Abstract: Compaction,a key factor for reservoir quality evolution and prediction,is generally considered as one of the major diagenesis of sandstones during shallow and intermediate burial instead of deep burial.However,prominent differential compaction is observed in the deep Cretaceous sandstone reservoirs of Kuqa foreland thrust belt and studied in-detail through thin section observation,CL and grain size analysis.Differential compaction of deep sandstone is mainly controlled by grain diameter,cementation and tectonic compression.The compaction degree of the deep sandstone reservoirs shows certain regularities from north to south on different tectonic positions and appears to change inversely with burial depth.Moreover,differentiation of compaction enhances with decreasing cementation.For medium-grained sandstone and fine sandstone,differentiation of compaction lowers along with their compaction degree.The existence of significant diffe-rential compaction in the deep-buried sandstone reservoir implies that much attention should be paiyed to the influence of compaction to reservoir quality differentiation when predicting deep-buried sandstone reservoirs.

Key words: compaction, diagenesis, deeply-buried reservoir, Kuqa Depression, Tarim Basin