Natural and Laboratory Oxidation of Low-Organic-Carbon-Content Sediments: Comparison of Chemical Changes in Hydrocarbons
详细信息 查看全文
- 作者：M. Elie ; P. Faure ; R. Michels ; P. Landais ; and L. Griffault
- 刊名：Energy & Fuels
- 出版年：2000
- 出版时间：July 2000
- 年：2000
- 卷：14
- 期：4
- 页码：854 - 861
- 全文大小：107K
- 年卷期：v.14,no.4(July 2000)
- ISSN：1520-5029
文摘
Callovo-Oxfordian argillaceous rocks collected in HTM 102 borehole recently drilled in thenortheast of the Paris Basin (France) have been studied. Several parameters suggest a lowmaturity level of the organic matter. The chloroform soluble material from low-total-organic-carbon-content (ranging between 0.4 and 1%) samples is characterized by the presence ofunsaturated biomarkers. A Callovian sample has been oxidized in a ventilated oven at 60 
Cand 130 C. This sample has also been pre-extracted and then oxidized at 130 C for 64 h. Tovalidate these experiments, the samples have been stored for 3 years. Additional studies on twocuttings, collected from older boreholes drilled in the same geological formation in the Paris Basin,have also been carried out. The chemical changes in the bitumen phase of the Callovo-Oxfordiansediments upon natural alteration and laboratory oxidation are similar in nature and inmagnitude. At 60 C-256 h or for 3 years of storage, the relative abundance of the biomarkersdecreases and the n-alkane distribution is shifted toward low-molecular-weight compounds. Dataclearly show that the effects of oxidation are more pronounced at 130 C-1024 h and for theParis Basin cuttings originating from older boreholes. The gas chromatography-mass spectrometry analyses performed on the aliphatic fraction reveal mature distributions for hopanes andsteranes. The results indicate that the effects of natural oxidation can be simulated in a ventilatedoven. The artificial oxidation of a pre-extracted sample suggests that the kerogen alterationinduces the generation of stable biomarkers. These results demonstrate that core samples undergoa rapid air oxidation, which significantly modifies the geochemical signature of the organic matter.Then, subsequent interpretations concerning the depositional environment, oil-to-source rockcorrelations, or maturity assessment may be affected by the natural oxidation of organic matterduring long-term storage of sediments.
Cand 130 C. This sample has also been pre-extracted and then oxidized at 130 C for 64 h. Tovalidate these experiments, the samples have been stored for 3 years. Additional studies on twocuttings, collected from older boreholes drilled in the same geological formation in the Paris Basin,have also been carried out. The chemical changes in the bitumen phase of the Callovo-Oxfordiansediments upon natural alteration and laboratory oxidation are similar in nature and inmagnitude. At 60 C-256 h or for 3 years of storage, the relative abundance of the biomarkersdecreases and the n-alkane distribution is shifted toward low-molecular-weight compounds. Dataclearly show that the effects of oxidation are more pronounced at 130 C-1024 h and for theParis Basin cuttings originating from older boreholes. The gas chromatography-mass spectrometry analyses performed on the aliphatic fraction reveal mature distributions for hopanes andsteranes. The results indicate that the effects of natural oxidation can be simulated in a ventilatedoven. The artificial oxidation of a pre-extracted sample suggests that the kerogen alterationinduces the generation of stable biomarkers. These results demonstrate that core samples undergoa rapid air oxidation, which significantly modifies the geochemical signature of the organic matter.Then, subsequent interpretations concerning the depositional environment, oil-to-source rockcorrelations, or maturity assessment may be affected by the natural oxidation of organic matterduring long-term storage of sediments.