Field evidence of subsidence and faulting induced by hydrocarbon production in coastal southeast Texas

Gulf Coast Association of Geological Societies Transactions
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Abstract

Three large, mature hydrocarbon fields in coastal southeast Texas were examined to evaluate competing hypotheses of wetland losses and to characterize subaerial and submerged surfaces near reactivated faults and zones of subsidence. Detailed topographic and bathymetric profiles and shallow cores at the Port Neches, Clam Lake, and Caplen Fields provide a basis for distinguishing between (1) extensive land-surface subsidence without significant subaqueous erosion, and (2) localized minor subsidence near faults accompanied by extensive subaqueous erosion. Subaqueous erosion results from submergence of wetlands, current and wave excavation of surface sediments and organic detritus, and exportation of the eroded sediments through adjacent water bodies with swift currents such as navigation channels.


Responses to induced subsidence and fault reactivation are different at each field site. Detailed stratigraphic correlations of sediment cores show that at Port Neches, subsidence of 35 to 90 cm and minor marsh erosion (20 to 35 cm) created more than 15 million m3 of accommodation space in a nearly circular pattern over the field. At Caplen the marsh surface subsided only about 4 cm, but the surface eroded 30 to 40 cm vertically, creating about 3.5 million m3 of accommodation space. The breakup of wetlands and their conversion to open water appears to be in an initial stage at the Clam Lake Field where marsh plants are being submerged along a fault. The different surficial responses and wetland losses at each field are related to the primary type of hydrocarbon produced and the rates of production. Although the absolute magnitude of induced subsidence may be less than 1 m, even a minor reduction in land elevation is sufficient to cause major wetland losses.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Field evidence of subsidence and faulting induced by hydrocarbon production in coastal southeast Texas
Series title Gulf Coast Association of Geological Societies Transactions
Volume 51
Year Published 2001
Publisher Gulf Coast Association of Geological Societies
Contributing office(s) Coastal and Marine Geology Program
Description 10 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Gulf Coast Association of Geological Societies Transactions
First page 239
Last page 248
Country United States
State Texas
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