Reservoirs Features Of The Second Member Of Sangonghe Formation In Moxizhuang Area

Moxizhuang Oilfield is located in the west of Maqiao uplift in central anticlinal belt.And it is in favorable directional zone of hydrocarbon migration. However, the genetic types and distribution features of the reservoirs in the main producing layer Member 2 of Sangonghe formation are not clear. And the reservoir property and oil-water distribution of the trap under the nose structure remain unclear. The reservoir develops several oil-water systems due to the strong heterogeneity. And it leads to many contradictions about rapid production decline, high water content and stable production stage shorten. Therefore, the integrated geology study of the reservoirs in Member 2 of Sangonghe formation is carried out. Through the following research, like realizing the sandbody distribution and analyzing the reservoir property, the main factors that control the reservoir are revealed and the reason about complex reservoir that influence the different enrichment of the reservoir is understood. For all this, the excellent reservoir zone could be found.The paper is based on plentiful information of drilling, core, analysis of laboratory and logging data. Using a combination of the contrast of sequence stratigraphy and cycle-thickness, through identifying the unconformity, lithology or lithofacies transition surface and flooding surface, the equivalent sequence framework is built. Based on the regional deposition backgrounds and source direction, through the study of facies indicators,braided stream facies develops in J1S22 and braided delta facies develops in J1S21. The types and characteristics of sedimentary facies are clear. The stratum presents the vertical sedimentary sequence evolution of sedimentary base-level rising cycle. And the superimposed relationship between sandbody and intercalated bed is uncovered. Analyzing the rock composition, pore types and structure characteristics of the reservoirs, The reservoir space is mainly original intergranular pore, followed by dissolved inter-grain pores and dissolved intra-grain pores. Transitivity analysis shows that reservoir is mainly characterized by low porosity and low permeability and part is low porosity and super-low permeability. Among it, the physical property in the 3rd, 4th, 5th sand groups are the best.Diagenesis shows that decreasing pore by the mechanical compression is the major event during early diagenesis stage, followed by calcareous cementation and quartz secondary enlargement. In the late diagenetic period, cementation is proceeding and dissolution effectively improves the reservoir property. It is speculated that the reservoir is featured by weak velocity sensitivity and acidic sensitivity by the whole rock analysis. The paper analyses the factors that control the reservoir through the aspects of sedimentary,diagenesis and early filling, it is considered that the channel bar and braided stream with the characteristics of high maturation of texture, low levels of plastic rock debris and high compression capability are the excellent reservoir zone. The early filling during the end of Cretaceous suppresses decreasing pore by compression and cementation, and it has positive effects on pore type reservoir protection.