A Study On Heterogeneities Of Chang 8₁ Reservoir Of The Yanchang Formation At Baimanan Area In Ordos Basin

Ordos Baimanan area is located on the southwestern Yishan slope of Ordos Basin. The structure is gentle, nose-like uplifts is partly distributing. The mian type of reservoirs is lithologic reservoirs. Chang 8₁ mainly developed lake Delta deposit, Chang 8₁ in Baimanan area developed delta deposit at the background of lake sediment. Sandbody developed in Chang 8₁ layer, Chang 8₁ is one main layer that control the oil reserves.Compositive analyze the well logs and drilled cores from the predecessors, The main types of rock is sandstone, In addition, there is a few of lithic sandstone. The maturity of composition is on low side and structural maturity is middling. Directional distributing of clasts and horizontal enrichment of biotite are usually seen in study area.At the same time, summarize research results from the predecessors, The type of interstice of the reservoir rock is mainly macro-pore, micro-pore, mixed pore, compact pore in the study area . The properties of pore and permeability direct affected by the development of pore and permeability,so, the preconditions to the study of heterogeneity is research into the pore structure. The sandstone had undergone compaction, cementation, metasomatism, dissolution and fracturing diagenesis. summarize research on the pore structure and diagenesis from the predecessors,the main factors of Chang 8₁ layer predecessors are pore structure and diagenesis.The heterogeneity character of reservoirs is mostly inner cause affecting oil, gas and water seeping and oil and gas recovery ratio. The macro-scale heterogeneity of reservoirs included horizontal heterogeneity, Intralayer heterogeneity, Interlayer heterogeneity and heterogeneity of porosity and permeability. Show the main heterogeneity of reservoirs by correlative parameter that calculated from porosity and permeability of sands . Indicate that horizontal heterogeneity is strong , Intralayer heterogeneity is weak and Interlayer heterogeneity is strong in the Chang 8₁ layer of reservoirs in the Ordos Baimanan area.Water displacing oil experiment use the micro-real-sand model , from the general observation of the course of water displacing oil experiment dynamic analysed the affect factors of the microscopic water displacing oil, confirm the relationship between distributing of...