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广西南丹大厂中泥盆统古油藏固体沥青及其潜在烃源岩——同区泥盆系深水槽盆地相优质泥岩均已达到过成熟热演化阶段,其沥青“A”含量均很低,并且强烈的热改造作用和后期抬升接近地表后可能发生的生物降解作用,严重影响了用沥青“A”中常规生物标志物进行油源研究的准确性。目前固体沥青的来源缺乏直接的分子有机地球化学证据。本文运用了催化加氢热解技术释放古油藏固体沥青及同区中泥盆统深水槽盆地相优质泥岩干酪根大分子上共价键键合的生物标志物,根据催化加氢热解产物中的甾萜类生物标志物的组成特征、正构烷烃的碳同位素值等指标,并结合石油地质背景资料对该古油藏进行了精细的油源对比研究。结果表明南丹大厂中泥盆统古油藏固体沥青应来源于南丹地区中下泥盆统深水槽盆地相优质泥岩。同时本文的研究也表明,催化加氢热解法从干酪根(固体沥青)大分子上获取的以共价键键合的生物标志物能够运用到高-过成熟有机质的烃源对比研究中,生物标志物所包含的反映有机质类型和沉积环境的信息具有良好的原生性,该方法有望为我国南方古生界众多高演化古油藏的烃源研究提供有力手段。
The solid bitumen and its potential source rock of the Middle Devonian paleosol in Nandan Dachang, Guangxi Province, have reached the mature thermal evolution stage, and their bitumen “A” content Are very low, and the strong thermal remodeling effect and the subsequent biodegradation that may occur after uplifting near the surface severely affect the accuracy of oil source studies with conventional biomarkers in bitumen “A”. The current sources of solid bitumen lack direct molecular organic geochemical evidence. In this paper, catalytic hydro-pyrolysis was used to release biomarkers of covalent bonding of solid bitumen in paleo-oil reservoirs and kerogen macromolecules of high-quality mudstone in the middle-deep-basin basin of the Middle Devonian. Based on the catalytic hydrogenation pyrolysis products The composition of sterol biomarkers, the carbon isotope value of n-paraffins and other indicators, and in combination with the petroleum geological background data of the paleo-oil reservoirs conducted a fine oil source comparative study. The results show that the middle-Devonian solid reservoirs in Nandan should be derived from the high-quality mudstone in the middle and lower Devonian deep-sink basins in Nandan area. At the same time, the research in this paper also shows that the covalent-bond biomarkers obtained from kerogen (solid pitch) macromolecules by catalytic hydrogenation pyrolysis can be applied to the comparative study of hydrocarbon sources of high-over mature organic matter, Biomarkers contain good information about organic matter type and sedimentary environment. Therefore, this method is expected to provide a powerful tool for studying the hydrocarbon source of many high-evolution paleo-reservoirs in South Paleozoic in China.