Abstract: In the later stage of development, the exploitation of an oil field should be focused on the low aquifers with medium- or low-permeability. An oil pool engineering often pays more attention to the inhomogeneity of reservoirs and its effects on pool recovercy but less attention to the intraformational interferences caused by different water contents. The differences in intraformational permeability are interpreted as the internal geological factors giving rise to the intraformational interferences. The present paper deals in detail with the differences in order to conduct the well spacing adjustment and intraformational digging.