Carbonate Cemented Zone in Deep-water Lacustrine Sandstones of Huaqing Area,Ordos Basin:Origin,Distribution and Effect on Reservoir Properties

摘要

1 Introduction Deep-water lacustrine sandstones of Yanchang 63 are characterized by low porosity,low permeability and ultra low permeability with the porosity of 11.5%on average,the permeability of 0.48×10-3 um2,and form a major oil reservoir in the Huaqing field.These well-sorted,poorly rounded,very fine-grained arkoses and lithic-arkose