The anisotropy of distribution of volcanic reservoir property is very strong, thus it's a difficult but important task to seek the distribution regularity of volcanic reservoir property in oil and gas exploration and development. Base on the bore cores, their experimental data and so on, the vertical distribution regularity of reservoir property of Carboniferous volcanic rocks in Dixi area has been summarized for the aspects such as the best section of reservoir property among cores, the worst section, the distribution patterns of reservoir property for the weathering crust of volcanic rocks, for the thin lava and for the thick lava. Meanwhile, the horizontal distribution regularity also has been analysized. The vertical diversity of reservoir property of lava is mainly controlled by lithofacies in diagenesis stage and by tectonism, weathering, dissolution and so on in later stage. Affected by lithofacies in the diagenesis stage, the upper subfacies and lower subfacies of effusive facies are likely to form good reservoir property. For example, the core box #1 from Dixi401 well is one of the sections with best reservoir property among all the volcanic cores in Dixi area, which is mainly influenced by the factors of lithofacies in diagenesis stage, partly combined with the factors of thin bed lava, and so on. The thin bed lava interbedded with clastic rocks often has good reservoir property, typically as Dixi173 well. For thick lava interbedded with clastic rocks, the bottom part is always in good reservoir property, followed by the top part, while the central part is often in poor reservoir property. A typical example is the thick bed lava composed of core box #10 and #11 from Dixi1414 well that shows good conformability to this distribution pattern of thick lava. In particularly, the central part of this thick bed lava is one of the sections with worst reservoir property among all the volcanic cores in the study area. The vertical zoning structure for a weathered crust can be divided into 5 zones composed of weathered clay layer, strongly weathered zone, moderately weathered zone, weakly weathered zone and unweathered zone. Among the 5 zones, the moderately weathered zone often has relatively fine reservoir property. Such as the moderately weathered zone situated in the core box #3 from Dixi18 well performances a relatively fine reservoir property. Evaluating the degree of weathering of volcanic rocks in Junggar basin by using a new tool named W index of weathering shows a multi-stage weathering process and a large number of unweathered, weak weathered and moderate weathered volcanic rocks remained, from which some lithology sections with excellent reservoir performance can exist. From the view of planar distribution maps, the reservoir property of volcanic rocks in study area is featured by a strong anisotropy, often enriched locally (such as drops 401, drop the west near well 172) and change rapidly at random.
