Geologic studies of deep natural-gas resources in the United States

摘要: Deep parts of sedimentary basins in the United States contain large volumes natural gas. producing reservoirs, accounted for 7 percent total cumulative gas production through 1989 (50 trillion cubic feet (Tcf) 698 Tcf). The distribution and character undiscovered deep accumulations can be better understood following: (1) Internally sourced hydrocarbons contribute to porosity preservation some reservoirs at depth Anadarko Basin Rocky Mountain Basins. (2) Measurements capillary pressure, which are very sensitive confining stress, suggest that small-pore throats (<0.1 micrometer), common fine-grained clastic rocks, limit flow well bore. (3) In selected region, structural partitioning prior thrusting, sequential breakup foreland during Late Cretaceous Paleocene may have strongly affected volume natural-gas accumulations. (4) flanking Mid-continent Rift Grand Canyon Middle Proterozoic source active hydrocarbon seeps, favorable thermal maturities generating preserving gas, indicate a potential economic (5) Methane generation by decomposition C[sub 15+] takes place verymore » high maturation ranks. (6) Significant amounts carbon dioxide presence hydrogen sulfide thermochemical sulfate reduction simultaneous oxidation dominant control on nonhydrocarbon composition carbonate reservoirs. (7) Where geologic information is available concerning known or suspected [open quotes]deposit simulation[close quotes] based model reservoir most appropriate assessment methodology. 54 refs., 19 figs., tabs.« less