Controlling factors of order degree of dolomite in carbonate rocks：A case study from Lower Paleozoic in Tahe Oilfield and Triassic in northeastern Sichuan Basin
Online published: 2009-09-16
As an important mineralogical characteristic, the order degree of dolomite is widely used in the study of dolomite formation mechanism and carbonate reservoir research. Based on the X-ray diffraction analysis of Cambrian-Ordovician carbonatite samples in Tahe Oilfield and Triassic carbonatite samples in northeastern Sichuan Basin, the controlling factors of the order degree of dolomite are discussed. The conclusions obtained as follows: ①The order degree of dolomite is related to its crystallinity. For example, the order degree of the dolomite with ethereal and relatively large crystals is higher than that of micritic dolomite. ②The lower the molar percentage of CaCO3 in dolomite is, the higher the order degree of the dolomite is. ③ The order degree of dolomite undergone dolomitization completely is higher than that undergone incompletely dolomitization. ④In all controlling factors, including other mineralogical elements, crystalline temperature is the most important one. For instance, the order degree of dolomite which formed in high temperature is higher than that formed in lowtemperature. As a result, in regard to dolomitization mechanism, the order degree of dolomite associated with penecontemporaneous dolomitization (seepage reflux dolomitization, evaporationpump dolomitization and so on) is low, while the order degree of dolomite connected with burial dolomitization is high and the order degree of dolomite concerned with dorag dolomitization maybe among the above two.
SU Yuping , LI Jian , LIU Yafeng , WEI Jianbo , DENG Zhaoyuan . Controlling factors of order degree of dolomite in carbonate rocks：A case study from Lower Paleozoic in Tahe Oilfield and Triassic in northeastern Sichuan Basin[J]. Lithologic Reservoirs, 2009 , 21(3) : 50 -55 . DOI: 10.3969/j.issn.1673-8926.2009.03.010
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