Abstract: Through the research on coring analysis,testing data,geological and geophysical well logging data,with the application oil-bearing occurrence,experience statistics and mercury injection parameters method,the lower limit of Chang-6 reservoir in Shangzhenzi area was determined.The research results indicate the lower limit of the lithology in Chang-6 reservoir belong to fine sandstone,lower limit of oil-bearing is oil stains,lower limit of porosity is 7%,lower limit of permeability is 0.1×10~(-3)μm~2,lower limit ofresistivity is 20Ω·m,lower limit of acoustic travel time is 220μs/m and lower limit of water saturation is 60%.