Case StudyFluidMatch™ Improves FR Performance and Reduces Overall Fluid Costs
A customer in the Powder River Basin sought higher performance in the category of high brine tolerant friction reducers. The friction reducer previously utilized by the customer was selected primarily based on price but exhibited suboptimal performance relative to tubular friction pressure at high pumping rates. The customer recognized the risks of utilizing incompatible friction reducers with higher treating pressures that could cause stress on surface equipment and compromise casing integrity. Inferior and incompatible polymer chemistries can also cause formation damage if they do not decompose properly which will lead to poor well performance. Fluctuations in water chemistry reported by the customer magnified the need for a versatile product with optimal friction reduction properties delivered at a reasonable cost per treated barrel.
The customer enlisted Rockwater to identify a potential replacement for the customer’s current friction reducer. This process began with the collection of source water samples for a complete FluidMatch™ analysis. From the samples, fluid rheology, dynamic friction loop testing, kill studies, and a full water profile provided a basis for a compatible product recommendation. During the flow loop analysis, the previous friction reducer exhibited a lack of performance stability over longer pump times indicating the polymer shear stability and compatibility was not optimized. To improve fluid performance, Rockwater’s potential recommendations were reviewed for sensitivity to shear, degradation over time, and any interaction with the water chemistry at a molecular level. In this case, a sub-group of viscoelastic friction reducers were identified that perform in the same multivalent cationic, sulfate, and bicarbonate categories.
Each potential replacement was tested for use in produced water with up to 150K TDS. A viscosity breaking test and regained conductivity test was performed to study any potential polymer decomposition and verify the proposed solution will not cause formation damage. Rockwater proposed an anionic emulsion as the most versatile solution for the commingled produced water utilized by the customer during fracturing. This viscoelastic friction reducer was designed for improved intermolecular interaction in divalent cationic and sulfate brines to improve both pumpability and viscoelasticity, and fluid integrity.
A field trial was completed running the recommended product in alternating stages against the incumbent product to evaluate performance comparisons. While lab results do not always predict field performance, Rockwater was confident in the proposed product based on matches to the existing database of over 10,000 water samples across all US basins.
The previous friction reducer was dosed at 1.2 gpt during the field trial. Rockwater’s product was run at an average rate of 0.72 gpt and still outperformed the competitor while exceeding the customer’s expectations. Rockwater’s optimized polymer reduced the total volume of polymer introduced into the formation, lowering the risk potential of polymer damage and well performance issues. The new friction reducer lowered the cost per treated barrel by over 30% in most cases and continues to be used by the customer on multiple pads in the region.
