Study On Regional Sedimentary Facies And Reserviors Of Ordovician Carbonate Rocks, Lunnan Palaeo-uplift

Under the guidance of new principles and methods of modern Carbonate Petrology, Sedimentology, Reservoir Geology and Diagenesis, this thesis has taken the sedimentary facies and diagenesis as the main targets of the study and has carried out detailed research work on formation correlation, petrological characteristics, depositional environments, sedimentary characteristics and reservoir diagenesis of the Ordovician carbonate rocks.Based on the core, slice observation, geology logging, log and seismic data from more than 15 typical wells, combined with the data of the adjoining area, through macroscopical and microcosmic study and according to the analysis of the kinds and characteristics of the rock components, four types of the sedimentary facies of the study area have been recognized, including Carbonate Platform, Continental-shelf, Slope and Basin. Furthermore, sunken platform, open-shelf and rimmed-shelf have been recognized for the first time. In terms of the analysis on the sedimentary facies and depositional environments of typical and connecting wells in different areas and facies belts, together with the Ordovician tectonic evolution characteristics of the Palaeo-uplift, the distribution and evolution for each Formation of the study area have been clearly discovered both vertically and laterally by means of the combination of the dominant and special facies. Many advanced analysis measures, including electron microscope, electronic probe, inclusion and so on, have been applied to the diagenesis study. The controlling diageneses to the development and evolution of the reservoirs, such as cementation, corrosion, tectonic and karstification have been studied. The establishment of models for reservoir diagenesis and pore evolution occurred reasonably as a result. According to the analyses on the predominant factors in the development of the reservoirs, general evaluation and prediction of favorable reservoir belts have been produced, so that more scientific, reliable and direct geologic evidences are available during the process of further exploration for oil-gas pools with great reserves and production and favorable targets in Ordovician carbonate rocks, Lunnan Palaeo-uplift.