Modern Clastics of the Texas Gulf Coast
Course Details
Incised valleys contain a mosaic of fluvial, lacustrine, and, where proximal to a seaway, shallow marine deposits that each present unique challenges as subsurface reservoirs, such as in Canada (Clearwater, McMurray, Bluesky Fm) and the US (Muddy, Morrow Fm). Where they intersect a coastline, complex interactions of tides, waves, and fluvial processes produce predictable depositional elements with discrete facies distribution within and between valleys. Sediment supply is the key to determining whether a coastline will prograde, aggrade, or be transgressed and whether a valley will fill or remain as a marine embayment.
The modern Texas Gulf Coast is a world-renowned natural laboratory and type location for a number of classic clastic facies models for good reason. Participants will have the opportunity to examine:
- Underfilled incised valley systems
- Overfilled incised valley systems
- Meandering fluvial point bars
- Microtidal bayhead deltas
- Barrier islands, spits, and tidal inlets
- Flood tidal deltas
- Wave-dominated deltas
- Tidal flats, creeks, and oyster reefs
- Chenier plain beach ridges at the mouth of, but not deposited by, fluvial systems.
- Proximal-distal vs. strike-fed coastal reservoir bodies
Many of these deposits and locations have formed the basis of the most commonly used depositional models for coastal and fluvial geobodies. Participants will learn when these are and are not the best analogs to use and how unique features of each system affect its resulting stratigraphy and sedimentology. A variety of outcrop and core images will be used to connect the modern examples to preserved remains of their ancient equivalents.
By the end of the trip, you will be able to:
- Identify fluvial, deltaic, tidal inlet, bay, and barrier island/shoreface deposits based on grain size profile, sedimentary structures, and ichnofossils.
- Predict reservoir properties of a variety of fluvial and coastal geobodies away from well bore using appropriate analogs.
- Predict locations of fluvial point sources for coastal sand bodies using proximal-distal facies and grain size trends.
- Construct depositional environment maps calibrated by appropriate modern and ancient analogs.
- Recognize that individual fluvial systems and their associated incised valleys are primarily driven by sediment supply and climate in the drainage basin and can be decoupled from sea level changes.
Who Should Attend
- Geologists
- Geophysicists
- Petrophysicists
- Engineers
- Geomodelers
- Drillers
This course is designed for geoscientists and reservoir engineers who are focused on subsurface characterization of fluvial and coastal geobodies, including incised valleys.
Need more information?
Course Outline
Day 1
You will be arriving the day before the course starts at George Bush International Airport, Houston, Texas, USA. The next morning we will meet at 9:00 am at the hotel meeting room for introduction and orientation. Safety briefing, orientation, lectures on key stratigraphic surfaces associated with valley incision and fill, barrier islands, and offshore deposits.
After lectures, we will drive to the Trinity River to examine point bar deposits and fluvial processes. We will compare the modern river to the older, mid-Holocene river and a variety of outcrop and subsurface analogs. After lunch, we will drive to the Trinity bayhead delta to look at the fluvial-marine transition in an underfilled valley and then head across the Bolivar Peninsula and Galveston tidal inlet. For dinner and lodging, we will be on the historic sea wall in Galveston.
Day 2
Morning lectures on barrier islands in time and space and the importance of tidal inlets and flood tidal deltas.
In the field, we will investigate the facies distribution and reservoir body anisotropy in the barrier island and the flood tidal delta. We will compare these deposits to subsurface and outcrop analogs.
Day 3
Classroom module on back barrier systems and their role in source rock and coal accumulation.
In the field, we will use boats to visit oyster reefs, flood tidal delta lobes, tidal flats, and tidal creeks. These will be compared to examples from other climatic, tectonic, and sea level cycle settings.
Day 4
Morning classroom module on deltas and deltaic reservoirs, with an emphasis on the link between deltas and incised valley systems and the role of key sedimentary processes.
We will visit an overfilled valley and the wave-dominated delta at its coastline and examine the role of avulsion and sediment supply in delta progradation.
Day 5
Geomorphology is not always the key to unraveling sedimentary process. Morning lectures will focus on the need to integrate all available data sets when deciphering subsurface reservoir bodies.
We will visit an underfilled valley that paradoxically appears to have a wave-dominated delta at its coastline.
From here, we will drop you off at George Bush International airport in Houston, Texas for an evening departure.
This course is offered upon request and costs $6500/person. This all inclusive rate includes five nights hotel stay, all meals, snacks and drinks in the field, fuel, permits, transportation during the field trip, tuition and field guide.
Field leader is Dr. Anton Wroblewski
