深层烃源岩热模拟过程中气态烃产物变化特征――以济阳坳陷沙四段和昌潍坳陷孔二段烃源岩为例

对济阳坳陷沙四段和昌潍坳陷孔二段的泥岩样品进行热模拟实验并对其气态烃产物进行分析后表明，气态烃产率随热模拟温度升高而增大，350℃时开始急剧增大；产物中甲烷含量和C2―C5重烃含量均随模拟温度的升高而增大，C2-C5占C1-C2的比例呈降低趋势。对气态烃的稳定碳同位素进行分析后指出，甲烷碳同位素在350℃之前有所减小，当温度超过350℃后逐渐增大；C1―C4烃类气体碳同位素分布在-24．6‰～-42．6‰之间。还指出济阳坳陷和昌潍坳陷深层烃源岩在进入成熟演化阶段后具有生油气的潜力，但烃源岩的原始有机碳含量对油气的生成量有影响。

EVOLUTION CHARACTERISTICS OF GASEOUS HYDROCARBON DURING THERMAL SIMULATION OF DEEP SOURCE ROCKS

Low mature mudstone from Jiyang depression and Changwei depression have been studied by the thermal simulating experiment. The results show that yield of gaseous hydrocarbon become more and more with increasing simulation temperature and begin increasing rapidly at 350℃. With the simulation thermal heightened, the contents of methane and heavy hydrocarbon are augment and （C2-C5）/（C1- C5） is reducing. Stable carbon isotope analyses display that methane carbon isotope has depressed（350℃ ） and building up exceed 350C. Gaseous carbon isotopic distribution at -24.6‰-42.6‰. The result show that the source rocks can produce oil and gas if they are mature.