Solid first-half profits at China’s state-owned oil companies have paved the way for further expansion overseas as the country’s oil needs continue to rise.

Sinopec, the world’s second-largest oil refiner, said on Sunday it intended to raise up to Rmb50bn ($7.8bn) through the sale of bonds and convertible bonds to fund projects, boost working capital and pay debts. The instruments will be issued or placed with existing shareholders, Sinopec said.

The fundraising plan accompanied the company’s announcement of a 12 per cent rise in net profit to Rmb41bn, in the first half of the year, beating analysts’ expectations.

Results were rosier still for offshore producer Cnooc, which reported first-half net profit of Rmb39bn, up 51.4 per cent, despite production disruptions from a recent oil spill.

PetroChina, the listed subsidiary of China’s largest oil and gas producer China National Petroleum Corporation, reported net profit of Rmb66bn for the first half, up 1 per cent from a year earlier, the weakest profit growth among its peers. Profits at both PetroChina and Sinopec were dented by Beijing’s price controls on fuel, which capped gasoline and diesel prices this spring even while Brent soared above $120 a barrel.

Analysts agreed Chinese oil companies were likely to sustain interest in overseas acquisitions as they seek to grow their production base.

China is the world’s biggest energy user and second-largest consumer of oil, after the US. Its state-owned oil companies have emerged as a big force in global mergers and acquisitions in the past five years, as they carry out their mandate to improve China’s energy security by pinning down new supplies of oil.

Big Chinese oil deals this year include Cnooc’s $1.3bn investment in shale oil projects with Chesapeake Energy of Oklahoma, and more recently Cnooc’s $2.1bn purchase of Opti Canada, an oil sands producer.

But other prominent deals – including PetroChina’s proposed $5.4bn tie up with Encana, the Canadian energy company – have fallen through, underscoring the difficulties of M&A at a time of volatile crude prices.

Some industry executives also point out that recent leadership changes at China’s state-owned oil companies may damp M&A activity this year as people settle into new roles.

In a state-directed reshuffle this spring, Fu Chengyu, Cnooc chairman, was appointed chairman of Sinopec, while Su Shulin, Sinopec president, was promoted to a political role in Fujian province.