Research On Sedimentary Facies And Reservoir Characteristics Of Badaowan Formation In Baikouquan Oil Field, Junggar Basin

The oil and gas exploration and development of Baikouquan Oil Field has achieved a breakthrough in District Baizhong-7, District Bai-106 and District Jian-188 of Badaowan Formation, Junggar Basin, which can take over the horizon as an important oil and gas exploration in this oilfield. These reservoirs are all lithologic- stratigraphic reservoirs, with the characteristics of quick changes through vertical and horizontal reservoirs, so the sequence stratigraphy, sedimentary facies and reservoir characteristics need to be further studied.The understanding of the tectonic evolution and characteristics in the study area are deepened combined with previous research. Focusing on the use of logging and core analysis on this basis, Badaowan formation is divided into three third-order established isochronous stratigraphic frameworks, the foundation for the subsequent study of sedimentary facies and reservoir characteristics. On this basis, with the use of logging and core analysis, Badaowan formation is divided into three third-order sequences, isochronous stratigraphic framework is established, which lay the foundation for the subsequent study of sedimentary facies and reservoir characteristics.Using the method of sedimentology and heavy mineral analysis, the characteristics of the study area is near provenance and double provenance, the main provenance area is the Zaire Mountain to the western, the secondary provenance is the northern region, along the two provenance directions are two ancient water systems, which control the depositional system development of this area. With the control of sequence stratigraphic framework and provenance, by identifying petrology marks, paleontologist marks and log facies marks, analyzing single well-phase, phase profile and plane distribution of sedimentary facies characteristics, the conclusion is drawn that alluvial fan facies are developed in sequence Ⅰ, braided river facies are developed in sequence Ⅱand Ⅲ. Fan root, fan and fan edge subphacies are mainly identified, braided channel microfacies are well-developed. Channel subfacies and river flood subfacies are mainly developed in braided river facies, including channel microfacies and flood land filling microfacies development and slight diara microfacies development.With the use of logging, core and analysis of test data, the reservoir petrolog characteristics, distribution characteristics and pore types and characteristics of Badaowan formation in Baikouquan Oil Field are analyzed, and the reservoir is preliminarily evaluated. The reservoir lithology of Badaowan formation in Baikouquan Oil Field is mainly medium, fine sandstone and conglomeratic sandstone, followed by glutenite, characterized by a low compositional maturity and medium structure maturity. The rock types are mainly lithic sandstone, followed by feldspar lithic sandstone. The sorting characteristics are medium-well, the roundness is second round- subangular, the cementation type is mainly pore, the support form is mainly particulate support. Kebai fracture has a certain control on the reservoir distribution and physical properties, footwall is significantly greater than on disk of the reservoir thickness distribution in Kekebai fracture, the lower reservoirs have a maximum reservoir thickness. The reservoir properties are good, but the plane is very unevenly distributed, with an average porosity ranged from 13 ~ 17%, accounted for 62.7%, and permeability generally increases rapidly near the Kebai fault. Pore Types are mainly intergranular porosity and various dissolution pores, followed by the intergranular porosity.Badaowan reservoirs generally are good, the main reservoirs are type and type of Ⅲ Ⅳreservoirs. The type of reservoirs contiguously and local develop at nearby Kebai fault. Ⅱ Ⅴtype of reservoirs are mainly distributed in the lower part of the slope zone. The lower reservoirs of Baikouquan Oil Field sets an overall rating of Ⅲ- Ⅴtype of reservoirs, most areas are type of reservoirs. The middle ReservoirⅣ s have an overall rating of Ⅱ-Ⅴ type of reservoirs, Kebai fault disc is mainly Ⅲ type of reservoirs,the footwall reservoir is worse than the previous disc. The upper Reservoirs have an overall rating of Ⅱ- Ⅳ type of reservoirs, the main part belongs to the Ⅱ and Ⅲ type of good- better reservoirs, and the upper Reservoirs have the best reservoirs in the study area with the minimum thickness.The favorable sedimentary facies are alluvial fan braided channel microfacies, braided river channel filling and diara microfacies, the microfacies of the sand or gravel, better properties, these microfacies of the sand or gravel have better properties, horizontally continued and vertically superimposed, especially The lower reservoirs constituting a good oil and gas transporting system with the top Triassic unconformity, while being covered or surrounded by silt and mud deposited from overflows, forming a good reservoir-cap combination, which provides good conditions for forming lithologic- stratigraphic reservoirs.