Answer

No. First, the default assumption is that it is for its own sake. If you are studying, it is presumably for the sake of the commandment. Second, it is enough to say before learning that it is being done in order to fulfill your obligation. You do not need to have intention at every moment in any ongoing commandment, and especially not in learning, where it is impossible to intend this at every moment, since you are thinking about the learning itself. Third, there is no obligation to study Torah beyond reciting the Shema morning and evening, so in any case no intention is required in order to fulfill the obligation.