Research On Sedimentary Microfacies And Reservoir Characteristics Of Dongying Formation In Jinjia Region, Dongying Depression

Jinjia region is located in the southern of Jinjia-Zhenglizhuang nose structure of Boxing subsag, Dongying depression. Exploration in the region have been confirmed that the region has great potential of exploration and development, thus with making full use of existing technology and data, the study on sedimentary microfacies, reservoir characteristics and secondary well-logging interpretation has an important significance to the work such as accelerating the pace of progressive exploration and development, enlarging exploration achievement and guiding next drilling.Based on grasping and collecting regional geological data, along with previous research results of the study area, using the basic principles and methods of sedimentology, logging geology and petroleum geology as guiding theory, combination of drilling, logging, core and seismic data, this paper has conducted in-depth study on sedimentary microfacies and reservoir characteristics of Dongying formation, Jinjia region in Dongying depression, by investigating sedimentary textures, lithological combination, logging response characteristics and microscopic characteristics of the reservoir synthetically, and then analysed the plane distribution characteristics of sedimentary microfacies.On the basis of the location of horizon marker about regional contrast, using lithological contrast method, stratigraphic classification of individuall well of Dongying formation in Jinjia region has been carried out, it has been showed that the Dongying formation could be divided into two sands groups, the Ed₃4 and the Ed₃3, with combination of actual field production situation, further, make the Ed₃4 and the Ed₃3 be divided into three layers and four layers respectively. Based on above, four backbone cross sections have been builded and stratigraphic classification and contrast have been finished in the study area.Based on core observation and description, combination of sedimentary facies markers such as color and types of rock, sedimentary textures and structures, palaeontologic fossils, log morphologic characteristics and so on, it has been identified delta front and shore-shallow lake subfacies, and has been identified four sedimentary microfacies including mouth bars, sand sheets, underwater distributary interchannels and shore-shallow lake muds. With the stratum framework in control, each layer's spatial distribution of sedimentary microfacies has been analyzed. The sand body in the study area mainly includes mouth bar sand body and sand sheet sand body located in delta front, basically which existed in Ed₃4³, Ed₃3⁴ and Ed₃3³ have the following characteristics: thick individual layer, stable distribution and extensive distribution.Petrologic characteristics of reservoir, physical properties of reservoir, types of reservoir space and pore texture characteristics have been studied according to the data about casting thin slice, capillary pressure curve, core classification and analysis. Then the reservoir diagenesis has been discussed and the distribution characteristics of sand body have been analyzed. It's presented that the reservoir sandstone of Dongying formation in study area has feature as middle textural maturity, the type of sandstone is mainly lithic arkose, the physical property is good and the primary reservoir type in the study area is medium-high porosity with medium-high permeability. The main pore type of the reservoir in this area is primary intergranular pore, followed by corrosion pore, and pore texture is mainly medium-high pore with medium-large throat. The diagenesis in the area includes mainly compaction, cementation and denudation, among which denudation plays a constructive impact on development of reservoir.