Tuhai Oilfield explores new approaches to enhance recovery efficiency

As of May 17, after applying CCUS-EOR (carbon dioxide capture, utilization and storage-enhanced oil recovery) technology in the Niuquanhu East area of Santanghu Oilfield, Turpan-Hami Oilfield has achieved cumulative oil production increase exceeding 20,000 tons in the pilot block, with a recovery factor improved by 1.4%, effectively doubling production in the test area.

Turpan-Hami Oilfield features diverse and complex reservoir types. As development progresses, conventional reservoirs in mature areas exhibit high water content, while new areas primarily rely on unconventional production, leading to rapid production decline. Therefore, effective methods for enhancing recovery are urgently needed. After years of research and breakthroughs, the oilfield has successively overcome multiple technical challenges, including early water injection in "three-lows" sandstone reservoirs, oxygen-reduced air foam flooding in deep heavy oil reservoirs, gravity miscible gas flooding using natural gas in medium-to-high permeability light oil reservoirs, and CCUS-EOR in low-permeability, low-viscosity reservoirs.

To effectively develop the low-pressure, ultra-low-permeability reserves in the Xishanyao formation of the Niuquanhu block, Turpan-Hami Oilfield developed an advanced water-injection development model. After full-scale implementation across the entire area and continuous optimization, a series of technologies—including gentle water injection, chemical profile modification, and repeated fracturing—have been established, enabling the natural decline rate of sandstone reservoirs to be gradually controlled within 10%.

The Luqueqin heavy oil reservoirs are deeply buried and highly heterogeneous, characterized by "four highs and one moderate"—high density, high viscosity, high pour point, high non-hydrocarbon content, and moderate wax content. The technical team focused on displacement mechanisms and ultimately developed a "oxygen-reduced air flooding + cyclic steam stimulation" technology system. After application, the recovery factor in the pilot block increased more than twofold, surpassing 30%.

In revitalizing mature fields, addressing the challenges of high recovery rates and high water content at Pubei Oilfield, the team deepened geological understanding and continuously optimized the natural gas gravity miscible flooding scheme, successfully expanding sweep volume and improving oil displacement efficiency.