Abstract: The Pai 66 Carboniferous igneous rocks have a complex lithology and various reservoir space types. There is still uncertainty about favorable reservoir-development characteristics and distribution patterns. However, for effective development of oil reservoirs, it is necessary to analyze the genetic model of the reservoir for guidance on the exploitation of the oil reserves. We used a geostatistical method for analyses, based on the data of the rock cores, imaging, and analysis assays. The results indicate that andesite and tuff are the main rock types in the area. The main reservoir spaces include dissolution holes and cracks. The primary pores alone are unable to form an effective reservoir owing to weak development. After studying the distribution characteristics of three types of reservoirs, an igneous reservoir genetic model was established for this area. This is because the lithology controls the scope of the reservoir, tectonic movement is the immediate cause of crack formation, and diagenesis shapes the development of the present reservoir. A fracture-cavern reservoir is generally distributed along the fault zone, controlled by a favorable diagenetic facies running lengthwise.

Key words: fault, Carboniferous, dissolved pores, fissure eruption, matrix