Analysis of the ordovician carbonate hydrothermal process in tadong area, Xinjiang, China

Abstract

Hydrothermal activity played an important part in the formation of the Ordovician dolostone reservoirs in Tadong area (eastern Tarim Basin). By applying the technologies of thin rock section microscopic identification, cathodoluminescence analysis, carbon and oxygen isotope analysis, trace element, rare earth element analysis, among others, the mineralogical characteristics and geochemical characteristics of the hydrothermal process are studied. It can seen that the Ordovician hydrothermal process has represented by dolomite in various forms in the aspect of petrology and mineralogy. It is mainly composed of medium-megacryst crystalline dirty dolomite and powder-megacryst crystalline cleaner dolomite. The geochemical characteristics are the hydrothermal origin, medium-megacryst crystalline dirty dolomite with lower δ18O value, high Mn-Fe content, and positive Eu anomaly. The powder-megacryst crystalline has cleaner dolomite, with higher δ18O value, the Mn content low, and the negative Eu anomaly. Provide a reference for the Ordovician carbonate in Tadong area oil and gas exploration in the study.