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The Pennsylvanian unconformity, which is a detrital surface, separates the beds of the Permian-aged strata from the Lower Paleozoic in the Central Basin Platform. Seismic data interpretation indicates that the unconformity is an angular unconformity, overlying multiple normal faults, and accompanied with a thrust fault which maximizes the region's structural complexity. Additionally, the Pennsylvanian angular unconformity creates pinch-outs between the beds above and below. We computed the spectral decomposition and reflector convergence attributes and analyzed them to characterize the angular unconformity and faults. The spectral decomposition attribute divides the broadband seismic data into different spectral bands to resolve thin beds and show thickness variations. In contrast, the reflector convergence attribute highlights the location and direction of the pinch-outs as they dip south at angles between 2° and 6°. After reviewing findings from RGB blending of the spectrally decomposed frequencies along the Pennsylvanian unconformity, we observed channel-like features and multiple linear bands in addition to the faults and pinch-outs. It can be inferred that the identified linear bands could be the result of different lithologies associated with the tilting of the beds, and the faults may possibly influence hydrocarbon migration or act as a flow barrier to entrap hydrocarbon accumulation. The identification of this angular unconformity and the associated features in the study area are vital for the following reasons: 1) the unconformity surface represents a natural stratigraphic boundary; 2) the stratigraphic pinch-outs act as fluid flow connectivity boundaries; 3) the areal extent of compartmentalized reservoirs' boundaries created by the angular unconformity are better defined; and 4) fault displacements are better understood when planning well locations as faults can be flow barriers, or permeability conduits, depending on facies heterogeneity and/or seal effectiveness of a fault, which can affect hydrocarbon production. The methodology utilized in this study is a further step in the characterization of reservoirs and can be used to expand our knowledge and obtain more information about the Goldsmith Field. [ABSTRACT FROM AUTHOR]

This document is an editorial from the journal Energy Geoscience, discussing recent advancements in reservoir characterization. Reservoir characterization involves creating a detailed model of a reservoir to understand its capacity for storing and producing hydrocarbons. The editorial acknowledges the challenges in this field, such as complex pore structures and declining well productivity. The special issue of the journal includes papers on various topics related to reservoir characterization, such as analyzing reservoir heterogeneity, studying fractures, and examining gas hydrate saturation. These papers provide case examples and highlight the progress made in both conventional and unconventional reservoir characterization. Additionally, the document includes a list of references and acknowledgments for articles published in the journal, expressing gratitude to contributors, reviewers, and supporting individuals. It also provides brief biographies of the authors, detailing their educational background and research interests. [Extracted from the article]

Active macro seepages of methane that occur in between the north bank of the Brahmaputra river and Himalayan foothill region of Assam Arakan Basin, India, indicate the presence of hydrocarbon accumulation in the subsurface, but the hydrocarbon prospects in this region are not well studied. We carried out an extensive field sampling, which included a total of 58 sediment core collections from an active gas seepage location and nearby areas at a depth of 2–2.5 m. Our sample locations are placed at 1 km intervals laterally. We performed laboratory investigations and mapped near-surface chemical alterations associated with active macro seepages and microseepages. The analysis of geochemical composition of hydrocarbon gases in the sediment indicates both the biogenic and thermogenic origins of seeped hydrocarbons. The stable isotope analysis of methane suggests the presence of thermogenic as well as mixed biogenic-thermogenic gases. The presence of such mixing of gases is caused by the secondary alteration processes during their migration through potential faults and fractures. The trace elements of the sediments show anomalous concentrations at different parts of the study area, with a wide range of concentrations for Ba (54 to 492 ppm), Cu (1–25 ppm), Cr (61–329 ppm), Ni (1–42 ppm), Pb (2–48 ppm), Th (2–32 ppm), U (4–39 ppm), V (19–133 ppm) and U (0.87–6.5 ppm). There are higher concentrations of adsorbed gases, trace elements, and microbes along the identified lineaments. Such higher concentration can be triggered by high hydrocarbon-oxidizing bacteria count, which is greater than 104 cfu/gm of soil of bacterial growth around the lineaments. We identified potential hydrocarbon prospects based on the macro and micro seepage analysis using integrated geological, geochemical and microbial techniques in the study area. [ABSTRACT FROM AUTHOR]