Calgary, Canada-based PetroKazakhstan Inc said its second half net income rose 53% to US$209.5 million from year-ago levels on income of US$721.4 million, compared with US$503.5 million from second quarter 2003. PetroKazakhstan Inc is a vertically integrated, international energy company into its seventh year of operations in Kazakhstan. It is engaged in the acquisition, exploration,…