| Songliao Basin is one of the large-scale meso-cenozoic continental basin in China,which is rich in oil and gas resources. Thus petroleum exploration targets in recent years towards depression center and deep formation, and has made a great breakthrough. Pu363-Mao405 block gets close to Qijia-Gulong source depression and Sanzhao source depression, ample oil source, reservoir development, source-reservoir-seal assemblage is better. It is a large area of favorable oil-bearing zone. Even though the reservoir thickness is thin, but the oil property is good, reservoir pressure is high. It is an abnormal high pressure reservoir. high capacity single-well, better cost-effectiveness. Therefore, in recent years, according to information obtained in the area, carried out the characteristics of reservoir geology and reservoir model of research on the area to determine the next step by enabling optimization of storage blocks, the authors evaluate the control design Well, it is significance for exploration and development and increasing reservior volume of the block.In this paper, I have started from the regional geological characteristics, combined with the existing drilling, logging, regional geological data. First of all, from the reservoir rock characteristics of the study area divided into Putaohua reservoir diagenesis stage. And according to the existing empirical formula of the study area for calculating porosity,oil saturation of the study area exploration wells and evaluation wells Putaohua layer , the porosity of sandstone distribution will be described and classified. Secondly, summarized accumulation period of time, migration pathway of the study area Putaohua hydrocarbon, combined with oil-source correlation and oil-water distribution data. Through analysis of a typical oil and gas reservoir, set up Putaohua reservoir accumulation model in the study area. Finally, the combination of the above studies, classified the reservoir bed of th Putaohua in the study area, and proposed a standard for the classification of reservoir in the area, the reservoir of study area is divided into four grades, come to the result of the reservoir distribution characteristics of classification about 6 small layer of Putaohua of the study area.On the basis of the research of petroleum geology background in the study area, through the collation and analysis of drilling data, and a comprehensive study of the diagenesis of the area, identified the northern and central of the study area belongs to the A sub-period late diagenetic stage, can form a lot of time into pore; the southern of the study area belongs to the B sub-period of early diagenesis stage, the retention of primary porosity and secondary porosity can be seen a small amount. To determine the rock type of the study area is mainly debris feldspar sandstone. The sandstone is mainly fine-grained sandstone and coarse siltstone, and medium maturity.According to the existing empirical formula of the study area, by logging data to calculate porosity and oil saturation of exploration wells, evaluation well in the study area, describe porosity of eight small layer and oil saturation characteristics of six small layer in Putaohua reservior of the district. The porosity of Putaohua of the study area is generally between 22.05%~9.16%. The average is 13.41%, belong to the medium porosity. The porosity is high in the north-west and central of Pu 363 - Mao405 block, also high porosity in the south-east, and a small number of wells in southwestern and central is lower porosity. The oil saturation of Putaohua is generally between 30% ~ 48% in the study area. The oil saturation of PI1, PI2, PI3 small layer is higher.According to sandstone thickness of a single well, we map out thickness distribution of the sandstone of seven small layer of Putaohua of the study area. Overall, the middle-thick sandstone of the whole study area mainly develope in Tai 42-45 well to the central of Portugal 363 to the west of Tai 12 wells in the south, the sandstone of other areas less vertically overlay. The thickness map of the small layer of every sandstone in this area also revealed that characteristics of the water body turbulence changes in the sedimentary period of Putaohua oil layer, 5 to 7 small layer in the south of study area belong to deep water sedimentary environment and sandstone does not develop, the most are special thin sandstone reservoirs. 1~4 small layer are the main sandstone reservoir layer for Putaohua reservoir of the study area.Combination with drilling data, well logging data, we summarized the law of oil and water distribution of the study area. Good fault sealing, the fault block has the independent oil-water interface, the study area does not have a unified oil-water interface, the local structural traps or lithologic traps control the reservior, whcih is obvious for the impact of the oil-water distribution of the reservior, oil-water relations are more complicated.Water and oil-water layers are mainly distributed in the northern part of the study area, the block has a different oil-water system.It shows that the fault has a good sealing. The degree of the southern reservoir development of the study area is mainly affected by degree of control and development of sandbody and physical property of reservoir, poor physical properties is for the dry layer, good physical properties is for the oil layer, only a small amount of oil-water layers is seen in the central of the study area, and fault formed a large area with lithology and fault - lithologic reservoir, the complexity of the relationship between oil and water distribution. Not only can block the high part of the high oil content, low-low block can also be parts of the oil-rich, high-site for the oil-water layers, and low parts of not only non-water, but also the main oil-bearing. Structure has a certain control function for oil and gas accumulation.The source rocks of Putaohua reservoir is the dark mudstone in first stage of Qingshankou group. Regional seal is the gray-black mudstone in first stage of Nenjiang group, the direct seal is the mudstone in second and third stage of Yaojia group. The way of hydrocarbon accumulation oil and gas accumulation is mainly that normal reservoir, migration closly. The oil and gas migration major channel is the faults, the secondary channel is the sandstone layer. We consider that the accumulation model of Putaohua reservoir in the study area should be: in first stage of Qingshankou group, the source rocks provided oil and gas, which travel along with the activities faults, then, the short-distance lateral migration by blocking the faults and lithological boundaries. Sanzhao Depression as the center, migration to the surrounding slopes, is the mode of accumulation.Using of "weight" evaluation method, select five parameters,which are the best indicator of reservoir property: porosity, permeability, oil saturation, sedimentary micro-facies, sandstone thickness. According to the comprehensive evaluation of six small layers to determine reservoir classification types, the six small layers of Putaohua layer are divided intoâ… ,â…¡,â…¢,â…£four kinds in the study area. The results showed that: the reservoir ofâ… type is not development,â…¡,â…¢types are more development, althoughâ…£-type reservoir has more layers, but the thickness is thin. Which,â… type is lower, total thickness of the small layer accumulated 10.3m, 6.28 percent;â…¡,â…¢types are the main reservoirs, total thickness of the small layer accumulated 49.8m, 93.27m,30.39 percent,56.91 percent;â…£type is the lower reservoir, total thickness of the small layer accumulated 10.52m, 6.42 percent. Through comprehensive evaluation, we can conclusion that PI1, PI2, PI3, PI4 four small layers are the favorable reservoirs: medium porosity and low permeability reservoirs, sandstone thickness is more than 1m. Oil saturation is over 30 percent.In this paper, I have studied the reservoir geologic characteristic of Putaohua reservoir with a large number of the basic geological data, given a certain reference standard, for the next step by submitting a favorable reservoir optimization block and the design of evaluation control wells.
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