Reservoir Evaluation And Petroleum Pool Formation Model Of CB 30 Hidden Hill In Chendao Oilfield

Hidden hill petroleum reservoirs are characterized by a complicate combination of rock types, heavy weathering and erosion of strata, strong effects by multi-tectonic movements and fault activities, and deep burial, which lead to great difficulties for exploration and development as well as well data explanation. Up to now, there have been no systemic methods suitable to evaluate hidden hill reservoirs and petroleum pool formation model. CB30 structure unit from the Chengdao Oilfield is a typical hidden hill petroleum pool , rich oil and gas resources. The reservoir is Precambrian metamorphic rocks and early Paleozoic carbonates, and the source rocks are the Tertiary dark mudstones. Since this area is located at offshore, with the addition of not enough research and exploration work which was carried out, there have been many questions about reservoir evaluation and petroleum pool formation. In this study, a combination method has been applied which integrated different fields including tectonics, reservoir geology, petroleum geology, geophysics and organic geochemistry and so on, to investigate reservoir properties, petroleum origin, source rock petroleum generation history, petroleum pool- filling time and petroleum pool model. Some important results have been obtained: (1). A method has been suggested to identify reservoir types, and evaluate different kinds of porosity by means of systemic well data and the geological distribution of type I and type II reservoirs has been evaluated by this method. (2). Hydrocarbon generation kinetics method has been used to evaluate petroleum generation history of the source rocks and it has been realized that the significant source rocks of the CB 30 hidden hill are the ED2 and ES3 source rocks distributed in the slope area of the Bazhong Depression. (3). The petroleum pool model of the CB 30 structure unit has been established. It is hidden hill petroleum pool with fissure-cavity reservoirs, originated from deeper source rocks. This results are not only a case study of hidden hill petroleum pool, but provide very important guide to the petroleum exploration in this area.