Characteristics Cyclicity And Sedimentary Control Of Coal Measures Sandstone Reservoirs In Linxing Block

The depositional environment,sequence stratigraphic framework and typical sandstone development characteristics from the Benxi formation to the upper Shihezi formation in Linxing Block of northeastern margin of Ordos Basin are analyzed,and the vertical development regularity and sedimentary control of the characteristics of the coal sandstone reservoir are also explained.5 sedimentary facies,8 subfacies and 19 microfacies are identified from the Benxi formation to the upper Shihezi formation.By identifying sequence boundary and sequence stratigraphic correlation,Benxi to upper Shihezi formation in the study area are divided into 5 two order sequence and 21 three grade sequence,which are the marginal type of the land surface sea gentle slope basin,the land surface sea gentle slope type,the shallow water deltaic delta type,the gentle slope shallow water braided river delta type and shallow water deltaic delta type in continental lake basin.And the sequence stratigraphic framework is established.Based on the sequence stratigraphic framework,the reservoir characteristics of the typical strata in the sandstone of Qiaotou,Shan member 2,He-8 member and He-4 member are dissected in detail.The results show that the four sections of sandstone have similar cathodoluminescence characteristics and high cuttings content.The four sandstone is from the similar parent rock area.The four stage sandstone quartz and feldspar content reflect the distance between source rocks and tectonic activities of sandstone in each section,which corresponds to the sedimentary background of each sequence.Compaction is the main cause of the deterioration of the physical property of the four typical sandstone reservoirs.The cementation makes the sandstone reservoirs in each section further compact,and the secondary pores produced by the dissolution are the main pore types,which can correspond well with the pore structure.The lithology and physical properties from the Benxi formation to the upper Shihezi formation are vertically cyclical,and can be divided into five cycles from bottom to top,which are controlled by the key layers,sedimentary facies and diagenesis at the boundary of the sequence framework.Joint-mining is not considered in the ?,? and ? cycles,which can be tried in the ? and ? cycles...