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Evaluation and Optimization of a Nitrogen-Assisted Viscosity Reduction Technology in Karamay Heavy Oil Reservoir

Author(s)

Qiang Zang

Affiliation(s)

Karamay Vocational & Technical College, Karamay, Xinjiang, China

Abstract

To address challenges of rapid production decline and poor recovery in the high-water-cut, high-viscosity, and energy-deficient T2k reservoir of Karamay Oilfield, nitrogen-assisted composite viscosity reducer technology was applied. Based on data from nine wells treated in 2023, this study analyzes the mechanism, effectiveness, and influencing factors. Results show that nitrogen energy enhancement and chemical viscosity reduction synergistically remove near-wellbore blockages, supplement energy, and reduce viscosity, with significant effect in wells having formation depletion <700 mPa·s viscosity, yielding 578 t cumulative and 64 t average incremental oil per well. Optimization includes: multi-stage (e.g., three-stage) outperforms single-stage treatment; prepad nitrogen should match perforation thickness, viscosity reducer ≤200 m³; post-treatment casing pressure and submergence control are crucial. Typical well analysis summarizes failure causes and proposes refined "one-well-one-strategy" selection and parameter optimization, supporting efficient application in similar high-viscosity reservoirs.

Keywords

Nitrogen Energy Enhancement; Chemical Viscosity Reduction; Blockage Removal; High-Viscosity Reservoir; Effectiveness Evaluation; Treatment Optimization

References

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