Abstract: S7 block in Jiangsu oilfield is characterized by complex geologic conditions, small structures, thin reservoirs and low permeability. When geometric steering technology is used to drill horizontal wells in this kind of oilfield, it is very difficult to penetrate the optimum geologic targets. Geosteering technology is used and the effects are good. Resistivity and gamma ray logging while drilling are used to guide the real time adjustment and control of well trajectory in S7P1 horizontal well. Proposals are presented for utilization of geosteering drilling technology in this block.