THE DIAGENETIC CHARACTERS OF PUTAOHUA CLASTIC RESERVOIRS IN HARWEN AND LONGNAN AREAS SONGLIAO BASIN

The major rock types of Putaohua clastic reservoirs in Harwen and Longnan areasinclude fine-grained sandstones such as feldspathic litharenite, lithic arkose, feldspathicquartzose sandstone, lithic quartzose sandstone, lithic sandstone and addingly slightlysiltstone or argillaceous siltstone as well. The reservoir rocks with lower compositionalmaturity, medium-well sorting nature and subsharp-subcircle roundness have beengreatly influenced by the following diagenetic processes as mechanical compaction, ce-mentation, replacement and dissolution. The initial pores have been modified to someextent and the new-generated compressed pores and secondary pore spaces presented atthe same time. The reservoir rocks have undergone B subperiod of late diagenetic stage.