--> Abstract: Timing Of Source Rock Maturation In The Northern Gulf Of Mexico Basin: Preliminary Results From Thermal Modeling Of A Regional Profile, by P. Weimer, E. Nelson, J. Caldaro-Baird, and B. C. McBride; #90928 (1999).

Datapages, Inc.Print this page

WEIMER, PAUL1, NELSON, ERIC1, CALDARO-BAIRD, JULIA1, and McBRIDE, BARRY C.2
1Department of Geological Sciences, University of Colorado, Boulder, CO, 80309-0399
2HS Resources, Denver, CO 80202

Abstract: Timing of Source Rock Maturation in the northern Gulf of Mexico Basin: Preliminary Results from Thermal Modeling of a Regional Profile

Maturation modeling of a 600 kin long restored cross section in the northern Gulf of Mexico Basin allows for estimating the timing of source rock maturation. Thirty-four 1-D thermal models, at a spacing of 15-25 km, were done on a series of restored cross sections (66.5, 40, 21.5, 12.5, 10.5, 8.8, 5.5, 3.0, 1.1 Ma, and Present). The cross section extends from northern Louisiana to south of the Sigsbee Escarpment. Source intervals vary along the profile; their location and kerogen type were based on published reports.

In northern Louisiana, Turonian source rocks entered the oil window between 56-48 Ma (0.6%Ro), reaching peak oil generation (0.9% Ro) at 31 Ma. In the Oligo-Miocene detachment province (southern Louisiana; Terrebonne Trough), Eocene source rocks entered the oil window between 16 to 14 Ma; peak oil generation at 12-14 Ma, and gas window (1.2% Ro) at 5 to 2.5 Ma.

In all offshore provinces, considerable variations exist in the maturation windows based on the presence of allochthonous salt, its rates of deformation, and its effect on heat flow. In the late Miocene-Pliocene province (South Pelto to South Timbalier), Eocene source rocks entered the oil window between 10 and 20 Ma, peak oil window is between 14 and 5.5 Ma, and top gas window is between 15-0.3 Ma. In the Plio-Pleistocene detachment province (Ewing Bank, northern Green Canyon), the Tithonian source rocks reached maturity between 42 and 9 Ma; peak oil was between 5 and 17 Ma, and top gas window I I to 5 Ma.

The tabular salt-minibasin province comprises southern Green Canyon (Tithonian source) and Walker Ridge (Oxfordian source). In southern Green Canyon, oil window varies from 100-48 Ma; peak oil from 65 to 10 Ma, and top gas window is from 29 to 5 Ma. In Walker Ridge, oil windows vary from 76-30 Ma, peak oil from 9.5 Ma to not reached yet.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas