关键词: 关键词：阿瓦提凹陷, A 井区, 构造特征, 油气地质条件, 塔里木盆地

Abstract: Abstract：Few large oil and gas fields have been presently discovered around the Awati Sag in western Tarim Basin. However，
in recent years，with both the improvements of drilling technology and level of understanding，it is obviously urgent to carry
out related re-evaluation upon those potential favorable structural traps or zones. In this paper，based on previous studies，
using both pre-existing and newly-obtained 2D seismic data covering the A structure together with drilling data，we firstly
conduct seismic data interpretation and delineate structural maps of key reflector layers（the bottom surface of the Tertiary and
the top surface of the mid-upper Ordovician limestones）. The results show that the A structure is an integrated compressional
anticline trending NW-SE within the Mesozoic-Cenozoic interval，but within Palaeozoic interval it is a large-scale thrust-diapir
domal anticline structure，which is quietly different from previous understanding. Further analysis on oil and gas conditions
indicatethatthethrust-diapirdomalstructurepossessessomeessentialelementsforformingpotentialgiantreservoir，including：
1）a large-scale trap with an area of 260 km2and a closure height of 1 100m；2）location beside available source rocks of
the mid-upper Ordovician blocked-trough；3）fractured reservoir of the Upper Cambrian–Middle Ordovician carbonate rocks；
4）lateHercynianpaleostructuraltrapconditiontogetherwithcontinuoushydrocarbonchargingfromCretaceoustothepresent；
5）massive shale sealing condition as well as the fault sealing condition within the shale beds. The adverse factors for this
structure are its depth of burial with target layers up to 6 400∼7 500 m，and may be affected by the neighboring large-scale
volcanic intrusion to its northeast.

Key words: Key words：North Awati Sag, A Well Area, structural feature, hydrocarbon geological condition, Tarim Basin