Process controls on the development of stratigraphic trap potential on the margins of confined turbidite systems, and aids to reservoir evaluation

W. D. McCaffrey, Benjamin Charles Kneller

Research output: Contribution to journalArticle

95 Citations (Scopus)

Abstract

Stratigraphic trapping at pinch-out margins is a key feature of many turbidite-hosted hydrocarbon reservoirs. In systems confined by lateral or oblique frontal slopes, outcrop studies show that there is a continuum between two geometries of pinch-out configuration. In type A, turbidites thin onto the confining surface - although the final sandstone pinch-out is commonly abrupt - and individual beds tend not to erode into earlier deposits. In type B, turbidite sandstones commonly thicken toward the confining slope, and beds may incise into earlier deposits. These two types may occur in combination, to give a wide spectrum of pinch-out characteristics. Our analysis suggests the principal control in determining pinch-out character is flow magnitude, with smaller flows producing type A and larger flows producing type B.

In areas of poor seismic control it can be difficult to assess either pinch-out character or the proximity of wells to con fining slopes. Because estimates of paleoflow magnitude can be made from core or high-quality log image data, however, it is possible to make reasonable estimates of pinch-out character even from wells such as exploration wells, which may be placed conservatively, away from the field margins. Furthermore, systematic paleoflow variations and thickness trends are commonly seen in individual turbidite sandstones as they approach confining slopes. For example, dispersal directions indicate now deflection parallel with the strike of confining topography; beds thin toward type A onlaps and thicken toward type B onlaps. These relationships can be exploited via analysis of vertical successions to constrain well position with respect to the slope. Similarly, the presence, location, and frequency of locally derived debrites can provide information on the presence and proximity of confining slopes.

Original languageEnglish
Pages (from-to)971-988
Number of pages17
JournalAAPG Bulletin
Volume85
Publication statusPublished - 2001

Keywords

  • SEDIMENT GRAVITY FLOWS
  • WELSH BASIN
  • CURRENTS
  • REFLECTION
  • DEFLECTION
  • DEPOSITION
  • SANDSTONES
  • MODELS

Cite this

Process controls on the development of stratigraphic trap potential on the margins of confined turbidite systems, and aids to reservoir evaluation. / McCaffrey, W. D.; Kneller, Benjamin Charles.

In: AAPG Bulletin, Vol. 85, 2001, p. 971-988.

Research output: Contribution to journalArticle

@article{bbe9567d89c0472f94651b3838871cc8,
title = "Process controls on the development of stratigraphic trap potential on the margins of confined turbidite systems, and aids to reservoir evaluation",
abstract = "Stratigraphic trapping at pinch-out margins is a key feature of many turbidite-hosted hydrocarbon reservoirs. In systems confined by lateral or oblique frontal slopes, outcrop studies show that there is a continuum between two geometries of pinch-out configuration. In type A, turbidites thin onto the confining surface - although the final sandstone pinch-out is commonly abrupt - and individual beds tend not to erode into earlier deposits. In type B, turbidite sandstones commonly thicken toward the confining slope, and beds may incise into earlier deposits. These two types may occur in combination, to give a wide spectrum of pinch-out characteristics. Our analysis suggests the principal control in determining pinch-out character is flow magnitude, with smaller flows producing type A and larger flows producing type B.In areas of poor seismic control it can be difficult to assess either pinch-out character or the proximity of wells to con fining slopes. Because estimates of paleoflow magnitude can be made from core or high-quality log image data, however, it is possible to make reasonable estimates of pinch-out character even from wells such as exploration wells, which may be placed conservatively, away from the field margins. Furthermore, systematic paleoflow variations and thickness trends are commonly seen in individual turbidite sandstones as they approach confining slopes. For example, dispersal directions indicate now deflection parallel with the strike of confining topography; beds thin toward type A onlaps and thicken toward type B onlaps. These relationships can be exploited via analysis of vertical successions to constrain well position with respect to the slope. Similarly, the presence, location, and frequency of locally derived debrites can provide information on the presence and proximity of confining slopes.",
keywords = "SEDIMENT GRAVITY FLOWS, WELSH BASIN, CURRENTS, REFLECTION, DEFLECTION, DEPOSITION, SANDSTONES, MODELS",
author = "McCaffrey, {W. D.} and Kneller, {Benjamin Charles}",
year = "2001",
language = "English",
volume = "85",
pages = "971--988",
journal = "AAPG Bulletin",
issn = "0149-1423",
publisher = "AMER ASSOC PETROLEUM GEOLOGIST",

}

TY - JOUR

T1 - Process controls on the development of stratigraphic trap potential on the margins of confined turbidite systems, and aids to reservoir evaluation

AU - McCaffrey, W. D.

AU - Kneller, Benjamin Charles

PY - 2001

Y1 - 2001

N2 - Stratigraphic trapping at pinch-out margins is a key feature of many turbidite-hosted hydrocarbon reservoirs. In systems confined by lateral or oblique frontal slopes, outcrop studies show that there is a continuum between two geometries of pinch-out configuration. In type A, turbidites thin onto the confining surface - although the final sandstone pinch-out is commonly abrupt - and individual beds tend not to erode into earlier deposits. In type B, turbidite sandstones commonly thicken toward the confining slope, and beds may incise into earlier deposits. These two types may occur in combination, to give a wide spectrum of pinch-out characteristics. Our analysis suggests the principal control in determining pinch-out character is flow magnitude, with smaller flows producing type A and larger flows producing type B.In areas of poor seismic control it can be difficult to assess either pinch-out character or the proximity of wells to con fining slopes. Because estimates of paleoflow magnitude can be made from core or high-quality log image data, however, it is possible to make reasonable estimates of pinch-out character even from wells such as exploration wells, which may be placed conservatively, away from the field margins. Furthermore, systematic paleoflow variations and thickness trends are commonly seen in individual turbidite sandstones as they approach confining slopes. For example, dispersal directions indicate now deflection parallel with the strike of confining topography; beds thin toward type A onlaps and thicken toward type B onlaps. These relationships can be exploited via analysis of vertical successions to constrain well position with respect to the slope. Similarly, the presence, location, and frequency of locally derived debrites can provide information on the presence and proximity of confining slopes.

AB - Stratigraphic trapping at pinch-out margins is a key feature of many turbidite-hosted hydrocarbon reservoirs. In systems confined by lateral or oblique frontal slopes, outcrop studies show that there is a continuum between two geometries of pinch-out configuration. In type A, turbidites thin onto the confining surface - although the final sandstone pinch-out is commonly abrupt - and individual beds tend not to erode into earlier deposits. In type B, turbidite sandstones commonly thicken toward the confining slope, and beds may incise into earlier deposits. These two types may occur in combination, to give a wide spectrum of pinch-out characteristics. Our analysis suggests the principal control in determining pinch-out character is flow magnitude, with smaller flows producing type A and larger flows producing type B.In areas of poor seismic control it can be difficult to assess either pinch-out character or the proximity of wells to con fining slopes. Because estimates of paleoflow magnitude can be made from core or high-quality log image data, however, it is possible to make reasonable estimates of pinch-out character even from wells such as exploration wells, which may be placed conservatively, away from the field margins. Furthermore, systematic paleoflow variations and thickness trends are commonly seen in individual turbidite sandstones as they approach confining slopes. For example, dispersal directions indicate now deflection parallel with the strike of confining topography; beds thin toward type A onlaps and thicken toward type B onlaps. These relationships can be exploited via analysis of vertical successions to constrain well position with respect to the slope. Similarly, the presence, location, and frequency of locally derived debrites can provide information on the presence and proximity of confining slopes.

KW - SEDIMENT GRAVITY FLOWS

KW - WELSH BASIN

KW - CURRENTS

KW - REFLECTION

KW - DEFLECTION

KW - DEPOSITION

KW - SANDSTONES

KW - MODELS

M3 - Article

VL - 85

SP - 971

EP - 988

JO - AAPG Bulletin

JF - AAPG Bulletin

SN - 0149-1423

ER -