The Diagenesis Of Feldspar And Its Effect On Reservoir Property

Ordos basin is an important natural gas exploration,upper palaeozoic strata,the layer reservoir for dense reservoir on the whole,sandstone experienced strong diage-nesis,which is mainly feldspar in the change in the process of diagenesis and its influ-ence on reservoir property.Therefore,it is helpful to know the physical characteristics of Paleozoic reservoir in ordos basin and its reservoir prediction.Most scholars believe that the changes of feldspar in the diagenetic process have been eroded by the dissolution and the dissolution of the granule.The chip for the analysis as the main means,combined cathodoluminescence analysis means such as,scanning electron microscope,the casting thin sections,a new sense of feldspar in the diagenetic process of change,analyzed the feldspar and intergranular dissolved pore,intragranular dissolved pore and pore,combined with the understanding of the distribution of feldspar sandstone in river courses,has carried on the plane to pore types forecast,the main conclusions are as follows:1)different types of feldspar due to differences in morphology,density,has the trend of relatively concentrated distribution in the river,on the whole,at the river bifurc-ation basic plagioclase relative enrichment,in the river straight or endings,alkali feldspar relatively concentration.2)the research district stone occurred in the process of diagenetic diagenesis mainly include the plagioclase carbonatization,kaolinite of plagioclase and alkali feldspar,kaolinite,alkali feldspar yili petrochemical.Feldspar's increased cementation is seen,and the corrosion of feldspar is common.3)through the chemical thermodynamics,chemical reaction mechanism and the chemical equilibrium analysis,combining with dissolved pore morphology and solution pores in the residual carbonate analysis,think solution pores feldspar formed by dissolution,side by side instead of feldspar carbonatization,carbonate dissolution formation.The development of the dissolution pores and the development of intergranular pores are controlled by the diagenetic changes of feldspar.After the carbonation of feldspar carbonate,the carbonate dissolution formed an oversize karst or granule insoluble hole,and kaolinite was formed by the formation of kaolinite and the intergranular pore formed in the kaolinite.4)pore types in the study area is given priority to with intragranular dissolved pore,followed by intergranular pore,intergranular solution pores,intergranular pore and mixed solution pores,among them,the intergranular dissolved pore + intragranular solution pores,intergranular pore,intergranular pore + intergranular dissolved pore and pore types combined the best reservoir property.5)based on the diagenetic process analysis,the diagenetic products of feldspar were predicted by using the taiyuan group in the eastern part of ordos basin as an example.The prediction results show that kaolinite cementation mainly develops in the transition zone of delta plain to the leading edge and the leading edge area of the delta,and the most development of kaolinite at the intersection of the river,followed by the downstream channel.Illite mainly distributes the marginal part of the channel and the end of the channel;The insoluble hole in the granule is mainly developed in the bifur-cation point of the river and is the second in the river.The intergranular pores are mainly developed at the intersection of the river and the straight course of the river.