1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. Jilin Land Surveying and Planning Institute��Changchun 130061��China; 3. Geological Institute of Jilin Province��Changchun 130012��China

Based on the observation of drilling cores��petrographic slides��cast slides and measurement of mercury intrusion porosimetry��the petrological characteristics and physical property evolution of the Devonian reser- voirs in Bachu-Maigaiti area of Tarim Basin have been studied�� The results show that the reservoir rocks mainly consist of quartz sandstones and lithic quartz sandstones�� The Devonian Donghetang Formation was deposited in a littoral sedimenrary environment�� The foreshore sands��developed in primary porosity��have the best reservoir physi- cal properties with the ultra-low porosity and ultra-low permeability�� The Devonian Kerziertag Formation was deposi- ted in a deltaic-tidal flat sedimenrary environment�� The distributary channel sands are shown as ultra-low porosity and ultra-low permeability��or low porosity and low permeability reservoirs because of well-developed secondary po- rosity�� Compaction and siliceous cementation are ubiquitous in reservoir sands��and the latter one is often shown as overgrowth quartzes�� Carbonate cementation is relatively common in the reservoirs��filling pore spaces or experien- cing metasomatism with other clastic grains�� Such cementation serves to decrease the reservoir porosity and permea- bility��therefore shown as destructive diagenesis�� Dissolution significantly impacts reservoirs by improving their physical properties��shown as constructive diagenesis��