| Bao 14 block is located in the middle of the west of Lujiabao depression.In this paper,the object of study is the Group I of the upper part of the Jiufotang formation in Bao14 block,and the sedimentary characteristics of the target layer are studied by the means of geophysical exploration,well logging and other means,so as to analyze the regularity of oil-bearing distribution of the reservoir and the heterogeneity of the reservoir,providing a certain geological basis for the further development of this area.By identifying the sequence interface,the Jiufotang formation in the west of Lujiabao depression is divided into a low-water system domain,a lake invasion system domain,and a high-water system domain.The Group I of the upper part of the Jiufotang formation is located in the high-water system domain.In this paper,the well-to-seismic integration is used to divide the Group I of the upper part of the Jiufotang formation into 5 ultra-short-term cycles.It is found that the single sand body of each layer in Group I is relatively thin by stratigraphic correlation,and the sand body is generally thicker in the middle and thinner on the top and bottom of the Group I.According to the logging facies,seismic facies and core,the sedimentary facies and sedimentary microfacies are studied.It is considered that the Group I of the upper part of the Jiufotang formation is an underwater fan,with fan-mid and fan-end subfacies developed.There are several braided channels in the region.The underwater fan in Layer I3 and I4 has a large scale,and the vertical stacking pattern is dominated by the retrogradation pattern.The oil distribution of Group I is studied by the core and other data,and it is found that the pebbled sandstone in the target layer has the best oil content.The braided channel contains pebbled sandstone in the study area.The area with good oil content is the area in the middle of the the study area where braided channels are developed,and the area with poor oil content is located at the edge of the study area.According to the statistics of core and logging interpretation data,the permeability of each layer in Group I is low permeability,which is greatly affected by fractures,especially artificial fractures caused by artificial fracturing.The reservoir heterogeneity of Group I is not only controlled by sedimentary facies,but also affected by artificial fracturing and depth regulation. |
