The Delicate Reservoir Research On Second Segment Of Shuangyang Formation In Yi59 Oil Field Of Moliqing Fault Depression, Yitong Basin

Y59 oil field is in the Moliqing fault depression of Yitong basin. Moliqing fault depression is the secondary Structural Unit of the Yitong Basin. To which the East Liaohe fault depression and the Yehe fault depression adjacent in the south-west . In the north-east is the Yidan uplift and the Luxiang fault depression. because of the basin controlling fault which is in the north-west of the basin and in the south-east is a gentle slope, the Moliqing fault depression which is called half graben basin is full of compensation fault.On the plane,the Moliqing fault depression can be divided into three tertiary unit that is Kaoshan falling, Maanshan terrace and Jianshan structure. The centre of fault depression is nearing the west of the basin.The region of interest is the Kaoshan structure in the north-west of the Moliqing fault depression ,and the purpose of the research is to understand features of sedimentary facies belt and distributing rules of reservoir bed, getting the detailed research for the reservoir physical property and it's aeolotropism to provide some reference for the oil field.The Yitong basin has a complex structure and gets much more sand body that made by density current.so we should face the two questions following in the Moliqing fault depression:1) The main aim reservoir beds in Moliqing fault depression are alluvial fan , fan delta, subsea apron and sublacustrine fan .All of these lithosomic body get complex develop,it's lithologic character changing fast in the vertication and horizontation and it has a unstable reservoir zonation in space.2) The main aim reservoir beds in Moliqing fault depression are low porosity and low permeability reservoir which have a low deliverability,and this restraint the exploration and development of the oil field.According to the situation above,we ues the theory of the sequence stratigraphy and sedimentary system to establish depositional model and have the research of the characteristics of sedimentary facies in Shuangyang sand group of Yi59 oil field.Analyze the overlay relationship and deposite evolvement of sand body in sublayer,and this will supply a theory for understanding the reservoir-forming rule of oil and gas.At the same time, we need to have a research which include reservoir space type of the Shuangyang group , reservoir physical property and heterogeneity to explore the law of reservoir physical property changing in space and the relationship with hydrocarbon Accumulation.All above doing is for the optimize of reservoir bed, division of the layer series of development reasonably and improve the effect of the development to supply a assured geological basis.according to detaied analyze of the Shuangyang group which is divided into 5 sand groups and 23 sub layers.The sand groupⅤis divide into 4 sub layers.The sand groupⅣis divide into 5 sub layers. The sand groupⅢis divide into 4 sub layers. The sand groupⅡis divide into 5 sub layers. The sand groupⅠis divide into 5 sub layers.Using the core observation and logging data analysis we found that this area is mainly sublacustrine fan facies,some place is lake facies.We have drawn up the isopach map of sandstones and isopach map of sand-layer ratio to get base for the sedimentary system of this area.The reservoir of this area is mainly have 3 pore types and two of these are appeared in pattern: primary intergranular pores～intergranular dissolved pores and dissolved pores in grains.According to the sign of classification of pore structure in fragmental reservoir composed by Dishixiang(1991) , mercury intrusion parameters and main lithologic characteristic,dividing the lever of pore configuration in this area into the levelⅡand levelⅢand each of lever can be divided into sublevel A and sublevel B.The meaning of each sublevel is good(ⅡA),normal(ⅡB),poor(ⅢA) and very poor(ⅢB).The style of pore structure this area are sublevelⅡA and sublevelⅢB.According to the ordinary physical property data and the oil pattern of this area,we found that the valuable oiliness sublayers areⅣ-3,Ⅳ-1,Ⅲ-3,Ⅲ-2,Ⅱ-4,Ⅱ-2andⅠ-5. The reservoir has the characteristics of medium porosity and medium permeability or medium porosity and low permeability.The research of reservoir physicalproperty show that the reservoir has intensity aeolotropism in or between layers,same the aeolotropism in area.Multidisciplinary analysis of the microscopic feature and macrofeature above show that the element that effect the reservoir physical property of this area include sediment and diagenesis. What effect on sediment is that the pore structure, degree of porosity and permeability of reservoir in middle fan of sublacustrine fan is better than inner fan and outer fan. Dissolution made the physical property of some layers better,and which creat high degree of porosity and permeability at 2200-2400 metres deep.This will supply a good place for concentration of oil.