The two-phase flow exists in many industrial activities, for example, in the nuclear energy generation, in the food processing and in the oil and gas extraction and production. This work is related to oil and gas activities, and presents numeric flow simulations in which one phase is gas and the other is liquid, changing the flow pattern. The Two Fluid Model is employed and the conservation equations are discretized with the finite volume method. To solve the algebraic system, the Block TDMA and Sequencial TDMA approaches were implemented and compared. The results indicates that the Block Method has potential, since it requires a smaller number of iterations than the sequential method. However, it demands more computational time in each iteration. Only, when there is a significant reduction on the total number of iteration, the Block method shows a reduction on the total computational time. This happens in simple problems, such as stratified flow. For slug flow situations, the block method presented a greater computational time. In a future research, to reduce the computational time, the coupling between equations can be increased.