About This Item
- Full TextFull Text(subscription required)
- Pay-Per-View PurchasePay-Per-View
Purchase Options Explain
Share This Item
The AAPG/Datapages Combined Publications Database
AAPG Bulletin
Abstract
AAPG Bulletin, V.
1Manuscript received February 4, 1998;
revised manuscript received February 23, 1999; final acceptance February
28, 1999.
2PetroQuest International Inc., "Foxbourne,"
Hamm Court, Weybridge, Surrey, .KT13 8YA, United Kingdom; e-mail: [email protected]
3Department of Geology, Royal Holloway,
University of London, Egham, Surrey, TW20 0EX, United Kingdom.
ABSTRACT
Uplift of well-lithified carbonate minimally results
in an areally extensive runoff surface that controls the development of
positive karst landforms. Uplift also commonly induces faulting and fracturing
that further control the distribution of karst land forms. Hydrocarbon
production from the resulting karst is geared to matrix porosity: the higher
the matrix porosity, the greater the rate of deliverability of matrix oil
to produced fracture and karst conduit oil.
In contrast, the lowering of the base level of
erosion due to a fall in sea level is generally less than that induced
by uplift and, consequently, minimizes positive karst relief development
relative to that of uplift. Subaerial exposure induced by passive sea level
fall also minimizes the potential for the related occurrence of fracturing
and faulting, which of itself mitigates against the general development
of positive karst relief. The subaerial consequences of passive sea level
fall are commonly preserved in the geologic record and result in karst
reservoirs dominated by extensive moldic and vuggy porosity interconnected
by solution channels. These reservoirs lack the production problems commonly
attending fractured karst reservoirs with little matrix porosity.
Tropical karst landscapes exhibit a predominance
of positive relief features relative to the negative relief features (i.e.,
sink holes, dolines, etc.) of temperate karst areas and yet, paradoxically,
have never been observed in the subsurface on seismic sections. To understand
why this is the case, topographic profiles were made over the positive
karst relief features of China, Java, and Jamaica and were used to construct
synthetic seismic sections. The results indicate that in most instances
the magnitude of the topographic relief is sufficient to be seen on seismic
sections. A possibility of misinterpreting karst highs as reefs seems clear,
but more important in explaining the paradox is the fact that the magnitude
of modern karst relief expression is largely attributable to uplift over
an extended period. The probability of preservation of these positive relief
solution residuals is dependent on the karstification process being aborted
by the deposition of overlying sediment, an event not likely to occur in
an uplift area.
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
Watermarked PDF Document: $14 | |
Open PDF Document: $24 |
AAPG Member?
Please login with your Member username and password.
Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].