Study On Fracture Reservoir Of Carboniferous Pyroclastic Rock In Sul3 Block Of Junggar Basin

Junggar Basin is a large compressional composite superimposed basin,and the study area is located in the northwest margin of Junggar Basin.The lithology is mainly tuff,tuffaceous sandstone and tuffaceous mudstone,and the fractures and pores are the main reservoirs,belonging to the fractured reservoirs in structural oil and gas reservoirs.This study by restricting Sue 13 wellblock are faced with the problem of exploration and development,the integrated use of lithology,well logging,mud logging,geology and seismic data,combined with the petrology,structural geology,logging geology,reservoir geology and related theory,car row son bump Sue 13 pieces for the stratigraphic lithology identification and classification,combined with the pattern of fracture structure,fracture identification work by logging data,and discusses the factors of fracture development,using the seismic data section and plane fissure prediction,make the distribution of the surface cracks arbitrary time slice,provide the basis for the next step prospecting work.Through the study of fault structure,it is found that there are large thrust faults in the region,which are cut by many faults to form many complex fault blocks,and the high Angle faults are relatively developed in the region,which can be divided into three grades according to the size of fault distance.Through the discriminant method of identifying fractures by logging curves,it can be found that the log curves of the interval where fractures may develop are mainly manifested as the sudden increase of acoustic time difference,the decrease of density and the increase of neutron porosity,the negative anomaly of spontaneous potential,the decrease of resistivity and the separation trend of resistivity curves at different detection depths.According to the identification results,the relationship between lithology and fracture development is summarized,among which the tuffaceous mudstone has the largest formation thickness and the sedimentary tuff is easier to develop fractures.According to the statistical results of fracture identification,the fracture development thickness in the study area accounts for 17.2%of the total formation thickness.Based on the processing of seismic data by ant technology,the prediction of fractures in any section and in plane at any time is completed.The physical properties of the reservoir revealed that the pyroclastic rocks in the study area had poor overall porosity and permeability,with an average porosity of 6.33%and an average permeability of 0.416 10-3 m2.The reservoir was generally a medium-low permeability reservoir.Combined with the study of physical properties and fracture development,it is believed that the formation oil-bearing property is mainly affected by lithology and fractures,among which lithology will not only lead to the difference in pore permeability performance,but also affect the formation oil-bearing property.At the same time,due to the different mechanical properties of different lithology,the ability to develop fractures is not the same.