The Study Of Bedrock Characteristics And Advantages Of Reservoir Of Central Paleouplift In Northern Songliao Basin

The paper observe and identifie the rock and reservoir characteristics of the central paleouplift in Songliao Basin,combined with relevant geological data,to predict wether the central paleouplift has good potential for the development of the advantageous basement hydrocarbon reservoir.In the process of writing papers,I have observed and identified 200 pieces of the bedrock rock thin section,common cast thin sheets 200 sheets,determined two dozen of the lithology,not only the Metamorphic and Igneous,as well as the altered rock and a small amount of pyroclastic rocks and sedimentary rocks.which indicates that metamorphism occurred in the central uplift uniform,wai Inhomogeneous.Except the regional metamorphism,It may also be superimposed on a thermal metamorphism.We observed the bedrock Reservoir characteristics,found that different lithology types of bedrock has developed the different types of Fissures.The Sedimentary rocks mainly developed the pores between the granule.The metamorphic rocks and altered rocks mainly develop the cracks along with the tectonic fracture or metamorphic strip,which always getting bigger through the Feldspar and Hornblende.According to the theory of "advantageous lithologic sequence" which was brought forward by Xing Zhou et al.The paper suggest that all of the Metamorphic have the potential to develop an advantageous reservoir.There are two most important factors to control the development,the first one is the type of the lithology and mineral,the second one is the various of the Geological actions the reservoir has experienced.Therefor,this paper proposed the mechanism of Granodiorited reservoir rock,and believed that Granodiorite has the most perfect Proportion of Quartz,feldspar and mica to develop an advantage bedrock reservoir.According to the main controlling factors of the advantageous reservoir development,combined with the corresponding seismic section and sedimentary facies,we can predict and initially confirmed that the central paleouplift is the advantageous reservior just for the following reasons: The first,the central paleouplift located in the early weathered zone which has develop the bedrocks' cracks;Secondly,after the whole basin has settlement,the hydrocarbon-generation sunken between the central paleouplift transport the water which was under the ground or in the oilfield to the central paleouplift,which resulting in the dissolution inside the bedrock,and increses the porosity of reservoir space and connectivity;The third,the main lithology of the Palaeohigh bedrock is metamorphic ntrusive rocks and volcanic rocks,a certain degree of metamorphism and Alteration is both increased physical and chemical stability of rock,and metamorphic minerals produced but also increases the potential of bedrock to develop an advantageous reservoir;Last,Xujiaweizi fault-depression combined with the the central paleouplift by a large fault.The contact area is large enough to make sure the oil and gass of the Shahezi Sedimentary strata may be able to have the central ancient provide sufficient hydrocarbon sources.