A Novel Downhole Pulse-Based Stimulation Method for Enhancing Hydraulic Fracturing

Abstract Conventional hydraulic fracturing in mature shale reservoirs is limited by high pressure losses in the drill string, restricted near-wellbore conductivity, and inefficient proppant placement—factors that contribute to rapid production decline and low estimated ultimate recovery (EUR). This study presents a downhole pulse-based stimulation system that departs fundamentally from surface-driven treatments by generating high-energy hydraulic pressure transients directly at reservoir depth, where pressure transmission efficiency and near-wellbore stimulation effectiveness are greatest. The system converts elastic strain energy stored in the drill string into short-duration hydraulic surges using a pulse generation tool, which are subsequently shaped and amplified by a pulse shaping/ amplification tool positioned at the reservoir. A coupled numerical–analytical framework was developed to model pulse generation, propagation, amplification, and near-wellbore fracture response, with baseline fracture geometry and stress conditions calibrated to industry-accepted hydraulic fracture growth models. Numerical modeling demonstrates that coordinated operation of the downhole pulse and amplification modules produces near-rectangular hydraulic pressure pulses characterized by peak transient overpressures exceeding 250 % above local baseline pressure. The resulting waveforms exhibit a rapid rise phase (~5–10% of pulse duration), a dominant high-pressure hold interval (~70–85%), and a controlled decay (~10–20%), enabling localized fracture-scale overstress, tensile flaw activation, cyclic fatigue-driven aperture modulation, and enhanced proppant entry at the near-wellbore interface. The results establish a physics-based foundation for downhole pulse-based stimulation and outline a pathway for laboratory calibration and pilot-scale field trials. Findings indicate that cyclic, high-energy pressure transients delivered at depth can significantly enhance near-wellbore conductivity, fracture density, and proppant distribution in unconventional shale wells—offering a scalable, next-generation refracturing mechanism for revitalizing depleted assets without increasing surface pumping rates or total injected volume.