(A) Microscopic view of pores (blue areas) from the limestone reservoir rock at Aneth field;
(B) schematic microscopic view of pores containing water (brine) and unproduced oil;
(C) same diagram, now showing injected CO2 and now-mobile oil mixed with CO2;
(D) carbon dioxide stored as a gaseous state and dissolved in brine.
Graphics courtesy of Utah Geological Survey