• 责任者：Duan Wei (Key Laboratory of Tectonics and Petroleum Resources ; Ministry of Education ; China University of Geosciences ; Wuhan 430074 ; China) ; Chen Jinding
• 刊名：Acta Petrolei Sinica
• 出版年：2013
• 卷期：34(6)
• 关键词：超压 ; overpressure ; 成岩作用 ; diagenesis ; 莺歌海盆地 ; Yinggehai Basin
• 页码：p.1049-1059
• 图表：13 illus., 4 tables, 35 refs.
• 分类号：1003
• issnNo：ISSN0253-2697
• isbnNo：CN11-2128/TE

     An obvious overpressure system was found within shallow strata in the Dongfang block of Yinggehai Basin and the burial depth of its top interface increases gradually from the center of the basin to the edge. Based on pyrolysis analyses, biomarkers, petrographic microscopic identification and scanning electron microscopy, the impact of formation overpressure on diagensis was deeply discussed. The result showed that the overpressure does not bring on a recognizable effect on geochemical indicators which reflect the thermal evo- lution stage of organic matter （vitrinite reflectance, pyrolysis peak temperature, production index）, but obviously restricts the transfor- mation of clay minerals and the evolution of hydrocarbon structures because these products vary greatly in concentrations and have a strong effect of cubical expansion. Formation overpressure can delay the mechanical compaction of sandstones, thus effectively save the porosity. Formation overpressure can also decrease the formation of cements by suppressing the transformation of clay minerals, and meanwhile restrain the formation of cements mainly by increasing the solubility of carbonates in a fluid medium. Moreover, reser- voirs in the research region generally contain high CO2, and the solubility of CO2 in geological fluids will increase in an overpressure environment so as to promote corrosion by producing more H ＋ . Besides, the mudstone overpressure can accelerate the discharge of acidic fluids through hydrocarbon generation, which may promote the dissolution of adjacent sandstones in reservoirs and favor the generation of secondary porosity, thus an anomalously high porosity zone develops to form a favorable reservoir.