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The identification and characterization of the phosphate preservation of the spherical microfossils in the Ediacaran Doushantuo time and the Early Cambrian has long been controversial. Modern artificial simulation experiments of phosphate animal eggs can provide scientific evidence to settle the aforementioned disputes. This experiment simulated environmental changes to observe the early morphological changes of the Bluntnose black bream eggs ( Megalobrama amblycephala). It was found that the eggs can show a different morphology in the phosphate environment and that these eggs exhibited considerable morphological variations under different conditions. Thus, those eggs cannot be ascribed to the same species based only on the features. The experimental results are expected to provide a useful reference for the identification of phosphatized microfossils and provide a more empirical basis for their genesis. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) accumulation models include continuous gas accumulation and staged gas accumulation. However, studied on the geochemical characteristics and indices to evaluate staged accumulation CBM are lacking. This study for the first time obtained the carbon and hydrogen isotopic compositions of methane and ethane generated at different evolution stages using thermal simulation of samples prepared by treating an herbaceous swamp peat at different temperatures. The results showed that the carbon isotopic compositions of methane and ethane were obviously affected by the thermal evolution level of the starting sample, while the hydrogen isotopic compositions were closely related to the maturity of gases. The carbon and hydrogen isotopic compositions of gases generated by coal-forming organic matter with R values from 1.2%, 1.7%, 2.4%, 3.2% and 3.7% to 5.2% were determinated. The relationship between R values and the carbon and hydrogen isotopic compositions of gases generated by coal-forming organic matter at different evolution stages as well as the carbon or hydrogen isotopic relationships between methane and ethane were established. The results provide a scientific basis for studying the genesis of CBM generated at different maturity intervals and understanding the geochemical characteristics of staged accumulation CBM. These results were applied to a case study on CBM from the southern Qinshui basin, and it was found that the CBM accumulated after the Middle Jurassic and was characteristic of staged gas accumulation. This is consistent with the result of geological studies, and further showed that the results of thermal simulation experiments are very important for evaluating the genesis of natural CBM. [ABSTRACT FROM AUTHOR]

Natural gas releasing simulation experiments were carried out in laboratory for researching the gas storage capacity in state of high temperature and high pressure and its gas releasing potential in process of temperature decreasing and decompression. The exiting phase state was studied through measuring gas adsorption of coal and PVT phase calculating of natural gas. Gas volume, gas molecular and isotope compositions in process of temperature decreasing and decompression were measured, natural-gas yields released from the Upper Paleozoic coal strata after later Cretaceous (K3) were calculated and the formation of the reservoir was studied combining with the geological background. The results indicate that natural gas stored in coal has still bigger releasing potential after the uplift of Upper Paleozoic strata. There exists a weak gas supply-effluent equilibrium in the reservoir of Ordos Basin, which is another possible evidence that the Upper Paleozoic gas reservoir may be a deep basin gas reservoir. [ABSTRACT FROM AUTHOR]