Abstract: Under the influences of peculiar reservoir-forming condition and sedimentary environment, the low-permeable oil reservoir has some characteristics, such as the complicated spore configuration, the exiguous pore throat, the low permeability, generally less than 100×10^-3μm², the serious reservoir heterogeneity, the plane permeability varies greatly, the big displacement pressure, existing certain starting pressure, natural fracture growth and existing man-made fracture, etc. Therefore how to establish the effective displacement radius, and the reasonable and economic well density with different permeability, it's important to raise the oil-water displacement efficiency, recovery efficiency factor and exploitation level of the low-permeable oil reservoir. This paper takes the He 135 fault block as an example, studies systematically reservoir heterogeneity and crack of the He 135 block, and founds the reservoir heterogeneity-crack model. Based on the geological study, conform the different technical limited well spacing and economic and reasonable well spacing with different permeability and sedimentary microfacies, and proposing the befitting pattern considering crack.