The reservoir-forming model of buried-hill and reservoir prediction in Jiyang depression

摘要

In this paper, by analyzing the trapping conditions and reserving properties of buried-hill oilfields, reservoir-forming conditions of buried-hills are summarized , many types of buried-hill reservoirs such as fault block, unake, folded and stratigraphic unconformity etc. are classified, the reservoir-forming mechanism and model are further studied and revealed . Fractures can act as important reserving spaces in buried-hill pools, although a single fracture is hard to recognize on seismic section, the fracture belt shows some variation features. Buried-hill reservoirs are predicted by analyzing geophysical features of fracture reservoirs and by applying the logging-constrained inversion technique, absorbing coefficient technique, seismic facies classification and coherence analysis. Four reservoir description techniques above have made good applied results in buried-hill Chegu 201. Numerous and large-scale Archaeozoic, Palaeozoic and Mesozoic buried-hills occur in Jiyang depression. The reservoir space is dominated by fractures. The exploration of Jiyang depression began in the early of 1960s. The exploration drillings reached to Teritiary were 965, 284 of them got industrial. hydrocarbon flow. 20 buried-hill reservoirs were found which distribute in three depressions such as Zhanhua, Chezhen and Dongying. The oil-bearing area of Jiyang depression is 107.4km~2 , the geological reserve is 1.34 X 10~8t. The buried-hill reservoirs, such as Yihezhuang, Zhuangxi, Chengdao, Chegu 201 have been found during several decades. With discovery of buried-hills, the knowledge of buried-hills of geologists has been improved. With the exploration improvement of Tertiary, buried-hill reservoirs become one of the next key points of Shengli Oil Field. The hydrocarbon production of buried-hill is related to growth of fractures. So researching the exploration technology of fractured reservoir in buried-hill is important for breakthrough and discovery of pre-Tertiary reservoir.