Addressing Pump Rate Limitations in High-Friction Environments
During recent frac pad operations in Upton County, an operator encountered severe pump rate limitations across multiple formations, including the Upper and Lower Jo Mill, Upper Spraberry, and Wolfcamp A, B1, and B2. The primary objective was to sustain a maximum pump rate of 110 bpm; however, operations were severely restricted by a 9000 psi maximum threshold on the wellhead. Consequently, during the first 10 stages, the average pump rate hovered around only 93 bpm—representing a 17 bpm deficit per stage. This inability to reach the target rate was driven by pipe friction that exceeded 3000 psi, leading to longer pump times and highly inefficient operations.
To diagnose the root cause of this excessive friction, the operator conducted a water analysis, which revealed high levels of iron (25 ppm against an acceptable limit of 10 ppm) but normal levels for specific gravity, sulfates, pH, hardness, and total dissolved solids. Although an iron control application was tested across all wells, it failed to produce a reduction in treating pressure. Further area comparisons demonstrated that Upton County possessed a friction gradient roughly 26% higher (0.17 psi/ft) than neighboring regions like Howard (0.125 psi/ft) and Reagan (0.148 psi/ft) counties.
In response, alternative solutions were evaluated, including sourcing water from Howard County (95 miles away at a hauling cost of $0.50 per bbl) and conducting flow loop testing to evaluate different friction reducers and ensure no gelling was occurring. Economically, the initial failure to hit the target rate carried a heavy penalty. The first 48 stages accumulated 13.8 hours of extra pump time, incurring a total overspend of $85,861.37. With an average frac service charge of $6,200 per hour, this inefficiency translated to an extra 17 minutes and $1,756.67 in overspend per stage.
