Abstract:

The palaeouplift in Zhu Ⅰdepression is the most important factor for controlling hydrocarbon. This paper analyzes the conditions and distribution characteristics of palaeouplifts from the qualitative and quantitative views. According to the analysis of regional tectonic and formation evolution, the paper clarified regional distribution characteristics of three level paleouplift tectonics. A three-stages of tectonic evolution was identified for the palaeouplift, including Eocene, Early-Mid Miocene and the Late Miocene. In general, the evolution of palaeouplifts have characteristics of inherited long-term development. Moreover, the paper summarized the palaeo-uplifts geological characteristics of controlling hydrocarbon from three aspects. Firstly, the range of palaeouplifts controlled the distribution of oil and gas reservoirs. Secondly, the tectonic evolution of palaeouplift controlled the types of traps and oil gas reservoir. Thirdly, the position of palaeouplift controlled the direction of oil and gas migration. A geological model and a mathematical model for Zhu Ⅰdepression were established, which based on the application of Multi-factor Matching Model. From this research, the palaeouplifts which controlled the critical reservoiring condition and reservoir controlling rule were clear. Not only the top and upper of palaeo-uplifts controlled 93% of the reserves distribution, but also the oil fields’ number and reserves were decreases with the increase of distance to the top of palaeouplifts. Base on the pattern of palaeouplifts reservoir controlling, the research predicted favorable exploration zones of palaeouplifts in five target layers, which include Dongsha uplift, northern uplift zone, the southwest of Huizhou sag, and the periphery of Lufeng sag, PY4 sag and Enping sag.

Key words: Zhu Ⅰ depression, palaeouplift, characteristics of controlling hydrocarbon, quantitative analysis, prediction of favorable exploration zone