Constraints on Pipe Friction and Perforation Cluster Efficiency from Water Hammer Analysis
The authors present a novel methodology to resolve the nonuniqueness associated with standard step-down tests by analyzing water hammer responses measured by high-rate wellhead pressure sensors following abrupt injection rate drops. By tracking the subsequent depressurization rate and the amplitude of the reflected wave, operators can independently determine the Darcy-Weisbach pipe friction factor and perforation friction. The paper applies this method to field data from the Wolfcamp and Bone Spring Formations, demonstrating that higher-than-predicted perforation friction indicates not all clusters connect to fractures. Ultimately, this provides a cost-effective, noninvasive tool for real-time monitoring of perforation cluster efficiency to complement traditional fracture diagnostics.
