Characteristics and genesis of Chang 4+5 tight reservoir in Dingbian area
In view of the unclear physical properties of Chang 4+5 reservoir in Dingbian area,based on core observation and sampling,the samples of Chang 4+5 reservoir were tested and analyzed by using cast thin section,scanning electron microscopy,mercury injection and well logging.The results show that the delta front sedimentary sub-facies are developed,the lithology is mainly of feldspathic sandstone and lithic feldspathic sandstone,and the pore type is mainly of inter-granular pores.The porosity is 3.4%～15.5%,with an average of 12.2%,and the permeability is 0.05×10-3～3.7×10-3 μm2,with an aver-age of 0.57×10-3 μm2,which belongs to low and ultra-low porosity and permeability reservoirs.The main factor affecting reservoir quality is compaction,followed by cementation.The porosity loss caused by compaction is 22.4%,with a loss rate of 55.7%;while by cementation is 8.27%,with a loss rate of 20.6%.The dissolution improves the physical properties and helps to preserve the original pores,and the contribu-tion rate to the porosity is 2.93%.
国家科技期刊平台
NSTL
万方数据
