After reaching a plateau, the production of oil reservoirs starts to decline, which substantially determines their life expectancy. Declining production data from three 58- to 71-yr-old oil pools in Alberta, Canada, have been documented and analyzed to show and predict their life span. Two declining phases of oil production can be distinguished: a short 4–11-yr substantially declining phase and a long

The risk of anthropogenic earthquakes created by fluid injection and completion of horizontal wells is managed using maps of recent seismicity and by creating buffer zones around previously mapped faults. In Madison and Fayette Counties, Ohio, faults were identified in 1969 using analogue paper-recorded seismic reflection technology. These faults were located primarily by mapping a prominent “Conasauga

Oil and gas accumulations in the sandy conglomerate diagenetic traps that developed in the fan delta of the Triassic Baikouquan Formation of the Mahu sag, Junggar Basin, differ from stratigraphic accumulations controlled by sedimentary facies. This study uses conventional gas chromatography–mass spectrometry measurements, mineralogical and petrological data, fluid inclusion analyses, and geophysical

Gas storage capacity estimates of shales are routinely assessed using laboratory data from unconfined methane sorption and porosity measurements. In this study, the stress dependence of the methane excess sorption capacity and specific pore volume are investigated simultaneously. Experiments were performed on dry core plugs (Cambrian–Ordovician Alum, Jurassic Bossier, Late Cretaceous Eagle Ford, and

Within New Zealand, the East Coast Basin represents the primary shale oil and gas play in which the Whangai Formation is widespread. This formation is oil and gas prone and prevalent throughout a large area of the East Coast Basin and is typically composed of the Upper Calcareous, Porangahau, and Rakauroa Members.The primary goal of this study was to develop an integrated methodology to define the

The northeastern Sichuan Basin thrust belt located in southwestern China, is a large-scale intracontinental thrust system with multiple detachments represented by a series of subparallel chevron anticlines. We conduct a comprehensive study of the geometry and kinematics of the thrust belt and its implications for the petroleum system based on seismic-reflection profile interpretation, field investigation

Unconventional opal-A and opal-CT diatomaceous reservoirs in the Monterey Formation of the San Joaquin Valley in California have produced for more than 30 yr. These opal-A reservoirs are characterized by high porosity (>50%) and low permeability (<10 md) making them a challenge to produce. Five diatomaceous reservoirs in the Monterey Formation are described, with locations at Lost Hills, Cymric, and

Understanding and predicting the main controls on the sealing capacity of carbonate cap rocks is of great significance for ultradeep carbonate reservoir exploration and production. This study focuses on revealing the pore networks and sealing capacity of the Ordovician carbonate cap rocks in the Tarim Basin by analyzing samples from outcrop analogues using optical and scanning electron microscopy and

With the emergence of the “continuous petroleum accumulations” concept and unconventional petroleum exploration, the traditional source-to-trap petroleum system model becomes vague spatially because the source, reservoir, and seal may intermingle within the same stratigraphic unit. In such a system, the spatial distribution of key petroleum system elements therefore depends on sedimentary facies heterogeneities

The Permian Basin of the southwestern United States has produced approximately 35 billion bbl of conventional oil over the past century, and until recently, it was broadly viewed as an overdeveloped basin in the twilight of its effective life. Over the past decade, however, this perspective has changed because of the extraordinary success in oil recovery from unconventional upper Paleozoic shale reservoirs

Existing definitions for passive and active salt diapirism are somewhat overlapping and ambiguous. These terms are also equated to downbuilding and upbuilding, respectively, which are problematic concepts as originally conceived and even as subsequently modified. This results in conflicting usage and lack of consensus in the literature, creating confusion and decreasing the utility of the terms. For

The oils of Shuntuoguole low uplift of Tarim Basin in western China have high contents of saturated hydrocarbons and a high loss of light hydrocarbon components because of volatilization. These oils are characterized by low abundance of hopanes and high abundance of C28–30 tricyclic terpanes and dibenzothiophenes and relative high abundance of C20–23 terpanes, C21–22 5α-steranes, and diasteranes in

The Re-Os geochronometer constrains the timing of petroleum formation and provides an oil-source isotopic correlation tool for improved geologic knowledge and exploration success. However, the effects of secondary processes that may sometimes complicate interpretations are not well understood.This paper discusses Re-Os systematics in a petroleum system that experienced extensive asphaltene precipitation

Carbonate rocks commonly exhibit multiscale pore networks because of the interplay of depositional, diagenetic, and structural controls. This interplay commonly leads to carbonate reservoirs with complex pore networks that affect our ability to accurately characterize reservoir quality and be predictive about in-place volumes and hydrocarbon recovery. In particular, the preservation of paleocavern

Investigating the timing, structural style, and development of multiphase extensional fault systems is essential for understanding rift basin evolution and for assessment of structural trap integrity. Borehole-controlled interpretation and analysis of two-dimensional and three-dimensional seismic data sets from the eastern Dampier subbasin indicate that a northeast-trending basement weakness zone was

Gas and water samples were collected from coalbed methane (CBM) wells, rivers, and springs in the southern Junggar Basin (SJB). These samples were analyzed for gas composition, stable isotopes, 16s ribosomal ribonucleic acid sequence, chemical compositions, and radioisotopes. The objective of this study was to understand CBM genesis in the Junggar Basin, the reason for abnormal CO2 accumulation, the

Fifty crude oils from reservoirs ranging in age from Cambrian to late Permian and distributed widely over the Permian Basin were geochemically characterized to assess their stratigraphic interrelationships and provenance. Detailed characterization using stable carbon isotopic composition and biomarker characteristics recognized five genetic groups. Genetic group I oils originate from a type II kerogen

During the years 2007–2015, a new direction for industry was appearing. Revitalized waves of production emerged from the world’s richest petroleum bearing basins (Ahlbrandt, 2015; Fryklund, 2018). An all-out effort to optimize extensive infrastructure, using new technology and basin scale thinking, required an action plan for geoscientists.In 2018–2020, AAPG responded with a new series of programs

The AAPG Super Basin Initiative creates an action plan to help geoscientists revisit the world’s most productive petroleum basins by providing resources through conferences, online presentations, and publications like this special issue of the AAPG Bulletin. Understanding super basins better enables us to apply technologies that can reveal each unique super basin’s full resource development potential

Super basins are sedimentary basins with more than 5 billion BOE cumulative production and at least 5 billion BOE remaining recoverable resources. Super basins are characterized by two or more source rocks, stacked reservoirs, mature infrastructure, established service sectors, large amounts of data, and access to markets. Super basins commonly have multiple operators that form a community whose competitive

With more than 6000 m of sedimentary thickness and several superimposed petroleum systems, the Neuquén Basin of Argentina has all the elements to be considered a super basin. The basin developed during the Triassic–Early Jurassic in a rift environment that generated a localized petroleum system. Continued subsidence during the Early Jurassic resulted in the first marine ingression (Los Molles Formation

The Williston Basin Bakken petroleum system is a giant continuous accumulation. The petroleum system is characterized by low-porosity and -permeability reservoirs, organic-rich source rocks, and regional hydrocarbon charge. Total Bakken Formation and Three Forks Formation production to June 2019 is 3.3 billion bbl (0.52 billion m3) and 4.8 tcf of gas (0.135 trillion m3) from 19,075 wells. Daily production

The northern Gulf of Mexico federal offshore area easily qualifies as a super basin based upon estimated petroleum endowment of more than 100 BOE and cumulative production of 60 BOE. Like other super basins, it has multiple petroleum systems and stacked reservoirs. Examination of four key elements of these petroleum systems (reservoirs, source rocks, seals, and traps) yields important insights to the

The Sureste Basin of southern Mexico has all the components to be classed as one of the world’s super basins for hydrocarbon exploration and production. This is because of its endowment with one of the world’s great source rock systems, namely, the Late Jurassic Edzna Formation, in combination with stacking of multiple potential reservoirs in a highly structural salt basin.This paper discusses the

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