Abstract:

 The study of detrital composition of sandstones is an important method for understanding provenance types, basinrange evolution and tectonic attributes. The sandstone framework grains of the Xiagou Formation of Lower Cretaceous in western Jiuquan Basin generally show low detrital maturity, characterized by source from recycled orogen and part of magmaticarc. The Xiagou Formation mainly consists of provenances of metamorphic and intermediate acidic volcanic (few sedimentary rocks). The detrital compositions show obvious differences in provenance between the western and eastern area of western Jiuquan Basin. The detrital composition of Baiyanghe Formation is very different from that of Xiagou Formation, implying the changes in provenance attribute. Combined with previous research results, the changes in provenance attribute reflect the evolution of tectonic diversity and basinrange pattern, which control the oil and gas enrichment and the late hydrocarbon accumulation in western Jiuquan Basin. The detrital composition that controls the reservoir space and development law of fractures is worthy of further study.

Key words: western Jiuquan Basin, sandstoneconglomerate reservoir, detrital composition, basinrange pattern, hydrocarbon accumulation