Effects of microscopic pore structure heterogeneity on the distribution and morphology of remaining oil

Junjian LI,Yang LIU,Yajun GAO,Baoyang CHENG,Fanle MENG,Huaimin XU

Table 1 Classification results of Donghe sandstone reservoirs with different pore-throat structures in Hadeson Oilfield.

Type of pore- throat structure Porosity/% Permeability/ 10-3 μm2 Range of pore-throat radius/μm Range of porosity/% Range of permeability/ 10-3 μm2 Classification result Average saturation of residual oil /% Maximum pore- throat radius Average pore radius Average throat radius Large pore, medium throat 22.90 1 492.6 >20 >15 >8 >20 >500 Class I: Medium- thin throat high permeability type 37.4 Medium pore, medium throat 18.48 812.5 Large pore, thin throat 19.38 1 088.0 Medium pore, thin throat 17.43 270.2 5-20 5-15 2-8 15-20 100-500 Class II: Thin throat medium permeability type 32.1 Small pore, thin throat 9.15 26.2 <5 <5 <2 <15 <100 Class III: Thin- tiny throat low permeability type 46.4 Small pore, tiny throat 4.05 1.4