Formation mechanism of reservoir cement of Yanchang Formation in Ordos Basin and its geological significance
Online published: 2014-04-06
The reservoir of Triassic Yanchang Formation in Ordos Basin generally is characterized by complex composition, low maturity and roundness of rocks and poor physical properties, and belongs to typical ultra-low porosity and low permeability reservoir. Strong cementation and compaction are the main controlling factors for reservoir densing. X-ray diffraction, scanning electron microscopy and polarizing microscope were applied to analyze the distribution, assemblage types and occurrence of cements. Based on the study of modern lake sedimentology, the relationship between deposition and formation fluid composition and clay, carbonate and siliceous cements was discussed. The results show that the sedimentary fluid controls the distribution of detrital clay minerals in the lake basin, controls the conversion from detrital clay minerals to authigenic clay minerals, and controls the formation and distribution carbonate cements. Formation fluid chemical composition provides material basis and specific diagenetic environment for the cementation. This study provides the basis for the qualitative-semiquantitative prediction of favorable diagenetic facies.
XIAN Benzhong , LU Zhiyong , SHE Yuanqi , WANG Xin , WANG Lu , HUANG Handong . Formation mechanism of reservoir cement of Yanchang Formation in Ordos Basin and its geological significance[J]. Lithologic Reservoirs, 2014 , 26(2) : 102 -107 . DOI: 10.3969/j.issn.1673-8926.2014.02.016
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