Subsidence and Hydrocarbon Production
In the Gulf Coast region, subsidence was first linked to hydrocarbon production in the mid-1920's at the Goose Creek Field near Galveston, Tex. (Pratt and Johnson, 1926). Subsidence at Goose Creek of about 1 meter (m) was enough to change the setting from a vegetated upland to open water.
A similar pattern of production-induced subsidence, which led to wetland replacement by open water, occurred at the Port Neches Field, Tex., between 1956 and 1978 (figs. 2 and 3). The similarity in area of wetland loss in 1978 compared with present conditions suggests that the subsidence was rapid initially but then slowed or possibly stopped.
Induced subsidence cannot be sustained indefinitely. Instead, the duration of surface adjustment is related to the history of production. As shown in figure 3, there was a time gap between the onset of production and the first visible evidence of surface disturbance and wetland loss. Whatever losses are occurring today, they are occurring at a much slower rate than when the wetlands deteriorated between 1956 and 1978. This reduction in rates of subsidence corresponds to the rapid decline in hydrocarbon production.