Abstract:

Abstract: Boxshaped variation curves of dissolution rates of carbonate rocks in CO₂ aqueous solution were obtained from simulated dissolution experiments designed with simultaneously changing temperature and pressure. It shows that the dissolution of carbonate samples increases with rising temperature from the very beginning and then forms a boxlike plateau when the temperature reaches 60~120℃ and pressure reaches 13~31 MPa. The curves indicate that the dissolution rate of carbonate rocks in CO₂ aqueous solution remains high within a certain burial depth range (the socalled dissolution window) of the carbonate rocks. When the depth is beyond the upper bound of the range, the dissolution rate declines rapidly and reaches the lowest point (only a little bit higher than that at room temperature) at the depth of about 4 000 meters（150℃，41 MPa）. The experiment and its results bear great significances for a better understanding of carbonate reservoirs and a more accurate prediction of favorable exploration targets.