Unconventional gas resources in theCantabrian Zone(NW Spain): A comprehensive preliminary assessment

Abstract

With the aim of acquiring a better knowledge of the potential for unconventional gas resources in Spain, 134 rock samples were taken from 12 lithostratigraphic units in the Cantabrian Zone (north‐west Spain) and studied for a 3‐year period. The selected units gather, a priori, the basic conditions to constitute potential source rocks for unconventional hydrocarbons. Petrographic studies and total organic carbon analyses were carried out for all samples, whereas Rock‐Eval pyrolysis and vitrinite reflectance measurements with kerogen visual analysis were performed on selected samples. Lutites, litharenites, limestones, and slates are the predominant petrographic types. In most cases, the mean total organic carbon content is below the 2% limit for good quality potential source rocks. Only the Jurassic Rodiles and Tereñes limestones show total organic carbon values above this threshold. Rock‐Eval data reveal very low potential for hydrocarbon generation in almost all cases, with the exception of the dark mudstones of the Carboniferous Barcaliente Formation and the Rodiles Formation (fair and good potential for hydrocarbon generation, respectively). As regards thermal maturation, only the Ordovician formations are located in the peak of the gas generation interval. The Barcaliente and Rodiles formations are near the frontier oil/wet gas maturation areas, and the rest of the units are immature for gas generation.

Climatic and cave settings influence on drip water fluorescent organic matter with implications for fluorescent laminations in stalagmites

“…The bedding is sub vertical, dipping 70° to the North. The Barcaliente Formation is rich in amorphous organic matter and classified as containing types II and III kerogen (Álvarez et al, 2019). Numerous block falls throughout the cave are consistent with a seismically active shallow crust (Delavaud et al, 2012).…”

Relationship of seasonal variations in drip waterδ13CDIC,δ18O, and trace elements with surface and physical cave conditions of La Vallina cave, NW Spain

“…La Vallina cave (43 • 24 36 N, 4 • 48 24 W; 70 m a.s.l.) is situated in Carboniferous limestone (Barcaliente formation; Gibbons and Moreno, 2002;Álvarez et al, 2019) and belongs to the North Iberia Speleothem Archive (NISA; Stoll et al, 2013Stoll et al, , 2015Fig. 1a).…”

Definition of a thermal conductivity map for geothermal purposes

“…Rocks with a higher thermal conductivity are more efficient at transferring heat energy, so the accuracy of rock thermal conductivity determination affects the design of these workings. Nevertheless, this work focuses on geothermal uses as the main application of the knowledge of this parameter (Wang et al 2021;Álvarez et al 2019;Popov et al 2016).…”