STUDY ON THE LOWER LIMIT OF HYDROCARBON EXPULSION OF MARINE CARBONATE ROCKS

The pyrolysis and hydrous pyrolysis simulating experiments of samples with differentTOC which confected by burned calcite,smectite,limestone and mudstone added into the same organic mat-ters respectively,show that the content of absorpted hydrocarbon by the marine carbonate rock is usually about 0.35 mg/g and the range is 0.2-0.85 mg/g,the content of absorpted hydrocarbon by the shale is usually about 1.25 mg/g and the range is 0.46-2.62 mg/g.The lower limit of total organic carbon(TOC) is about 0.08% for hydrocarbon expulsion of high-to-over mature marine carbonate rock and about 0.3% for mature marine carbonate rock rich in hydrocarbon.The lower limit of total organic car-bon(TOC) for hydrocarbon expulsion is related with the quantity of absorpted hydrocarbon by source rocks,the type of kerogen and the maturity of organic matters.