CNOOC expands oil and gas reserves with Beibu Gulf breakthrough and Bohai Sea project

CNOOC Limited has achieved a major breakthrough in offshore oil and gas exploration with a significant discovery in the Beibu Gulf Basin, reinforcing its position as a leader in China’s offshore energy sector. The company’s latest find in the Weizhou 10-5 oil and gas field marks a turning point in the exploration of buried hill reservoirs, an increasingly important focus for energy security and resource expansion.

Located in the Beibu Gulf of the South China Sea, the Weizhou 10-5 oil and gas field sits in waters approximately 37 meters deep. The WZ10-5-1Sa exploration well has identified an oil and gas pay zone extending 283 meters and reaching a total drilled depth of approximately 4,840 meters. Initial test results indicate daily production of 13.2 million cubic feet of natural gas and around 800 barrels of crude oil, highlighting the field’s strong potential for long-term development.

This discovery represents a significant step forward in unlocking hydrocarbons from granite buried hills in the Beibu Gulf Basin. These geological formations, characterized by complex reservoir structures, present both challenges and opportunities for offshore exploration. In recent years, buried hill reservoirs have gained attention due to their potential to yield substantial hydrocarbon reserves, making this discovery particularly valuable for China’s energy strategy.

What Makes Buried Hill Reservoirs in the Beibu Gulf Basin a Valuable Energy Source?

Buried hill reservoirs have become an essential focus for offshore exploration, particularly in areas like the Weixinan Depression, where carbonate formations serve as major hydrocarbon reservoirs. The Beibu Gulf Basin discovery is crucial in advancing geological understanding and optimizing extraction techniques for these complex formations.

Geological studies of the Weizhou 10-5 field reveal that the carbonate buried hill reservoir consists of karst formations that have been shaped by tectonic activity and long-term weathering. These formations are divided into different zones, with the epikarst zone and runoff corrosion zone demonstrating the best reservoir properties for hydrocarbon accumulation. The reservoir’s natural gas is believed to originate from oil shale in the Liushagang Formation, with hydrocarbons migrating through fault networks that have been active since the early Holocene period.

The impact of multistage tectonic uplift has further enhanced reservoir potential by creating extensive storage space for hydrocarbons and facilitating migration conditions for oil and gas accumulation. This discovery reinforces the importance of buried hill reservoirs in supporting long-term energy production while improving the efficiency of offshore exploration techniques.

How Will the Beibu Gulf Discovery Shape Offshore Energy Development?

CNOOC Limited’s success in the Beibu Gulf Basin provides valuable insights that could guide future offshore exploration strategies. The breakthrough highlights the company’s focus on deepening geological research and adopting advanced extraction technologies to maximize the potential of complex reservoirs.

The discovery not only enhances the buried hill reservoir portfolio but also strengthens the company’s ability to maintain a stable energy supply. By developing offshore reserves efficiently, CNOOC Limited contributes to China’s broader energy security goals, ensuring a steady production capacity that can meet rising demand.

What Role Does the Luda 5-2 North Oilfield Play in CNOOC Limited’s Offshore Expansion?

Alongside the Beibu Gulf discovery, CNOOC Limited has made significant progress in developing the Luda 5-2 North Oilfield Phase II Development Project in the Bohai Sea. Production officially commenced in late February 2025, reinforcing the company’s commitment to expanding its offshore oil and gas capabilities.

Situated in the central Bohai Sea, the Luda 5-2 North Oilfield operates in waters with an average depth of 30 meters. The second phase of development includes the installation of a new auxiliary production platform and a production wellhead platform, supporting a total of 29 development wells. This includes 28 production wells and one water source well, with peak production expected to reach 6,700 barrels of oil equivalent per day by 2026.

A key aspect of the Luda 5-2 North Oilfield Phase II is its focus on super heavy oil production, making it the first offshore oilfield in China to employ thermal recovery techniques for extracting super heavy crude. This milestone reflects CNOOC Limited’s ability to deploy advanced technological solutions for offshore energy production.

How Is CNOOC Limited Optimizing Offshore Super Heavy Oil Production?

The Luda 5-2 North Oilfield is a crucial asset in China’s offshore energy landscape, particularly in the development of super heavy oil reservoirs. Since the launch of Phase I in 2022, CNOOC Limited has made substantial technological advancements to enhance extraction efficiency.

The Phase II expansion incorporates Jet Pump Injection-Production Technology, an optimized technique designed to maximize production efficiency while ensuring economic viability. By leveraging this technology, the company has improved the overall recovery rate of heavy crude oil, further strengthening its offshore energy capabilities.

The development of super heavy oil reservoirs represents a major step toward increasing domestic energy output. With rising energy demand and a focus on reducing dependence on imported crude, the expansion of the Luda 5-2 North Oilfield plays a critical role in supporting China’s energy security strategy.

What Does This Mean for the Future of Offshore Oil and Gas Exploration?

CNOOC Limited’s advancements in both buried hill reservoirs in the Beibu Gulf Basin and super heavy oil production in the Bohai Sea highlight the company’s strategic approach to offshore energy development. The integration of geological research, advanced extraction techniques, and large-scale development projects underscores its commitment to resource optimization.

The latest discoveries reinforce the potential of buried hill reservoirs as a long-term energy source while demonstrating how innovative recovery methods can enhance super heavy oil production. These projects not only contribute to CNOOC Limited’s growing resource base but also support China’s broader efforts to maintain stable energy supplies and reduce reliance on foreign oil imports.

With continued investments in offshore exploration and technological innovation, CNOOC Limited is well-positioned to drive further growth in China’s offshore oil and gas sector.