Subsurface hydrocarbon observations at any scale serve as critical clues to understand and reconstruct migration pathways and charge histories through geological time to assess the risk of petroleum exploration targets. Hydrocarbon migration commonly occurred millions of years ago, and the pathways can rarely be observed in wells or in outcrops. Therefore, hydrocarbon migration modeling tools are important

The underexplored Barents shelf petroleum province is a globally unique example where naturally occurring underpressure is observed offshore and onshore. In the offshore parts of the northern Barents shelf, minor underpressure (up to 23 bar below hydrostatic pressure) is observed in the fault-bounded Mesozoic reservoirs of the Fingerdjupet subbasin. More severe (50 bar below hydrostatic pressure although

The Sulige gas field in the Ordos Basin is the largest gas field in China. The studied area, the northern Tianhuan depression, is located west of the gas field and is considered as a potential gas-producing area. The complex diagenetic alteration history and its effects on the pore-throat network and reservoir quality of the tight gas sandstones are explained. The upper Paleozoic first member of the

Detrital zircon provenance studies of Terra Nova oil field strata, offshore Newfoundland, were conducted to constrain the depositional age and correlation of synrift sandstone units in the Jeanne d’Arc basin and test continuity with coeval rocks in adjacent regions. Braided fluvial sandstone intervals of the Jeanne d’Arc Formation from delineation wells K-18, C-09, and E-79 yield Mesozoic to Archean

Pore-throat structure characterization is crucial in tight-oil sandstone reservoir studies. To better understand pore-throat size distribution and the effects on reservoir oil saturation, petrographic, scanning electron microscopy, quantitative grain fluorescence (QGF), nuclear magnetic resonance (NMR), and pressure-controlled mercury injection investigations were performed on a suite of tight sandstones

Based on limited geophysical and outcrop data, shortening of the strata in the Appalachian Plateau above the Silurian salt detachment was interpreted to have occurred by layer-parallel shortening (LPS) plus gentle folding. Recently acquired high-quality, three-dimensional seismic reflection and well data reveal that strata from the Silurian Salina Group and the Devonian Marcellus Shale shortened through

It is difficult to determine flow pathways of paleofluids in sedimentary basins. Petrography, fluid inclusion, and isotopic compositions from different phases of calcite veins in the Ordovician in the Tazhong area were studied. Our results reveal a complex diagenesis process with two importantly crossformational fluid movements, coupled with three phases of calcite veins (C1, C2, and C3) precipitation

The sedimentary and diagenetic control on tight sandstone reservoir quality is a key focus of hydrocarbon exploration. This paper compares reservoir characteristics, such as diagenetic processes, pore types, and porosity evolution, of cores and outcrops of the Yanchang Formation, the Ordos Basin, northwestern China, to identify diagenetic trends and processes responsible for improving reservoir quality

We found the paper “Application of horizontal wells in three-dimensional shale reservoir modeling: A case study of Longmaxi–Wufeng shale in Fuling gas field, Sichuan Basin” by Wang et al. (2018) interesting because it deals with methods for modeling reservoir properties in shale reservoirs. The paper has merit, and it is quite thorough in investigating several problems, including the construction of

We appreciate the comments by Yin, Ma, and Gomez on our recent paper on shale reservoir modeling by primarily using data from horizontal wells (Wang et al., 2018). Three “unclear or suboptimal” points were proposed by Yin et al. (2020), and we will respond to these three points one by oneIn three-dimensional (3-D) geological modeling, well data, including core testing data, logs, and so on, are limited

The Morro Vermelho Cave (MVC) (Brazil) developed within the Morro Vermelho karst system, which affected Neoproterozoic limestones (Salitre Formation). The MVC experienced little interactions with meteoric processes and is an example of a hypogenic cave formed during strike-slip deformation. The Salitre carbonates in the MVC experienced distributed deformation along an elongated domain overlying a buried

This study investigates the origin of dolomite by examining thick lacustrine sequences of evaporites, mudstones, and deep-water sublacustrine fan sandstones in the lower unit of the fourth member of the Eocene Shahejie Formation (Es4x) in Bohai Bay Basin, China. This petrographic, geochemical, and numerical modeling study recognizes evidence for microbially mediated dolomite precipitates in the Es4x

Extensively developed hydrocarbon reservoirs within the Illinois Basin will soon reach the end of their production history without technological intervention. Although many of these mature fields have been waterflooded for decades and show significant production declines, substantial amounts of residual oil remain in place, making them ideal candidates for enhanced oil recovery (EOR). This research

Lower Cretaceous volcanic rocks that contain major natural fractures are the main natural gas reservoirs in the deep Xujiaweizi depression of the northern Songliao Basin in China. Natural fractures are mainly tectonic fractures, in addition to some shrinkage, dissolution, and cryptoexplosive fractures. Analyzing various sources of data revealed that fractures are generally better developed in the rhyolites

Total organic carbon (TOC) values of the Carboniferous shales and coals of the western Black Sea Basin of Turkey range from 0.72 to 71.52 wt. %, with an average of 32.3 wt. %, and generation potential chance from 0.33 to 184.64, with an average of 82.47 mg HC/g rock. Hydrogen index (HI) values of the shales and coals range from 24 to 384 mg HC/g TOC. The HI versus pyrolysis temperature at the maximum

The North Yellow Sea Basin (NYSB) is one of the petroliferous basins in the offshore region of eastern China. An integrated sequence stratigraphic–geochemical investigation was carried out to identify and assess the effective source rocks of recent oil discoveries in the NYSB. A total of four third-order sequences (the first [J2SQ1] and second [J2SQ2] third-order sequence within the Middle Jurassic

The petroleum systems of the Malargüe fold–thrust belt in the northwestern Neuquén Basin, Argentina, comprise multiple reservoir and seal rocks and three major source rocks of the Lower Jurassic (Los Molles Formation [Fm.]), the lower Tithonian to lower Valanginian (Vaca Muerta Fm.), and the lower Hauterivian to lower Barremian (Agrio Fm.). The thermal history of the Mesozoic source rocks has been

A rock-based geologic characterization was completed on a continuous core through the Austin Chalk Group section, an active exploration target in southern Texas. Because this core (located in the Pearsall field) is continuous and includes both lower and upper contacts, it can be used as the type cored section for the southern Texas Austin Chalk. Several general lithofacies are defined. Two lithofacies

The northern Gulf of Mexico (GOM) features all necessary elements for the formation and preservation of subsurface gas hydrates, including a prolific petroleum system, a variety of structural and stratigraphic migration pathways that focus hydrocarbon migration into the shallow sediments, variable geothermal gradients that support a locally thick gas hydrate stability zone, and silt- and sand-rich

The University of Texas Hydrate Pressure Coring Expedition (UT-GOM2-1) recovered cores at near in situ formation pressures from a gas hydrate reservoir composed of sandy silt and clayey silt beds in Green Canyon Block 955 in the deep-water Gulf of Mexico. The expedition results are synthesized and linked to other detailed analyses presented in this volume. Millimeter- to meter-scale beds of sandy silt

In May 2017, The University of Texas Hydrate Pressure Coring Expedition Gulf of Mexico 2-1 (UT-GOM2-1) drilled two adjacent holes in Green Canyon Block 955 in the deep-water Gulf of Mexico as part of The University of Texas at Austin and US Department of Energy Deepwater Methane Hydrate Characterization and Scientific Assessment. Expedition operations included testing two configurations of a rotary

The base of the gas hydrate stability zone (GHSZ) is a critical interface, providing a first-order estimate of gas hydrate distribution. Sensitivity to thermobaric conditions makes its prediction challenging, particularly in the regions with dynamic pressure–temperature regime. In Green Canyon Block 955 (GC 955) in the northern Gulf of Mexico, the seismically inferred base of the GHSZ is 450 m (1476

Gas hydrate in the Green Canyon area (Block 955) in the northern Gulf of Mexico is hosted by relatively clay-free silty levee deposits bounding a Pleistocene submarine channel. During the initial phase of channel development, the channel axis experienced sediment bypass while silty to sandy flanking levees formed. Development of high levees prompted gravitational collapse along normal faults dipping

We interpret the sedimentologic evolution of a deep-water channel-levee deposit in Green Canyon Block 955 (deep-water Gulf of Mexico) by analyzing hydrate-bearing pressure cores and nonpressure cores collected during The University of Texas-Gulf of Mexico 2-1 (UT-GOM2-1) Hydrate Pressure Coring Expedition that preserve remarkable sedimentary structures. The levee is composed of alternating beds of

We present results from 30 quantitative degassing experiments of pressure core sections collected during The University of Texas-Gulf of Mexico 2-1 (UT-GOM2-1) Hydrate Pressure Coring Expedition at Green Canyon Block 955 in the deep-water Gulf of Mexico as part of The University of Texas at Austin–US Department of Energy Deepwater Methane Hydrate Characterization and Scientific Assessment. The hydrate

We explore the petrophysical behavior of the two interbedded lithofacies (sandy silt and clayey silt) that constitute the Green Canyon Block 955 hydrate reservoir in the deep-water Gulf of Mexico by performing experiments on reconstituted samples of the reservoir material. Sandy silts reconstituted to the in situ porosity have a permeability of 11.8 md (1.18 × 10−14 m2), which is similar to the intrinsic

We present a seismic- and well-based interpretation of a large leakage zone above the Scarborough gas field, Exmouth plateau, North West shelf of Australia. This leakage zone, well imaged on three-dimensional seismic data, extends over a region of 100 km2 (39 mi2), encompassing both the crest and flanks of the anticlinal trap, and is termed here as distributed crestal leakage. The present-day gas–water

The Gudong oil field offers a unique opportunity to characterize thin meander-belt sandstones in an area with a dense network of wells (100 wells per square kilometer or 259 wells per square mile). The goal of this study is to evaluate the evolution of subsurface meander-belt complexes through analysis of their overall stratigraphic architecture defined by the spatial distribution of sedimentary structures

The Lower Cretaceous Agrio Formation is a source rock considered to be a possible unconventional reservoir. However, no detailed microstructure characterization of this hydrocarbon play has been performed. An exceptional oil-prone level is determined through outcrop information, petrography, x-ray diffraction, geochemical analysis, and x-ray micro–computed tomography (µCT). Microscopic studies reveal

New organic–geochemical investigations of the Eocene Cambay Shale (Cambay Basin, India) from five wells and an open-cast lignite mine reveal that the total organic carbon ranges from 0.37 to 10.68 wt. %, with an average of 2.43 wt. %. The pseudo–Van Krevelen diagram, hydrogen index versus the maximum pyrolysis yield temperature (Tmax) crossplot, and the visual kerogen assessment of the Cambay Shale

The fluorescence characteristics of individual oil inclusions and molecular composition analysis of oil inclusions in 20 Eocene sandstone samples from the Dongying depression were used to assess the relationship between the fluorescence colors of the oil inclusions and their thermal maturity. The oil inclusions from the Shahejie Formation member III middle submember, member III lower submember, and

For more than 60 yr, the term “Barrow arch” has been used to describe a regional structural high beneath northern Alaska and the Beaufort and Chukchi Seas that is of chief importance to the area’s petroleum systems. However, there are multiple interpretations of what, precisely, constitutes the Barrow arch. For example, most, but not all, interpretations invoke the arch as a basement feature. Other

Structurally deformed coal (SDC) influences not only gas outbursts during coal mining but also coalbed methane (CBM) production. Different SDCs have different mechanical strengths and physical properties. The structurally constrained petrophysical and mechanical properties of a CBM reservoir from the southern Qinshui Basin (SQB), northern China, have been investigated by using a coal structure index