Senlac/Winter horizontal well performance is characterized by a short period of high-oil-cut production followed by water cut increases over a several month period to very high water cuts. Previously, the more viscous high-oil-cut fluids have typically been trucked to more distant treating facilities, while the subsequence high-water-cut fluids have been pipelined. This project was initiated to field test the feasibility of a novel method of transporting early life high-oil-cut fluids using high-water-cut fluids from mature wells as the push water, thereby reducing capital costs, operating costs, and environmental risk. The push water system worked well, indicating that Senlac area development can be considered for areas more distant from facilities. Further when the produced water cuts increased sufficiently to be pipe-lined without push water, the push water source line was reversed and is now being used to enhance the capacity to carry produced fluids from the new well area to the treating facilities. This paper discusses the design and operation of the push water system. Also discussed is the phenomenon of core annular flow of heavy oil/produced water mixtures, which may be spontaneously occurring at the conditions in the Senlac Push Line.