Abstract: With principle of conformal transformation and mirror reflection, a mathematical model of flow field in a mixed injection production well pattern was established. Five point horizontal well and vertical well pattern are used for an example. Mathematical expressions of potential function and stream function are derived. Distribution maps of potential line and flow line in a mixed injection production well network with five point method are obtained. Influence of key parameters on internal flow field distribution of mixed injection production well network is analyzed. It shows that at both ends of horizontal well flow lines are relatively dense, and liquid producing capacity at both ends is stronger. The longer the horizontal section, the greater the discharge area of flow line control. As horizontal well is 45 degree angle with vertical wells connection line, displacement effect of horizontal well is relatively good. As horizontal well is perpendicular to direction of main permeability, streamlines are concentrated to production well. Linear displacement is formed and the displacement effect is good. As horizontal well is off center position greater, streamline distribution density differentiation is more obvious.

Key words: mixed well pattern, five point pattern, conformal transformation, potential function, stream function