Research Of Conglomerate Rservoir Characteristics Of Triassic Baikouquan Formation In Mabei Slope

The sequence stratigraphy, rock facies types and characteristics, source direction, sedimentary facies types and characteristics, reservoir characteristics and distribution of favorable reservoir of Baikouquan Formation of Mabei slope has been detailedly researched by Comprehensively utilizing core, logging data, analysis and test data and seismic data, and adopting the method of combining the macroscopic research and microscopic analysis. Eventually, the plate distribution of favorable reservoirs of Baikouquan Formation is predicted. The research results has important reference value for the oil and gas exploration and development of this area in the future.According to the stratigraphic cyclicity, we divide the Baikouquan Formation into 3 section of T1b1、T1b2、T1b3, which correspond to three mid-cycle, in which the T1b1 and T1b2 section are the found and developed oil sections at present. On the basis of small layer classification and comparison, we subdivide T1b2 into T1b22、T1b21 two sand layer, which corresponds to two short cycle.On the basis of investigating and surveying the research status of Glutenite reservoirs domestic and overseas, we adopt the classification thought of sedimentary origin, dividing the Glutenite into traction current sandy conglomerate and gravity flow glutenite. The lithofacies types of Baikouquan Formation of Mabei area could be divided into traction current sandy conglomerate lithofacies, gravity flow glutenite lithofacies, Conglomeratic sandstone lithofacies、sandstone lithofacies and mudstone lithofacies. The research of distribution rules of across-well profiles and plate lithofacies show that major lithofacies types turn from gravity flow glutenite lithofacies、traction current sandy conglomerate lithofacies. Conglomeratic sandstone lithofacies、sandstone lithofacies to mudstone lithofacies from provenance to lake basin depocenter, and the change rule is very clear.The Baikouquan Formation develops a fan-delta sedimentary system which is formed by the alluvial fan into the lake, which has the typical characteristics of mutual deposition of gravity current and traction current, and can be identified out of fan-delta plain subfacies、fan-delta front subfacies and frontal fan-delta subfacies and 10 kinds of microfacies types of debris flow、stream channel、floodplain、underwater distributary channel、underwater debris flow、tributary bay、river mouth bar, far sand bar, predelta mud and slump debris flow. The sedimentary evaluation rule of profile and plane is very clear, which overall shows a process of continuous rising lake level.The lithology of Glutenite reservoir of Baikouquan Formation is mainly the Glutenite、conglomeratic sandstone、sandstone and mudstone, among them, the clastic particles composition of the conglomerate contains the tuff, andesite、felsite and so on, which is mainly the tuff; The type of clastic particles of sandstone mainly is lithic, quartz and feldspar content is low; the matrix composition mainly is argillaceous、 hydromica argillaceous and Kaolinite, etc; The cement contains clay cement、siliceous cement and calcite cement, mainly is clay cement; The cementation type is mainly "contact cementation"; Pore type mainly is secondary porosity in general; it is overall the low porosity and low permeability reservoir, and the heterogeneity is serious.Through the macroscopic observation of core characteristics and the analysis of microscopic pore types, we found that different genetic glutenite has a huge difference on the macro and micro level, and these differences further lead to the differences of reservoir physical properties. Among them, the pore types of traction current glutenite is mainly residual intergranular pore, and the mud matrix content is low, and mercury injection shows its good pore throat sorting、larger pore throat radius, thus it has a better physical property and oil property; Whereas, the pore types of gravity flow glutenite mainly is the secondary dissolution pores, its mud matrix content is higher, the mercury injection shows that the pore throat sorting is worse, and its pore throat radius is smaller, thus, its physical property and oil property are worse. Because of the late diagenetic transformation effect of glutenite reservoir of Baikouquan Formation is small, on the basis of analysis of factor of difference of the oil testing conclusion of oil testing sectors, we think that the sedimentary origin of Glutenite is the underlying factors which control the reservoir physical property、oiliness and test the effect. And therefore, we conduct the comprehensive evaluation of the glutenite reservoir of Baikouquan Formation, we classify traction current glutenite、conglomeratic sandstone of the river channel、underwater distributary channel microfacies as the first favorable reservoir, and we classify gravity flow glutenite of the debris flow and debris flow microfacies as the second unfavorable reservoir, and we classify the mudstone and silty mudstone of lthe floodplains、tributary bay、predelta mud microfacies into the unable reservoir.Above all, the traction current glutenite and conglomeratic sandstone of river channel and underwater distributary channel is the most favorable reservoir in the study area; the traction current gravel rock body of every period of layer is the first target of promoting production in the study area for the future.