China strikes high-yield natural gas reservoir 18,930 feet down in Bohai Sea volcanic rock

Reports suggest China has tapped into a massive volcanic reservoir that could help power millions of homes across the capital region.

China National Offshore Oil Corporation (CNOOC) announced the discovery of a “high-yield volcanic oil and gas well” in deep formations of the central Bohai Sea. Reportedly, the reservoir lies 5,770 meters (18,930 feet) down in this region. The find sits adjacent to the Bozhong Sag, the largest hydrocarbon-rich depression in the Bohai Sea.

The discovery could support China’s push to extract natural gas from extreme offshore environments.

Volcanic gas well in Bohai Sea

During testing, the well yielded about 800,000 cubic meters of natural gas per day from a cumulative gas-pay zone more than 120 meters thick in volcanic rock. For the Beijing-Tianjin-Hebei region and the broader Bohai Rim, this area serves as a vital energy lifeline.

“The success of this well has opened up a new play for offshore ultra-deep natural gas exploration ​and expanded the ​scope ⁠of deep oil and gas exploration in Bohai,” said Xu Changgui, ​chief scientist and chief geologist of ​CNOOC, as Reuters reported.

However, drilling at such depths comes with a lot of challenges. Extreme heat flow, intense tectonic activity, and complex rock structures make it difficult to predict underground reservoirs.

To overcome these obstacles, CNOOC independently developed multi-source broadband three-dimensional seismic technologies, along with new methods for identifying high-quality reservoirs in ultra-deep buried hills.

Gas-bearing pay zones in volcanic formations are underground layers of cooled magma and ash that hold commercially extractable natural gas. In sedimentary reservoirs, gas rests between sand grains, whereas in volcanic rock traps, gas is trapped inside tiny eruption-formed bubbles and tectonic fractures.

Over millions of years, natural gas migrates upward from deeper source rocks into these porous pockets, where a dense overlying rock layer seals it in place.

Beijing’s energy security goals

The development arrives as Beijing doubles down on domestic energy security. A five-year development plan from the National Development and Reform Commission and the National Energy Administration calls for intensified exploration to solidify independent supply. Reportedly, the target is 440 million tons of domestic oil and gas equivalent by 2030.

Offshore production is already carrying much of that momentum. Data from the Ministry of Natural Resources shows China‘s offshore crude output climbed 3.5 percent year-on-year during the first nine months of 2026.

Washington has long placed CNOOC on trade blacklists, including the Commerce Department’s Entity List and the Pentagon’s Section 1260H list, cutting off its access to advanced American oilfield services, specialized software, and deepwater drilling hardware.

Reaching a nearly 6,000-meter depth without relying on Western oilfield giants like SLB, Baker Hughes, or Halliburton shows that Beijing’s push for technological self-reliance in energy infrastructure is paying off.

U.S. energy majors like Chevron, Shell, and ExxonMobil routinely drill ultra-deep wells in the Gulf of Mexico. CNOOC’s project stands out because it targets volcanic rock in an active tectonic zone, whereas U.S. Gulf Coast drilling primarily focuses on sedimentary sandstone reservoirs.

Source: https://interestingengineering.com/energy/china-strikes-major-gas-reservoir