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Organic-carbon–rich shales of the lower Marcellus Formation were deposited at the toe and basinward of a prograding clinothem associated with a Mahantango Formation delta complex centered near Harrisburg, Pennsylvania. Distribution of these organic-carbon–rich shales was influenced by shifts in the delta complex driven by changes in rates of accommodation creation and by a topographically high carbonate bank that formed along the Findlay-Algonquin arch during deposition of the Onondaga Formation. Specifically, we interpret the Union Springs member (Shamokin Member of the Marcellus Formation) and the Onondaga Formation as comprising a single third-order depositional sequence. The Onondaga Formation was deposited in the lowstand to transgressive systems tract, and the Union Springs member was deposited in the transgressive, highstand, and falling-stage systems tract. The regional extent of parasequences, systems tracts, and the interpreted depositional sequence suggest that base-level fluctuations were primarily caused by allogenic forcing—eustasy, climate, or regional thermal uplift or subsidence—instead of basement fault reactivation as argued by previous workers. Paleowater depths in the region of Marcellus Formation black mudrock accumulation were at least 330 ft (100 m) as estimated by differences in strata thickness between the northwestern carbonate bank and basinal facies to the southeast. Geochemical analysis indicates anoxic to euxinic bottom-water conditions. These conditions were supported by a deep, stratified basin with a lack of circulation.
We use three-dimensional seismic reflection data and new map-based structural restoration methods to define the displacement history and characteristics of a series of tear faults in the deep-water Niger Delta. Deformation in the deep-water Niger Delta is focused mostly within two fold-and-thrust belts that accommodate downdip shortening produced by updip extension on the continental shelf. This shortening is accommodated by a series of thrust sheets that are locally cut by strike-slip faults. Through seismic mapping and interpretation, we resolve these strike-slip faults to be tear faults that share a common detachment level with the thrust faults. Acting in conjunction, these structures have accommodated a north –south gradient in westward-directed shortening. We apply a map-based restoration technique implemented in Gocad to restore an upper stratigraphic horizon of the late Oligocene and use this analysis to calculate slip profiles along the strike-slip faults. The slip magnitudes and directions change abruptly along the lengths of the tear faults as they interact with numerous thrust sheets. The discontinuous nature of these slip profiles reflects the manner in which they have accommodated differential movement between the footwall and hanging-wall blocks of the thrust sheets. In cases for which the relationship between a strike-slip fault and multiple thrust faults is unclear, the recognition of this type of slip profile may distinguish thin-skinned tear faults from more conventional deep-seated, throughgoing strike-slip faults.

Offshore sequences of volcaniclastic rocks (such as hyaloclastite deposits) are poorly understood in terms of their rock properties and their response to compaction and burial. As petroleum exploration targets offshore volcanic rifted margins worldwide, understanding of volcanic rock properties becomes important both in terms of drilling and how the rocks may behave as seals, reservoirs, or permeability pathways. The Hawaiian Scientific Drilling Project phase II in 2001 obtained a 3 km-(2-mi)-long core of volcanic and volcaniclastic rocks that records the emergence of the largest of the Hawaiian islands. Core recovery of 2945 m (9662 ft) resulted in an unparalleled data set of volcanic and volcaniclastic rocks. Detailed logging, optical petrology, and major element analysis of two sections at depths 1831–1870 and 2530–2597 m (6007–6135 and 8300–8520 ft) are compared to recovered petrophysical logs (gamma ray, resistivity, and P-wave velocity). This study concludes deviation in petrophysical properties does not seem to correlate to changes in grain size or clast sorting, but instead correlates with alteration type (zeolite component) and bulk mineralogy (total olivine phenocryst percentage component). These data sets are important in helping to calibrate well-log responses through hyaloclastite intervals in areas of active petroleum exploration such as the North Atlantic (e.g., Faroe-Shetland Basin, United Kingdom, and Faroe Islands, the Norwegian margin and South Atlantic margins bordering Brazil and Angola).


The petroleum trap for the Athabasca oil sands has remained elusive because it was destroyed by flexural loading of the Western Canada Sedimentary Basin during the Late Cretaceous and Paleocene. The original trap extent is preserved because the oil was biodegraded to immobile bitumen as the trap was being charged during the Late Cretaceous. Using well and outcrop data, it is possible to reconstruct the Cretaceous overburden horizons beyond the limit of present-day erosion. Sequential restoration of the reconstructed horizons reveals a megatrap at the top of the Wabiskaw-McMurray reservoir in the Athabasca area at 84 Ma (late Santonian). The megatrap is a four-way anticline with dimensions 285 x 125 km (177 x 78 mi) and maximum amplitude of 60 m (197 ft). The southeastern margin of the anticline shows good conformance to the bitumen edge for 140 km (87 mi). To the northeast of the anticline, bitumen is present in a shallower trap domain in what is interpreted to be an onlap trap onto the Canadian Shield; leakage along the onlap edge is indicated by tarry bitumen outliers preserved in basement rocks farther to the northeast. Peripheral trap domains that lie below the paleospillpoint, in northern, southern, and southwestern Athabasca, and Wabasca, are interpreted to represent a late charge of oil that was trapped by bitumen already emplaced in the anticline and the northeastern onlap trap. This is consistent with kimberlite intrusions containing live bitumen, which indicate that the northern trap domain was charged not before 78 Ma. The trap restoration has been tested using bitumen-water contact well picks. The restored picks fall into groups that are consistent both with the trap domains determined from the top reservoir restoration and the conceptual charge model in which the four-way anticline was filled first, followed by the northeastern onlap trap, and then the peripheral trap domains.


“One man was at the head waters of the River Amazon among the headshrinkers when he was recalled to come to Iraq; another came from Argentina, another from Mexico, still another had been in Romania, one in Indo-China, several in Venezuela and the East Indies.”

Explorer Article

"Breakthrough elegance": ExxonMobil geologists Jeff Ottmann and Kevin Bohacs shared their highly-coveted knowledge on sweet spots and producibility thresholds at a recent Geosciences Technology Workshop on Unconventional Reservoir Quality.


This article describes a 250-m (820-ft)-thick upper Eocene deep-water clastic succession. This succession is divided into two reservoir zones: the lower sandstone zone (LSZ) and the upper sandstone zone, separated by a package of pelitic rocks with variable thickness on the order of tens of meters. The application of sequence-stratigraphic methodology allowed the subdivision of this stratigraphic section into third-order systems tracts.

The LSZ is characterized by blocky and fining-upward beds on well logs, and includes interbedded shale layers of as much as 10 m (33 ft) thick. This zone reaches a maximum thickness of 150 m (492 ft) and fills a trough at least 4 km (2 mi) wide, underlain by an erosional surface. The lower part of this zone consists of coarse- to medium-grained sandstones with good vertical pressure communication. We interpret this unit as vertically and laterally amalgamated channel-fill deposits of high-density turbidity flows accumulated during late forced regression. The sandstones in the upper part of this trough are dominantly medium to fine grained and display an overall fining-upward trend. We interpret them as laterally amalgamated channel-fill deposits of lower density turbidity flows, relative to the ones in the lower part of the LSZ, accumulated during lowstand to early transgression.

The pelitic rocks that separate the two sandstone zones display variable thickness, from 35 to more than 100 m (115–>328 ft), indistinct seismic facies, and no internal markers on well logs, and consist of muddy diamictites with contorted shale rip-up clasts. This section is interpreted as cohesive debris flows and/or mass-transported slumps accumulated during late transgression.

The upper sandstone zone displays a weakly defined blocky well-log signature, where the proportion of sand is higher than 80%, and a jagged well-log signature, where the sand proportion is lower than 60%. The high proportions of sand are associated with a channelized geometry that is well delineated on seismic amplitude maps. Several depositional elements are identified within this zone, including leveed channels, crevasse channels, and splays associated with turbidity flows. This package is interpreted as the product of increased terrigenous sediment supply during highstand normal regression.

Predicting the presence and connectivity of reservoir-quality facies in otherwise mud-prone fluvial overbank successions is important because such sand bodies can potentially provide connectivity between larger neighboring sand bodies. This article addresses minor channelized fluvial elements (crevasse-splay and distributary channels) and attempts to predict the connectivity between such sand bodies in two interseam packages of the Upper Permian Rangal Coal Measures of northeastern Australia. Channel-body percent as measured in well logs was 2% in the upper (Aries-Castor) interseam and 17% in the lower (Castor-Pollux) interseam. Well spacing were too great to allow accurate correlation of channel bodies. The Ob River, Siberia, was used as a modern analog to supply planform geometric measurements of splay and distributary channels so that stochastic modeling of channel bodies was possible. The resulting models demonstrated that (1) channel-body connectivity is more uniform between minor distributary channels than between crevasse-splay channels; (2) relatively good connectivity is seen in proximal positions in splays but decreases distally from the source as channel elements diverge; and (3) connectivity tends to be greater down the axis of splays, with more isolated channel bodies occurring at the margins.
DL Abstract

It is quite common for reservoir engineers to adjust the geological modelling without recoursing to the geologists by multiplying the porosity, the permeability, the anisotropy (kv/kh), the relative permeabilities, the well factors and many other parameters within their numerical world.

DL Abstract

Information on fractured reservoirs is often controversial. Engineers see lost circulation, negative skin and fracture well test signatures. Geologists see only matrix properties in their cores.

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In-Person Training
Salt Lake City Utah United States 14 September, 2014 21 September, 2014 151
Salt Lake City, Utah, United States
14-21 September 2014

Participants will learn a specific and comprehensive methodology for finding and developing conventional and unconventional oil and gas resources associated with lake deposits. The seminar will start with the Quaternary Bonneville basin in Utah, to build familiarity with lacustrine depositional processes. Participants then examine world-famous exposures of organic-rich mudstone, fluvial sandstone, and carbonate microbialite facies in Wyoming.

Naples Italy 20 September, 2014 26 September, 2014 36
Naples, Italy
20-26 September 2014

The main part of the field seminar will focus on the description of the fractured carbonates and the extrapolation from the outcrop observations to the subsurface for building geologically plausible reservoir models.

Barcelona Spain 22 September, 2014 26 September, 2014 153
Barcelona, Spain
22-26 September 2014

Participants will examine illustrative outcrops of thrusts, fault-related folds, stratal architectures and facies of depositional systems affected by growing structures, which are good analogues for hydrocarbon reservoirs. Objectives include interpreting complex thrust structures, identifying and understanding strain and fracture systems in fold-thrust belts, and analyzing patterns of growth strata in areas with synsedimentary folding.

Denver Colorado United States 25 October, 2014 26 October, 2014 9125
Denver, Colorado, United States
25-26 October 2014

Unconventional petroleum systems are becoming much more important world wide in oil and gas exploration and development. This field trip will examine several unconventional systems in the Denver and Florence-Canon City basins.

Houston Texas United States 10 November, 2014 10 November, 2014 10401
Houston, Texas, United States
10 November 2014

A one-day series of lectures covers the basic architecture of particulate sedimentary rocks, methods for petrologic characterization, grain assemblages, and diagenesis, including compaction, cementation, grain replacement, and fracturing. Examples of the nature and causes of reservoir quality variations in sandstones at low and high temperatures are provided with a focus on using the character of the primary grain assemblage as a predictive guide to what will happen in the subsurface.

Houston Texas United States 10 November, 2014 11 November, 2014 10487
Houston, Texas, United States
10-11 November 2014

This course summarizes the major advances and current controversies in dolomite research.

Houston Texas United States 12 November, 2014 12 November, 2014 10570
Houston, Texas, United States
12 November 2014

This course is designed to present the concepts of sedimentary geochemistry and biogeochemistry, along with the framework to interpret elemental and mineralogical records in such organic rich mudstone sequences.

Houston Texas United States 13 November, 2014 13 November, 2014 10572
Houston, Texas, United States
13 November 2014

The course begins with a short review of the basic principles of carbonate well logging and goes on to detail the different carbonate pore types and the logging methods used to differentiate the various pore types and to determine their hydrocarbon productive potential.

Houston Texas United States 08 December, 2014 11 December, 2014 1517
Houston, Texas, United States
8-11 December 2014

This course is designed to give participants the basic working tools to explore and develop hydrocarbons in salt basins. Because no two basins are alike, the focus is on understanding the processes and styles of salt-related deformation. At course completion participants should be able to under the depositional setting of layered evaporites, describe the mechanics of salt flow, interpret salt and stratal geometries associated with diapirs, salt welds, and minibasins, and assess more accurately the risks in the exploration of salt basins.

Houston Texas United States 27 January, 2015 28 January, 2015 8997
Houston, Texas, United States
27-28 January 2015

Reserve your space now to learn how and where new knowledge and technology geology, engineering, and geophysics come together to make deepwater and shelf exploration and development more successful. 

Oklahoma City Oklahoma United States 19 February, 2015 19 February, 2015 11378
Oklahoma City, Oklahoma, United States
19 February 2015


14 February, 3000 14 February, 3000 7815
14 February, 3000 14 February, 3000 7813
14 February, 3000 14 February, 3000 7816
14 February, 3000 14 February, 3000 7812
Online Training
02 October, 2014 02 October, 2014 10593
2 October 2014
This course is ideal for individuals involved in Midland Basin exploration and development. Successful development of Wolfcamp shale oil relies on complex inter-relationships (ultimately interdependencies) within and between a wide variety of scientific disciplines, financial entities, and company partnerships. 
09 September, 2014 09 September, 2014 10591
9 September 2014
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. 
08 December, 2011 08 December, 2011 1480
8 December 2011

This e-symposium focuses on methods for predicting connectivity within clastic fluvial systems.

30 August, 2012 30 August, 2012 1489
30 August 2012

The entire Middle Pennsylvanian–to–top Precambrian basement (500 m) interval was cored in early 2011 in the BEREXCO Wellington KGS #1-32 well in Wellington Field, Sumner County, KS.

07 November, 2013 07 November, 2013 1500
7 November 2013

This e-symposium presentation places the interpretation of deep-water turbidites discernible in 3-D seismic inversion data within a geological context.

07 June, 2012 07 June, 2012 1488
7 June 2012

Unger Field, discovered in1955, has produced 8.6 million barrels of oil from a thinly (several ft) bedded, locally cherty dolomite containing vuggy and intercrystalline porosity.

01 January, 2013 01 January, 9999 1459
1 January 2013 - 1 January 9999

There are more approximately 1,000 oil and gas fields in the world that have been classified as "giant," containing more than 500 million barrels of recoverable oil and /or 3 trillion cubic feet of gas.

24 October, 2013 24 October, 2013 1499
24 October 2013

This e-symposium will be introducing signal processing techniques as a means to maximize extracting geomechanical data from petrophysical logs.

13 December, 2012 13 December, 2012 1494
13 December 2012

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

10 May, 2012 10 May, 2012 1486
10 May 2012

Recognition and Correlation of the Eagle Ford, Austin Formations in South Texas can be enhanced with High Resolution Biostratigraphy, fossil abundance peaks and Maximum Flooding Surfaces correlated to Upper Cretaceous sequence stratigraphic cycle chart after Gradstein, 2010.

10 November, 2011 10 November, 2011 1481
10 November 2011

This work investigates how heterogeneity can be defined and how we can quantify this term by describing a range of statistical heterogeneity (e.g. coefficient of variation and the Lorenz coefficient).

21 February, 2013 21 February, 2013 1495
21 February 2013

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

05 March, 2014 05 March, 2014 3812
5 March 2014

Explore three of the great wonders of the geological world. Take a guided tour of classic geological sites on the Colorado Plateau.

25 August, 2011 25 August, 2011 1475
25 August 2011

This e-symposium provides highlights of the hydraulic fracturing mechanics, analysis, and design, and is derived from a two and one-half (2-1/2) day course which is designed for drilling, completion, production engineers, engineering technicians, geologists, well-site and completion supervisors, and managers, who desire to possess a comprehensive and integral knowledge of Hydraulic Fracturing.

28 April, 2011 28 April, 2011 1471
28 April 2011

The Niobrara Petroleum System of the U.S. Rocky Mountain Region is a major tight petroleum resource play.

17 March, 2011 17 March, 2011 1470
17 March 2011

This e-symposium will provide information on which tools, processes, and procedures all geoscientists, engineers, and technical professionals working in shale plays need to understand and implement.

17 February, 2011 17 February, 2011 1469
17 February 2011

This presentation is designed for exploration/production geologists and geological managers or reservoir engineers.

09 December, 2010 09 December, 2010 1466
9 December 2010

The Mississippian-Devonian Bakken Petroleum System of the Williston Basin is characterized by low-porosity and permeability reservoirs, organic-rich source rocks, and regional hydrocarbon charge.

11 November, 2010 11 November, 2010 1465
11 November 2010

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

19 August, 2010 19 August, 2010 1462
19 August 2010

This presentation will show where there are cases of missing sections, but none of them can be attributed to normal faulting.

29 April, 2010 29 April, 2010 1457
29 April 2010

This presentation will focus on the seismic stratigraphic and seismic geomorphologic expression of deep-water deposits, including both reservoir and non-reservoir facies.

22 October, 2009 22 October, 2009 1452
22 October 2009

This course can help you gain the ability to describe the complex and highly variable reservoirs, which are typified by complex internal heterogeneity.

01 November, 2013 01 November, 9999 452
1 November 2013 - 1 November 9999

This online course provides an overview of the petroleum industry from what is natural gas and crude oil to how to explore, drill, and produce oil and gas.

14 February, 3000 14 February, 3000 7817
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