Slickwater fracturing generally contains approximately 95% sand and 5% other production chemicals, such as scale inhibitor (SI), friction reducers (FRs), surfactants, etc. It is important to study the effect of FRs on SI inhibition performance because of the interactions between both chemicals when pumped together during slickwater fracturing treatments.
Most FRs used in the industry are usually a combination of polyacrylamide- (PAM-) based polymers, acrylic acids, and acrylamido-methyl-propane sulfonate polymer (AMPS) copolymers, which readily interact with components of SIs. This paper examines the effect of FRs on SI performance and the scaling tendency of produced water. Conclusions drawn regarding static bottle tests, dynamic tube blocking tests, and inductively coupled plasma (ICP) analysis of data from a series of performance tests under reservoir conditions are discussed. The laboratory methods used to qualify and measure the performance of the SIs during these tests are also discussed.
Tests were conducted using produced water brine from the Rulison field in Colorado. The testing results demonstrated diminished performance of SI when combined with a FR. Five SIs of different chemistries were run to observe the resulting performance effects of the SIs with and without FRs. Static bottle tests conducted using only SIs exhibited a minimum effective concentration (MEC) of ≥ 20 to 50 ppm for complete scale control. With the addition of 0.25 gpt of FRs, the MEC increased to approximately 100 to 250 ppm for the different SIs based on ICP elemental analysis data. Additionally, the test results demonstrate that a denser amount of solid precipitation occurs with the combination of both FR and SI. Results obtained from this study provide more awareness to the resulting effects of combining these fracturing fluids during slickwater fracturing. This work provides insight into making proper scale control decisions, particularly when SIs and FR are pumped simultaneously, thereby helping reduce damage.