Geology of the West White Lake, South Bosco-Duson-Ridge, Abbeville-Perry-South Perry structures, South Louisiana

Abstract

The West White Lake, South Bosco-Duson-Ridge, and Abbeville-Perry-South Perry structures are located in the Oligocene and Miocene oil- and gas-producing trends of south-central Coastal Louisiana. Strata encountered by drilling are primarily Pliocene, Miocene, and Oligocene in age. Wells drilled to sufficient depth encounter three distinct facies: first a shallow-water, massive, Pliocene and Miocene, sand facies deposited under near-shore and continental conditions, then an intermediate facies consisting of alternating sand and shale bodies laid-down in a Miocene continental-shelf environment, and finally a deep-water shale facies deposited mainly in a continental-slope environment during Oligocene time. Structurally, the West White Lake, South Bosco-Duson-Ridge, and Abbeville-Perry-South Perry features are faulted, elongate, ridge-like anticlines. The folds are elongated normal to the regional strike of the beds. All faults are normal and include both down-to-the-basin and up-to-the-basin faults. The down-to-the-basin faults are generally regional in nature, while the smaller up-to-the-basin faults are compensating faults confined to individual structures. Fault throws generally increase gradually with depth. Of all the faults mapped, only one extends upward in the section into strata of Pliocene age. ...