Objective Long-distance oil and gas pipelines develop toward larger diameters, higher steel grades and higher operating pressures. Sub-millimeter microcracks on girth welds and service-induced stress concentration are major hidden risks leading to pipeline failure. Conventional non-destructive testing (NDT) technologies, including magnetic flux leakage, eddy current, ultrasonic testing, and metal magnetic memory testing, have inherent drawbacks. They cannot reliably identify weld microcracks smaller than 0.3 mm and early-stage buried damages. Quantum precision measurement technology is urgently needed to break through the bottleneck of weak magnetic signal detection.

Methods This study systematically analyzes the operating principles, performance indicators and NDT research progress of four types of quantum magnetic sensors: optically pumped atomic magnetometers, diamond Nitrogen-Vacancy (NV) center magnetometers, superconducting quantum interference devices, and quantum well Hall magnetometers. A comparative analysis is carried out from four dimensions: magnetic sensitivity, spatial resolution, operating conditions, and engineering adaptability, which clarifies the applicable range of each sensor in pipeline inspection. A miniature differential gradient testing platform based on atomic magnetometers is established for microcrack tests. The platform requires no saturated magnetization. It relies only on the residual magnetization of pipe materials to identify girth weld microcracks with an opening width of 0.2 mm and buried defects under a pipe wall thickness of 10 mm at a high signal-to-noise ratio, which verifies its capability to detect sub-millimeter defects. Meanwhile, a tensile test system is constructed with diamond NV center magnetometers. Variations of magnetoelastic coupling magnetic fields of steel under stepped loads ranging from 0 MPa to 270 MPa are collected. The complete stress evolution process of components including loading, load holding and unloading is fully reproduced, proving that the system can quantitatively characterize stress concentration zones of pipelines.

Results Quantum precision measurement technology achieves ultrahigh magnetic sensitivity at the fT-to-nT level, making it capable of capturing faint magnetic signals, and its lightweight advantage is prominent. Therefore, it is applicable to complex pipeline structures such as welds, elbows, and tees. Nevertheless, its engineering deployment faces several critical challenges: high overall system power consumption, difficult multi-source magnetic noise decoupling, a lack of quantitative inversion models for defects and stress, and poor adaptability to high-speed in-line inspection. Among these approaches, optically pumped atomic magnetometers are well-suited for in-line detection of minor pipeline defects, whereas diamond NV center magnetometers demonstrate superior performance in evaluating pipe material stress.

Conclusion Quantum precision measurement provides an innovative technical approach for the early detection of micro-damage and stress hazards in oil and gas pipelines. It represents a key development direction for high-precision upgrading of pipeline in-line inspection. Future research should focus on critical technologies—including low-power sensor integration, anti-interference signal decoupling, and quantitative inversion algorithms—to drive the industrialization and field application of quantum inspection equipment.