الفهرس 
CHAPTER (1)Only 14 pages are availabe for public view
 |  | from | 62 |  |  |
| | | from | 62 | | |
Abstract
Cooper (2000) conducted a detailed study of fracture orientations in surface exposures
of the Parkman Sandstone of the Mesa Verde Formation. His model is characterized by three
dominant fracture sets: hinge-parallel, hinge-perpendicular, and hinge oblique. Cooper et al.
(2006) have mapped the fractures at the Teapot Dome. They found three sets that can be
summarized as follows: hinge-parallel fractures, west-northwest-striking hinge-oblique fractures,
and northeast-striking hinge-perpendicular fractures. Schwartz (2006) conducted a detailed
analysis of the open fracture network observed in FMI logs from five wells distributed along the
axis of Teapot Dome. One of his research objectives was to determine if the fracture orientations
in the Tensleep could be predicted by fracture orientations seen at the surface by Cooper (2000).
He found that the hinge-parallel and hinge-perpendicular sets observed at the surface by Cooper
(2000) were seldom encountered in the borehole. Schwartz (ibid) generated stochastic fracture
models using the FRACGEN code developed by McKoy (1996). FRACGEN generates fracture
networks based on borehole derived fracture parameters including aperture, length, density,
fracture strike, and fracture intersection density. FRACGEN assumes all fractures are oriented
normal to bedding and that all fractures within a layer extend through the entire layer. Garcia
(2005) concluded that a dual porosity model with variable fracture permeability provides a good
reproduction of oil and water production rates from the highly fractured Tensleep Formation at
Teapot Dome. Garcia (2005) also, to explain cumulative water production, evaluated two single
porosity cases through history matching. The permeability in the single porosity model (rock
matrix without fractures) could not explain the observed water production data. Thus it was
necessary to explore dual permeability cases where fracture permeability could be introduced
into the model. The fracture networks enabled substantial water production over the single
porosity models. Roth et al. (2005) (RMAG/DGS 3D Seismic Symposium – Denver, Colorado –
2005), using representative data and information from the Teapot Dome field, combine 3D
seismic attributes, horizon and fault surfaces, VSP data, outcrop and core pictures, well log data,
graphics technology and computer gaming techniques, illustrate how new techniques for covisualization
and analysis are essential to support integrated workflows for fault and fracture
detection. Gilbertson (2006) quantified the changes in fracture orientation in a reservoir flow
model of the Teapot Dome (NPR-3) oil field. He used the emerging technology of LiDAR in the
Tensleep Sandstone exposed at Alcova anticline, Natrona County, Wyoming in a way that will
allow the data to be used in a fractured reservoir flow model of analogous structures.
12
Okojie-Ayoro (2007), in an attempt to more fully understand the potential for reservoir
partitioning in the shallow Shannon reservoir at Teapot Dome field, has combined two highresolution
seismic techniques with conventional 3D seismic and drill-hole data. The study
indicateed that some of the deeper faults propagate upward into the shallow producing Shannon
interval. Such knowledge is important as these faults may serve as conduits or barriers to fluid
flow. Okojie-Ayoro et al. (2008), Using the Teapot Dome Field as a test case, demonstrate how
high-resolution seismic surveys furnish a clearer picture of shallow reservoirs and the
relationship between deep and shallow faults. They (ibid) identify faults and deformation
structures that penetrate and could potentially partition the Shannon reservoir A(the shallowest
petroleum reservoir at Teapot Dome (about 76–198 m). Gao et al. (2011), to delineate faults and
fracture zones in seismic structural interpretation; used 3D seismic curvature and flexure at
Teapot Dome. They observed many seismically-visible faults have no curvature expression,
while many curvature anomalies do not correlate to any seismically-visible faults. Instead, major
seismically-visible faults are typically located at the maximum absolute gradient of curvature.
Saikia et al. (2014) (International Petroleum Technology Conference, Kuala Lumpur, Malaysia,
2014) using one-dimensional (1D) and three-dimensional (3D) basin modeling determined the
timing, maturity, and generation of hydrocarbon in the Powder River basin petroleum system.
1.5 Geological Settings:
1.5.1. Structure Geology:
Teapot Dome is an elongate, asymmetric, doubly plunging, basement-cored anticline,
approximately north-west trending domal structure (Fausnaugh & LeBeau, 1997; Cooper et al.,
2001; Roth et al., 2005).
The surface exposure at the dome starts with the Upper Cretaceous Mesa Verde
sandstone and extends downward through the Paleozoic section. The Precambrian granites form
the basement in the region. Major producing intervals in the field consist of the Shannon
sandstone, Wall Creek 1, 2, and 3 sandstones, Niobrara shale, and Tensleep A and B
sandstones (Figure 4-A).
The development of the dome is due to a basement up-thrust along the western edge of the Power River Basin (Smith, 2008). Harding (1985) mentioned that the dome was developed 75 to 55 million years ago primarily in response to the Late Cretaceous to mid Tertiary Laramide Orogeny. The Laramide Orogeny was a widespread mountain-building event that affected the Rocky Mountain and Colorado Plateau provinces. The deformation extends from northern Montana to southern New Mexico and from the western High Plains to eastern Utah.
.