Ultra-deep extra-heavy oil refers to extremely difficult-to-extract petroleum resources buried thousands of meters underground, with viscosity over a hundred times that of conventional crude oil, and almost no fluidity at room temperature, resembling black mud.

Located in the hinterland of the Turpan Basin and the southern foothills of the Flaming Mountains, the heavy oil layers of the Lukeqin Oilfield are generally buried over 2,300 meters deep, with the deepest reaching 5,200 meters. It is not only the world's lowest-altitude ultra-deep extra-heavy oil development block but also the deepest buried heavy oil reservoir under large-scale development in China.

Wang Sheng, Reservoir Geology Research Department, Lukeqin Oil Production Management Zone, PetroChina Tuha Oilfield: The crude oil here features high density, high viscosity, and high pour point, recognized as a world-class challenge in oil and gas development.

Due to the excessive burial depth of the heavy oil in the Lukeqin Oilfield, significant heat loss occurs during long-distance wellbore transportation, rendering traditional thermal recovery technologies completely inapplicable. In the early stages of development, the oilfield faced a dilemma of "no mature experience to draw upon and no supporting technologies to adopt."

Zou Chenglin, Head of Lukeqin Oil Production Management Zone, PetroChina Tuha Oilfield: By innovatively adding light oil into the wellbore, the heavy oil, which was originally "unable to flow or be pumped," is smoothly lifted from the 3,000-meter-deep formation to the surface. The oilfield's recovery rate has increased by 11 percentage points compared to the early development stage, achieving large-scale and cost-effective utilization of difficult-to-recover reserves.

Technological breakthroughs have boosted the annual output of the Lukeqin Oilfield from 30,000 tons to a peak of 800,000 tons, maintaining stable production above 400,000 tons for 10 consecutive years.