Tight Sandstone Reservoir Microscopic Pore Throat Structure Fine Characterization

With the further development of oil and gas geological theory and methods of exploration and development,unconventional oil and gas resources has become a new luminescent spot of increase of oil and gas production in recent years.In this paper,comprehensive utilization of unconventional testing technology such as maps imaging analysis technology and combined with the conventional analysis methods,which characterized the micro pore throat structure of G3 and G4 of Gaotaizi oil layer in Qijia area.On this basis,the main controlling factors of pore throat structure were clarified,and the microscopic comprehensive classification of the tight sandstone reservoir were established.It is very important to further explore and development of tight sandstone oil in Qijia area.In this paper,of the current fine description means of micro pore throat structure were summarized,and focus on the application of digital core analysis technology,maps imaging analysis technology,constant pressure mercury and other technologies,at the same time,combined with conventional methods such as casting thin sections,the types of reservoirs are discussed from three aspects: pore,throat and microfracture,which focuses on the pore from the cause and the size of the two angles were divided;based on the study of microscopic reservoir space types,the microscopic storage space,microscopic pore throat distribution and microcosmic connectivity of different microscopic scales were compared,the seepage ability of microscopic pore-throat structure in the tight sandstone reservoir is also quantitatively analyzed;finally,the maps imaging analysis technique was used to clarify the microscopic relationship between pore throat and tight oil,the microscopic existing state of tight oil mainly includes bead,vug,flocculent and thin films,the intergranular dissolution pore is the largest,and preliminary determinate micro-pore throat oil lower limit.The tight sandstone reservoir in the study area is controlled by the two factors of sedimentation and diagenesis,the characteristics of three-dimensional pore structure of tight sandstone reservoirs with different physical properties and different sedimentary microfacies are different;mechanical compaction and cementation have a damaging effect on the pore structure of the tight sandstone reservoir,and dissolution plays an important role in the construction.The pore throat structure parameters were combined with sedimentation,diagenesis and brittleness index distribution,on this basis,the micro comprehensive classification of tight sandstone reservoirs in the study area were established,and predicted the distribution of various types of reservoirs with the combination of macro parameters in the plane,the ?,? type reservoir should be next key research direction of tight reservoir.