Study Of Permeability Heterogeneity Of Sandstone, Mudstone And Coal

The heterogeneity of permeability of sandstone, mudstone and coal has a major impact On the amount of oil and gas migration. Through the experiment of permeability in parallel and vertical dimension of porous sandstone and mudstone, the experiment of permeability in parallel and vertical dimension of fratured sandstone and porous sandstone, the permeability experiment of porous sandstone in the increasing and reducing process of pressure, the permeability experiment of fractured sandstone in the increasing and reducing process of pressure, the permeability experiment of porous mudstone in the increasing and reducing process of pressure, the permeability experiment of fractured mudstone in the increasing and reducing process of pressure, the permeability experiment of fractured coal in the increasing and reducing process of pressure, this paper analysis the permeability heterogeneity of sandstone, mudstone and coal in Upper Paleozoic of Ordos basin. The conclusions as follows:1.Permeability characteristics of the heterogeneity of sandstone(1)The permeability of porous sandstone in parallel planes direction is greater than that in vertical level direction. When the pressure that perpendicular to level increased the permeability that parallel to the level decreased greatly; When the pressure reduced the permeability rose again but it did not go back to the original permeability. When the pressure that parallel to level increased the permeability that perpendicular to the level decreased greatly; When the pressure reduced the permeability rose again but it did not go back to the original permeability.(2)Fractured sandstone permeability is much greater than the permeability of the sandstone not developing cracks. The permeability ratio of fractured sandstone and porosity sandstone is generally between 12833.0 and 795127.0.(3)The relationship between stress and fractures direction of sandstone influences the changes of permeability. When the applied stress direction perpendicular to the crack, with the pressure increases the permeability reduces and the range is great; When the pressure reduces, the permeability increases but in a lesser extent. When the applied stress direction and fractured in the same direction, with the pressure increases, the penetration rate increased and decrease; pressure decreases, the permeability generally decreased.1.Permeability characteristics of the heterogeneity of mudstone and coal(1)Argillaceous rocks and coal rock, whether the presence of cracks, the permeability parallel to the direction of the penetration level is greater than that in the vertical level direction; When the rock fractures exist in argillaceous rocks and coal rock, the permeability is greater than non-fracture permeability in argillaceous rocks and coal.(2)When the pressure that perpendicular to level increased the permeability of porous mudstone that parallel to the level decreased greatly; When the pressure reduced the permeability rose again but it did not go back to the original permeability. When the pressure that parallel to level increased the permeability that perpendicular to the level decreased greatly; When the pressure reduced the permeability rose again but it did not go back to the original permeability.(3)The permeability,in vertical dimension,of the fractured mudstone and coal, decreased when the pressure perpendicular to level and parallel to level increased. With the pressure that perpendicular to level and parallel to level reduced, the permeability rose back in different rate but not to the original level.