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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)
Workshop
Khobar, Saudi Arabia
Monday, 8 May Wednesday, 10 May 2023, 8:00 a.m.–5:00 p.m.

“Wait! There is a short cut. Turn right from here”. That’s probably the sound of an electric current bypassing the resistive hydrocarbons, in a maze or network of porous media, when traveling from transmitter to receiver. This workshop will serve the participants need with the up to date advancements in describing and characterizing low resistivity and low contrast pay, and eventually, maximize resources.

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Tuesday, 16 April 2013, 12:00 a.m.–12:00 a.m.

The goal of this e-symposium is to provide an overview of the latest trends and technologies for water management for oil and gas drilling, completions, and production.

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 21 February 2013, 12:00 a.m.–12:00 a.m.

The course will review core data, petrophysical comparisons, rock physics modeling (including pseudo logs and mechanical properties).

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Tuesday, 9 September 2014, 2:00 p.m.–3:00 p.m.

Water cut is a big factor in gauging the success of horizontal drilling in the Mississippi Lime Play (MLP). The contributing factors are related in part to the spectrum of producing lithofacies and reservoir quality encountered that varies laterally and vertically, sometimes dramatically. 

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 23 April 2015, 2:00 p.m.–3:00 p.m.

Recent laboratory studies have revealed previously unknown behaviors in shale gas which unlock secrets of permeability and sweet spots in shale gas reservoirs. The presentation presents the findings and also goes into detail about how the new information can be applied in order to potentially improve recovery in reservoirs.

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Thursday, 9 February 2012, 12:00 a.m.–12:00 a.m.

Projects in several shales will be discussed, including Marcellus, Eagle Ford, Haynesville, Fayetteville, Montney, and Barnett, as will several seismically-detectable drivers for success including lithofacies, stress, pre-existing fractures, and pore pressure.

American Association of Petroleum Geologists (AAPG)
Online e-Symposium
Friday, 1 November 2013, 12:00 a.m.–1:00 a.m.

This presentation demonstrates how 3D seismic data will contribute significantly to the understanding of the Marcellus.

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Tuesday, 5 May 2020, 12:00 p.m.–1:00 p.m.

Sequence stratigraphy is a method for stratigraphic interpretation, pioneered by Vail and colleagues in the mid 70’s, which explains the complex geometries that sediments create as they fill accommodation in response to changes in rates of sedimentation, subsidence, uplift and eustasy. This method was developed based on observations and concepts developed as early as in the 1800’s. Based on this strong scientific foundation, pioneer work from Caster, Sloss, Wheeler, Campbell, and Asquith established the basis for the methodology. These researchers established a new way to correlate stratigraphic units, demonstrating the time-transgressive nature of lithostratigraphic formations.

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American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Monday, 19 October 2020, 12:00 p.m.–1:30 p.m.

In this webinar, Stephen Ehrenberg will present a review of the various processes that interact to determine the wide variations in porosity found in carbonate strata containing petroleum reserves. Presentation is via Zoom on Monday 19 October at 12:00 London time.

American Association of Petroleum Geologists (AAPG)
Webinar
Virtual Webinar
Wednesday, 12 January 2022, 8:00 a.m.–9:00 a.m.

Using global examples and based on 40 years’ experience in mainstream geology and in Petroleum Systems Analysis, Andrew Pepper will discuss how re-thinking some of our paradigms can open up our minds to new Discovery Thinking in any old or new basin.

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

Salt welds form due to salt thinning by mechanical (e.g., salt-flow) and/or chemical (e.g., salt-dissolution) processes. This webinar explores how we use 3-D seismic reflection, borehole, and biostratigraphic data to constrain the thickness and composition of salt welds, and to test the predictions of analytical models for salt welding.

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)
VG Abstract

The Betic hinterland, in the westernmost Mediterranean, constitutes a unique example of a stack of metamorphic units. Using a three-dimensional model for the crustal structure of the Betics-Rif area this talk will address the role of crustal flow simultaneously to upper-crustal low-angle faulting in the origin and evolution of the topography.

Request a visit from Juan I. Soto!

American Association of Petroleum Geologists (AAPG)
DL Abstract

Around 170 million years ago, the Gulf of Mexico basin flooded catastrophically, and the pre-existing landscape, which had been a very rugged, arid, semi-desert world, was drowned beneath an inland sea of salt water. The drowned landscape was then buried under kilometers of salt, perfectly preserving the older topography. Now, with high-quality 3D seismic data, the salt appears as a transparent layer, and the details of the drowned world can be seen in exquisite detail, providing a unique snapshot of the world on the eve of the flooding event. We can map out hills and valleys, and a system of river gullies and a large, meandering river system. These rivers in turn fed into a deep central lake, whose surface was about 750m below global sea level. This new knowledge also reveals how the Louann Salt was deposited. In contrast to published models, the salt was deposited in a deep water, hypersaline sea. We can estimate the rate of deposition, and it was very fast; we believe that the entire thickness of several kilometers of salt was laid down in a few tens of thousands of years, making it possibly the fastest sustained deposition seen so far in the geological record.

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Request a visit from Frank Peel!

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)
VG Abstract

In comparison with the known boundary conditions that promote salt deformation and flow in sedimentary basins, the processes involved with the mobilization of clay-rich detrital sediments are far less well established. This talk will use seismic examples in different tectonic settings to document the variety of shale geometries that can be formed under brittle and ductile deformations.

Request a visit from Juan I. Soto!

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)
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

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

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)

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