Abstract
The effectiveness of hydraulic fracturing fluids is critical to minimizing formation damage and maximizing oil recovery. Traditional fracture fluid selection has been driven primarily by surface performance metrics such as friction reduction efficiency and cost. However, this approach overlooks the long-term impact of fluid interactions with the reservoir, which can significantly affect hydrocarbon production.
Ovintiv evaluated over fifteen friction reducer (FR) commercial products in both fresh and produced water, using a comprehensive testing methodology that includes flow loop tests for friction reduction, regain fracture conductivity tests to assess proppant pack damage, spontaneous imbibition tests in an Amott cell to determine oil recovery from actual core field samples, and emulsion test to examine the final selected FR compatibility with oil and water formation fluids. Due to the large volume of data generated, this paper reports only the FR results in fresh water.
For FR performance in fresh water, eight FR products were evaluated. In this evaluation, the oil recovery performance had the highest weight in the evaluation, followed by regained permeability, compatibility with formation fluids, and friction reduction performance. Results show that a few friction-reducer products performed excellently in the flow loop testing; however, their performance did not reach the expected regained permeability and oil recovery target performance. This aligns with Ovintiv's evaluation view, which requires balancing the surface operation perspective with subsurface reservoir outcomes. Only one product (UltraFlo 217S) met the overall target performance and thus was selected for the field injection operation.
UltraFlo 217S was injected as a first trial into the Midland Basin field during the last fracturing stages to compare with another commercial FR product, UltraFlo 217S significantly decreased the treating pressure by ~2,000 psi and pumping efficiency increased by 10 barrels per minute (BPM). Since the successful execution of a field trial, UltraFlo 217S has been widely used by Ovintiv. The oil gain target performance was achieved in many cases when UltraFlo 217S was pumped.
The results highlight the importance of selecting fracture fluids based on their overall impact on formation integrity and hydrocarbon mobilization, rather than solely on their surface performance. A shift in fracture fluid selection criteria is necessary to optimize longterm well productivity by balancing friction reduction with formation compatibility and oil recovery efficiency.
