| Comprehensive comparision is used in this paper, combined with core analysis, logging, oil testing and so on, in order to carried out a detailed study and analysis on sedimentary facies, reservoir characteristics, reservoir characteristics and potential analysis of Chang 4+5 reservoir of Yougou area in Wuqi oil field. The main achievements are as follows:1.The structure of Yougou area in Wuqi oil field is a west-dipping monoclinic, while locally developed low noseuplift structure,which has a controlling role in gathering oil. Chang 4+5 reservoir of Yougou area in Wuqi oil fieldis is the river-controlled lacustrine delta front,which develop underwater diversion channel and diversion bay sedimentary microfacies. The development of sand body is medium. The underwater diversion channel of lacustrine delta front developeg in two regions, and the source direction is north-east.2. The rock types of Chang 4+5 reservoir of regional is fine-grained feldspathic lithic sandstone,the roundness is subangular, better sorting, The contact relationship is mainly point linear, low maturity composition,and medium texture maturity. Chang 4+5 reservoir of Yougou area is evaluated as pores and fine throat(III type) reservoir in the classification criteria of Changqing Oilfield.3. The impact of Chang 4+5 reservoir distribution by Source center,raw reservoir cap assemblage advantageous arrangement, favorable reservoir facies, nasal swelling, fracture and related cracks. The controlling factors of the formation of oil reservoirs is palaeogeomorphology, sedimentary environment and low noseuplift structure,ect. The distribution in the longitudinal direction is that Chang 4+522 has the best oiliness, Chang 4+521 secondly,and the oiliness of Chang 4+51 is the worst.The reservoir type is Structure-Lithologic reservoir drived by solution gas elasticity which with good oil quality,shallow reservoir depth, low porosity, low permeability and low saturation. |
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