Compaction of Wilcox sandstones to 14,500 feet

Conference · Wed Mar 01 04:00:00 EST 1989 · AAPG Bull.; (United States)

OSTI ID:5796138

McBride, E F; Wilson, J C; Diggs, T N

Changes in packing and porosity resulting from compaction were studied in 38 Wilcox sandstones from 12 cores. Burial depths, adjusted for erosion in updip areas, range from 1100 to 14,500 ft. Neither quartz (/anti x/ = 5.6%) nor carbonate cement (/anti x/ = 2.9%) were introduced shallow enough or in sufficient abundance in the sandstones to significantly retard compaction. As a result, compaction continued to maximum burial depth and was the main cause of porosity decrease with depth (r = 0.82). As measured by increases in packing indices, sands compacted rapidly to depths of 2500 to 4000 ft (where intergranular volume averages approximately 30%) and more slowly and variably at greater depths. At all depths the amount of porosity lost by grain rearrangement was about twice the porosity lost by ductile grain deformation or by pressure solution. Ductile grain deformation was identified as shallow as 1100 ft (the shallowest sample) and pressure solution as shallow as 1915 ft. At shallow depths, only clay rip-up clasts deformed ductility; at greater depths micaceous rock fragments, micas, and glauconite deformed also. Surprisingly, porosity loss by ductile deformation has only a poor correlation (r = 0.62) with total amount of ductile grains. Quartz is the main mineral that undergoes pressure solution, although feldspar and volcanic rock fragments locally pressolve also.

• Research Organization: Univ. of Texas, Austin (USA)
• OSTI ID: 5796138
• Report Number(s): CONF-890404-
• Conference Information: Journal Name: AAPG Bull.; (United States) Journal Volume: 73:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
CHALCOGENIDES
DIAGENESIS
DRILL CORES
FEDERAL REGION VI
GEOLOGIC DEPOSITS
MINERAL RESOURCES
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PETROLEUM DEPOSITS
POROSITY
QUARTZ
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SILICON COMPOUNDS
SILICON OXIDES
TEXAS
USA