CAJ | 학술논문

在限定体系(密封金管-高压釜体系)下,采用珠江口盆地下渐新统恩平组低成熟度碳质泥页岩全岩及分离干酪根样品进行了生烃热模拟实验。在24.1 MPa压力条件下,以20℃/h (373.5~525.0℃)和2℃/h (343.0~489.2℃)升温速率实验测定了气态烃类的生成量和化学组成。实验结果采用Kinetics 05生烃动力学软件模拟获得了有机质裂解生成甲烷及同系物等气态烃形成的动力学参数。结果表明,泥页岩不同升温速率(2℃/h和20℃/h)有机质热裂解过程中,相同温度下,全岩样品的气态烃产量和C2-C4等重烃气体的转化率明显低于干酪根样品,但两者的甲烷转化率相近。全岩及干酪根具有相似的甲烷、乙烷、丙烷及丁烷的活化能分布(52×4.1840~64×4.1840 kJ/mol)。干酪根的分离对动力学参数几乎没有影响。对比表明,干酪根热解生气的两个温度段为：135.0~165.0℃和165.0~190.0℃,液态烃二次裂解生气的两个温度段为：190.0~225.0℃和225.0~260.0℃。热模拟晚期阶段重烃产量降低和甲烷产量的持续增加与早期形成的高碳数烃类分解有关。应用动力学方法外推到珠江口盆地的地质条件,表明珠江口盆地在约19.6 Ma干酪根开始裂解生气,目前仍处于干酪根裂解生气阶段。
재한정체계(밀봉금관-고압부체계)하,채용주강구분지하점신통은평조저성숙도탄질니혈암전암급분리간락근양품진행료생경열모의실험。재24.1 MPa압력조건하,이20℃/h (373.5~525.0℃)화2℃/h (343.0~489.2℃)승온속솔실험측정료기태경류적생성량화화학조성。실험결과채용Kinetics 05생경동역학연건모의획득료유궤질렬해생성갑완급동계물등기태경형성적동역학삼수。결과표명,니혈암불동승온속솔(2℃/h화20℃/h)유궤질열렬해과정중,상동온도하,전암양품적기태경산량화C2-C4등중경기체적전화솔명현저우간락근양품,단량자적갑완전화솔상근。전암급간락근구유상사적갑완、을완、병완급정완적활화능분포(52×4.1840~64×4.1840 kJ/mol)。간락근적분리대동역학삼수궤호몰유영향。대비표명,간락근열해생기적량개온도단위：135.0~165.0℃화165.0~190.0℃,액태경이차렬해생기적량개온도단위：190.0~225.0℃화225.0~260.0℃。열모의만기계단중경산량강저화갑완산량적지속증가여조기형성적고탄수경류분해유관。응용동역학방법외추도주강구분지적지질조건,표명주강구분지재약19.6 Ma간락근개시렬해생기,목전잉처우간락근렬해생기계단。
Pyrolysis experiments were performed in a closed system of sealed gold tube using both whole rock and its kerogen separated from the low maturity carboniferous shale of the Lower Oligocene Enping Formation in the Pearl River Mouth Basin, China. The pyrolysis temperatures range from 373.5 to 525.0 ℃ and from 343.0 to 489.2 ℃ with heating rate of 20 ℃/h and 2 ℃/h, respectively. The pyrolysis pressure keeps constant at 24.1 MPa. The gaseous hydrocarbons released in pyrolysis have been analyzed for their yields and chemical compositions. The simulation data were used to calculate kinetic parameters (activation energy distribution and pre-exponential factor) in the generation of gaseous hydrocarbons by software Kinetics 05. The results showed that the yields of CH4 from whole rock and its kerogen continually increase with increasing heating temperatures. Whereas, the yields of C2H6, C3H8 and C4H10 firstly increased at the early stage of kerogen cracking but decreased thereafter. The whole rock shows significantly lower yields of gaseous hydrocarbons and lower conversion rate of C2-C4 than its kerogen at the same temperature. But whole rock showed conversion rate of CH4 similar to its kerogen. At the same temperatures, the yields and conversion rate of gaseous hydrocarbons at the heating rate of 2 ℃/h are higher than those at the heating rate of 20 ℃/h. Whole rock and its kerogen show similar distributions of activation energies in the generation of CH4, C2H6, C3H8 and C4H10, ranging from 52×4.1840 kJ/mol to 64×4.1840 kJ/mol. Hydrocarbon generation kinetics of shale and its kerogen show that gaseous hydrocarbon is formed by kerogen cracking at two temperature intervals of 135.0-165.0 ℃ and 165.0-190.0 ℃, respectively. Similarly, gaseous hydrocarbon is formed by cracking of liquid hydrocarbon at two temperature intervals of 190.0-225.0 ℃and 225.0-260.0 ℃. The continuous increase of the yield of methane is accompanied by the decrease of heavy hydrocarbons at the late stage of pyrolysis. It could be related to the decomposition of high carbon number hydrocarbons that are generated at the early stage of hydrocarbon generation. The kinetic parameters of gaseous hydrocarbon generation had been extrapolated to the geological conditions of the Pearl River Mouth Basin. It suggests that the Pearl River Mouth Basin started to generate gaseous hydrocarbon by kerogen cracking at ca. 19.6 Ma, and it is currently at the stage of kerogen cracking.