Based on the narrow strip and continuous distribution of subaquatic distributary channel sand bodies, as well as small sheet and strip shaped subaquatic distributary inter river sand bodies, the sand bodies in the S area of the northern part of B oilfield are mainly developed. The horizontal phase transformation of the sand bodies is fast, the thickness is relatively thin, gradually decreasing from north to south, and the single-layer thickness is small. This article focuses on the problems of high water cut stage, low degree of water drive control, insufficient formation energy, decreased oil recovery rate, decreasing potential for measures, diverse well network forms, and significant differences in development effects in the S area of northern B oilfield This paper redefines the development units,for the problems of diverse well patterns and different development effects in the area of S in the north of B Oilfield, it analyzes the development effect of different well spacing and well pattern, according to the degree of water flooding control, water-cut increasing rate, the curve relationship between recovery percent of reserves degree and comprehensive water content. Through comprehensive analysis, it is concluded that the adaptability of well pattern with small well spacing is better. It is considered that by reasonably reducing well spacing and increasing well pattern density, optimizing the well network,the injection-production relationship of single sand body can be improved, the production degree of reservoir can be enhanced, and the overall development level can be improved.