Research On Sedimentary Facies And Reservoir Characteristics Of Xujiahe Formation In Anyue-jianyang Area

Based on the data of surface outcrops, cores drilling, logging, combining with the and analysis results, and leaded by theories of sedimentology, the reservoir geology and petroleum geology, this paper has thoroughly studied the formations, sedimentary facies and reservoir characteristics of Anyue--Jianyang area. And the main results are listed below:1. Xujiahe formation has been divided into six parts from the bottom to top, Xu1 ~Xu6 separately. On the basis of stratigraphic division and contrast, this paper studies the characteristics of formation horizontal distribution of every part of Xujiahe formation.2. Based on the research of identification marks of sedimentary microfacies, Xujiahe formation in Anyue-Jianyang area has been divided into braided river delta system and lake sedimentary system. Further, braided river delta front and front delta facies are found in delta sedimentary, lakeside and shallow lake subfacies in lake sedimentary. Besides, On the basis of the study of single well and crosswell deposition comparison, this paper has made a systematic study for sedimentary facies plane exhibition in Anyue-Jianyang area. The results show that the study area reservoir section(Xu2, Xu4 and Xu6) are braided river delta front, spreading from south to north.3. On the basis of the observation of the drilling core, general wafer and the casting thin sections and identification of them, this paper systematically studied the characteristics of the reservoir lithology reservoir and pore structure of the Xujiahe formation in Anyue-Jianyang area. The major part of reservoir lithology in the study area is feldspar lithic sandstone, lithic feldspathic sandstone, part of them is lithic sandstone. Pore types of Xujiahe formation can be divided into primary intergranular porosity within the intergranular dissolution pores, miscellaneous based micro pores, intragranular dissolution pores and cracks. Primary intergranular pore and intergranular dissolution pore are two kinds that have significant meanings. The throat type contains the necking throat, the punctual throat, the laminated throat, the curved lamellar throat, and the control shape throat.4. According to analysis materials of core physical characteristics of Xujiahe formation in Anyue-Jianyang area, Xujiahe formation belongs to special low porosity and low permeability reservoir. The main type of the reservoir is pope type reservoir, together with the fracture- pore type reservoir.5. This paper has divided the reservoir into four categories with Q-type cluster analysis methods: typeⅠfor good,typeⅡfor better, typeⅢ for medium, and typeⅣ for poor. Among them, type Ⅲ is the main reservoir type, type Ⅱ is scattered distributed and typeⅠis the least.6. On the basis of the reservoir evaluation standard, after classifying the single well reservoir and researching the vertical evolution characteristics of the reservoir in the studied area, this paper has created the map of the reservoir porosity and thickness of Xu2, Xu4 and Xu6, and systematically studied the plane distribution of each section in the reservoir.