China Petroleum and Chemical Corp or Sinopec, one of the world's largest refiners, continued to lead its peers in net profits for three consecutive years, thanks to its refining and downstream integration advantages.

Net profit of Sinopec reached 63.09 billion yuan ($9.4 billion) for 2018, a year-on-year increase of 23.4 percent, the company said in a statement to the Shanghai Stock Exchange.

It was followed by China National Offshore Oil Corp, the nation's largest producer of offshore oil and gas, with 52.7 billion yuan, up 113.5 percent, compared with the same period of the previous year, and China National Petroleum Corp, the country's largest oil and gas producer and supplier, with a net profit of 52.59 billion yuan, up 130.7 percent year-on-year.

Analysts said Sinopec's continuous lead has mostly to do with the steadily growing demand for chemical products in the country and the company's adjustment to the country's stringent environmental regulations.

The company said earlier it will continue enhancing its competitiveness in refining and the sales sector, shifting to high-end chemical business.

Operating profit of the refining segment of the company totaled 54.8 billion yuan, with that of the chemicals segment reaching 27.0 billion yuan and the marketing and distribution segment seeing 23.5 billion yuan.

Against the increasing demand for natural gas in the past few years, Sinopec has also been pushing ahead with the construction of natural gas facilities, supply, storage and a marketing system, increasing natural gas production and sales volume.

Li Li, research director at energy consulting company ICIS, said Sinopec's leading position in net profit is within expectations, as the low oil price cycle since 2014 is beneficial for the downstream sector players.

All the three Chinese national oil giants will raise their capital expenditure in pursuit of higher energy output, part of the government's effort to raise domestic output to bolster national energy security.

Planned capital expenditure of Sinopec this year will be 136.3 billion yuan, compared with 118 billion yuan in 2018. Most of the investment will be in oil and gas capacity construction including the Shengli oilfield in Shandong province, China's second-largest oilfield complex, and Fuling shale gas field in Chongqing, as well as construction of domestic gas pipelines and storage and overseas oil and gas projects.

China has become the world's largest crude and gas importer, importing 440 million metric tons of crude oil and 125.4 billion cubic meters of gas in 2018, up 11 percent and 31.7 percent year-on-year. The foreign oil and gas dependence ratio reached 69.8 percent and 45.3 percent, according to China National Petroleum Corp's Economics and Technology Research Institute.