Sinopec has topped an annual ranking of the biggest-earning Chinese enterprises for the eighth straight year, showed the latest results.
Energy firms are poised to seek assets overseas to diversify as domestic earnings are depressed by State-controlled prices for processed fuels.
China Petroleum and Chemical Corporation said that its net profits for the first half dropped 40.5 percent year-on-year to 24.5 billion yuan.
China Petrochemical Corp, or Sinopec, Asia's biggest refiner, has made total investments of more than 600 billion yuan ($95 billion) in 55 countries and regions.
Sinopec has established a HK$10-million fund to assist green groups in cleaning up the millions of plastic pellets washed ashore in Hong Kong.
Sinopec Group is to acquire a 49-percent equity interest in Talisman Energy's assets in the North Sea for $1.5 billion.