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Petrophysics and Well Logs

Search and Discovery Article

Measurements of fluid wetting characteristic are made routinely on rock samples. However, there are no published petrophysical models to differentiate between oil-wet and water-wet fractions of a reservoir sequence using commonly available log suites. This presentation builds on our previous publication that describes the unconventional reservoir petrophysical model we have developed (Holmes, 2014). Essentially, we define four porosity components, namely total organic carbon, clay porosity, effective porosity, and “free shale porosity.” This last component is an indirect calculation if the first three components do not sum to total porosity.  Porosity/resistivity plots can be constructed for the total porosity and interpreted in a standard fashion. These will mostly indicate a water-wet system where the effective porosity fraction is examined. A second porosity/resistivity plot compares resistivity with “free shale porosity,” and is clearly interpreted to indicate Archie saturation exponents of much larger than 2 — frequently in excess of 3 — indicating the oil-wet fraction of the reservoir system. Additionally, the plots suggest low to very low values of cementation exponent, ranging from 1.0 to 1.5.   Examples from the Bakken of Montana and North Dakota, the Niobrara of Colorado, and the Wolfcamp and Spraberry of Texas are presented showing quantitative distinction of water-wet vs. oil-wet reservoir components.

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American Association of Petroleum Geologists (AAPG)
Explorer Article

The forum will include presentations given by leading experts from companies who have been successfully operating in the basin.

American Association of Petroleum Geologists (AAPG)
Explorer Article

Thanks to advancements in data management and seismic sensing, geophysical modeling has become indispensable in the search for oil. What will it become in the century ahead?

American Association of Petroleum Geologists (AAPG)
PSGD Blog

The AAPG Petroleum Structure and Geomechanics Division (PSGD) has announced the 2016 Best Paper Awards at the Annual Convention and Exhibition in Calgary, Alberta, Canada. Congratulations to Richard H Groshong, Jr., awarded 'Best Seminal Publication' for '3-D Structural Geology: A Practical Guide to Quantitative Surface and Subsurface Map Interpretation 2nd Edition'. We thank everyone for nominating the candidates. We also thank Bob Krantz, Bob Hatcher, and Gary Couples for their diligent work on the PSGD Best Paper Committee.

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American Association of Petroleum Geologists (AAPG)
Learn! Blog

Optimizing reservoirs and developing an ever-evolving intelligent model of a reservoir are key concerns for operators, particularly in challenging times. For that reason, they must have good production geologists on hand. A production geologist bridges a number of disciplines, most notably geology and engineering, but also geochemistry, geophysics, and numerical methods. Welcome to an interview with Terngu Utim who discusses production geology, its new potential and opportunities.

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American Association of Petroleum Geologists (AAPG)
Learn! Blog

The dynamics of fluid behavior and structural movement on the nano-scale can be complicated and not always what was expected. New research that analyzes the well information and cores using new techniques and technologies is yielding important and useful results. Welcome to an interview with Wen Zhou, Chengdu University of Technology, who discusses recent research findings.

American Association of Petroleum Geologists (AAPG)
Learn! Blog

Primary research in hydrocarbon generation is yielding new insights into the natural gas geochemical characteristics of conventional and unconventional reservoirs, along with discoveries relating to the geomechanical processes. Welcome to an interview with Chenglin Liu, China University of Petroleum-Beijing, who discusses enlightening new findings regarding the relationship between salinity and hydrocarbon geochemical characteristics.

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

Understanding the complex makeup of reservoirs is essential, and it requires considerable evaluation and time.

American Association of Petroleum Geologists (AAPG)
Learn! Blog

How does diagenesis affect rock physics? What is the relationship of the burial history to the rock physics? Both have a dramatic impact on the rock physics properties of not only the reservoir, but also the source and seals. Welcome to an interview with Per Avseth, who discusses rock physics and quantitative seismic interpretation. He also talks with us about how developing an effective rock physics model requires the integration of geological, geophysical, geochemical, and petrophysical information.

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American Association of Petroleum Geologists (AAPG)
Learn! Blog

You may not be aware that there was a super-Greenhouse environment during the Cretaceous, and that there were super-storms associated with it, and that analyzing the sediments deposited during that time can provide insight into the potential warming of climates, and also the cross-shelf transport of sediments. That is just one of many fascinating new areas of research that looks at data through new lenses, and with new analytical techniques. Welcome to an interview with Lesli J. Wood, Weimer Distinguished Chair and Professor in Sedimentary and Petroleum Geology, Colorado School of Mines.

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American Association of Petroleum Geologists (AAPG)
Field Seminar
Muscat, Oman
Sunday, 5 April 2026, 8:00 a.m.–4:30 p.m.

This one-day advanced course delivers a focused and highly practical framework for interpreting structural styles in the Middle East, combined with the unique advantage of applying Generative AI (GenAI) to elevate geological understanding and decision-making. Built for geoscientists working in exploration, development, or basin modeling, the course emphasizes practical techniques, hands-on interpretation, and modern tools that increase accuracy, speed, and confidence in structural workflows. We begin with a foundational module designed to unify all participants, regardless of background, around the principles of fault mechanics and structural style recognition. Participants will revisit faulting fundamentals, mechanical stratigraphy, and structural style classification. The goal is to align interpretation techniques with geological processes, and to establish a shared vocabulary for the day. An introduction to GenAI highlights its role in managing structural ambiguity and enhancing workflows, helping geoscientists clarify options when data is incomplete or conflicting. Normal Faulting Through a sequence of focused exercises, participants explore fault segmentation, growth history, and interpretation in extensional domains. This segment reinforces practical skills in identifying and validating fault geometries in map and section views. GenAI is introduced as a scenario-building tool: participants will use it to explore structural uncertainty, generate alternative models, and compare extensional interpretations, all using fragmented or incomplete datasets, not as a seismic interpreter but as a powerful thought partner. Strike-Slip and Transtension This module targets the complexity of strike-slip and transtensional systems. Participants learn to distinguish pure strike-slip geometries from transtensional overprints, assess compartmentalization, and model realistic deformation patterns. Interpretation exercises develop structural reasoning in map and cross-sectional views. GenAI is applied here to integrate multi-source inputs, such as field data, analogs, and internal reports, to support rapid synthesis and generate testable structural concepts. Salt Tectonics The final segment introduces key diagnostic features of salt-related deformation: welds, reactive and passive diapirs, and halokinetic sequences. Exercises train participants to recognize salt-influenced geometries and link them to broader structural evolution. GenAI then supports pattern recognition and memory mining, leveraging archived knowledge from prior studies, case histories, and analog reports to help geoscientists build and validate interpretations faster and with more confidence. What makes this course different? This is not a theoretical seminar. It’s a learning accelerator, where foundational concepts are applied in realistic interpretation settings, then extended with state-of-the-art GenAI capabilities. You’ll not only sharpen your structural reasoning, but learn how to delegate time-consuming tasks, like synthesizing legacy reports, generating alternative scenarios, or exploring interpretation options, to an intelligent AI partner. By the end of the day, participants will: Recognize and differentiate key fault styles with confidence Improve fault interpretation quality and geological risk assessment Use GenAI to test structural scenarios and extract insight from fragmented or incomplete datasets Accelerate their ability to interpret, communicate, and make decisions in structurally complex plays This course equips you with what matters most today: deep geological understanding, elevated by the best of modern AI. Who Should Attend and Why This course is ideal for both new hires and experienced geoscientists working across exploration, development, and reservoir modeling. Its exercise-driven format ensures that participants with diverse backgrounds, geologists, geophysicists, geomodelers, can engage, learn, and apply. While some familiarity with geosciences is beneficial, prior structural geology training is not required. What makes this course indispensable is its ability to bridge theory and practice: participants will gain a clear understanding of how rocks deform over time, how fault geometries evolve, and how these structures influence seismic interpretation, mapping, and static/dynamic modeling. By integrating real case studies and GenAI-enhanced workflows, the course delivers practical tools to improve subsurface outcomes and build models that match project maturity and business objectives. Main Objective This course delivers the structural geology foundations every geoscientist needs to confidently interpret faults and build or validate static models. Derived from decades of project reviews, interpretation support, and applied field experience, these “must-know” concepts include fault mechanics, growth, segmentation, and structural style recognition, relevant to both exploration and production settings. Participants will strengthen their ability to recognize deformation styles, interpret fault geometries in map and section view, assess mechanical stratigraphy and reactivation risk, and QC interpretations with confidence. Throughout the course, GenAI is introduced not as a software tool, but as a workflow enhancer, used to reduce ambiguity, test structural hypotheses, and extract insight from fragmented datasets or legacy documentation. This empowers geoscientists to think more clearly, work more efficiently, and improve the geological soundness of their models. Key Points Date: 5th April,2026 Venue: Crowne Plaza Hotel, OCEC Registration Fee: $590 Registration Deadline: 22nd February,2026 *Registration will be opening shortly Instructors Pascal Richard PRgeology Jan Witte Falcon-Geoconsulting

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American Association of Petroleum Geologists (AAPG)
Field Seminar
Muscat, Oman
Thursday, 9 April Friday, 10 April 2026, 7:30 a.m.–7:00 p.m.

The Jabal Akhdar in the Central Oman Mountains forms a ~90 km × 60 km dome. The core of this dome consists of Cryogenian to Ediacaran siliciclastics and carbonates, including source rocks. These rocks are separated from the overlying rocks by a spectacularly exposed angular unconformity. The rocks above this unconformity are Permo-Mesozoic shelf carbonates of the Arabian passive margin. The rocks below the unconformity are folded twice, while those above show no such folding. During the Late Cretaceous, Arabia was overthrust by the Samail Ophiolite and Hawasina deep-sea sedimentary rocks. Final doming occurred during the late Eocene to early Miocene. The Jabal Akhdar Dome is a textbook example of stratigraphy and structural geology development from the Cryogenian to the present. Furthermore, findings from the dome can be used as a natural laboratory and serve as an analogue for the hydrocarbon-bearing sequences in interior Oman. The two-day field trip will start at the Saiq Plateau where we will examine Cryogenian Snowball-Earth diamictites with cap carbonates, blended within the scenic landscape of Jabal Akhdar. The second day will start at a breath-taking vista point at Wadi Bani Awf. From there we will descend into the core of the Jabal Akhdar and explore the structural style of the Cryogenian and younger succession. Field Trip Information: Date: 9th – 10th April 2026 Time: 7:30am – 7pm Field Trip fee: $550 Registration Deadline: 5th March 2026 (*registration will be opening shortly) Fees Include: 1 night accommodation in a hotel Guided hiking tour through rose farms and ancient villages in Jebel Akhdar (2–3 hours) Traditional Omani lunch hosted at a local home BBQ dinner in a scenic open area at Jebel Akhdar All transportation (4x4s) Field Trip Leaders Andreas Scharf GUtech Oman Ivan Callegari GUtech Oman Wilfried Bauer GUtech Oman

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American Association of Petroleum Geologists (AAPG)
Workshop
Muscat, Oman
Monday, 6 April Wednesday, 8 April 2026, 8:00 a.m.–5:00 p.m.

The AAPG Structural Styles of the Middle East is back! This exciting and highly anticipated Geoscience Technology Workshop will take place from 6 – 8 April 2026, in Muscat, Oman. This workshop aims to explore the diverse structural styles resulting from the different deformation phases on the tectonostratigraphic framework of the Arabian Plate and adjacent regions.  

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 28 January 2010, 12:00 a.m.–12:00 a.m.

This 1-hour web-cast will arm the G&G asset team professionals with a core-competency understanding of these critical field realities, with direct reference to recent documented field experience and learnings

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 11 November 2010, 12:00 a.m.–12:00 a.m.

This e-symposium is ideal for geologists, geophysicists, engineers and other geoscientists who are involved in gas shale exploration and production.

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 12 April 2012, 12:00 a.m.–12:00 a.m.

This seminar focuses on the role geoscience leaders and mentors play in retaining top talent.

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Wednesday, 9 February 2022, 8:00 a.m.–9:00 a.m.

 This talk will provide information to better understand the principles of surface geochemistry (SG), how best to use SG data in exploration or development programs, how to develop a cost effective sampling and analytical program, and will also explore best practices for the interpretation and integration of SG data.

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Wednesday, 17 June 2020, 7:00 p.m.–8:30 p.m.

Join us for 'Sustainability-Focused Opportunities'. A webinar to explore investment trends, new opportunities, and strategies for pivoting for new revenue and diversification in today's times. Webinar will be presented via Zoom 7:00pm - 8:30pm CDT 17 June 2020.

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Thursday, 8 October 2020, 3:00 p.m.–4:00 p.m.

Join us as Doug Peacock discusses how changes in oil price impact reserves in theory, and with practical industry examples. Presentation will be via Zoom on Thursday 8 October 15:00 SGT (UTC+8) Singapore time zone

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Tuesday, 28 April 2020, 12:00 p.m.–1:00 p.m.

Em 2011 e 2015, apresentei uma avaliação do potencial de petróleo ainda por descobrir (YTF – Yet to Find) na região brasileira do pré-sal, utilizando uma ferramenta de modelagem de exploração e um método de simulação estocástica (Monte Carlo) para estimar as acumulações potenciais já descobertas e as restantes para ser descobertas. Embora da metodologia robusta usada, é compreensível que, à luz dos novos preços do petróleo, muito mais baixos, a avaliação do óleo YTF possa ser questionada sobre o quão realista poderia ser, num cenário prolongado de preço baixo do petróleo. Em 2016, apresentei essa avaliação, para preços do petróleo abaixo de US$ 50/bbl. Agora, com os preços do petróleo ainda mais baixos que podem representar um novo cenário de redução por mais tempo, volto a revisar as avaliações anteriores. Os resultados são apresentados no contexto de importantes implicações geopolíticas para em regiões do mundo onde os recursos de petróleo e gás provavelmente continuarão viáveis, apesar dos preços baixos do petróleo, e os rearranjos geopolíticos que isso implica.

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American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Tuesday, 31 October 2023, 12:00 p.m.–1:00 p.m.

Mississippian strata in the Ottawa County, Oklahoma, within the Tri-State Mining District, are a well-known hosts to MVT lead and zinc ore deposits. They are also important to our understanding of the geological story of the southern midcontinent. Join us for a virtual float trip down the Spring River in northern Oklahoma. We will explore the Middle Mississippian (Visean; upper Osagean-lower Meramecian) strata of the Boone Group as exposed in roadcuts, quarries, and natural outcroppings across Ottawa County in northeastern Oklahoma.

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American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Thursday, 10 September 2020, 3:00 p.m.–4:00 p.m.

Economic oil and gas fields have been increasingly found in deep-water continental margins for the past decade, where potential prospects record the key tectonic events associated with plate breakup and continental drift. In these regions, the exploitation of economic resources must take into account sustainable practices and environmental concerns of local populations. This talk will present case studies from multiple continental margins to then extrapolate major findings to basins in SE Asia.

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American Association of Petroleum Geologists (AAPG)
Webinar
Friday, 15 December 2023, 11:00 a.m.–12:12 p.m.

Featured speaker Jim Puckette of Oklahoma State University dives into silica enrichment in the Woodford and Caney Shales. In the Woodford Shale, silica enrichment is manifested as distinct silica-cemented bands that contain tests of radiolarians, the likely biogenic source of most silica in silica cement. Silica enrichment in the Caney Shale occurs without an obvious biogenic source of Si or developing the banding and beds evident in the Woodford Shale. Puckette notes identifying differences between reservoir and non-reservoir intervals, including density porosity, clay mineral content and resistivity.

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American Association of Petroleum Geologists (AAPG)
DL Abstract

For well over a century there have been conflicting indications of the strength of the crust and of faults and what controls them.  Much of our ignorance comes quite naturally from the general inaccessibility of the crust to measurement--in contrast with our understanding of the atmosphere, which is much more accessible to observation as well as more rapidly changing.  Crustal strength is best understood in deforming sedimentary basins where the petroleum industry has made great contributions, particularly in deforming petroleum basins because of the practical need to predict. In this talk we take a broad look at key issues in crustal strength and deformation and what we can learn from boreholes, earthquakes, active fault systems, and toy models.

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Request a visit from John Suppe!

American Association of Petroleum Geologists (AAPG)
VG Abstract

The carbonate sequences that were deposited in the now exhumed Tethyan Ocean influence many aspects of our lives today, either by supplying the energy that warms our homes and the fuel that powers our cars or providing the stunning landscapes for both winter and summer vacations. They also represent some of the most intensely studied rock formations in the world and have provided geoscientists with a fascinating insight into the turbulent nature of 250 Million years of Earth’s history. By combining studies from the full range of geoscience disciplines this presentation will trace the development of these carbonate sequences from their initial formation on the margins of large ancient continental masses to their present day locations in and around the Greater Mediterranean and Near East region. The first order control on growth patterns and carbonate platform development by the regional plate-tectonic setting, underlying basin architecture and fluctuations in sea level will be illustrated. The organisms that contribute to sequence development will be revealed to be treasure troves of forensic information. Finally, these rock sequences will be shown to contain all the ingredients necessary to form and retain hydrocarbons and the manner in which major post-depositional tectonic events led to the formation of some of the largest hydrocarbon accumulations in the world will be demonstrated.

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Request a visit from Keith Gerdes!

American Association of Petroleum Geologists (AAPG)
DL Abstract

The Energy sector is a changing business environment. Throughout the 20th century fluctuations of oil supply and demand produced changes in the barrel price that pushed the growth or shrinkage of the industry. In this 21st century, new challenges such as diversification of the energy mix, boosting gas demand, require the exploration of critical minerals and development of new technologies as well.

Request a visit from Fernanda Raggio!

American Association of Petroleum Geologists (AAPG)
DL Abstract

President Biden has laid out a bold and ambitious goal of achieving net-zero carbon emissions in the United States by 2050.  The pathway to that target includes cutting total greenhouse gas emissions in half by 2030 and eliminating them entirely from the nation’s electricity sector by 2035. The Office of Fossil Energy and Carbon Management will play an important role in the transition to net-zero carbon emissions by reducing the environmental impacts of fossil energy production and use – and helping decarbonize other hard-to abate sectors.

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Request a visit from Jennifer Wilcox!

American Association of Petroleum Geologists (AAPG)
DL Abstract

Three-dimensional (3D) seismic-reflection surveys provide one of the most important data types for understanding subsurface depositional systems. Quantitative analysis is commonly restricted to geophysical interpretation of elastic properties of rocks in the subsurface. Wide availability of 3D seismic-reflection data and integration provide opportunities for quantitative analysis of subsurface stratigraphic sequences. Here, we integrate traditional seismic-stratigraphic interpretation with quantitative geomorphologic analysis and numerical modeling to explore new insights into submarine-channel evolution.

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Request a visit from Jacob Covault!

American Association of Petroleum Geologists (AAPG)
DL Abstract

Local sea-level changes are not simply a function of global ocean volumes but also the interactions between the solid Earth, the Earth’s gravitational field and the loading and unloading of ice sheets. Contrasting behaviors between Antarctica and Scotland highlight how important the geologic structure beneath the former ice sheets is in determining the interactions between ice sheets and relative sea levels.

Request a visit from Alex Simms!

American Association of Petroleum Geologists (AAPG)
VG Abstract

Production from unconventional petroleum reservoirs includes petroleum from shale, coal, tight-sand and oil-sand. These reservoirs contain enormous quantities of oil and natural gas but pose a technology challenge to both geoscientists and engineers to produce economically on a commercial scale. These reservoirs store large volumes and are widely distributed at different stratigraphic levels and basin types, offering long-term potential for energy supply. Most of these reservoirs are low permeability and porosity that need enhancement with hydraulic fracture stimulation to maximize fluid drainage. Production from these reservoirs is increasing with continued advancement in geological characterization techniques and technology for well drilling, logging, and completion with drainage enhancement. Currently, Australia, Argentina, Canada, Egypt, USA, and Venezuela are producing natural gas from low permeability reservoirs: tight-sand, shale, and coal (CBM). Canada, Russia, USA, and Venezuela are producing heavy oil from oilsand. USA is leading the development of techniques for exploring, and technology for exploiting unconventional gas resources, which can help to develop potential gas-bearing shales of Thailand. The main focus is on source-reservoir-seal shale petroleum plays. In these tight rocks petroleum resides in the micro-pores as well as adsorbed on and in the organics. Shale has very low matrix permeability (nano-darcies) and has highly layered formations with differences in vertical and horizontal properties, vertically non-homogeneous and horizontally anisotropic with complicate natural fractures. Understanding the rocks is critical in selecting fluid drainage enhancement mechanisms; rock properties such as where shale is clay or silica rich, clay types and maturation , kerogen type and maturation, permeability, porosity, and saturation. Most of these plays require horizontal development with large numbers of wells that require an understanding of formation structure, setting and reservoir character and its lateral extension. The quality of shale-gas resources depend on thickness of net pay (>100 m), adequate porosity (>2%), high reservoir pressure (ideally overpressure), high thermal maturity (>1.5% Ro), high organic richness (>2% TOC), low in clay (<50%), high in brittle minerals (quartz, carbonates, feldspars), and favourable in-situ stress. During the past decade, unconventional shale and tight-sand gas plays have become an important supply of natural gas in the US, and now in shale oil as well. As a consequence, interest to assess and explore these plays is rapidly spreading worldwide. The high production potential of shale petroleum resources has contributed to a comparably favourable outlook for increased future petroleum supplies globally. Application of 2D and 3D seismic for defining reservoirs and micro seismic for monitoring fracturing, measuring rock properties downhole (borehole imaging) and in laboratory (mineralogy, porosity, permeability), horizontal drilling (downhole GPS), and hydraulic fracture stimulation (cross-linked gel, slick-water, nitrogen or nitrogen foam) is key in improving production from these huge resources with low productivity factors.

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Request a visit from Ameed Ghori!

American Association of Petroleum Geologists (AAPG)
DL Abstract

While there are many habitats that are associated with the deposition of organic-rich marine and lacustrine source rocks, one important pathway is linked to the onset of increased basin subsidence associated with major tectonic events. A key aspect is that this subsidence is spatially variable, with the uplift of basin flanks contemporaneous with the foundering of the basin center, resulting in a steeper basin profile.

Request a visit from Kurt W. Rudolph!

American Association of Petroleum Geologists (AAPG)
DL Abstract

As oil and gas exploration and production occur in deeper basins and more complex geologic settings, accurate characterization and modeling of reservoirs to improve estimated ultimate recovery (EUR) prediction, optimize well placement and maximize recovery become paramount. Existing technologies for reservoir characterization and modeling have proven inadequate for delivering detailed 3D predictions of reservoir architecture, connectivity and rock quality at scales that impact subsurface flow patterns and reservoir performance. Because of the gap between the geophysical and geologic data available (seismic, well logs, cores) and the data needed to model rock heterogeneities at the reservoir scale, constraints from external analog systems are needed. Existing stratigraphic concepts and deposition models are mostly empirical and seldom provide quantitative constraints on fine-scale reservoir heterogeneity. Current reservoir modeling tools are challenged to accurately replicate complex, nonstationary, rock heterogeneity patterns that control connectivity, such as shale layers that serve as flow baffles and barriers.

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Request a visit from Tao Sun!

American Association of Petroleum Geologists (AAPG)
DL Abstract

Climate change is not only happening in the atmosphere but also in the anthroposphere; in some ways the former could drive or exacerbate the latter, with extreme weather excursions and extreme excursions from societal norms occurring all over the earth. Accomplishing geoscience for a common goal – whether that is for successful business activities, resource assessment for public planning, mitigating the impacts of geological hazards, or for the sheer love of furthering knowledge and understanding – can and should be done by a workforce that is equitably developed and supported. Difficulty arises when the value of institutional programs to increase equity and diversity is not realized.

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Request a visit from Sherilyn Williams-Stroud!

American Association of Petroleum Geologists (AAPG)

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