THE POTENTIAL OF GENERATING HEAVY OIL AND SOLID BITUMEN OF EXCELLENT MARINE SOURCE ROCKS

It is concluded that excellent marine source rocks have the great potential of generating heavy oil and solid bitumen,by combining the results of a great deal thermal pressure hydrocarbon generation and expulsion simulating experiments of marine source rocks,pelagic algae and benthic algae with the reservoir solid bitumen and their characteristics in marine carbonate rock in Southern China.The main evidences are as follows:(1) Thermal pressure simulating experiments of oil generation of the pelagic algae as the main hydrocarbon generation organism in marine source rock show that the maximum yield of oil appears at the early mature stages(R_o=0.45%-0.7%),a great quantity of heavy oil with asphaltene and non-being dominant can be generated at this stage,and the peak value of yield per ton TOC can reach to 1 000 kg.The heavy oil is the main component of forming solid bitumen in reservoirs.(2) Immature excellent marine source rock(type Ⅰ-Ⅱ₁ kerogen and TOC2%) can also generate a mass of heavy oil dominated by asphaltene and non-hydrocarbons at early mature stage.The total oil yield per ton TOC can reach to 300 kg,which accounts for about 50% maximum oil yield and 40% of the total hydrocarbon yield.The total yield of heavy oil gradually decreases following the kerogen type becoming poor,the organic matter content decreasing(TOC2.0%) and the carbonte content(5%) reducing.(3) The heavy oils generated from the excellent marine source rock at the early mature stage and the suspending organic matters moving out at the penecontemporaneous to early diagenesis in the Permian and Silurian stratums in Southern China,can form lots of soild bitumens by later burial and high tempe-rature cracking and polymerization.