Abstract: Abstract：Based on drilling and logging data analysis，this paper studies the high-resolution sequence stratigraphy and palaeo-
geography of Cretaceous in northwest Tahe Oilfield by combining wells with seismic data. The Cretaceous can be classified
into 1 huge cycle，3 super-long-term cycles，6 long-term cycles and 16 medium-term cycle sequence，shown as transgressive
to regressive sedimentary cycle，where 3 kinds of sedimentary systems can be recognized；braided river delta，meandering
river delta and lacustrine deposit，representing 3 periods during lake basin evolution. The palaeo-geography features of each
long term cycle sequence are also discussed by combing with seismic properties analysis. The source of Cretaceous in this area
mainly came from ancient Tianshan Mountains，with sedimentary facies belt distributed as south-north direction. Various sand
bodies gradually pinch-out southwards and are prone to form structure-lithology composite trap since they are controlled by the
modern structural pattern of“the south part being higher than the north”.

Key words: Key words：Tahe Oilfield, Cretaceous, high-resolution sequence, sedimentary system, palaeo-geography