China's three State-owned oil giants are ramping up efforts to strengthen international collaboration in oil and gas development, with an increasing focus on transitioning to green energy, said industry experts and company executives.

The companies, collectively known as the "big three", signed contracts worth a total of $488.3 billion during the China International Import Expo (CIIE) held over the past seven years, forging partnerships that not only strengthen international collaboration in oil and gas resource development, but have also provided strong support for China's transition to greener energy in the oil and gas sector, they said.

While China Petrochemical Corp (Sinopec) has signed contracts totaling more than $285 billion over the past seven years, China National Petroleum Corp (CNPC) has secured procurement contracts worth over $127.3 billion with 190 international suppliers, underscoring their commitment to deepening open cooperation.

China National Offshore Oil Corp (CNOOC) saw its cumulative contract value over the past seven years surpass $76 billion, with signed contracts covering a wide range of sectors across the oil and gas industry, including crude oil, natural gas, deepwater oil and gas equipment, and advanced technical services, reflecting a continuous optimization of the procurement structure, it said.

Dai Houliang, chairman of CNPC, said as the energy industry is accelerating its shift toward cleaner, low-carbon, efficient and diversified solutions, the sector should expand oil and gas cooperation to jointly secure global energy supplies while emphasizing the importance of increasing openness and collaboration to accelerate transformation and upgrade efforts.

Foreign oil and gas companies also expressed their willingness to collaborate with the Chinese government, industry partners and local communities to support a low-carbon future in China.

"Throughout Chevron's history in China, partnership is core to everything we do," said Xiong Shu, president of Chevron China.

Chevron has built a solid presence in China over the past decades and it remains committed to working closely across the energy value chain and developing innovative solutions together with its partners here in China, said Xiong.

"Working with our local partners including CNPC, we have been collaborating to produce and supply energy from both onshore and offshore China, participating in a wide range of activities across the entire energy value chain," she said.

An analyst said the ever-growing cumulative contract volume by the "big three" Chinese oil companies at the CIIE underscores China's growing commitment to global energy cooperation.

"As the global energy landscape undergoes profound transformation, with a shift toward cleaner, low-carbon, more efficient and diversified energy sources, the emphasis on expanding oil and gas cooperation remains critical," said Wang Lining, director of the oil market department under the economics and technology research institute of CNPC.

"In this context, the 'big three' are not only focusing on securing oil and gas supplies, but also play a pivotal role in ensuring global energy security amid growing demand and geopolitical uncertainty," Wang said.

"Their increased efforts in liquefied natural gas (LNG) imports, in particular, highlight their strategic push to diversify energy resources and meet the dual goals of energy security and sustainability. This aligns with China's broader energy strategy, which increasingly incorporates clean and efficient solutions alongside traditional fossil fuel investments."

During the recently concluded CIIE this year, Sinopec signed a 15-year deal with TotalEnergies for 2 million metric tons of LNG annually for 15 years from 2028, which is expected to further advance the country's clean energy goals.

In China, natural gas is a key component of green energy transition as it mitigates the intermittency of rapidly growing renewable energies and helps reduce greenhouse gas emissions when it replaces coal in electricity production.