For The Characteristic Of The Dissolution Of Primary Minerals Related To Clastic Diagenesis Thermodynamics Model And Dissolution Experiment Modeling Effort For Secondary Porosity Forming Mechanisim Of Upper-Palaeozoic, Qrdos Basin

This paper studys the the interactions between solution of primary minerals ofthe reservoir sandstone, the deposition of authigenic mineral, and the formingmechanism of secondary porosity in Upper Paleozoic reservoirs in Ordos basin withthe modeling theory of Water-Rock Interaction, builds the correspondingthermodynamics database and dissolution experiment database, and provides thecomparable and quotative data for the Water-Rock Interaction modeling research ofreservoir rock.For reservoir sandstone, the different of the basic component before embedding,especially primary minerals is the mostly element for controlling the initial porosity,the reconstruct of initial porosity and the growth of secondary porosity. To know moreand better about the basic reservoir sandstone component before embedding in UpperPaleozoic reservoirs in Ordos basin, which is the experiment object for the modelingtheory of Water-Rock Interaction. The author creates the AutomaticallyDiscriminational Model for the Classification of Sandstones System (ADMCSS), thatis to say, people can complete the vastly sample' s classification of sandstonesaccurately and swiftly, meantime, diminish the possibility of mortal mistake.Based on the study of the basic sandstone component before embedding, the typeof authigenic mineral, and the forming mechanism of porosity in Upper Paleozoicreservoirs in Ordos basin, the author selects the reasonable experiment objects forWater-Rock Interaction modeling study, designs the relatively reactant and resultantduring the diagenesis period, builds the solid-liquid thermodynamics model with theprinciple of thermodynamic phase equilibrium for kinds of primary minerals (potashfeldspar, albite, anorthite, and pyroxene, hornblende) which dissolve in acidic media,and forms the corresponding thermodynamics test database. As a result, the author discusses the thermodynamics habitus for the minerals either.With the calculation of the thermodynamics modeling, we run the dissolutionmodeling experiments for primary minerals (potash feldspar, albite, anorthite, andpyroxene, hornblende), which is under the conditions of organic acidic and 20 varietytemperature and pressure. The dissolution modeling experiments include 4 anorthitedissolution experiments, 8 pyroxene dissolution experiments, 8 hornblendedissolution experiments. We catch the records on the X ray diffraction, chemistryanalysis, SEM (Scanning Electron Microscope)photos, and the PH parameters. By theway, we discuss the dissolution habitus for the minerals either.Basing on the result of thermodynamics calculative modeling and dissolutionexperiment modeling, the Geological Significance of Water-Rock InteractionModeling study with acidic dissolution condition has been opened out reasonable. Weprovide the probability of Primary mineral's dissolution for reservoir sandstone inUpper-Palaeozoic reservoirs in Ordos basin, and the relationship between thedissolution progress and the stratum conditions, such as temperature and pressure.Accordingly, the reasonable explanation is revealed for the sediment componentbefore embedding, the deposition of authigenic mineral, and the forming mechanismof secondary porosity. This paper will be the fundamental data on thermodynamicsand chemical experiment study for the reservoir quality prediction.