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Version 1.0 Introduction
Layer Information
System Requirements
Information For Advanced Users
References
Links
Version 1 User's Guide
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Layer Information
Base Geology:
This group contains a number of general geology layers that constitute an initial basic
data set useful in constructing the regional geologic framework. Some, such as the
fault and salt diapir layers, are also essential in the evaluation of smaller areas or
even individual fields. Much of the data are based on maps and figures contained in
The Geology of North America series published by the Geological Society of America
and reproduced here with permission of the Society. Multiple data sources were
reconciled using whatever information was available. Users are cautioned that most
of the map data were digitized from paper prints and therefore are approximately
located.
Seismic Lines:
The lines shown are those used by the USGS in developing the framework geology
and models used in assessing the oil and gas resources of the Gulf Coast
Region. The data set is comprised of both leased and borrowed company proprietary
data.
Anticlines:
Initially, only major structures such as those shown on Plate 2, Principal structural
features, Gulf of Mexico Basin (compiled by T.E. Ewing and R.F. Lopez), in
Volume J, The Geology of North America (1991), have been included, primarily for
reference.
Orogenic Belt:
General location map of the Ouachita and Appalachian structural fronts slightly
modified from Plate 4, Natural resources, Gulf of Mexico Basin (compiled by A.
Salvador and R. Nehring), in Volume J, The Geology of North America (1991).
Cretaceous Onlap:
Maximum extent of Cretaceous onlap generalized from Plate 3, Structure at the
base and subcrop below Mesozoic marine section, Gulf of Mexico Basin (compiled
by A. Salvador) in Volume J, The Geology of North America (1991).
Fault Zones:
Major fault zones as indicated on Plate 2, Principal structural features, Gulf of
Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in volume J, The Geology
of North America (1991).
Faults:
Mapped faults modified from Plate 2, Principal structural features, Gulf of
Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in Volume J, The Geology
of North America (1991); Plate 2, Geologic map of the U.S. Appalachians
showing the Laurentian margin and the Taconic orogen (compiled by D.R.
Rankin, A.A. Drake, and N.M. Ratcliffe) in Volume F-2, The Geology of North
America (1989); and Plate 9, Tectonic map of the Ouachita orogen (compiled by
W. A. Thomas) in Volume F-2, The Geology of North America (1989).
Salt Limit:
Approximate limit of Middle Jurassic salt from Plate 2, Principal structural
features, Gulf of Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in
Volume J, the Geology of North America (1991).
Salt Diapirs:
Locations and shapes modified after J.A. Lopez, 1995, Salt tectonism of the
U.S. Gulf Coast basin; Plate 2, Principal structural features, Gulf of Mexico
Basin (compiled by T.E. Ewing and R.F. Lopez) in Volume J, The Geology of
North America (1991); and U.S. Geological Survey Miscellaneous Field Studies
Map MF-1213, Distribution of salt structures, Gulf of Mexico, by R.G. Martin
(1980).
Volcanic Provinces:
Modified after Plate 2, Principal structural features, Gulf of Mexico Basin
(compiled by T.E. Ewing and R.F. Lopez) in Volume J, The Geology of North
America (1991).
Basins and Uplifts:
Generalized outlines of major basins and uplifts in the Gulf Coast region modi-
fied after Plate 2, Principal structural features, Gulf of Mexico Basin (compiled
by T.E. Ewing and R.F. Lopez) in Volume J, The Geology of North America
(1991).
Gulf Coast Geology:
The regional geology layer is from Geology of the Conterminous United States
at 1:2,500,000 Scale -- A Digital Representation of the 1974 P.B. King and H.M.
Beikman Map: USGS Digital Data Series 11 (1994).
Southern Lousiana Wells and Fields:
This group contains layers showing the location of oil and gas wells, information on
each well, the location of all fields in southern Louisiana, and those fields producing
from the Upper, Middle, and Lower Miocene. The wells are those contained in the
Louisiana Department of Natural Resources Strategic Online Natural Resource Information
System (SONRIS) that can be accessed through the “hyperlink” button. Field
and producing area polygons have been created to include all those wells satisfying
the requisite criteria.
Southern Louisiana State Wells:
Includes all wells in the southern part of the Louisiana Department of Natural Resources SONRIS database. The online data can be accessed by making this the active layer, clicking on the hyperlink button, and then selecting the well of interest.
Southern Louisiana Fields:
Field polygons were created by constructing a grid of 0.25 mi2. cells and proximal polygons centered on all wells within the field and then intersecting and combining the polygons. This includes wells that were drilled to any depth within the field.
Producing Areas:
Producing area polygons were created by constructing a grid of 0.25 mi2. cells and proximal polygons centered on all wells producing from the given interval within the field and then intersecting and combining the polygons. Although the polygons are based on the producing wells only, they may also include some dry holes. The producing interval is determined by comparing the depth of production to the structure contours (see Contouring section).
Southern Louisiana Drilling History:
The drilling history documents the wells testing a specific interval in 10-year increments from the first reported well to the year 2000. The wells included in each interval are determined by completion date and by comparing the depth of the wells to the structure contours (see Contouring).
Contouring:
All contoured structure, thickness, and percent sand data are in this group. The structure and thickness contours were created from biostratigraphic data in the Paleo-Data, Inc., Tenroc Regional Geologic Database. Because of their proprietary nature, no actual data can be shown and only those data points contained in the Louisiana State well database are included in the control points layers. Contouring was accomplished in Dynamic Graphics, Inc., EarthVision modeling software (v. 5) using minimum tension gridding. Minimum Tension Gridding algorithms calculate a smooth surface that closely fits the input data values using biharmonic-cubic spline techniques. Three custom programs were used to convert contour lines generated from grids in Earth-Vision to ArcInfo coverages and then to shapefiles. The sand percent contours were produced by the Louisiana Geological Survey and were digitized from Chapter 11, Cenozoic, in The Gulf of Mexico Basin, Volume J, The Geology of North America (1991).
Depositional Systems:
The depositional systems represented under this group are presented here with permission of W.E. Galloway and the Jackson School of Geosciences, University of Texas at Austin. For more information and discussion of the various depositional systems, the user is referred to Galloway and others, 2000, Cenozoic depositional history of the Gulf of Mexico basin: American Association of Petroleum Geologists Bulletin, v. 84, p. 1743-1774. The Lower Miocene is divided into an earlier (Lower Miocene 1) and later (Lower Miocene 2) depositional system separated by a prominent transgressive marine shale tongue containing the Marginulina A fauna (Galloway and others, 2000). The Middle Miocene is broken into a lower H system and an overlying I system based on basin center seismic sequences. It should be noted that although differing in detail, the onshore parts of the Lower Miocene depositional systems are very similar as are the onshore parts of the Middle Miocene systems. Each of the depositional system layers also contains the trace of the relict shelf margin break of the underlying system. The trace of the shelf margin break for the subject system is contained in a separate layer, as are the labeling symbols and outlines of the various depositional environments.
Base:
This group contains the geographic and cultural layers primarily for location purposes. All of the cultural layers were imported from the National Atlas while the hydrologic data come from the USGS Digital Line Graph (DLG) database. The petroleum province outlines for Region 6 are the same as they were for the 1995 National Assessment of Oil and Gas Resources.
Background options:
The layers under this group comprise the options for a base map on which to overlay the other layers in the database.
United States:
State outlines and names.
Mexico States:
The State outlines and names are reproduced here with the permission
of ESRI, Inc.
Shaded Relief:
The shaded relief map is a global digital elevation model (DEM) created by USGS EROS Data Center in Sioux Falls, South Dakota. At larger scales, as when zoomed in to a field or well, the image becomes too grainy or “pixelated” and automatically turns off.
U.S. Background:
A flat, neutral background for the U.S., particularly useful at large scales or when overlain by certain color combinations.
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