Samuel Eguiluz de Antuñano, 2001. "Geologic Evolution and Gas Resources of the Sabinas Basin in Northeastern Mexico", The Western Gulf of Mexico Basin: Tectonics,Sedimentary Basins, and Petroleum Systems, Claudio Bartolini, Richard T. Buffler, Abelardo Cantú-Chapa
Download citation file:
The Sabinas Basin is located in northeastern Mexico in the states of Coahuila and Nuevo León. Basin fill is composed mainly of Mesozoic marine sediments deposited during long-term subsidence and folded during Late Cretaceous and Paleogene Laramide orogenesis. The origin of the basin is related to a rift associated with the opening of the Gulf of Mexico. More than 5000 m of sedimentary rocks was deposited in the Sabinas Basin. Three supersequences have been defined. The first represents synrift sediments and is composed of conglomerates and evaporites with associated basic igneous rocks. The following supersequence (144–96 m.y.) comprises several higher-frequency cycles represented by carbonate, evaporite, and coastal siliciclastic deposits of extensive platforms on a passive margin. The youngest supersequence (96–39.5 m.y.) consists mainly of regressive, terrigenous clastic facies deposited in a foreland setting. Subsidence was 40% to 70% greater during the initial rift stage than during subsequent depositional stages. Several lateral and vertical facies changes in the basin were controlled by the Coahuila and Tamaulipas basement blocks, as well as other, smaller blocks.
Laramide deformation is of the thin-skinned type. Four areas with distinct structural styles are recognized: (1) where Jurassic salt is the regional detachment level; (2) where salt diapirs formed; (3) where deformation was controlled by a basement high northeast of the basin; and (4) where the absence of Jurassic salt resulted in the development of fault-bend folding. Structural shortening calculated for different areas of the basin ranges from 16% to 26%. The critical-wedge model has been used to explain some of the deformational variations in the basin. The structures have natural fractures that provide permeability in the hydrocarbon reservoirs.
The Upper Jurassic La Casita Formation is considered to be the main hydrocarbon source. Total-organic-carbon (TOC) values are favorable, and although the formation’s kerogens are mainly type III, they are characterized by a high transformation ratio.
In 23 years of exploitation, the Sabinas Basin has produced more than 350 bcf of dry gas. The average daily production rate per well ranges from 0.5 to 2.0 MMCFGD. Geostatistical modeling indicates that the La Gloria, La Casita, and Padilla-Virgen plays could contain total resources of more than 1000 bcf. Furthermore, a coal-degasification play may extend over an area exceeding 1000 km2 and could contain additional potential resources amounting to 147 bcf of gas. Both of these resources could supply much of the local industry’s methane needs for more than 20 years.