Complex sentence: In 2002, he had been granted a three-year H1-B visa for skilled workers, and after his marriage he petitioned to become a permanent resident, and was granted a green card in 2006.
Split into simpler sentences: In 2002, he had been granted a three-year H1-B visa for skilled workers. After his marriage, he petitioned to become a permanent resident, and was granted a green card in 2006.