Y3 fault-block of Shengli oilfield is a typical small complex fault-block oil reservoir. In order to further explore the potential of this kind of reservoir, surrounding water cone horizontal well is used on the basis of recognizing the enrichment pattern of remained oil distribution. This paper analyzes the characteristic of the reservoir of Y3 fault-block, introduces the design and drilling construction of the first surrounding water cone horizontal well-Y3P6 well and illustrates some technical difficulties and countermeasures in this well construction. By the successful operation of this well, it is proved that the surrounding water cone horizontal well is suitable for the potential tapping of remaining oil in old oil region of Shengli oilfield with popularization value.