Cangqing Oilfield’s Cutting-Edge Technology: Successful Independent Development of “Salt-Sensitive Intelligent Gel Profile Control” Technology

“The salt-sensitive intelligent gel profile control technology, independently developed by the National Engineering Laboratory for Exploration and Development of Low-Permeability Oil and Gas Fields in Changqing, has been tested in more than 20 wells in the field, resulting in a cumulative increase in oil production of over 4,000 metric tons.” On April 1, the head of the Water Shut-in and Drive Modification Technology Research Institute at the National Engineering Laboratory for Exploration and Development of Low-Permeability Oil and Gas Fields (hereinafter referred to as “the Laboratory”) explained. Thanks to its revolutionary “adaptive dynamic plugging” capability, this technology has successfully resolved the long-standing problem of water intrusion in mature oilfields with high water cut, opening up a new path for stabilizing production and improving efficiency in mature oilfields.

After more than half a century of continuous development, some of Changqing Oilfield’s main reservoirs have entered the high-water-cut production phase. Currently, there are over 10,000 wells with a comprehensive water cut exceeding 80%. These wells generally face the challenge of water intrusion—injected water advances rapidly and unevenly along highly permeable pathways, bypassing large oil-bearing zones and preventing the effective recovery of residual oil.
To tackle this persistent problem, the laboratory’s research team focused on material innovation and mechanistic breakthroughs, successfully developing the “salt-sensitive smart gel profile control” technology independently. Its core lies in endowing the profile control agent with “environmental sensing” capabilities; the gel system can sensitively respond to changes in underground fluid salinity and dynamically adjust its own blocking behavior, achieving a fundamental shift in high-water-cut management from a “crude and general” approach to a “precise and intelligent” one.
The lead researcher on the project used an analogy: it is like a “smart water-blocking force.” Gel particles injected underground shrink in brine, allowing them to easily penetrate deep into the oil reservoir; when they are carried by the water flow into channels that have long been eroded, they “taste” that the water has become less salty and immediately absorb water, expand, and block the waterway. Subsequent injected water has nowhere else to go and is forced to flow into areas previously inaccessible to water and from which oil could not be extracted, thereby displacing the remaining oil.
Field test data is impressive: trials conducted across multiple blocks in Changqing achieved an average increase of 225 metric tons in oil production and a reduction of 239 cubic meters in water production per well group. Compared to traditional profile adjustment methods—which are characterized by long construction cycles, high material consumption, and complex equipment—the new technology innovatively employs a “high-concentration, high-flow-rate, short-cycle” mineralized water preparation and injection process. This has reduced the amount of profile adjustment agent used per well by more than 95% and drastically shortened the construction time from several months to less than one day.
The cost-saving effects are particularly evident: compared to conventional profile adjustment operations, the new technology reduces direct costs per well by approximately 85%, making it worthy of large-scale implementation.