Enhanced CO2 storage capacity of Sleipner field by introducing a new injection method inspired from EOR methods

Abstract

Carbon capture and storage (CCS) -Capturing CO2 released from industrial sources and storing it underground in deep geological layers- is a top priority to contribute significantly to the reduction of atmospheric emissions of greenhouse gases [1]. Basically, by storing CO2 underground, the carbon released through oil, gas and coal is returned back to where it was originated. This allows us to continue fossil fuel supply by the current consumption rate for decades.

Among all CO2 storage sites in the world, Sleipner field is selected as the candidate storage site for this study. This is because of availability of both seismic data and well measurements such as pressure and injection rate. In addition, the Sleipner reservoir pressure and temperature are not far from the critical point and the effects of a designed injected stream can be observed with small variations in injection parameters. Existing compositional models for the Utsira formation where the CO2 is currently injected for the purpose of storage will be used to simulate the mentioned techniques.

Providing the safe and long term storage requires the ability to combine reservoir characterization, monitoring technology, smart wells and innovative flooding techniques in cross-disciplinary reservoir management projects [2].The purpose of this study is to apply the reservoir management techniques that are implemented in production of oil and gas reserves to the practice of CO2 storage in saline aquifers.

We propose a new injection strategy called LAG injection inspired from WAG injection that distribute CO2 plume distribution equally through the aquifer and consequently improve storage capacity and sweep efficiency. Combination of this new injection pattern with different well configurations, different cyclic alternating injection time, and simultaneous LAG injection can enhance storage capacity dramatically. The best cases show considerable increment of 81 % in storage capacity and 70 % in sweep efficiency dramatically.