Types，distribution of sandstone pore of Paleaogene and its controlling factors in beach area, Nanpu sag

Key words:  Paleaogene  secondary pore  genetic type  main controlling factor  Nanpu sag

Abstract:

Pore types, distribution and its controlling factors of the Palaeogene sandstone in beach area, Nanpu sag with low degree of prospecting were studied by using casting thin section analysis，cathodeluminescence and SEM combined with physical property data. The results show that primary residual pores are mainly in depth less than 2.5 km, and secondary pores derived from carbonate, feldspar and cutting dissolution are developed over 2.7 km. There are two secondary pore developed zones of 2.9 -3.3 km and around 4 km in study area. Lower geothermal gradient and higher heat rating are two advantage factors to pore preservation. And the organic acid derived from organic matter degradation maturation controlled the amount of secondary pore. The quality of shallow reservoirs in the formation of Edt was improved because organic acid came from deep maturation beds along activity fault. Three most favorable reservoir development areas are No, 1, No. 2 and No. 4 structural belts of Nanpu sag.