Study on Microscopic Pore Structure Classification for EOR of Low Permeability Conglomerate Reservoirs in Mahu Sag

The microscopic pore structure controls the fluid seepage characteristics, which in turn affect final recovery of reservoir. structures different reservoirs vary greatly; therefore, scientific classification is prerequisite for enhancing overall oil recovery. For low permeability conglomerate reservoir Mahu Sag, due to differences sedimentary environment and late diagenesis, various types have developed regions, so it very difficult develop using an integrated method. To effectively solve problem classification, Baikouquan Formation Well Block Ma18, Ma131, Aihu2 are selected as research objects. CTS, HPMI, CMI, NMR, digital cores used systematically analyze micro identify between types, optimize corresponding characteristic parameters classification. results show that Sag mainly intragranular dissolved pores residual intergranular pores, accounting 93.54%, microfractures shrinkage locally developed, 5.63%, other less only 0.83%. On basis clear divided into four based on physical properties parameters. Different good matching relationships with lithologies. Sandy-grain-supported conglomerate, gravelly coarse sandstone, sandy-gravelly matrix-supported argillaceous-supported correspond type I, II, III, IV reservoirs, respectively. From I IV, regular change among which, porosity gradually decrease, displacement pressure median increase, maximum throat radius, average capillary radius becomes worse overall. Apparently, determining type, clarifying its migration rule, formulating a reasonable development plan can substantially enhance rate reservoirs.