This critical review assesses drilling microchips (DMCs) as recoverable, untethered devices for acquiring downhole pressure and temperature measurements. It examines their measurement coverage, depth assignment, data-access latency, and deployment requirements in relation to established logging and fiber-optic systems and the larger Sensor Ball platform. Device specifications, laboratory tests, field demonstrations, and comparisons with thermal models are evaluated separately to distinguish demonstrated capabilities from proposed applications.
The reviewed evidence supports the feasibility of post-run temperature profiling, while pressure measurement and real-time decision support remain less well established. Physical recovery varies across deployments and does not by itself indicate the yield of complete, usable records. Differences in operating conditions and reporting practices limit direct comparisons between studies. Agreement with thermal models also varies and should not be interpreted as independent validation of sensor accuracy.
The most defensible near-term applications are post-run temperature profiling and thermal-model assessment where data access after device recovery is acceptable. Routine pressure-based diagnostics and reliable interpretation by depth require stronger reference measurements and validated methods for converting measurement time to depth. Support for live drilling decisions additionally requires a demonstrated end-to-end data-delivery workflow. The review identifies application-specific evidence gaps and emphasizes complete-dataset yield, depth uncertainty, and data-access latency as criteria for assessing practical readiness.