卟啉的研究现状及其应用

PRESENT RESEARCH SITUATION OF METALLOPORPHYRINS AND THEIR GEOLOGICAL APPLICATIONS

在前人研究资料及作者近年来的研究成果的基础上，综述了卟啉化合物地球化学研究的现状，包括金属卟啉的类型，卟啉的化学结构系列，高度脱链基卟啉和高碳数卟啉等及其它们在沉积物（如油页岩、煤和现代沉积物）中的分布特征和成因机理。指出了今后需要加强研究的领域，如沉积物中新的金属卟啉类型探讨和卟啉化学结构的确定等。文章还综述了卟啉化合物地球化学指标在地质勘探中的应用，如：评价生油岩质量，油源对比，油气运移研究，古沉积环境研究和有机质热成熟度研究等。

In this paper,present research situation of metalloporphyrin geochemistry, including metallo-porphyrin types,chemical structure series of porphyrins,highly dealkylated porphyrins,and highcarbon number porphyrins,and their origins and distributions in sediments(e.g.oil shales , coals andrecent sediments) , was summarized based on the research data from previous scientists and recent re-sults from the authors of this paper. In oil and source rock samples, nickel and vanadyl porphyrinsare the major metalloporphyrin types.Iron porphyrins.however , also exist in oil shales and coals.Copper complex was found in recent soft sediments. Metalloporphyrin distributions in coals are dif-ferent from those in oils, shales and source rocks. So far, only iron , gallium, manganese and nickelporphyrins have been detected in coals, without copper and vanadyl types.Evidences for cobalt andzinc complexes oceurring in sediments were obtained from ICP-MS and probe MS data, etc.,butthey need further confirmation. Geoporphyrins belong mainly to cycloalkanporphyrin and aetiopor-phyrin strueture series.The other three series , di-CAP,Rhodo-Aetio and Rhodo-CAP , are theminor ones.Usually , the carbon numbers of geoporphyrins are from C_(26)-C_(33). Highly dealkylatedporphyrins(HDP,<C_(26) ) and high carbon number porphyins(HCNP,>C_(33) ) with small amounts,however , have been discovered with nickel, copper and vanadyl complexes.The HDP and HCNPhave special geological and geochemical significaces.In the paper ,the authors pointed out that further work on metdlloporphyrin studies should becarried out in some areas , such as finding new metalloporphyrin types in sediments and determiningchemical structures of porphyrins.Applications of porphyri n compounds to geological exploration were summarized in this paper.Porphyrin is an important indicator for estimating source rock. Source rock with a high amount of porphyrin may be a high quality oil-generating rock.In general, samples with type Ⅰ-Ⅱ kerogen contain more porphyrins ,those with type Ⅱ kerogen contain medium amount of porphyrins ,and those with type Ⅲ contain relatively less porphyrins.Porphyrins are stable biomarkers and often used for correlative comparisons between oils; between source rocks; and between oil and source rock.During oil migration , porphyrins in oil may be absorbed by clay minerals;therefore , with in-creasing migrating distance, concentration of porphyrin in oil decreases gradually. In addition , aetio series are less polar than CAPs , and the former migrates faster than the latter , so, the CAP/(CAP+aetio ) ratio is an oil-migrating index. One of the main applieations of porphyrins to geology is the study of palaeo-environment of deposition. Nip/(Nip+V)=Op value is a useful indicator for ma-rine-terrestrial environment determination ,because terrestrial organic matter provides more nickel porphyrins , while marine organic matter produces relatively more vanadyl porphyrins.CAP/(CAP+aetio),average carbon number , minimum carbon number and maximum carbon number of por-phyrins are useful indices for determining maturity of organic matter. With incrcasing maturity , all of these indices decrease.