Abstract This paper presents the solutions obtained by using the boundary element method to simulate pressure behavior of horizontal wells in complicated reservoir-wellbore configurations. Three different types of wellbore and reservoir models studied by Jongkittinarukorn (1998) are reported in this study. They consist of a snake-shape horizontal wellbore intersecting a two-layer reservoir with cross-flow, a horizontal or inclined well in a three layer reservoir with cross flow and a vertical well intersecting a two-layer reservoir without cross flow. Special attention was paid to the influence of the wellbore inclination angle, the distance from the wellbore to the different boundaries and the permeability ratio.