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Carbonate pore structure and therefore permeability is controlled in large part by unique diagenetic events and products, and a complex wettability structure that is often dominantly weakly-oil wet. This produces a highly diverse array of pore types and size, styles of connectivity and tortuosity, and in turn flow behaviours. While changes in porosity can be directly related to diagenetic petrographic characteristics such as cement distribution and dissolution features, quantifying how these textures control attendant changes in permeability ismore challenging. The impact of individual diagenetic events and their products on flow properties can, however, be isolated and modelled using 3D pore architecture models.

Porosity and permeability evolution through many diagenetic scenarios often display several ‘diagenetic tipping points’ where the decrease in permeability is dramatically larger than expected for the associated decrease in porosity. The effects of diagenesis also alters the capillary entry pressures and relative permeabilities, so providing trends that can be applied to real rocks. In turn, such diagenetic pathway models can be used to provide constraints on predicted flow behaviour during burial and/or uplift scenarios using ‘diagenetic back stripping’ of carbonate rocks. In dominantly microporous carbonates, average pore radius controls single-phase permeability, but has minimal effect on multiphase flow. When moldic mesopores are added to a microporous matrix, they only impact flow when directly connected: micropores control the magnitude of single-phase permeability. Recovery, however, is dependent on both wetting scenario and pore network homogeneity: under water-wet imbibition, increasing proportions of microporosity yield lower residual oil saturations.

Process-based models of early cementation (isopachous and syntaxial) show that isopachous cement is effective in closing pore throats and limiting permeability, but permeability changes due to syntaxial cement growth (preferentially on monocrystalline grains) is highly dependent on monocrystalline grain location and direction ofthe grain crystal axis, as this can create a highly ‘patchy’ distribution of cement.

Show more American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/dl-rachel-wood-modeling-the-evolution-of-permeability-in-carbonites-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Modeling the Evolution of Permeability in Carbonates
 

The AAPG Annual Convention and Exhibition will feature a variety of field trips that will bookend the meeting, spanning from March 26 to April 8.

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/field-trips-set-for-ace-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Field Trips Set for ACE
 

The driving forces for conventional accumulations (structural or stratigraphic traps) are Forces of Buoyancy which are due to differences in densities of hydrocarbons and water. In contrast, the driving forces for unconventional tight accumulations are Forces of Expulsion which are produced by high pressures. That is an enormous difference and creates unconventional petroleum systems that are characterized by very different and distinctive characteristics. The Force of Expulsion pressures are created by the significant increase in volume when any of the three main kerogen types are converted to hydrocarbons. At those conversion times in the burial history, the rocks are already sufficiently tight so the large volumes of generated hydrocarbons cannot efficiently escape through the existing tight pore system, thus creating a permeability bottleneck that produces an overpressured compartment over a large area corresponding to the proper thermal oil and gas maturities for that basin. The forces initially created in these source rocks can only go limited distances into adjacent tight reservoirs (clastics or carbonates) above or below the source. The exact distance will vary depending on the pressure increase, matrix permeability, and fractures of that specific tight reservoir system. In general, the distances are small, in the orders of 10s to 100s of feet for oil and larger for more mobile gas systems. Those exact distance numbers are subject to ongoing investigations.  

A plot of the pressure data versus elevation for a given formation is critical in determining whether an accumulation is conventional or unconventional. Conventional accumulations will have hydrocarbon columns of 10s to 100s of feet with the pressure in the hydrocarbons and that in the water equal at the bottom of the accumulation (at the HC-water contact). In contrast, the unconventional accumulations will show HC column heights of 1000s of feet with the pressure in the hydrocarbon phase and the water phase being the same at the top of the accumulation (at the updip transition zone). Those significant differences are critical for understanding and differentiating these two play types. Because the system is a pore throat bottleneck with very little or minimum lateral migration, the type of hydrocarbon s are closely tied to the thermal maturity required to generate those hydrocarbons. Thus the play concept begins with two important geochemical considerations: (1) where are the source rocks and what are the kerogen types and organic richness (TOC), and (2 ) where are they mature in the basin for oil, condensate, and gas in the basin. These parameters will very quickly define the fairway for the play. Then one has to add the critical information on the reservoirs themselves: composition (brittleness), thickness, and reservoir quality (matrix porosity and permeability). In summary, these tight unconventional petroleum systems (1) are dynamic , and (2) create a regionally inverted petroleum system with water over oil over condensate over gas for source rocks wit h Type I or II kerogen types.

Show more American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/sd-Our-Current-Working-Model-for-Unconventional-Tight-Petroleum-Systems-Oil-and-Gas-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Our Current Working Model for Unconventional Tight Petroleum Systems: Oil and Gas
 

The AAPG Annual Convention and Exhibition will feature a variety of field trips that will bookend the meeting, spanning from March 26 to April 8.

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/field-trips-set-for-ace-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Field Trips Set for ACE
 

The eastern Mediterranean Sea could become the hottest offshore play in the Middle East area, depending on the outcome of a key exploration attempt later this year.

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/eastern-mediterranean-becoming-a-hot-spot-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Eastern Mediterranean Becoming a Hot Spot
 

The AAPG European Regional Conference, “Hydrocarbons in the Mediterranean: revisiting mature plays and understanding new and emerging ideas,” will be held Jan. 18-19 in Larnaca, Cyprus.

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/explorer-hero-2016-12dec.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true European Regional Conference Set for January
 
Desktop /Portals/0/PackFlashItemImages/WebReady/dl-arctic-and-marine-gas-hydrate-production-testing-lessons-learnedp-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Arctic and Marine Gas Hydrate Production Testing – Lessons Learned
 

Heterogeneity in carbonate reservoirs contributes to large ranges in hydrocarbon production rates. Reservoir heterogeneity is generated by processes related to deposition, diagenesis and structuring.

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/abstract-carbonate-vs-clastic-reservoir-eveluations.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Predicting Patterns of Hydrocarbon Production Rates in Carbonate Fields – Deconvolving Flow-Modifying Effects of Depositional, Diagenetic and Structuring Processes
 

Carbonate reservoir evaluations for either Exploration or Production studies are markedly different than those for clastic ones because of several important factors:

American Association of Petroleum Geologists (AAPG)
Desktop /Portals/0/PackFlashItemImages/WebReady/abstract-carbonate-vs-clastic-reservoir-eveluations.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Carbonate vs. Clastic Reservoir Evaluations - Why So Different?
 
Desktop /Portals/0/PackFlashItemImages/WebReady/dl-integrated-seismic-and-well-log-analysis-of-gas-hydrate-prospects-hero.jpg?width=100&h=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Integrated Seismic and Well Log Analysis of Gas Hydrate Prospects
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In-Person Training
Weymouth Dorset United Kingdom 13 October, 2017 15 October, 2017 40465 Desktop /Portals/0/PackFlashItemImages/WebReady/ice-2017-syn-rift-lacustrine-carbonates-field-trip-hero-1180.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Member, ICE 2017, Sedimentology and Stratigraphy, Carbonates, Field Trips, Conventions, Pre-Convention
 
Weymouth, Dorset, United Kingdom
13-15 October 2017

The aim of the filed trip is to study Upper Jurassic microbial carbonates and to compare the lower part of the Purbeck Limestone Group of the Wessex Basin with the South-Atlantic pre-salt carbonates.

Robin Hood's Bay North Yorkshire United Kingdom 18 October, 2017 20 October, 2017 40473 Desktop /Portals/0/PackFlashItemImages/WebReady/ice-2017-field-trip-7-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Member, Geochemistry and Basin Modeling, Source Rock, Sedimentology and Stratigraphy, Carbonates, ICE 2017, Field Trips, Conventions, Post-Convention
 
Robin Hood's Bay, North Yorkshire, United Kingdom
18-20 October 2017

We will visit sections of organic-rich, Lower Jurassic, mudstone-dominated strata where depositional, diagenetic and structural processes can be examined in the context of shale resources, and Zechstein (Upper Permian) lagoonal, reefal and lower slope carbonates which act as tight, fractured reservoirs from the North Sea to Poland.

Marrakech Marrakech-Médina Morocco 19 October, 2017 23 October, 2017 40516 Desktop /Portals/0/PackFlashItemImages/WebReady/ice-2017-ft-10-atlantic-margin-petroleum-systems-morocco-hero-1180.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Member, Sedimentology and Stratigraphy, Carbonates, ICE 2017, Field Trips, Conventions, Post-Convention
 
Marrakech, Marrakech-Médina, Morocco
19-23 October 2017

The five-day field trip will visit key localities to review the structural and depositional evolution of the Central Atlantic margin and build in depth knowledge of its key play elements.

Bari Agrigento Italy 19 October, 2017 22 October, 2017 40477 Desktop /Portals/0/PackFlashItemImages/WebReady/ice-2017-ft-8-fractured-carbonate-reservoirs-outcrops-hero-1180.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Member, ICE 2017, Sedimentology and Stratigraphy, Carbonates, (Carbonate) Shelf Sand Deposits, Conventions, Field Trips, Post-Convention
 
Bari, Agrigento, Italy
19-22 October 2017

The field trip will visit spectacular outcrops of the Cretaceous to Pliocene Apulian Carbonates sequence to gain an understanding of the complexity of carbonate fractured reservoirs.

Abu Dhabi - Yas Island Abu Dhabi United Arab Emirates 30 January, 2018 01 February, 2018 32793 Desktop /Portals/0/PackFlashItemImages/WebReady/gtw-mer-carbonate-reservoirs-of-the-middle-east-and-their-future-challenges-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Sedimentology and Stratigraphy, Carbonates, Geophysics, Seismic, Engineering, Reservoir Characterization, Geochemistry and Basin Modeling, Structure, Geomechanics and Fracture Analysis
 
Abu Dhabi - Yas Island, Abu Dhabi, United Arab Emirates
30 January - 1 February 2018

This three-day workshop builds on the success of the first AAPG Carbonate Reservoirs of the Middle East GTW, held in Abu Dhabi, UAE in 2015. It is dedicated to addressing the hydrocarbon bearing carbonate reservoirs of the Middle East, in the context of a changing oil market within a more challenging exploration and development environment. These challenges include the shift from traditional anticlinal traps to stratigraphic traps, and development strategies for dealing with maturing, long-producing, giant fields.

Al Ain Abu Dhabi United Arab Emirates 01 February, 2018 01 February, 2018 38233 Desktop /Portals/0/PackFlashItemImages/WebReady/gtw-mer-carbonate-reservoirs-of-the-middle-east-and-their-future-challenges-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Structure, Geochemistry and Basin Modeling, Sedimentology and Stratigraphy, Geophysics, Engineering, Geomechanics and Fracture Analysis, Carbonates, Seismic, Reservoir Characterization
 
Al Ain, Abu Dhabi, United Arab Emirates
1 February 2018

The main objective of this field trip is to offer participants the opportunity to study the structural style and fracturing of carbonate rocks analogous to reservoir units of the globally important UAE Oil Province. The clear exposure of these carbonate rocks in this tectonically complicated area provides a significant opportunity to study and explain the structural style and deformation history of the region. Although the carbonate rocks exposed in Jebal Hafit area are of Early Eocene–Miocene age (Rus, Dammam and Asmari Formations), the emphasis here is to study fractures pattern and fracturing mechanism with relation to the paleostress and the link to fractures conductivity.

The selected stops will demonstrate the stratigraphic relationship of the rock units and their fracture systems that have been developed during long geological deformation. There are significant similarities between these exposed rocks and those units seen in the Abu Dhabi Oil Fields by means of reservoir characteristics and fracture system and fracture related diagenesis (cementation/host rock alteration) with its impact on sealing potential.

Jebal Hafit, an elongated asymmetrical, double‐plunging, NNW‐SSW trending anticline with an elevation reaches up to ~ 1140 m high, is situated at the border between Oman and UAE. It extends ca 30 km in the direction NNW–SSE with average width of 4 to 5 km.

Al Ain Abu Dhabi United Arab Emirates 01 February, 2018 01 February, 2018 38235 Desktop /Portals/0/PackFlashItemImages/WebReady/gtw-mer-carbonate-reservoirs-of-the-middle-east-and-their-future-challenges-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true Structure, Geochemistry and Basin Modeling, Sedimentology and Stratigraphy, Geophysics, Engineering, Geomechanics and Fracture Analysis, Carbonates, Seismic, Reservoir Characterization
 
Al Ain, Abu Dhabi, United Arab Emirates
1 February 2018

The modern carbonate-evaporite depositional environments along the Abu Dhabi shoreline and offshore Abu Dhabi belong to the few areas of the world where the geoscientist can observe the interplay between carbonate and evaporite sedimentation.

Supratidal (sabkha) to intertidal and shallow subtidal (microbial mat and peloid-skeletal tidal-flat) environments will be studied in the vicinity of Al-Qanatir Island.

Al-Qanatir Island

In the vicinity of the road to Al-Qanatir Island participants will be able to study a complete and undisturbed lateral facies succession from the upper supratidal to the lower intertidal and shallow subtidal:

  • Upper supratidal stranded beach ridges
  • Topographic highs, some cm above the adjacent upper sabkha environment
  • Upper sabkha (upper supratidal)
  • Surface covered by polygonally-cracked halite crust
  • Middle sabkha (middle supratidal)
  • Surface covered by finely-crystalline, whitish anhydrite polygons
  • Lower sabkha (lower supratidal)
  • Surface covered by shiny, sparkling gypsum crystals
  • Upper to lower intertidal microbial mat
  • Crenulated or crinkled microbial mat above gypsum mush facies
  • Blistered and pinnacle microbial mat
  • Polygonal and tufted microbial mat
  • Lowermost intertidal to shallow sub-tidal
  • Peloid-skeletal tidal-flat

Many of these depositional environments and facies successions correspond to those observed in cores from the subsurface of the Arabian Peninsula.

Online Training
19 March, 2015 19 March, 2015 16283 Desktop /Portals/0/PackFlashItemImages/WebReady/New-Insights-into-the-Stratigraphic-Framework-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
19 March 2015

A detailed biostratigraphic analysis and stratigraphic framework of the Paleocene and Eocene Chicontepec Formation in the Tampico-Misantla basin, onshore eastern Mexico, was conducted using 33 wells.

10 November, 2011 10 November, 2011 1481 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-heterogeneity-in-carbonate-reservoirs.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
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).

01 January, 2013 01 January, 9999 1459 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-cc-giant-oil-and-gas-fields.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
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.

30 August, 2012 30 August, 2012 1489 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-mississippian-carbonates-in-kansas.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
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.

24 October, 2013 24 October, 2013 1499 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-geomechanical-data-from-petrophysical-logs.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
24 October 2013

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

07 June, 2012 07 June, 2012 1488 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-new-production-in-oil-fields.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
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.

21 February, 2013 21 February, 2013 1495 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-petrophysics-of-carbonates.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
21 February 2013

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

28 April, 2011 28 April, 2011 1471 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-niobrara-petroleum-system-a-major-tight-resource-play.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
28 April 2011

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

11 November, 2010 11 November, 2010 1465 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-geochemical-evaluation-of-eagle-ford-group-source.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
11 November 2010

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

14 February, 3000 14 February, 3000 7817 Desktop /Portals/0/PackFlashItemImages/WebReady/oc-es-generic-hero.jpg?width=100&height=100&mode=crop&anchor=middlecenter&quality=75amp;encoder=freeimage&progressive=true
 
Request a Visit
 

Carbonate pore structure and therefore permeability is controlled in large part by unique diagenetic events and products, and a complex wettability structure that is often dominantly weakly-oil wet. This produces a highly diverse array of pore types and size, styles of connectivity and tortuosity, and in turn flow behaviours. While changes in porosity can be directly related to diagenetic petrographic characteristics such as cement distribution and dissolution features, quantifying how these textures control attendant changes in permeability ismore challenging. The impact of individual diagenetic events and their products on flow properties can, however, be isolated and modelled using 3D pore architecture models.

Porosity and permeability evolution through many diagenetic scenarios often display several ‘diagenetic tipping points’ where the decrease in permeability is dramatically larger than expected for the associated decrease in porosity. The effects of diagenesis also alters the capillary entry pressures and relative permeabilities, so providing trends that can be applied to real rocks. In turn, such diagenetic pathway models can be used to provide constraints on predicted flow behaviour during burial and/or uplift scenarios using ‘diagenetic back stripping’ of carbonate rocks. In dominantly microporous carbonates, average pore radius controls single-phase permeability, but has minimal effect on multiphase flow. When moldic mesopores are added to a microporous matrix, they only impact flow when directly connected: micropores control the magnitude of single-phase permeability. Recovery, however, is dependent on both wetting scenario and pore network homogeneity: under water-wet imbibition, increasing proportions of microporosity yield lower residual oil saturations.

Process-based models of early cementation (isopachous and syntaxial) show that isopachous cement is effective in closing pore throats and limiting permeability, but permeability changes due to syntaxial cement growth (preferentially on monocrystalline grains) is highly dependent on monocrystalline grain location and direction ofthe grain crystal axis, as this can create a highly ‘patchy’ distribution of cement.

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Request a visit from Rachel Wood!

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