STUDY ON RESERVOIR MICRO-CHARACTERISTIC OF CLASTIC ROCKS IN CHANGLING FAULTED DEPRESSION OF THE SONGLIAO BASIN

Based on macro-sedimentary characteristics of clastic rocks and observed by cored samples,several analysis methods such as logging data,rock thin section,casting slice,scanning electron microscope,physical properties and pore structure are used to study the clastic reservoir in Changling Faulted Depression.The result showed that the petrologic types of reservoir in the Changling Faulted Depression mainly include feldspathic lithic sandstone,feldspar sandstone and debris feldspar sandstone.The reservoirs are mainly fractured-porous reservoirs.The physical properties of clastic rocks reservoir is low porosity and permeability or extra low porosity and permeability.The reservoir in this area is characterized by higher drainage capillary pressure and saturation medium pressure value,small pore throat radium and worse pore texture parameters.The stronger compaction-pressolution is the main reasons for the formation of low porosity and permeability.According to the diagenesis stage division,the faulted depression in Dongling area is regarded as A stage of late diagenesis.However,the faulted depression in Yaoyingtai area is grouped into B and C stage of late diagenesis.Combined with evaluation standard of clastic rocks,it was generally considered that the calstic rocks reservoir in Changling Faulted Depression is regarded as Ⅲ or Ⅲ-Ⅳ,and the favorable exploration area is mainly developed in Dongling and Shuangshen Well 1 area,then in Yaoyingtai area.