Investigating Shale-Fluid Interactions and Its Effect on Proppant Embedment Using NMR Techniques

TitleInvestigating Shale-Fluid Interactions and Its Effect on Proppant Embedment Using NMR Techniques
Publication TypeConference Paper
Year of Publication2021
AuthorsAlagoz, E., and M. M. Sharma
Conference NameUS Rock Mechanics/Geomechanics Symposium
Date Published06/2021
PublisherAmerican Rock Mechanics Association
Conference LocationJune 18-25, 2021
Other NumbersARMA-2021-1129
Abstract

It is essential to know about any adverse interactions between a shale and fracturing fluid additives. Some frac fluids can alter shale rock petrophysical properties and this can lead to shale softening and fines generation. The softer the shale, the more proppant embedment will occur, and the more severe the reduction in fracture conductivity as the effective stress increases. In this study, we present a Nuclear Magnetic Resonance (NMR) technique to evaluate various frac fluids. We show that the extent of proppant embedment correlates very well with the extent of imbibition of water into the shale (as measured by NMR). For example, our test results show that Surfactant#7 and a clay inhibitor with KCl significantly reduced water imbibition into the shale. These chemicals also showed the least embedment. The primary reason for this reduction is due to a decrease in rock plastic deformation. The effect of shale mineralogy was also studied in this work using X-ray fluorescence. The results show that water imbibition into a shale is also sensitive to its mineralogy. The higher the clay content, the more the imbibition and embedment. This correlation between NMR-measured imbibition and proppant embedment can be used to evaluate the impact of different fracturing fluids on proppant embedment. Such tests will significantly simplify the testing of different frac fluid additives for compatibility with shales.