Diagenesis of the sandstone of Devonian Donghetang Formation in Yuqidong area, Tarim Basin,China and its influence on the reservoirs

Through scanning the thin sections and casting thin sections by electron microscope and other methods.The paper researches the influencing factors of sandstone diagenesis,diagenesis evolution and reservoir development in Devonian System Donghetang Formation of the Yuqidong areas and adjacent areas in Tarim Basin.It is clear and definite that this set of reservoirs in the buried process mainly experienced compaction,cementation,dissolution,metasomatism and authigenic minerals formation process.These reservoirs have reached the B phase of early diagenesis at present.The main factor of destructing the primary pores in early diagenesis is compaction.Cementation includes carbonate cementation,quartz overgrowth,pyrite and cementation of clay minerals.The contribution of the carbonate cementation to the reservoir physical properties is greater than its destruction.The damage of oil reservoirs is attributed to quartz overgrowth,ferruginous cementation and cementation of clay minerals.The important factor of improving the reservoir physical properties is the dissolution of unstable components caused by the carbonated hydrothermal and the organic acid released by humus on B phase of early diagenesis.