# Analysis of Hydrocarbon Enrichment in Tight Sandstone Reservoirs in the Eastern Baiyun Depression
## 4 Basic Characteristics of Paleogene Reservoir Formation Elements in the Eastern Baiyun Depression
### Reservoir Development Characteristics  
Oil and gas accumulation and accumulation in sedimentary basins are a series of physico-chemical processes of oil and gas generation, migration and accumulation in dynamic fields controlled by temperature, pressure and potential energy. The source of elastic material in the Paleogene reservoir in the Pearl River Estuary Basin is diverse, complex and variable. Based on the above analysis, the sources of the favorable reservoir sand bodies of the Paleogene in the eastern Baiyun are mainly palaeuplift and Yundong low bulge. After weathering denudation and moving along certain transport channels, the corresponding deltas are formed in the slopes and fault channels at the edge of the uplift or uplift, and a certain scale of shoreline beach bar facies storage collective is developed in local underwater low uplift. The paleogene reservoir studies revealed by the existing wells (LGH-4, LGH-6, and WXD-5) in eastern Baiyun are mainly located at the margin of the Yunli low uplift and the western margin of the Yundong low uplift. Overall, the location distribution of the three exploration wells is relatively dispersed, among which WXD-5 is distributed in the western margin of the Yundong low uplift and reveals the filling deposit of faultditch 1, while LGH-4 and LGH-7 are distributed in two different structures in the northern margin of the Yunli low uplift. According to the relevant sample research of drilling, the above three wells are mainly lithologically composed of lithologic quartz sandstone and lithologic sandstone, but there are great differences in rock types, grain size and diagenetic types (Figure 6). The LGH-4 well is located on the east side of the north margin of the Yunli low uplift, and its lithology is mainly uneven-grained sandstone with gravel, low content of mud base and poor sorting. The Wenchang Formation can be found kaolinite-rich gravel sandstone. LGH-7, located in the west of the north margin of the Yunli low uplift, is mainly composed of clastic sandstones with large differences in the content of the mud matrix and poor sorting. WXD-5 is located on the western margin of the Yundong low bulge, and its lithology is mainly quartz sandstone with a high content of mud matrix and great sorting difference. Wenchang Formation can be seen in tufaceous solution microporous sandstone. Due to the development of volcanic tufaceous matter at the bottom of well WXD-5, volcanic tufaceous matter easily blocks the roar channel. Therefore, although the porosity of the Wenchang Formation in well WXD-5 is large, the permeability is low, showing the characteristics of low permeability to ultra-low permeability. Relatively speaking, the reservoir property of the Enping Formation is relatively good, showing certain characteristics of \"middle porosity and permeability\". Figure 6: Composition maturity map of the Paleogene in the eastern Baiyun Depression. Fractures can be seen in the eastern Baiyun basement, but there is also chlorite development. Chlorite can effectively inhibit the occurrence of quartz secondary enlargement and reduce the filling pores of cement, which plays a role in improving the reservoir. The autologenic chlorite requires a relatively iron-rich sedimentary environment. It is clear from the previous comprehensive regional geological study that there were relatively common volcanic eruptions in the eastern Baiyun during the Upper Wenchang and Enping periods, and the pyroclastic rocks and tufaceous rocks were relatively developed, which provided corresponding favorable basic conditions for the development of the chlorite rim. Through analysis, the target of the WXD-5 region is a high-energy sedimentary facies zone, which has the basic conditions for the development of a high-quality reservoir. WXD-6 well drilling reveals that the porosity of the coarse-grained sandstone reservoir in the EP Formation can reach 14.4%, and the permeability can reach 18.1 mD.