| The “Donghe sandstone”here refers to the Lower Carboniferous Donghe sandstone Member (a member of Bachu Formation), which is the typical deep-buried marine clastic reservoir, distributing in Donghetang, Hanikatam and Hadexun areas in the central part of northern Tarim Basin. The heavy-minerals and rock detrital component methods are used in provenance analysis for Donghe sandstone. Based on the distribution illustrations of clustering sample groups, stability coefficients and ZTR maturity indexes of heavy-minerals, as well as the clastic component content and detrital types of the sandstone, it is indicated that the sediments in Donghe sandstone derived from two predominant provenance
systems with different supplying patterns to the study area. According to the seismic reflection features, the plane distribution of detrital components and the grain-size-related hydrodynamic conditions, it is shown that sediments were supplied by the way of wave-dominating delta into Donghetang and Hanikatam from Luntai Uplift on the northwest and by the way of common wave erosion to fill up to lower areas in Hadexun. It is deduced that a mixing zone of both sediments would exist between both of areas. Core descriptions and logging dada analysis have further proved the development of shoreline sedimentary facies from different provenances in the Donghe sandstone areas due to frequent wave reformation. Foreshore sandstone beach subfa cies develops in Donghetang and Hanikatam and foreshore conglomeratic and sandstone beach subfacies is in Hadexun. Mid-upper shoreface subfacies and lower shoreface-neritic subfacies develop respectively in the middle and the south of the study area. |
