Difference between revisions of "Fault plane profile construction"
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==Example: FFP that cross seals, cross leaks== | ==Example: FFP that cross seals, cross leaks== | ||
| − | + | <gallery mode=packed widths=200px heights=200px> | |
| − | + | file:evaluating-top-and-fault-seal_fig10-16.png|300px|{{figure number|2}}The fault plane profile with cross sealing at the fault/reservoir intersection in the lowest foot-wall sand. | |
| − | + | file:evaluating-top-and-fault-seal_fig10-26.png|300px|{{figure number|3}}Fault plane profile of a fault in a Gulf Coast field. | |
| − | + | </gallery> | |
The fault plane profile in [[:file:evaluating-top-and-fault-seal_fig10-16.png|Figure 2]] is similar to the profile in [[:file:evaluating-top-and-fault-seal_fig10-15.png|Figure 1]] except that the fault is cross sealing at the fault/reservoir intersection in the lowest foot-wall sand. Despite a sand/sand juxtaposition at the crest of this reservoir, the fault traps hydrocarbons at a cross sealing segment. Higher sands continue to cross-leak. The percent fill of the lowest sand is limited by either the P<sub>d</sub> of the fault zone, the charge volume, or the top seal—not a JLLP. | The fault plane profile in [[:file:evaluating-top-and-fault-seal_fig10-16.png|Figure 2]] is similar to the profile in [[:file:evaluating-top-and-fault-seal_fig10-15.png|Figure 1]] except that the fault is cross sealing at the fault/reservoir intersection in the lowest foot-wall sand. Despite a sand/sand juxtaposition at the crest of this reservoir, the fault traps hydrocarbons at a cross sealing segment. Higher sands continue to cross-leak. The percent fill of the lowest sand is limited by either the P<sub>d</sub> of the fault zone, the charge volume, or the top seal—not a JLLP. | ||
Revision as of 15:56, 20 May 2014
| Exploring for Oil and Gas Traps | |
| |
| Series | Treatise in Petroleum Geology |
|---|---|
| Part | Predicting the occurrence of oil and gas traps |
| Chapter | Evaluating top and fault seal |
| Author | Grant M. Skerlec |
| Link | Web page |
| Store | AAPG Store |
Afault plane profile (FPP) is a cross section in the plane of the fault that shows both the hanging wall and footwall cutoffs.
An FPP is distinctive in two ways:
- It is a cross section in the plane of the fault rather than normal to the fault.
- Both the hanging wall and footwall stratigraphic cutoffs are shown on the same cross section.
Procedure[edit]
We construct an FPP as we do any geologic cross section. Using structure-depth maps, we project the top of each mapped stratigraphic unit at its intersections with the fault plane to its correct depth on the fault plane profile.[1]
Because only a fraction of the stratigraphy is mapped routinely, well logs are used to project the remainder of the detailed stratigraphy onto the FPP.
Example: FPP of cross-leaking fault[edit]
Figure 1 is a simple example of a fault plane profile. The sand reservoirs in the hanging wall (dark gray) and footwall (light gray) are shown on the same cross section drawn in the plane of the fault. In this example, all hydrocarbon accumulations (black) are limited by JLLPs (juxtaposed lithology leak points). Hydrocarbons cross-leak from the footwall sands into the hanging wall sands.
The fault cross-leaks along its entire surface at sand/sand juxtapositions. At each sand/sand juxtaposition, a JLLP spills the hydrocarbons across the fault. There is sufficient charge to fill all closures to a fault-dependent leak point. Potential reservoirs with JLLPs at the crest are dry. The percent fill for other sands is constrained by the JLLPs.[1] If bed dips in the hanging wall allow entrapment against the fault, hydrocarbons could be trapped in both the hanging wall and footwall reservoirs. With sufficient charge, common hydrocarbon contacts could exist.
Example: FFP that cross seals, cross leaks[edit]
Figure 2 The fault plane profile with cross sealing at the fault/reservoir intersection in the lowest foot-wall sand.
Figure 3 Fault plane profile of a fault in a Gulf Coast field.
The fault plane profile in Figure 2 is similar to the profile in Figure 1 except that the fault is cross sealing at the fault/reservoir intersection in the lowest foot-wall sand. Despite a sand/sand juxtaposition at the crest of this reservoir, the fault traps hydrocarbons at a cross sealing segment. Higher sands continue to cross-leak. The percent fill of the lowest sand is limited by either the Pd of the fault zone, the charge volume, or the top seal—not a JLLP.
Figure 3 is an example of a fault plane profile of a fault in a Gulf Coast field.
See also[edit]
References[edit]
- ↑ 1.0 1.1 Allan, U., S., 1989, Model for hydrocarbon migration and entrapment within faulted structures: AAPG Bulletin, vol. 72, no. 7, p. 803–811.
External links[edit]
| find literature about Fault plane profile construction |
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