| The Upper Permian Changxing and Lower Triassic Feixianguan Formaions are good reservoirs in LG area,Sichuan Basin. The Changxing reservoir comprises two types of pores, Type LG-Ⅰ( in the platform margin) and Type LG-Ⅱ(in the inner platform). The former commonly is intergranular and intercrystalline dissolved pores and the latter mainly is visceral foramen and case wearing pores. The Feixianguan reservoir comprises intergranular/innergranular pores, intercrystalline dissolved pores and moldic pores. These reservoirs are all of rich fractures and or pores but the development of fractures or effective fractures is observably differential between the both, which means that the number
of effective fractures in Changxing Formation is 2 to 5 times as high as that in Feixianguan Formation and the Changxing contributes much more fractures，cracks and pores than the Feixianguan. Changxing Formation is 24.62 m thick in average and develops in a limited scale and exhibits poor continuity while Feixianguan Formation is 39.15 m thick in average and does better continuity in the central LG area. |
