Oil and Gas
Oil and Gas | Clastics
Deltaic depositional systems are excellent settings for the examination and application of sequence stratigraphic concepts and outcomes. This course provides a comprehensive review of deltaic processes and their resultant deposits, focusing particularly on the application of high-resolution sequence stratigraphy methods in a high frequency, high amplitude glacio-eustatic context.
Duration and Training Method
A six-day field course based in the Upper Carboniferous Clare Basin. The proportion of field time to classroom time is approximately 80:20. Participants will be trained in the sedimentology and sequence stratigraphy of deltaic deposits via integrated lectures, exercises, field observations and discussion.
Participants will learn to:
- Characterise deltaic key sub-environments and their associated sandstone bodies, including delta front, delta plain and associated fluvial settings.
- Assess the sedimentology and stratigraphic architecture of deltaic settings through the recognition of key stratigraphic surfaces; specifically sequence boundaries and a spectrum of transgressive flooding surfaces that commences with maximum and initial flooding surfaces.
- Evaluate parasequences and their stacking patterns in a deltaic context.
- Develop correlative frameworks in deltaic deposits that utilise key stratigraphic surfaces, rather than lithostratigraphy.
- Evaluate lowstand deposits including incised valleys, their associated interfluve surfaces and prograding lowstand wedges composed of shelf-edge deltaic deposits.
- Characterise deposits of the transgressive and highstand systems tracts.
- Assess the relative importance of different systems tracts to the overall stratigraphy in a given case study.
- Evaluate the nature and extent of synsedimentary deformation in deltaic systems, including the key processes, deformational types and implications for reservoir characterisation.
Their location at the margin of basins results in records of relative sealevel change that can provide predictive models for the deltas themselves and also for the down-dip, deepwater systems they commonly supply. Understanding the nature of deltaic sedimentation is therefore critical to many aspects of clastic basin fill stratigraphy and petroleum exploration. The Upper Carboniferous Clare Basin contains an upward shallowing siliciclastic succession capped by 900 m of fluvio-deltaic deposits that outcrop along 60 km of the western Ireland coast. The Clare deltas are fluvial-dominated with significant wave-influence and were deposited in a near tideless intra-cratonic basin. Both deepwater and shallow-water deltas are represented along with thick, regional-scale sandstone bodies. The ice-house world of the Upper Carboniferous resulted in high magnitude and high frequency fluctuations in relative sealevel. These global conditions promote a sequence stratigraphic record in the deltas that allows confident recognition of key surfaces and identification and mapping of depositional systems tracts.
The Clare deltas exhibit a wide variety of instability related structures, including growth-faults, mud-diapirs and slumps and slides. These synsedimentary deformation features are a common constituent of sub-surface deltaic systems (e.g. Gulf of Mexico, Nigeria, SE Asia, North Sea) and are rarely exposed as well as in the Clare Basin.
The quality and orientation of the Clare outcrops compliments other GTA deltaic courses and provides the following contrasting sedimentological and stratigraphic opportunities:
- Large, continental-scale sediment supply and fluvial-dominated systems
- Mixture of shelf-margin deltas and shelf deltas
- High subsidence rates in a passive, post-rift tectonic setting
- Strong glacio-eustatic control on sequence stratigraphic signatures
- Strike orientated outcrops that deliver an extensive range of key surface expressions
- Linkage to down-dip deepwater settings
The course will examine the following aspects of deltaic sedimentation and stratigraphy:
- Lowstand wedges, including shelf-edge deltas
- Incised valley fills and related interfluve palaeosols
- Transgressive systems tracts, including shelf deltas
- Hierarchy of flooding surfaces, including regional condensed sections
- Synsedimentary deformational features; their variety and stratigraphic significance
- Gamma ray spectrometry of sequence stratigraphic key surfaces and sediment bodies
- Deltaic sedimentation within a high resolution biostratigraphic framework
Arrival and transfer to Kilkee.
Evening course safety brief and introductory lecture followed by group dinner.
Day 1: Lectures and Field
Introduction to deltaic depositional systems; and basin margin sequence stratigraphy; Introduction to the regional context and the Upper Carboniferous deltaic systems of the Clare Basin.
Day 2: Field
Lowstand System Tracts: prograding wedges and incised valley sedimentation and stratigraphy.
Day 3: Field
Transgressive System Tracts: variety of flooding surfaces, condensed section sedimentation and variability in valley fills.
Day 4: Lectures and Field
Synsedimentary deformation in deltaic systems; processes, structures and implications to stratigraphic analysis and reservoir characterisation. Outcrop examples; growth-faults, slumps, slides, gullies and diapirs.
Day 5: Exercises and Field
Application of sequence stratigraphic concepts to subsurface examples; systems tract recognition and predictive implications.
Testing of methods at outcrop.
Day 6: Field
Sequence boundaries and interfluves - sedimentology, palaoesols and subsurface recognition.
Low accommodation settings at the basin margin; comparison with deepwater deltas and down-dip changes in incised valley fills.
Review and summary discussion of key learnings.
Transfer from Kilkee and departure.
Who Should Attend and Prerequisites
Geologists and geophysicists concerned with analysing data from up-dip, basin margin locations in terms of reservoir presence and characterisation. More specifically, those wishing to gain a pragmatic, practical guide to the use of sequence stratigraphic methods in analysing, correlating and interpreting deltiac systems in the subsurface. Also those concerned with the prediction of deepwater deposits fed directly via up-dip deltaic settings.
Dr. Andy Pulham has more than 35 years of industrial and academic experience. Since early 2005 Andy has been constructing his own consulting and training company and alliances. He has consulted in South America, USA, Europe and Africa.
After graduating, Andy spent 12 years with BP Exploration as a Petroleum Sedimentologist and for BP worked in NW Europe, North America and South America. Highlights in Andy’s industrial career have been regional studies in the Jurassic of the North Sea and the Cenozoic of the deepwater Gulf of Mexico and the appraisal of the Cusiana Field in Colombia. From 1995-2001 Andy was Principal Investigator for Reservoir Geology at the Energy and Minerals Applied Research Center in the Department of Geological Sciences at the University of Colorado. While in Colorado, Andy conducted research into the production characteristics of marginal marine siliciclastic oil and gas reservoirs and alluvial architecture in the Big Horn Basin of Wyoming. Subsurface projects were drawn from the Americas, Europe and Papua New Guinea. In 2001 Andy gained an appointment as the Canada Research Chair in Petroleum Geosciences in the Department of Earth Sciences, Memorial University of Newfoundland and taught undergraduate and graduate petroleum geology and sedimentology and advised graduate students in subsurface reservoir, seismic stratigraphy and outcrop sedimentology projects. Andy left academia in 2003 and joined Nautilus USA as VP of Geoscience and acted as the senior technical liaison and technical manager for the Geoscience Training Alliance in North America.
Andy’s primary interests are clastic sedimentology and stratigraphy. Andy’s portfolio of geoscience training classes now number eleven schools and include deepwater clastics, marginal marine and deltas, play fairway analysis and exploration prospecting and petroleum systems.
Affiliations and Accreditation
PhD University College of Wales, Swansea - Geology
BSc University of Liverpool, England - Physical Geography and Geology
AAPG - Member
SEPM - Member
IAS - Member
RMAG - Member
N087: Play Fairway Analysis & Exploration Prospecting
N009: Sedimentology, Stratigraphy & Reservoir Geology of Deepwater Clastic Systems (County Clare, Ireland)
N011: High Resolution Sequence Stratigraphy: Reservoir Applications (Utah, USA)
N042: Reservoir Sedimentology & Stratigraphy of Coastal and Shelfal Successions: Deltas, Shorelines and Origins of Isolated Sandstones (NW Colorado, USA)
N115: High Resolution Sequence Stratigraphy: Application to Deltaic Systems and Reservoirs (County Clare Ireland)