Can regional porosity occurrence in carbonate slope and basin facies systems be predicted

Conference · Tue Mar 01 04:00:00 EST 1994 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6833025

Mazzullo, S J ^[1]

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1. Wichita State Univ., Wichita, KS (United States)

Subsurface carbonate depositional sequences (i.e., coeval platform-to-basin facies mosaics), which can most readily be identified by application of seismic sequence analysis, include porous units of complex geometry and occurrence. A highly sought-after occurrence of reservoir-grade porosity commonly, but not always, is associated with sequence boundaries. Therefore, porosity can be predicted to possible occur in already-lithified platform strata beneath significant unconformities of regional extent (e.g., cavernous porosity). By this method, however, the possible existence of porosity in carbonate slope and basin deposits may be overlooked because they do not lie beneath sequence-bounding unconformities insofar as they are not usually exposed subaerially during platform emergence. Yet, such facies compose locally significant hydrocarbon reservoirs in the Permian basin by virtue of high porosities and permeabilities and water-free production histories. Short of drilling or seismic wavelet analysis, can porosity in such facies be predicted a priori Reservoirs in carbonate slope and basin deposits in the Midland basin include both porous limestones and dolomites. Petrographic and geochemical studies indicate that syndepositional and shallow-burial diagenesis of such deposits mainly involved porosity reduction via calcite cementation, dolomitization, and compaction. Most of the porosity present in reservoirs in these facies was created by later dissolution in the deep-burial environment as a consequence of rock interaction with connate fluids enriched in carbonic and sulfuric acid and/or organic acids generated during hydrocarbon maturation. These fluids migrated up and out from deeper parts of the basin through slope and basin deposits and into platform carbonate strata. Insofar as fluid migration pathways can be mapped or at least inferred by various means, it follows that porosity created (or destroyed) by these fluids also can be mapped predictively.

• OSTI ID: 6833025
• Report Number(s): CONF-9404148--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 78:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CALCITE
CARBONATE MINERALS
CARBONATE ROCKS
CHEMISTRY
DIAGENESIS
FLUID FLOW
FORECASTING
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
HYDROCARBONS
MAPPING
MATURATION
MICROSTRUCTURE
MIGRATION
MINERALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PERMIAN BASIN
PORE STRUCTURE
POROSITY
RESERVOIR ROCK
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
SURVEYS