STRUCTURAL DEFORMATION CHARACTERISTICS AND THEIR CONTROL ON OIL AND GAS IN KONGQUEHE AREA, THE TARIM BASIN

According to stratigraphic sequence and contact relationship,sediments in Kongquehe area of the Tarim Basin are divided into 3 tectonic layers,and structural units in the region are redetermined based on Paleozoic and Mesozoic structural layers.Faults,mainly striking in NE and NW directions,are divided into 4 groups.There are 5 types of fracture-fold combination patterns,among which the compressional structures are dominant.Structural deformations are both compounding and stacking,with unsymmetrical compound anticlines from east to west and fault-nose structures and slopes from south to north.Vertically,lower Paleozoic is characterized by large nose-1ike uplifts formed from late Caledonian to Hercynian;Carboniferous is characterized by gentle sags and gentle slopes;Mesozoic is characterized by a large slope dipping in southwest direction,forming faulted anticlines during early Yanshanian.Long term tectonic evolutions control the formation of various types of traps.Palaeohighs and palaeoslopes are favorable destinations for hydrocarbon migration.Faults linking to source rocks are basic conditions for hydrocarbon accumulation.Preservation conditions are also critical for oil and gas accumulation.Finally,4 favorable oil and gas exploration targets are pointed out,including interior structures of Cambrian—Ordovician buried carbonate hills in Kunan,Carboniferous anticlines and stratigraphic overlap traps in Caohu,Jurassic and Silurian anticlines in Puhui and Longkou—Weima—Kaiping.