Advancements in Downhole Monitoring for Horizontal Well Hydraulic Fracturing

As the primary downhole isolation tool enabling multi-stage hydraulic fracturing in horizontal shale gas wells, composite bridge plugs have become universally deployed throughout domestic shale gas operations. The dissolution kinetics and mechanical integrity of degradable bridge plugs exhibit intrinsic dependence on downhole environmental conditions, particularly formation temperature and annular pressure. Consequently, precise acquisition of real-time downhole temperature and pressure (T&P) profiles during plug deployment is essential for optimizing tool selection based on specific well conditions. During high-rate fracturing operations, downhole pressure manifests dynamic fluctuations due to variable-rate fluid injection, proppant concentration changes, and near-wellbore friction effects. Simultaneously, temperature profiles are disrupted by the injection of large volumes of surface-temperature fracturing fluids into heated formations. Furthermore, reservoir heterogeneity induces complex fracture networks that create localized pressure sinks and thermal anomalies, generating significant deviations between actual downhole T&P conditions and predicted formation characteristics. This study introduces an integrated monitoring solution featuring a dissolvable frac collet retrofitted with a intelligent frac ball which has high-resolution T&P sensing chip in it (design as Fig. 1) . The corrosion-resistant sensor package, embedded within the collet assembly, continuously logs annular pressure (0-15,000 psi) and temperature (0-300°C) throughout the tool's operational lifecycle—from setting and fracturing through dissolution initiation. Engineered with high-stability MEMS piezoresistive pressure transducers and platinum RTD temperature sensors, the module captures data at programmable sampling intervals while withstanding extreme downhole vibrations. Following fracture treatment completion, the controlled electrolytic dissolution of the magnesium-alloy collet and composite ball releases the encapsulated sensor package. This cylindrical module subsequently returns to surface entrained within flowback fluids, its buoyancy-enhanced design preventing settling in lateral sections. Surface recovery enables direct data extraction via USB interfaces, providing access to high-fidelity pressure transient records and thermal gradient profiles across all fracturing stages. Analysis of this dataset reveals critical behavioral patterns, including: Instantaneous shut-in pressure (ISIP) variations between stages, Near-real-time fracture propagation signatures, Fluid thermal recovery profiles during soaking periods, Dissolution rate correlation with formation temperature. The acquired downhole measurements enable quantitative validation of fracture models while informing future dissolvable tool selection based on actual well-specific conditions. This passive monitoring methodology eliminates wireline intervention risks and provides previously unattainable data from the fracture initiation zone throughout the entire plug functional cycle.