Porosity, permeability, and pore structure of the tight Mesa Verde sandstone, Piceance Basin, CO

Conference · Sat Sep 01 04:00:00 EDT 1984 · Soc. Pet. Eng. AIME, Pap.; (United States)

OSTI ID:6169725

Soeder, D J; Randolph, P L

Special core analyses on 44 tight Mesa Verde sandstone samples from the U.S. DOE Multiwell Experiment were combined with petrographic investigations in an attempt to relate the porosity and permeability of the cores to the pore structure of the rocks. Core analysis was performed on one inch (2.54 cm) diameter horizontal plug samples using a computerized steady-state flow measuring device. This equipment routinely measures flow rates with a resolution of better than 10/sup -6/ cm/sup 3//sec. All samples were selected from intervals expected to be gas productive on the basis of wireline well logs, and were taken from the portion of the interval that showed the lowest gamma ray log response. The core plugs were measured for dry permeability to gas, relative permeability at various water saturations, porosity to gas, and pore volume compressibility. Petrographic samples were taken directly off the plug ends and were analyzed with both an optical microscope and a scanning electron microscope. The petrographic study was explicitly directed toward observing the flow paths and pore structure that had been deduced from the core analysis data. Petrographic observations revealed that the pore geometry of sandstone can be broken down into three categories: grain-supported pores, solution pores connected by narrow intergranular slots (the most common pore structure in the Mesa Verde) and matrix supported grains. Core analysis measurements correlated fairly well with pore geometry. Solution pores connected by slots varied by a factor of two in porosity and pore volume compressibility; the dry permeability values fell within the range of 0.1 to 10.0 microdarcies. Calculation of slot-like flow path dimensions from the permeability data revealed a characteristic width of only about 0.1 micron. Special core analysis of the Mesa Verde also showed trends that correlated with various depositional environments in the formation.

• Research Organization: Inst. of Gas Tech.
• OSTI ID: 6169725
• Report Number(s): CONF-8409104-
• Conference Information: Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Journal Volume: SPE13134
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030300* -- Natural Gas-- Drilling
Production
& Processing
COLORADO
COMPUTER CALCULATIONS
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FEDERAL REGION VIII
FLOW RATE
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ROCK MECHANICS
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SANDSTONES
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