Study On Clay Minerals Of No.6 Yanchang Layer,Ordos Basin

The study of this paper based on a alrge amount of core samples,well log and mud log date,using the method of mormal rock sections,casting thin sections,scanning electron microscope,X-Ray diffraction,constant-rate mercury injection experiment,porosity measurement experiment,reservoir sensitive experiment,and relative permeability/water displacing oil experiment.The connection between reservoir and clay minerals are summarized,the results can contribute to oil production.In order to total understanding the characteristics of clay minerals in reservoir,the study divided into followed steps.Firstly,learning sedimentary background,provenance system,sedimentary phases and other basic characteristics on the basic of core observing,well logging,mud logging.Secondly,by the methods of micro Polaris cope identifying,mercury penetration experiment,physical porosity measurement experiment,the characteristics of reservoir is learned.Next step is the learning of clay minerals,SEM,XRD,reservoir sensitive experiment,relative permeability/water displacing oil experiment are used.First is characteristics of clay mineral itself,Macroscopic and Microcosmic two parts.For macroscopic viewpoints are composition relations of different kinds of clay minerals,variation trend of clay mineral content,the distribution of different kinds of clay minerals horizontally.The microcosmic viewpoints are occurrence,crystal shapes,contact relation with clastic grains,formation mechanism with diagenesis and sedimentary.Second is the influence to reservoir from clay minerals.Cementation of clay minerals in pore and throat can not only destroy physical porosity but also might protect pore space by prevent the forming of other more damage cements.It also changes the structure of pore,throat and reservoir.During oil production,drilling fluid,mud fluid and other external liquid can react with clay minerals,make them expended,broken,precipitated and lock the throat,low down the permeability hugely.By compareing the date of sepage experiments and clay minerals content among different samples,this thesis studies the control by clay minerals to physical porosity,pore structure,reservior capacity,water sensitive and eventually reservoir productivity.