Reservoir characteristics and controlling factors of the Triassic clastic rocks in the Liangbei region,Xinjiang

The present paper deals,on the basis of cores,cast sections and scanning electronic microscopic examination,with the reservoir characteristics and controlling factors of the Triassic clastic rocks in the Liangbei region,Xinjiang.The rock types in the Triassic clastic rocks mostly consist of feldspathic litharenite and lithic sandstone which are characterized by low compositional maturity,moderate textural maturity,abundant intergranular solution openings and minor fissures suggesting the moderate-porosity,and moderate-to low-permeability reservoir rocks.The controlling factors of the reservoir development include sedimentary facies and diagenesis.The distributary channel and channel mouth bar sandstones are interpreted to have good porosity and permeability.Affected by meteoric water and organic acids,the dissolution of calcite,feldspar,lithclasts,quartz and matrix result in the generation of abundant solution openings,and thus are believed to be the key factors for the formation of excellent clastic reservoir rocks in the study area.