1. Title:
Reviewing proppant and its interaction with hydraulic fracturing fluids.
2. Objective:
An evaluation of the use of locally sourced proppant and the potential for negative impacts with chemistries present in frac fluid.
3. Results, Observations, Conclusions:
Fluids used in hydraulic fracturing of unconventional resources often contain a complex mixture of chemistries providing a variety of functions including friction reduction, mineral scale inhibition, microbial control, surfactants, etc. These chemical additives are often chosen after stringent performance and compatibility testing in the laboratory.
Alternately, proppant is traditionally selected based on its physical properties and function or more commonly in the current environment simply based on cost and regional availability. Proppant is conventionally viewed only as a material, but this fails to address its compatibility with the complex mixture of chemical additives present in fracturing fluids. Cost saving measures in proppant extraction and processing, such as eliminating the final drying step, can leave behind unforeseen or undesired residual chemicals. This issue highlights the need for more comprehensive testing
Herein we explore the effects of using locally sourced proppant, the impact of the wet vs dry proppant on frac chemicals and demonstrate that traditional laboratory testing of water and FR via friction flow loop and rheology does not adequately evaluate the behavior of the product in the presence of these proppants. These negative behaviors may include swelling and/or coagulation of the proppant in the presence of water as well as co-precipitation with other chemicals present in the frac fluid. In field studies this behavior has resulted in increases treating pressure during the frac. Additionally, we review different techniques used by Select Chemistry to counter the negative impacts to improve or restore performance on the pad.