关键词: 成岩作用, 孔隙演化, 沙一段, 歧口凹陷

Abstract:

Yan’an Formation and Yanchang Formation in Mahuangshan region of southern Ordos Basin are typical sandstone reservoirs with low permeability and low porosity. The fractures are the major filtration passages in the reservoirs and they have close relationship with the result of exploitation and the formation of the reservoir. Therefore, the characteristics and the identifications of the fracture are the key research work to the evaluation of the reservoir in this area. At present, the applications of new logging technique can identify fractures effectively, but they are always confined by the limitation of lacking data, and cannot be used in a large scale. The study starts fromthe fractures in the core, analyses the behaviour character of normal logging curve of the fractures in the reservoir, identifies the fractures by stepwise discriminant analysis, and builds up the fracture discriminant model according to the core and log parameters. Through the examination of coring samples and actual application, this model has a good effect.

Key words: diagenesis, pore evolution, the first member of Shahejie Formation, Qikou Sag