Diagenesis characteristics of carboniferous Donghe sandstone in Hudson area of Tarim Basin

Deposited at transgression background in Late Devonian to Early Carboniferous，Donghe sandstone is a set of transgression sandstone (gravel).Its main body is shore sandstone and the main sedimentary facies is terrigenous... [ view full abstract ]

Deposited at transgression background in Late Devonian to Early Carboniferous，Donghe sandstone is a set of transgression sandstone (gravel).Its main body is shore sandstone and the main sedimentary facies is terrigenous clastic shore epeiric facies. The carboniferous Donghe sandstone in Hudson area of Tarim Basin are quartz sandstone sublitharenite sandstone, whose compositional maturity and textural maturity are both high. The main diagenesis of the study interval in this region are compaction, pressure solution, metasomatism and cementation. Calcitic cementation is the main cementation. The content of calcareous cement shows rhythm with depth change, which is in inverse proportion with the siliceous cement content. Compared with the content of calcareous, the siliceous cement content is far more less, which has a strong inverse correlation with average particle size and the matrix content. The calcareous cements distribution shows a zontal characteristics. There are two kinds of reservoir diagenetic sequences: compaction before cementation, and compaction after cementation. The both kinds have relationship with calcium content. The calcium content of former is less than 15%, while calcium content of later is more than 15%.