The cementation factor of Archieʹs equation for shaly sandstone reservoirs

The cementation factor, m, of Archieʹs equation has specific effects on electric conduction processes in porous media. It depends on the shape, type, and size of grains; the shape and size of pores and pore throats; and the size and number of dead-end pores. The dependence of m on the degree of cementation is not as strong as its dependence on the shape of grains and pores. Therefore, it is suggested that it is more accurate to call m “shape factor” instead of “cementation factor”. In this study, m was derived from well-log data for the Hibernia and Terra Nova reservoirs in the Jeanne dʹArc Basin, offshore of the eastern Canadian coast. Empirical equations, linking m, tortuosity, pore-water resistivity, and electric and hydraulic anisotropy coefficients, were obtained. The cementation factor (shape factor) is not a constant, but is a variable depending on many physical parameters and lithological attributes of porous media. An average value of 2.28 was obtained for m, which can be used for similar reservoirs.