The most prominent challenge associated with offshore horizontal drilling is wellbore stability. In this paper, simulation of in-situ stresses around the wellbore is conducted to study the effects of transient pore pressure on the stability of horizontal wells. The rock mechanical analysis based on finite element technique lead to investigate a unique behavior found in subsea horizontal wells known as transient pore pressure behavior and near wellbore pressure gradients. The results demonstrate that near wellbore pore pressure gradient is only active in rock formations which possess transient pore pressure behavior; therefore, simulated solutions require adjustment to achieve accurate results.