Study of Salinity Evol ution of Geofluids during Syngenesis and Diagenesis Using Composition of Carbonate Minerals
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摘要: 以东营凹陷沙四段上部烃源岩为研究对象，利用电子探针微区测试技术，对同生、成岩及成岩期后不同阶段碳酸盐矿物进行了系统分析，揭示出不同古地理位置碳酸盐成分的三种变化情况，即Mg/Ca比值①由高到低，②一直保持很高，成岩期后降低，和③由低到高，反映了不同层段从沉积到成岩直至成岩期后水体或孔隙流体盐度的三种变化历程，进而确定了该凹陷中心区域烃源岩成岩过程中处于高盐度介质环境中，对于分析该区油气生成条件具有重要意义。本文的研究思路和方法对于其它地区的类似工作也有一定借鉴意义。Abstract: Sedimentational/syngenetic(SS),diagenetic(DG) and post-diagenetic(PD) carbonate minerals in the im-mature oil source rocks of the upper part of the Shasi member in Dongying Depression were identified undermicroscope and analyzed by EPMA(electronic probe micro-analysis). Three composition change patterns wereproposed as follows:(1) The Mg/Ca atomic ratio deceases from 0. 9 in the SS carbonate to 0. O1 in the DGone;(2)the Mg/Ca ratio keeps high values in the SS and DG ones，but it becomes very low in the PS ones;and(3) the ratio increase largely from the SS carbonate to the DG ones. According to the relationship betweensalinity of pore-fluids and the Mg/Ca ratio of carbonates,the above patterns were considered as the result ofdifferent environmental evolution histories from the SS to DG，then to PS stages. The salinity of diageneticpore-fluid was. proved very high in the center of the depression,which was believed to have been favorable. tothe generation of immature oil in the area. In addition,the research methods in this paper might be useful forsimilar studies in other areas.
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Key words:
- Dongying depression /
- carbonates generated at different times /
- EPMA /
- Mg/Ca ratio /
- salinity
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[1] 1 Mengo F D,et al. Role of transition-metal catalysis in the formation of natural gas. Nature,1994,368, 536-538
2 Helgeson H C,et al. Petroleum,oil field waters,and authigenic min- eral assemblages, are they in metastable equilibrium in hydrocarbon reservoirs? Geochim Cosmochim. Acta,1993,57:3295-3339
3 吴德云，张国防.盐湖相有机质成烃模拟实验研究.地球化学， 1994,23(增刊):173-181
4 Morrow D W. Diagenesis:Dolomite-partl, The chemistry of dolomitization and dolomite precipitation. Geoscience Canada,1982, 9s5-13
5 Muller G.Wagner F.巴拉顿湖(匈牙利)全新世碳酸盐的演化:对 气候和人类影响的反映，见:马特A.塔克ME主编，现代和古代 湖泊沉积物.贾振远译.北京:地质出版社。1984,44-63
6 徐其俊，吴必豪.江汉盆地q组含盐系中碳酸盐矿物的研究.中国 地质科学院矿床地质研究所刊，北京:地质出版社，1982. 65-71
7 陈瑞君，朱井泉，李任伟等.云南安宁地区晚侏罗纪世含盐系的主 要特点及沉积环境.岩石学报，1993,9C1)f94-104
8 Colson J, Isabelle Cojan. Groundwater dolocretes in a lake-marginal environment, an alternative model for dolocrete formation in conti- nental settings. Sedimentology,1996.43(1):175一188
9 周光甲.陆相块断盆地油气生成的地球化学模式.石油天然气地 质，1992,13(4):359一370
10 洪志华.未、低熟油的地质地球化学特征.见:中国油气地质理论 新进展，北京:石油工业出版社，1995
11 赵澄林，刘孟慧，纪友亮.渤海湾早第三纪断陷盆地含油气岩系 沉积学及沉积相的基本特征.石油学报， 1991.12(2):28--32
12 王秉海，钱凯.胜利油区地质研究与勘探实践.山东东营:石油大 学出版社，1992. 357
113 Melvin J I.Evaporites petroleum and minerals resources. Amster- dam. Elsevier.1991. 556
14 陈致林李素娟，周光甲.八面河油田低成熟原油的生物标志物 特征和油源.石油技术，1989,2:1-" 8
15 Hardie I. A. Perspectives on dolomitization;Critical view of some current views. J Sed Petrol,1987 , 57 ;166一183.
16 Stumn W, Mergan J J. Aquatic Chemistry, Wiley-Interscience, 1981,780
17 Mucci A. Influence of temperature on the composition of magesian calcite overgrowth precipitated from seawater, Geochim Cos- mochim. Acta ,1987 , 51:1977-1984
18 Morse J W , Makenzie F T. Geochemistry of Sedimentary Carbon- ates.New York;Elsevier.1990. 707
19 朱井泉，祝促蓉. Collins L B.西澳大利亚豪特曼群礁复活节岛 群全新世珊瑚礁的海底胶结作用.地质科学，1996,31(3):274 286
20 魏新俊，邵长锋，王饵力等.柴达木盆地西部富钾盐湖物质组分、 沉积特征及形成条件研究.北京:地质出版社，1993. 197
21 张水昌，黄汝昌.盐湖盆地沉积有机质中的脱经基维生素E.沉 积学报，1990.8(1):57-64 -
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