Pore Structure and Fluid Uptake of the Springer/Goddard Shale Formation in Southeastern Oklahoma, USA

Abstract

Hosting an emerging play of the Springer/Goddard shale, the South Central Oklahoma Oil Province (SCOOP), is also the main production field for the underlying Woodford Formation. Understanding the reservoir quality of the Chesterian-age Goddard shale, currently little has been achieved, is vital to sustainable hydrocarbon production and exploration. Using polar (DI water and/or API brine) and nonpolar (n-decane) fluids to probe hydrophilic and hydrophobic pore networks, the purpose of this study is to examine wettability, pore connectivity, fluid imbibition, and tracer migration of the Springer shale. To achieve this, we collected core samples from two wells located at the heart of the play and performed mercury injection capillary pressure, wettability, fluid imbibition, and vapor absorption tests. Results from these studies show that the Springer shale has a stronger affinity to oil (n-decane in this study), compared to DI water and API brine. With porosity values averaging at 6.32 ± 0.75% and permeability of 20.0 ± 6.52 nD, the majority of pore-throat sizes for the Springer shale are 5–50 nm. The utility of wettability tracers of different molecular sizes helps tease out the intertwined relationship of pore-throat sizes, connectivity, and associated wettability of shale. The imbibition results suggest a molecular entanglement effect at the scale of 0.5 nm, even for the tracer penetration of a wetting fluid of n-decane. A petrophysical analysis of the Springer shale presented in this work is beneficial to further understand the pore structure and fluid movement within the shale to facilitate increased production and accurate economic evaluations.

Quantitative Characterization of Full-Spectrum Pore Size and Connectivity for Shale with Different Sedimentary Facies from the Dongying Depression, Bohai Bay Basin, East China

“…Figure 13 compares the loglog plots of cumulative imbibition for DIW and 2DT. The imbibition curves of DIW are divided into two stages (stages I and II) [61].…”

Advances on the Mechanism of Reservoir Forming and Gas Accumulation of the Longmaxi Formation Shale in Sichuan Basin, China

“…Thermal simulation experiments can effectively solve the problem of strong heterogeneity in shale samples, and the shale sample composition, static rock pressure, system openness, water-bearing ability, and other factors can be independently controlled to study the entire pore evolution process of a single sample. 67−69 Hu et al 70 conducted high-temperature thermal simulation experiments on immature Woodford shale and found that as the maturity increased, the number of nanopores and the porosity of the shale increased. This research shows that the porosity decreases rapidly under the action of compaction and cementation at R o < 0.3% (Figure 3).…”

“…The differences in sedimentary environment and diagenesis determine the heterogeneity of organic matter and minerals. Thermal simulation experiments can effectively solve the problem of strong heterogeneity in shale samples, and the shale sample composition, static rock pressure, system openness, water-bearing ability, and other factors can be independently controlled to study the entire pore evolution process of a single sample. − Hu et al conducted high-temperature thermal simulation experiments on immature Woodford shale and found that as the maturity increased, the number of nanopores and the porosity of the shale increased.…”

Adsorption Characteristics and Controlling Factors of CH4 on Coal-Measure Shale, Hedong Coalfield

“…The proportion of adsorbed gas is approximately 20-85% in shale reservoirs [7]. Shale reservoirs, as a porous medium with strong heterogeneity, possess complex adsorption mechanisms for CH 4 [8,9]; thus, it is necessary to investigate the adsorption capacity, characteristics, influencing factors and control mechanism of CH 4 on shale reservoirs prior to shale gas development. Ross et al (2009) and Zhou et al (2019) concluded that organic pores and structures have high affinity to CH 4 , as their complex pore structure and huge internal surface area entail a strong gas storage capacity [10,11]; Gasparik et al (2014) and Jin et al (2014) demonstrated that the interlayers of smectite, mixed I/S and other clay minerals develop with a mass internal surface area, which is another significant occurrence space [12,13].…”