Abstract: The No.1 block in Jinlou oil field is characterized by high reserves abundance of dense oil,but major reserves have been mobilized after more than ten years development. Because of the shallow depth of burial of the major reservoirⅢ8-9 and the limitation of regular straight well and in- clined straight well,geological reserves of 61×10~4 t is hard to be recovered.On the base of fine pool description,the length of horizontal section and indexes of horizontal well such as hole pattern,spatial position,well track and comple- tion mode arc optimized and defined.After the field practice of the research findings in May 2007,daily output of individ- ual well by steam injection is up to 30～50 t,triple of adja- cent straight well,thus obtaining a superior development effect.