DISCUSSION ON THE EVALUATION STANDARDS OF CARBONATE SOURCE ROCKS

The prescribed minimum of hydrocarbon expulsion of carbonate is measured to be TOC=0.06%-0.12% through simulating tests, and it is considered that its conception and total organic carbon lower limits of carbonate source rocks are different. The former is the origin character of rocks, not a giving standard. The total organic carbon lower limit of carbonate source rocks is a evaluating standard, and its value can be equal to or more than the prescribed minimum of hydrocarbon expulsion of carb(-onate), but not less than that. By means of the research of richness, type, facies and maturity of organic matter in carbonate source rock, the evaluating standards that carbonate had been considered as typeⅠkerogen have been amended as types Ⅰ, Ⅱ1, Ⅱ2 kerogen, and carbonate source rock has been divided as four types, that is, very good source rock, good source rock, fair source rock and poor source rock. The total organic carbon lower limits of carbonate source rock is 0.2% to 0.4% in immature and mature stages; and 0.1% to (0.25%) in high mature and past mature stages.