Hi DiogoBarbosa,
were very slow and flat and let w develop his moyos.The sequence from
to 
only widens your territory by a few points (around 6*3, so 18 points). the wall white is getting looks to have much more potential than that (in fact, with the D4 wall opposite, much of this area looks like territory). To say it otherwise, b is building the lines numbered 14 to 16 while he (almost) gives white the rows 4 to 12, this can not be good.An alternative move for
might have been to erase w's moyo. Maybe the shoulder hit at D9 (but this could be too close to the D4 wall), perhaps erasing more lighlty at E10 is better.
Personally I might not choose the R15 direction -- the right side already has so many W stones. I may consider o16 direction,