Characteristics and Main Controlling Factors of Source Rock in Cambrian Yuertus Formation in Aksu Area, Tarim Basin

According to previous research, Cambrian Yuertus source rocks is considered to be an important source rocks in the Tarim Basin, which was affected by upwelling and deposited on the ramp platform facies. But the latest analysis of field reconnaissance and experimental results showed that Yuertus source rocks should be divided into two sections. Chert and mudstone are the main component of the lower section source rocks, Chert formation is influenced by the bottom of the hydrothermal which have been confirmed by trace element analysis, we believed that the source rocks formed in the restricted platform facies, and affected by the bottom hydrothermal; organic carbon content is relatively high, and average more than 5% in this section; kerogen carbon isotope ratios are mainly distributed in the -37‰∼-34‰.The main lithology of the upper source rock section was the shale interbedded with limestone, the sedimentary environment of the upper source rocks section is the slope basin facies, and controlled by the upwelling; total organic carbon content is relatively low, with an average of about 1% in this section; and kerogen carbon isotope ratios are mainly distributed in the-36‰∼-33‰, relative to the lower source rocks is more enriched ¹³C. Thus, the two sets of source rocks sedimentary environment and formation mechanism is completely different, we believe that the deposition process of Yuertus is complicated, so we should give full consideration about the main factors of the development of two sets of source rocks when predicting the distribution of Yuertus Formation source rocks.