The Research On Ordovician Sedimentology And Reservoir Property Of Leshan～Longnvsi Paleo-uplift In Centre Sichuan Area

Under the guide of the theories and methord of carbonate rock sedimentology, stratigraphy, reservoir geology, geo-chemistry and karstology, researched the sedimentary and reservoir characters, and the formation, evolvement of the paleo-weathering crust as well as the restoration of paleo-geomorphology in Leshan～Longnvsi area, predicted the distribution of the paleo-weathering crust, researched the diagenesis types and their influence,finally predicted and evaluated the favorable exploring blocks.According to the data of outcrops,cores and drilling,then through establishing sedimentary fades profiles in typical areas, divided the facies types into restricted platform,semi-restricted platform,open platform,slope and basin these five types and their sub-facies.through the analysis of thin sections, cathodoluminescene identified the diagenesis types including cementation,compaction and pressure solution,dolomitization,recrystalization , corrosion and structural cracking and so on.Through lithology , routine and special analysis on Ordovician reservoir characteristics,found out the favorable formations are Baota and Nanjinguan formations,the storage spaces were pores,caves and fissures,and the types of reservoir were fissure-pore type and fissure-cave type.further more, explored the controlling factors of reservoir development,which were sedimentary facies,diagenesis and structural cracking,and in which the karstification was the most important diagenesis influencing reservoir development.Using "copying method"restored the Ordovician paleo-geomorphology of the weathering crust before Permian Period,the relief of the paleo-geomorphology was not salient,and clearly presented the characteristic of being "two-high and two-low"and distributed from west to east.the division of karst landform played the crucial role in controlling the development of karst reservoir,and according to the relative depth, divided karst landform into height, slope and depression three paleo-geomorphological units and some subunits.After synthetically analyzing the characters of the paleo-geomorphology,the paleo-current system and paleo-climate, educed the controlling factors of the...