On May 27, Cnooc Limited announced that the Phase I development project of the Kenli 10-2 oilfield cluster, the largest shallow lithologic oilfield offshore China, has commenced full-scale production. Currently, the oilfield's daily crude oil output has surpassed 2,800 tonnes, providing crucial support for the Bohai Oilfield, the nation's largest crude oil production base, to maintain and increase its production steadily.
Against the backdrop of rising global energy security risks, the significance of the Kenli 10-2 oilfield extends beyond merely adding new production volume. It signifies China's accelerated efforts to enhance its capability to develop complex oil and gas resources.
Located in the southern waters of the Bohai Sea, the Kenli 10-2 oilfield has proven geological crude oil reserves exceeding 100 million tonnes. It is the first 100-million-tonne lithologic oilfield discovered in the shallow layers of the Bohai Bay Basin's depression zone. The Phase I development project's main production facilities include a newly built central processing platform and two unmanned wellhead platforms, with a total of 79 development wells drilled.
The Kenli 10-2 oilfield is also China's first offshore development of a dendritic heavy oil reservoir. The oil and gas are primarily stored in narrow, curved sand bodies that intertwine like the shadows of tree branches on the ground, presenting a "dendritic" pattern. Given the oilfield's "scattered, narrow, thin, and complex" distribution characteristics of hydrocarbon reserves, the project innovatively adopted a combined development model integrating cold production and thermal recovery, facing numerous implementation challenges.
A relevant official from the Engineering Technology Operations Center of Cnooc Limited's Tianjin Branch explained, "The drilling and completion operations at the Kenli 10-2 oilfield faced challenges including multiple well types, multiple layers, and multiple development methods. To address this, we implemented a 'one sand body, one reservoir, one well pattern' strategy, developing differentiated technical designs such as shallow extended-reach horizontal wells, deep directional wells, and heavy oil thermal recovery wells. This has driven new breakthroughs in shallow extended-reach well drilling technology, with the maximum horizontal displacement of development wells exceeding 3,000 meters, nearly three times the reservoir burial depth, increasing the reservoir drilling encounter rate by over 30%."
The combination of the "dendritic" reservoir type and "heavy oil thermal recovery" development method at the Kenli 10-2 oilfield had no mature precedents domestically or internationally. Cnooc Limited's technical team, based on the project's drilling data, summarized various thin-layer stacking patterns and explored the formation of a technical system for developing complex heavy oil reservoirs. With significantly improved reservoir identification accuracy, they achieved precise water injection and targeted heat injection for different thin sand layers, effectively overcoming challenges such as scattered reserve distribution, complex geological conditions, and a wide range of crude oil viscosities, thereby ensuring efficient and balanced reserve utilization.
A relevant official from the Bonan Operations Company of Cnooc Limited's Tianjin Branch stated, "Currently, all 33 designed cold production wells and 24 thermal recovery wells at the Kenli 10-2 oilfield have successfully commenced pump operation. This marks the full completion and commissioning of the oilfield's Phase I development project, effectively revitalizing China's complex offshore heavy oil resources. It provides a replicable and scalable technical solution for the efficient development of similar oilfields, further strengthening the contribution of offshore oil and gas to the domestic energy supply."
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