Research on the Accommodation Space Transformation System in the Es32 Member of the Gu'nan Sag in Bay Basin, China

According to the classic sequence stratigraphy concept, the change of the sea level or the accommodation space of the basin is unified. However, based on the analysis and research on the accommodation space, it was found that because of the influences caused by differential basement subsidence, sedimentary process and absolute lake level fluctuation, the changes of the accommodation space in a faulted basin are not unified. The increasing, decreasing, and transformation belt and its 3-dimentional distribution are called the accommodation space transformation system. According to the analysis above, combined with the previous research result, the theoretical model and its components have been analyzed. At the same time, the component and division scheme of the accommodation space transformation have also been expatiated. The Es32 member in Gu'nan sag as the researching object has been divided into a 3rd-order accommodation space transformation system and seven 4th-order transformation systems. Finally, according to the theory of petroleum geology and the vertical sequence characteristics of the transformation belt, the relationship between the transformation belt and the reservoir forming has been discussed. And with the analysis of classical reservoir, it is considered that the transformation belt has controlled the distribution of the oil and gas.