Abstract: Amu Darya Basin in Central Asia features in complex structural deformations and multiple types of traps for natural gas accumulation.The major factors controlling gas accumulation in various reservoirs have both similarities and differences.In order to reveal reservoir distribution and select new targets for next phase of exploration in the Basin,reservoir and single well production data and geophysical data are integrated with regional geological characteristics,depositional settings and reservoir property to analyze the reservoir characteristics in the targeted area.It is suggested that two common controlling factors have played main roles in the formation of the natural gas reservoirs in the region.Laterally,gas reservoir distribution were controlled by the development of paleo-highs and reef complex,and the paleo-highs provided favorable structure settings for hydrocarbon accumulation and formation of effective reservoir spaces from exposure and dissolution.Meanwhile,the structural highs are the preferential target areas for hydrocarbon migration and accumulation.Vertically,gas reservoir distribution was controlled dominantly by trap conditions and carrier systems like faults,unconformities and permeable sandstones.These factors jointly controlled the spatial distribution of natural gas reservoirs.Based on the analysis,it is recommended that exploration of the lower play should be focused on the target areas with well-develo-ped reef complex within paleo-highs,fault/unconformity carrier systems and evaporite cap rocks.In contrast,exploration of the upper plays should be focused on areas where well-developed reef complex within paleo-highs are overlain by the Cretaceous mudstone seals outside the pinch-out areas of the lower evaporates.

Key words: reef complex, fault, paleo-high, gas reservoir, Amu Darya Basin