The strong pressure dissolution resistance of dolostone is the key to the preservation of deep-ultra-deep carbonate reservoirs in the Longwangmiao Formation. However,it is found that there are great differences in the spatial and temporal distribution of dolostone in the Longwangmiao Formation. In order to improve the distribution prediction of dolostone reservoir in the Longwangmiao Formation,the type and distribution of dolostone,dolomitization mechanism and model have become the key issues to be solved. Based on petrology,sedimentology,sequence stratigraphy and geochemistry,this study focuses on the development and distribution of dolostone in the Longwangmiao Formation,Sichuan Basin. As a result,the following understandings are obtained. Five rock types related to dolostone have been identified in the Longwangmiao Formation,Sichuan Basin. The spatial and temporal distribution of dolostone is controlled by the paleogeomorphology and the sea level fluctuation. The dolostone is mainly distributed in the central Sichuan uplift and the central part of northern Sichuan Basin. The vertical distribution of dolostone is controlled by the coupling of the 3rd order and 4th order sea level change. The 4th order sequence,located in the middle and upper parts of the 3rd order sequence,has high dolomitization degree. The dolomitization fluid in the Longwangmiao Formation is seawater or seawater with a certain degree of evaporation,and three penecontemporaneous dolomitization models are established in the Longwangmiao Formation.
维普
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