On March 20, the successful completion of the first drilling phase of the "Ballast Project" for ultra-deep heavy oil in the Lukuqin area of the Tuoha Oilfield—well Yudong 204-1071—is now awaiting production, marking a key step toward the field’s cumulative production goal of 10 million tons.

In late 1994, the Aican-1 well in the Tuoha Oilfield discovered a 40-meter-thick heavy oil sand layer within the Triassic Xiaoyuangou Formation. In 1996, the discovery of the Lukuqin heavy oil field was recognized as one of China’s top eight onshore oil industry discoveries that year.

The Lukuqin heavy oil reservoir lies at depths ranging from 2,300 to 4,600 meters, with poor reservoir quality. It is characterized by "four highs and one medium": high density, high viscosity, high pour point, high non-hydrocarbon content, and medium wax content. At 50°C, the crude oil has a viscosity similar to freshly unpacked honey, making it extremely difficult to flow.

While most domestic heavy oil reservoirs are buried at about 1,000 meters, the deepest well in Lukuqin exceeds 5,200 meters, making it the deepest large-scale developed heavy oil reservoir in China. Due to its great depth and extraction difficulty, Lukuqin’s ultra-deep extra-heavy oil is nicknamed the “non-flowing oil field” and presents a world-class challenge in oil extraction.

Since development began, Tuoha Oilfield has overcome technical barriers through experimentation, establishing a series of cold production techniques including ambient temperature water flooding, gas huff-and-puff, and diluted crude lifting via pump mixing—pushing the limits of cold production for heavy oil.

During the 12th Five-Year Plan, Lukuqin’s ultra-deep heavy oil output grew at an average annual rate of 49.7%. In the 13th Five-Year Plan period, total output reached 3.29 million tons, the highest in its history. In 2015 alone, production hit 808,000 tons, contributing nearly half of Tuoha Oilfield’s total crude output.

In recent years, the field has maintained stable production from the Triassic formation by combining secondary and tertiary recovery techniques and advancing foam flooding and gas huff-and-puff methods.

Refined products from Lukuqin heavy oil, such as low-pour-point diesel and high-performance lubricants, hold strategic value for use in equipment operating in frigid climates. With a current recovery rate of only 7.49%, the field holds significant untapped reserves.

During the 14th Five-Year Plan period, Tuoha Oilfield has aligned with the national energy strategy by launching the "Lukuqin Deep Heavy Oil Ballast Project." The initiative aims to improve recovery through well network optimization, new capacity construction, and enhanced displacement technologies, targeting stable annual production of over 500,000 tons by 2028, thereby supporting national energy security with both technical insight and resource contribution.

To date, the Lukuqin field has produced 9.47 million tons of ultra-deep extra-heavy oil.