Impact of Salinity and Mineralogy on Slick Water Spontaneous Imbibition and Formation Strength in Shale

Abstract

Spontaneous imbibition is one of the mechanisms proposed to reveal the fate of fluids used during fracturing operations in shale reservoirs. However, the influence of salinity and mineralogy on the imbibition kinetics is not yet well understood. We performed imbibition experiments on samples collected from Woodford and Caney shale outcrops with slick water having salinities up to 15 wt % KCl. The impact of salinity on the imbibition rate and capacity shows a different trend for samples of varying mineralogy. A correlation between the carbonate/clay ratio and the imbibition rate is observed. This ratio and the illite content were linked to be factors affecting the impact of salinity on imbibition. This correlation suggests a maximum volume of imbibition at a ratio of 1.5. The impact of salinity on the formation strength seems to correlate with the amount of siderite and anhydrite present in the rock. It is worth noting that the swelling of the expansive clay minerals could mask the imbibition signature of the samples, where the apparent weight is used to estimate the liquid uptake. This is mainly apparent in the later stages when the bulk volume expansion can outweigh the liquid uptake; however, this effect does not reach the level of impacting the trends and correlations observed in this study.

A Multiscale Study on Shale Wettability: Spontaneous Imbibition Versus Contact Angle

“…A similar inverse correlation was observed at 0.1‐M concentration (K + < Na + < Ca 2+ < Mg 2+ ) except that K + uptake was lower than that of Na + . The nonmonotonous behavior of K + has been observed previously (Biaeopiotrowicz et al, ; Mehana et al, ; Puntervold et al, ). The reason for this exceptional behavior is that K + has swelling inhibiting characteristics due to its versatile hydration and leachability properties.…”

Investigation into the Classification of Tight Sandstone Reservoirs via Imbibition Characteristics

“…Wettability and oil viscosity are considered as the major influencing factors, and thus oil recovery from the reservoir they were studying could be improved by injecting steam, low-salinity water, and surfactant [29]. It has also been proposed that factors impacting the recovery efficiency of tight reservoirs are: wettability > brine, and salinity > residual oil saturation [30][31][32][33]. Ali Habibi et al suggested that the position for imbibition is random inside the same core, and that by soaking the core sample in brine solution the affinity between rock and fluids can be promoted, which further affects the wettability [34].…”

Spontaneous imbibition in shale: A review of recent advances

“…Gao and Hu (2016) tested samples on balance in directions parallel and transverse to the lamination and in imbibing fluids of deionized water and n-decane to investigate the influence of shale layers. Mehana et al (2018) The movement of imbibition front and the relationship between water loss and fracture aperture (Roychaudhuri et al, 2013).…”