Micropore Throat Structure and Movable Fluid Characteristics of Chang 63 Tight Sandstone in Baibao Area of Ordos Basin

Tight sand is an important unconventional reservoir. Aiming at the problem of large unused reserves and poor development effect Chang 63 reservoir, this paper researches reunderstanding reservoir evaluating reserves. Employing rock slice scanning electron microscope (SEM), experiment low-field nuclear magnetic resonance (NMR), water-oil relative permeability experiment, space, movable fluid, oil-water seepage characteristics was studied. The factors affecting NMR T 2 cutoff, controlling fluids, displacing efficiency in tight sandstone reservoirs are discussed. study demonstrates that (1) mean pore volume 4.4% 0.068 mD, respectively. pertains to sandstone, mainly intergranular dissolution pore, intercalated materials chlorite illite. (2) characteristic id="M2"> spectrum has bimodal can be subdivided into two classes: left peak dominant right dominant. value mobile fluid saturation 17.9%. (3) According curve pattern, it divided four categories, bound water 29.9%. average irreducible oil 40.6%. flooding 40.2%. (4) better pore-throat relationship, lower id="M3"> stronger ability migration ability, higher a percentage active fluid. low-permeability affected by reservoir’s physical property structure.