Rock geometry/mechanics study of the western tight gas reservoirs

Technical Report · Thu Sep 01 04:00:00 EDT 1977

OSTI ID:5230643

Generally available information about the generalized structure, stratigraphy, rock geometry, and rock properties is presented for the Cretaceous and Tertiary media which contain the gas resources in the ''Western Tight Gas Sands.'' These media consist primarily of ''blanket type'' marine sandstones and complex continental lenses that are internally quite heterogeneous. General geologic descriptions are presented for the Northern Great Plains, Wind River, Green River, Red Desert, Washakie, Uinta, Douglas Creek, Piceance, Sand Wash, Denver, San Juan, and Raton basins. More detailed information is presented for the Northern Great Plains, Uinta Piceance and Green River basins. Considerable uncertainty exists with respect to the values obtained for the mechanical and reservoir properties of the tight gas sands in these basins. Mechanical properties vary considerably, even within the sandstone lenses themselves. Sampled values of Young's Modulus range between 2.0 and 8.0 x 10/sup 6/ psi. Ranges for estimated average values for permeability and gas-filled porosity for four basins are tabulated. Studies of outcrop lens geometries in the Piceance Basin indicate that only about 18% of the equivalent radial sandstone volume is connected to the wellbore in a 320-acre drainage area. At 10-acre spacing, and below, the estimated connected volume approaches that for ''blanket'' sands. AUinta Basin study indicates that gas production may be influenced by natural fractures in certain areas. Generally, the data available for the Western tight gas sands are of poor quality. Considerable effort is needed, therefore, in developing new analytic and measurement techniques for generating credible data for use in modeling these complex reservoirs.

• Research Organization: GeoEnergy Corp., Las Vegas, NV (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5230643
• Report Number(s): UCRL-13778
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
COLORADO
GEOLOGIC DEPOSITS
GEOLOGY
INFORMATION NEEDS
MECHANICAL PROPERTIES
MONTANA
NATURAL GAS DEPOSITS
NEW MEXICO
NORTH AMERICA
PERMEABILITY
POROSITY
RESERVES
RESERVOIR ROCK
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
STRATIGRAPHY
USA
UTAH
WYOMING