With the continuous improvement of oil and gas exploration in the middle and shallow layers, the deep Paleogene in Raoyang sag has become an important exploration field of “increasing reserves and production” in North China. The recognition and control factors of deep effective reservoirs are unclear, which restricts the recognition effect of oil and gas exploration. The key to identify effective reservoirs is to determine the lower limit standard of reservoir physical properties. The single method for calculating the lower limit of physical properties has limitations. The lower limit of the effective reservoir physical properties of the Shahejie Formation in the Dawangzhuang area was obtained by comprehensively using physical property, well logging and oil test data. The data were analysed by oil testing method, metre oil production index test method and frequency curve intersection method. On this basis, combined with the cast thin-section observations, scanning electron microscopy and other test results, the comprehensive control of effective reservoir development of the Shahejie Formation in the Dawangzhuang area of the Raoyang sag was studied from various factors, such as formation pressure, sand body thickness and diagenesis. The results show that the lower limit of porosity was 9.73, 9.44 and 8.85% at depths of Es1, Es2 and Es3, respectively. The lower limit of permeability was 1.21 × 10–3, 1.18 × 10–3 and 0.59 × 10–3 μm2, respectively. Effective reservoirs are easier to form in areas with formation pressure coefficient greater than 1.2. Formation overpressure inhibits compaction and promotes dissolution. The proportion of effective reservoirs of sand bodies with thicknesses greater than 2 m can reach more than 75%. The influence of diagenesis on the reservoir is mainly manifested in compaction and cementation making the reservoir compact. The porosity reduction rate caused by compaction can reach 20–75%, while dissolution makes the reservoir form secondary pores. The average pore throat radius of secondary pores can reach 4 ~ 6.3 µm. This study makes use of the applicability of different methods, which is more instructive for predicting the effective reservoir of the Shahejie Formation in the study area. In addition, the research results provide a reference for the development mechanism of medium-deep clastic reservoirs.

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The continental faulted lacustrine basin is an important type of continental oil and gas basin with typical compound oil and gas accumulation characteristics. The traditional petroleum geological theory usually makes a general analysis of multiple reservoirs. It uses the structural model to understand the reservoir and has a vague understanding of the reservoir. The actual exploration is inconsistent with the traditional theory, which restricts exploration and development. In this case, taking the lower submember of Sha 1 of Shahejie Formation of L70 fault block in Raoyang sag as an example, the concept of reservoir unit is put forward, and the reservoir is redivided using the “four diagrams and four steps” method, the oil–water distribution is clarified, the type of reservoir unit is defined, and multiple potential reservoir units are proposed. It enriches and perfects the traditional petroleum geological theory, provides a new research method and idea for petroleum exploration and development, and ushers in new opportunities for the developed old oil fields.