T92 Geology and Geochemistry of Carbon Dioxide, Helium, and Other Low-BTU Natural Gas Systems

Monday, 26 September 2016
8:00 AM - 12:00 PM
Room 506

STRATIGRAPHIC, SPATIAL, AND STRUCTURAL STYLE OF NATURAL CARBON DIOXIDE GAS ACCUMULATIONS IN THE GREATER PERMIAN BASIN

Paper number: T92-9
Program: Technical Sessions
Time: 9:50 AM – 10:05 AM

Authors

Abstract

The Permian Basin of west Texas and southeastern New Mexico is one of most important and prolific petroleum-producing basins in the United States. Commercial production of oil and gas began in the early 20th century, and in the last few decades, carbon dioxide-enhanced oil recovery (CO2-EOR) has become increasingly important. In some regions of the basin, natural CO2 and small quantities of other non-flammable gases comprise most of the gas in the reservoirs.  However, limited physical and chemical data exists on CO2 reservoirs and CO2 systems in general in the Permian Basin. These high-CO2 gas fields are the current focus of a United States Geological Survey research initiative on CO2-EOR, natural CO2 resources, and analogues for anthropogenic CO2 storage. Overall, natural gas reservoirs in the basin containing CO2 are most abundant west of the Central Basin Platform, in a northwest to southeast trending fairway extending between the Delaware to Val Verde Basins. The CO2 fields occur mainly within block-faulted structural or anticlinal closures that occur along regional lineaments. In southern portions of this trend, reservoirs traps are associated with structural elements of the Marathon-Ouachita Thrust Belt. In both areas, geologic structures are important constraints on reservoirs.  Limited data on the CO2 fraction within these fields suggest a south and westward trend of increasing value; however, these trends are general and contain anomalies. Overall, the maximum amount of CO2 within individual reservoirs ranges from less than 5 %, to over 95 %—internally, reservoirs can exhibit variations in CO2 content. Reservoirs with high quantities of CO2 occur in multiple units that range from Ordovician to Permian in age and mostly in carbonate rocks. In some areas the CO2 fields are stratigraphically stacked; yet in other areas, gas fields overlying CO2 reservoirs lack appreciable CO2. Increased understanding of natural CO2 systems in the Permian Basin may lead to predictive modeling for exploration of this natural resource, potentially increasing the supply of natural CO2 available for EOR operations.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-285989

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