Download presentation
Presentation is loading. Please wait.
Published byBruce Perkins Modified over 9 years ago
1
Title U.S. Department of the Interior U.S. Geological Survey Probable Production Induced Subsidence, Fault Reactivation, and Wetland Loss in the Gulf Coast Region R. Morton, N. Buster, D. Krohn, and R. Peterson U.S. Geological Survey Center for Coastal and Watershed Studies St. Petersburg, FL 33701 http://coastal.er.usgs.gov/gc-subsidence/
2
SCIENTIFIC OBJECTIVES Investigate timing of subsidence and faulting Compare geological and historical rates of subsidence Evaluate geological and engineering factors that may influence induced subsidence and faulting
3
Objectives continued Examine mechanisms of subsidence and faulting Evaluate methods of regional subsidence detection and monitoring Develop predictive capabilities (subsidence susceptibility)
4
ENVIRONMENTAL APPLICATIONS Evaluate potential contributions to historical wetland losses Incorporate into resource management and coastal restoration plans Evaluate methods of subsidence mitigation
5
EVIDENCE OF INDUCED SUBSIDENCE AND FAULT REACTIVATION Temporal and spatial correlation of surficial changes and hydrocarbon production Large or rapid subsurface pressure decline (regional depressurization)
6
Evidence continued Consistent orientation and displacement of active surface and subsurface faults Historical subsidence rates significantly greater than geological subsidence rates Preservation of marsh sediments beneath open water (historical wetland loss)
7
Overburden stress
8
Fieldwork
9
COCODRIE TIDE GAUGE
10
Coring
11
Texas location map
12
Fields table Port Neches
13
Port Neches field map
14
Port Neches field graph
15
Port Neches diagram
16
Texas location map
17
Bolivar photo
18
Caplen Field map
19
Caplen Field graph
20
Caplen Field diagram
21
Texas location map
22
Clam Lake map
23
Aerial photo
24
Clam Lake graph
25
Wetlands photo
26
Louisiana map
27
Well field map
28
Fields table Valentine
29
Annual Production Valentine
30
BHP Valentine
31
Annual Production Houma
32
Annual production Lirette
33
Annual production Lapeyrouse
34
BHP Exposito
35
Pressure gradient decline
36
Core MB 06
37
Houma tide gauge
38
Loss lines
39
NGS Data 1965 - 1982
40
Benchmarks
41
NGS Data 1966 - 1993
42
Average geological and historical rates of subsidence for the Terrebonne delta plain region near Madison Bay.
43
Annual Production Lapeyrouse
44
DELTA PLAIN WETLAND LOSS
45
Prior studies attributed regional wetland loss to delta plain compaction, canal construction, and biogeochemical processes Subsidence associated with natural compaction should be slow and decrease with geologic time Some delta plain subsidence rates accelerated recently and are greater than geologic subsidence rates CONCLUSIONS
46
Marsh sediments are preserved where accommodation space is created by induced subsidence Prior explanations of regional wetland loss fail to explain the rapid increase and decrease in rates of loss (1950s-1970s) Close temperal and spatial correlations among regional wetland loss, highest historical subsidence rates, maximum rates of fluid extraction and pore- pressure reduction, and locations of potentially reactivated faults Decrease in wetland loss possibly related to decreased subsidence associated with decrease oil & gas production CONCLUSIONS CONTINUED
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.