China Petroleum and Chemical Corp, or Sinopec Corp, said its crude throughput in the first half of 2012 rose 1.13 percent over a year earlier, easing from a 3-percent expansion in 2011.
Output of ethylene, a building block for petrochemicals such as plastics, rubber and chemical fibre, slipped 4.1 percent in the period, compared to a 9.2-percent growth for the whole of 2011, according to a company statement issued late on Friday.
The figures offer fresh evidence that demand in the world's second-largest energy user was waning in tandem with a slowing economy.
The refiner, Asia's largest, processed 4.43 million barrels of crude per day in the January-June period, or a meagre 26,000 bpd increase over the same period a year ago. Sinopec said the operational figures were yet to be audited.
That compared to its annual target of a 150,000 bpd increase or 3.5-percent growth, meaning the refiner would need to accelerate production in the second half.
Production of diesel, a bellwether of industrial activities, rose only 1.7 percent, the slowest among main refined oil products, which also include gasoline and kerosene.
The fall in ethylene production echoed a slowdown in the Chinese economy, which grew at the slowest pace in the second quarter in more than three years. Petrochemicals are widely used in key sectors, such as automobiles and property, which face lacklustre demand or investment curbs.
Growth in domestic fuel sales also slowed to 2.57 percent in the first six months, compared to 7.6 percent in 2011.
Reuters' calculations based on government data showed China's total oil demand in the first half of the year rose a modest 2.2 percent year on year to about 9.5 million bpd. Oil consumption in the world's second-largest user was up 6.3 percent last year.
Sinopec, due to announce its second-quarter earnings in August, reported in April that its first-quarter profit fell by a worse-than-expected 35 percent due to losses in selling diesel and gasoline and government-controlled rates.
Sinopec, China's second-largest oil and gas producer, recorded 4.33 percent growth in crude oil production at 163 million barrels (896,100 bpd), after a rare dip of 1.9 percent last year, largely because of a fall in production in its African operations.
Sinopec said its overseas oil production rose 82 percent year on year at 11.13 million barrels in the period, which made up roughly 7 percent of its total crude output. The company did not specify where the overseas productions came from.
The following table shows its operational results for the first half of 2012 versus a year earlier. Crude oil output was in million barrels, natural gas in billions of cubic feet and the rest in millions of tonnes unless specified.