On December 24, China National Offshore Oil Company (CNOOC) announced a new hundred-million-ton-scale discovery in the shallow Neogene strata of the Bohai Sea—the Qinhuangdao 29-6 Oilfield. This marks the seventh hundred-million-ton oilfield discovered in Bohai Oilfield, China’s largest crude oil production base, since 2019, further strengthening offshore oil and gas reserves and playing an important role in safeguarding national energy security.

The Qinhuangdao 29-6 Oilfield is located in the central Bohai Sea, about 44 kilometers west of Jingtang Port. It represents another major hundred-million-ton lithologic oilfield discovery in recent years, following the Qinhuangdao 27-3 Oilfield. The discovery well encountered 66.7 meters of oil-bearing pay, reached a total depth of 1,688 meters, and tested at approximately 370 tons of crude oil per day per well, demonstrating promising exploration prospects.

The oilfield is situated on the slope belt at the margin of the Shijiutuo Uplift. Historically, the Shijiutuo Uplift was one of the main battlegrounds of early Bohai exploration. Traditionally, slope belts were regarded as migration pathways where hydrocarbons pass through but do not accumulate at scale due to the lack of major fault sealing, and decades of multi-layer, multi-stage exploration since the 1970s yielded limited results.

In 2024, the discovery of the hundred-million-ton Qinhuangdao 27-3 lithologic oilfield on the Shijiutuo Uplift provided new insights. By integrating extensive drilling data and experimental results, CNOOC researchers identified numerous microscopic “hidden” lithologic traps along hydrocarbon migration pathways, demonstrating that the slope belt of the uplift is capable of storing hydrocarbons. Building on this breakthrough, researchers combined sedimentological and geochemical studies to delineate hydrocarbon enrichment zones, clarify exploration targets, and conduct drilling, ultimately achieving a major hundred-million-ton lithologic oilfield discovery in the low, marginal, and gently inclined structural setting of the Shijiutuo Uplift slope belt.

According to CNOOC, advances in understanding hydrocarbon migration and accumulation models and related technologies in shallow Neogene slope belts have overturned the traditional view that hydrocarbons cannot be retained at scale in such settings, revealing significant exploration potential in uplift-adjacent slope zones under strong extensional–strike-slip fault activity.

As the second hundred-million-ton lithologic oilfield discovered in the mature Shijiutuo Uplift area, the Qinhuangdao 29-6 Oilfield highlights the value of refined exploration, consolidates the resource base for domestic reserve growth and production increase, and is of great significance for ensuring energy security and supporting coordinated development in the Beijing–Tianjin–Hebei region.