层序格架内成岩特征差异及其成因机制

综合利用各项资料,结合孔隙演化定量研究方法,对层序格架内成岩特征差异及成因机制进行研究。结果表明:层序格架内成岩特征差异包括层序界面和层序单元两个方面;层序界面对胶结作用和溶蚀作用控制较强,界面附近胶结物含量一般更高,部分层序界面附近溶蚀强度更大;层序单元方面,受层序演化控制,不同单元沉积环境、沉积物特征不同,经历相同的成岩过程后,其压实、胶结、溶蚀作用强度不同;对于压实作用,早期海侵前滨砂岩和早期高位过渡带砂岩强度较高,而晚期海侵临滨砂岩程度较弱;对于胶结作用,早期高位过渡带砂岩、早期海侵前滨砂岩、晚期海侵临滨砂岩胶结强度依次减弱;对于溶蚀作用,早期海侵前滨砂岩、晚期海侵临滨砂岩、早期高位过渡带砂岩强度依次增强。

Sequence stratigraphy 's control on diagenesis and its mechanisms

With a comprehensive use of multiple data and calculation method of porosity evolution, the mechanisms and differences in diagenesis characteristics of sequence stratigraphy framework were studied. The results show that the differences in diagenesis include sequence boundary level and sequence unit level. Sequence boundary has strong effects on cementation and dissolution. Compared with the sequence unit, the content of cements and degree of dissolution near sequence boundary are significantly higher. For the sequence units, the sequence framework controls the sedimentary environment and characteristics of the sediments. After diagenesis, the strength of compaction, cementation and dissolution of each sequence unit may be different. For compaction, the sequence framework controls the characteristics of the sediments, such as grain sorting and composition. The strength of compaction of early transgressive system tract (E-TST) and early high stand system tract (E-HST) is higher than late transgressive system tract (L-TST). For cementation, the sequence framework controls the geochemical characteristics of the pore water, the source of calcium and the distribution of feldspar, and the content of cements of E-HST, E-TST and L-TST decreased in sequence. For dissolution, the sequence framework controls the geochemical characteristics of the pore water and the source of cements, and the degree of dissolution of L-TST, E-TST and E-HST increases in sequence.