tight with no injectivity, making them unsuitable for CO₂ sequestration. Moreover, they were overlaid by a freshwater aquifer.

Faced with these limitations, SLB targeted an ultradeep saline aquifer over 3 km deep, with a virgin pressure surpassing 5,000 psi that was connected to productive hydrocarbon reservoirs. The challenge with this unconventional carbon storage choice is that deep reservoirs are usually highly tilted, surrounded by major faults, and have high salinity. These attributes act against the usual trapping mechanisms for CO₂ sequestration such as structural trapping, residual trapping, and CO₂ solubility.

To develop a viable solution, SLB conducted an integrated study to screen CO₂ storage sites in two fields and 10 reservoirs by performing a full field development plan and simulation. This consisted of three stages: site screening and ranking, site evaluation, and 3D geomechanical simulation. The first phase of screening and ranking applied an innovative approach to screen for ideal subsurface conditions to ensure reliable, economical, and sustainable carbon sequestration. The second phase consisted of static model reconstruction for the reservoirs of interest. This included configuration and subsurface parameter sensitivities, tornado charts, and simulation of the best, base, and worst case scenarios. In the third phase, SLB built a 3D geomechanical model to simulate and optimize injection schemes and CO₂ plume migration, as well as designed and engineered the CO₂ injection wells and surface facilities.

The study concluded that CO₂ can be securely sequestered in ultradeep saline aquifers within the Kharita Formation by implementing a managed sequential injection scheme beginning from the bottom and progressing upward. CO₂ solubility can be optimized by increasing the contact area with saline water and utilizing high pressures to overcome the low solubility in highly saline water. As a result, this project helps Cheiron and its partners, Capricorn Energy and BAPETCO, toward a 2040 net-zero target by capturing and sequestering 350,000 metric tons of CO₂ and utilizing another 15,000 metric tons annually.