Phase permeability of low-permeable collectors
Low-permeable reservoirs, which comprise a significant part of hard-to-recover hydrocarbon reserves, are studied. The difficulties of their development are associated with the special properties of low-permeable reservoirs and the specificity of filtration in them. The phase permeability of low-permeable reservoirs is determined by the nonlinear filtering parameters. It depends on the values of the initial pressure gradient in the field of high-speed filtration, and in the field of low-speed filtration, on the nonlinearity parameters. Complex relationships between phase and absolute permeabilities for low-permeable reservoirs have been established. It is shown that in the low-speed filtration area, phase permeability is a function of the pressure gradient. The relations of nonlinearity parameters in the power law of filtration in low-permeable reservoirs with absolute permeability and pore space microstructure are established. Ratios between phase permeabilities are determined for linear and nonlinear filtration in low-permeable reservoirs. The principal differences in the phase permeability of high- and medium-permeable reservoirs from the phase permeabilities of low-permeable reservoirs are shown.