Horizontal well is of capacity to improve the well production, reduce the development cost, increase economic benefits and other significant advantages, and it has become one of the advanced technique for field development, but with the development of oilfield, it has gradually exposed the problems such as the channeling along the dominant channel, and leading to high water cut and production decline rapidly, as well as the poor understanding on remaining oil distribution. Taking the bottom water reservoir of Nanpu onshore as example, the integrated use of physical simulation, numerical simulation method and data combined with the water exploration to find the approaches to study the reservoir properties, horizontal well trajectory and different development policies with respect to horizontal well water cut change, and the fluidity rule is also studied as well. Herein, we also introduce the new concept to reveal the fluidity rule for different types of bottom water reservoir. For the homogeneous reservoir, we also indicate the water channeling distribution for the horizontal wells with or without dog leg, and for the heterogeneous reservoir, the bottom water is inclined to form the conning in the high permeable zone, and is apron to accumulate the remaining oil in the low permeable area.