Shengli Oilfield: Multi-site Hydroxylamine Controllable Crosslinking System Boosts Crosslinking Efficiency by 4 Times and Gelation Time by 7.8 Times

"The injection pressure rose by 1.3 MPa, and the comprehensive water cut dropped by 7.2 percentage points!" At the site of Well Group LFLN3NB11 in Binnan Oil Production Plant, technicians stared intently at the fluctuating data on the monitoring screen, barely hiding their excitement. Recently, the independently developed Multi-site Hydroxylamine Controllable Crosslinking System created by Dr. Wu Hao’s team from the Tertiary Oil Recovery Research Institute of the Petroleum Engineering Technology Research Institute has completed profile control field tests on three well groups in mature oil districts including Binnan and Gudao. All tests delivered remarkable water control and oil stabilization effects, offering a new chemical technical support for stable and increased production in mature water-flooded oilfields at the ultra-high water cut stage.
Well Group LFLN3NB11 is a typical troubled mature well cluster. Under high-porosity and high-permeability reservoir conditions, conventional blocking agents diffuse uncontrollably like water splashed on sand. The injection pressure failed to climb, and severe channeling occurred in matching oil wells, making it impossible to track the flow paths of injected water and crude oil.
After deploying the new crosslinking system, the operating situation saw a fundamental turnaround: injection pressure increased while water cut decreased, and the peak daily oil output of associated wells rose by 2 tons. Up to now, this well group has achieved a cumulative incremental oil production of over 400 tons, with field operators commenting that the agent perfectly solves the reservoir problems.
At present, most mature oilfields in eastern China have entered the ultra-high water cut development stage, and water flooding operations suffer from severe low-efficiency and ineffective water injection. As a core measure to achieve uniform displacement, water shutoff and profile control face a dilemma: if the blocking agent cannot penetrate deep into formations, deep profile flooding cannot be realized; if it travels far enough, its mechanical strength becomes insufficient to seal high-permeability channels. Traditional blocking agents fail to balance both requirements. Fractures and large pore throats demand higher mechanical strength from blocking agents, while the degradation of polymer materials under high-temperature and high-salinity conditions remains an urgent industry-wide challenge, generating huge market demand for high-strength, long-duration blocking agents.
To tackle this common industrial challenge, Dr. Wu Hao’s team focused on developing crosslinking agents with elevated crosslinking efficiency.
Based on the structure-activity relationship of existing crosslinkers, the team identified a molecular design featuring small molecules with multiple crosslinking sites as the optimal route. Environmentally responsive shielding groups were grafted onto the molecular framework to realize controlled release of crosslinking sites. The research team finally developed a slow-release multi-site hydroxylamine crosslinker that enables precise regulation of crosslinking reactions. Simply put, the blocking agent travels slowly through deep formations and forms gel at the right timing, striking a balance between deep penetration and reliable sealing performance.
Data fully validates its superior performance: compared with traditional phenolic crosslinkers, the new crosslinking system delivers a 4-fold increase in crosslinking efficiency and a 7.8-fold extension of gelation time. Both laboratory evaluations and field applications verify that the new system achieves remarkable improvements in gel strength and thermal stability, perfectly reconciling injectability and plugging capacity — two properties that previously conflicted in conventional products.
In April 2026, this technological achievement underwent another key assessment at the 2026 International Symposium on Oilfield Chemistry Technology held in Chongqing, attended by academicians of the Chinese Academy of Sciences and Chinese Academy of Engineering as well as numerous industry experts. On behalf of the team, Dr. Wu Hao presented the research on the Multi-site Hydroxylamine Controllable Crosslinking System, which won unanimous recognition and claimed the Second Class Award. Industry specialists noted that this breakthrough is not merely an upgrade of blocking agent performance; more importantly, it provides a customizable and adjustable technical framework with extensive prospects for large-scale popularization.
"Chemical technology must keep pace to sustain stable production in mature oilfields," stated Dr. Wu Hao. Moving forward, the team will continuously optimize system formulas and injection processes tailored to diverse reservoir conditions, accelerate the commercialization of research outcomes, and deploy this new remedy to more troubled mature oilfields.