Quantitative Evaluation Of Hydrocarbon Generation Of Single Maceral And Organic Facies Of Carbonate Rocks

Carbonate rocks has important contribution to the resources of oil and natural gas,in ourcountry carbonate rocks are at high and over mature stage, so in this paper, studied on thethermal simulation experiments of hydrocarbon generation in the semi-closed system onmodern aquatic organisms, Shenfu coal, oil shale, carbonate rocks. Character of hydrocarbongeneration of different organic matter was comparative analyzed, the character ofhydrocarbon generation of organic facies of carbonate rocks in lower Paleozoic of Bohai baybasin was simulated by modern aquatic organisms in similar environment in order toquantitative evaluate the hydrocarbon potential of different organic facies.The results show that the yield of total hydrocarbon of Chlorella and Laminariaincreases first and then decreases with the temperature increases, the maximum value appearsat 350℃, is 345.75mg/g and 198.93mg/g respectively. The yield of oil of dried small shrimpsappears two peaks, the maximum value is 287.35mg/g at 400℃. The yield of totalhydrocarbon of Shenfu coal increases with the temperature increases, the maximum value is68.56mg/g at 500℃. The yield of gas of all samples increases with the temperature increases,the maximum yield of gas of Chlorella, Laminaria, dried small shrimps, oil shale and Shenfucoal is 116.1mL/g, 158.1mL/g,77.5mL/g,104.3mL/g, 99.4mL/g respectively. The gashydrocarbon of Shenfu coal generates mainly after 450℃, the liquid hydrocarbon of othersamples generates mainly in the whole simulation process, and the percentage of the yield ofliquid hydrocarbon in total hydrocarbon much higher than gas hydrocarbon. In threecarbonate rocks, carboniferous mud limestone has certain hydrocarbon potential (27.89mg/g),the hydrocarbon potential of mud limestone of 11 well of Lunnan is lower (15.59mg/g),limestone of 1 well of Mancan almost has no hydrocarbon potential.Gas chromatography analysis indicates that H₂ accounts for most in the gas products of modern aquatic organisms at 250⁴00℃, the gas product of Shenfu coal is mainly with H₂ at300³50℃. The content of H₂ is similar to CH₄ in the gas products of Chlorella andLaminaria at 400⁵00℃, the content of H₂ in the gas product of Shenfu coal is similar to CH₄at 250℃. The gas products of dried small shrimps and Shenfu coal are mainly with CH₄ after400℃, the gas product of oil shaleis mainly with CH₄ at 500℃. The gas products of modernaquatic organisms is mainly with CO₂ at 150℃, CO₂ accounts for most in the gas products ofcarbonate rocks at 500℃. The ultimate analysis shows that the changes of the content ofC,H,O in the solid residues of modern aquatic organisms can be divided into roomtemperature¹50℃and 150⁴50℃two stages, the changes of the content of C,H,O in thesolid residues of Shenfu coal and oil shale is not obvious. Infrared spectrum analysis displaysthat oxygen functional groups and lipid carbon are removed in the process of thermalsimulation of hydrocarbon generation.The yield of total hydrocarbon of closed flow sea organic phase is highest(418.1mg/g·TOC)in the the five organic facies of carbonate rocks, open sea organic phasetakes the second place, marl flat organic phase is similar to Yun-flat, the yield of totalhydrocarbon of shoal organic phase is lowest(268.1 mg/g·TOC). The yield of gas of open seaorganic phase is highest(176.6mL/g·TOC) in the five organic facies, Yun-flat organic phase isslightly higher than marl flat organic phase, closed flow sea is the fourth, the yield of gas ofshoal organic phase is lowest(133.3mL/g·TOC).