1. Gulf Of Mexico Petroleum Geology

We are conducting researches mainly in petrophysics, heat flow, and hydrocarbon maturation modeling in the northern deep-water Gulf of Mexico.  We have compiled well logs from more than 100 boreholes drilled recently on the continental slope offshore Texas and Louisiana.   We have also been using other geophysical data obtained by oil industry.  Students in our labs are currently working on reconstructing the history of sedimentation and the sedimentary thermal maturation processes in various parts of the deepwater Gulf.  We have user licenses of commercial oil and gas software packages such as Geographix PRIZM (Landmark), BasinMod (Platte River and Associates), GoCAD (Earth Decisions), and Neuralog (Neuralog) in addition to suites of geographic information systems (GIS) and mapping software packages.

Gulf of Mexico Well Database displayed in ArcView.

Publications:

Nagihara, S., J. G. Sclater, L. M. Beckley, E. W. Behrens, and L. A. Lawver, 1992, High heat flow anomalies over salt structures on the Texas continental slope, Gulf of Mexico: Geophys. Res. Let., v. 19, p. 1687-1690.

Nagihara, S., J. G. Sclater, J. D. Phillips, E. W. Behrens, T. Lewis, L. A. Lawver, Y. Nakamura, J. Garcia-Abdeslem, and A. E. Maxwell, 1996, Heat flow in the western abyssal plain of the Gulf of Mexico: Implications for thermal evolution of the old oceanic lithosphere: J. Geophys. Res., v. 101, p. 2895-2913. 

Kim, S. D., S. Nagihara, and Y. Nakamura, 2000, P- and S-wave velocity structures of the Sigbee abyssal plain of the Gulf of Mexico from ocean bottom seismometer data: Gulf Coast Association of Geological Societies Transactions, p. 475-484. 

Nagihara, S., and S. A. Hall, 2001, Three-dimensional gravity inversion using simulated annealing: Constraints on the diapiric roots of allochthonous salt structures: Geophys., v. 66, p. 1438-1449. 

Nagihara, S., J. M. Brooks, B. B. Bernard, N. Summer, G. Cole, and T. Lewis, 2002, Application of marine heat flow data important in oil, gas exploration: Oil & Gas J., v. 100.27, p. 43-49.

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2. Three-Dimensional Laser Scanning & Visualization

Texas Tech University owns a unit of Cyrax 2500, which is one of the most advanced, portable, three-dimensional (3-D) laser scanners currently available. A 3-D laser scanner is a type of land-based LIDAR (Light Detection and Ranging) instruments.  It sweeps the surrounding environment with optical rays.  The rays produce reflections when they encounter solid objects.  The instrument records the angle of each ray and measures the travel time of the corresponding reflection.  The survey data can be displayed on a computer screen as a cloud of reflection points that delineate the geometrical shape of the scanned objects.  The point cloud can be interpolated into a continuous 3-D surface or volume.  A series of scans around the target object yields a 3-D digital geometrical model of the object.

Using this instrument, one can quickly generate computer models of large objects (buildings, geologic outcrops, etc.) by digitally capturing their shape/topography in extreme detail.  It is also possible to paste photographic images over the topographic computer models obtained from the 3-D scans.   Thus, this technology is extremely useful for geologists studying outcrops, because, once they have captured the scan data in the field, they can revisit the place many times, rain or shine, within the virtual reality environment created by the computer.

We have so far conducted two scanning experiments.  In the summer of 2001, we mapped a section of the South Prong Canyon in the Caprock Canyon State in Texas.   In the summer of 2002, we mapped a section of the Carlsbad Caverns National Park in New Mexico.  For more detailed information on our 3-D scanning projects, please e-mail Dr. Nagihara or refer to the following publication.  

                         Top: A snapshot taken during our 3-D scanning experiment in the Caprock Canyons State Park, TX

                         Middle: Cyrax 2500 3-D laser scanner

                         Bottom: 3-D perspective image of a section of the South Prong River generated from the 3-D scan data.

Publications:

Nagihara, S., J. Hargis, R. Goss, J. Wright, and G. Hill, 2002, Sub-centimeter-resolution digital topography and surface lithology models obtained from a 3-D laser scanner survey in the South Prong Canyon, Texas Panhandle: ACSM-ASPRS Conference and Technology Exhibition, p. 12 p. (CD-ROM). 

Nagihara, S., R. Goss, B. Musgrave, J. Gamel, G. Hill, and T. Bemis, 2002, Three-dimensional laser scanning of speleothems in the Carlsbad Caverns: West Texas Geological Society Fall Symposium, p. 35-42.  

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Our group currently pursues two research topics.  The first is the geophysical inverse problem.  We have been developing new, robust inversion algorithms for geophysical potential field and geothermal heat flow with specific applications in subsalt exploration in the Gulf of Mexico.  We collaborate with researchers and graduate students at the High Performance Computing Center of the university for this effort.  The second is quantitative, small-scale geomorphology by utilizing data obtained from three-dimensional (3-D) laser scanning surveys.  Generating realistic 3-D togographic surface models, their visualization, and interpretation are the main research topics in this area.  Students and professors at the Environmental Visualization Institute at the College of Architecture are also involved in this effort.

Reflection point cloud display of the 3-D scan data obtained in the Big Room, Carlsbad Cavern.

Publications:

Nagihara, S., and S. A. Hall, 2001, Three-dimensional gravity inversion using simulated annealing: Constraints on the diapiric roots of allochthonous salt structures: Geophys., v. 66, p. 1438-1449. 

Nagihara, S., J. Hargis, R. Goss, J. Wright, and G. Hill, 2002, Sub-centimeter-resolution digital topography and surface lithology models obtained from a 3-D laser scanner survey in the South Prong Canyon, Texas Panhandle: ACSM-ASPRS Conference and Technology Exhibition, p. 12 p. (CD-ROM). 

Nagihara, S., R. Goss, B. Musgrave, J. Gamel, G. Hill, and T. Bemis, 2002, Three-dimensional laser scanning of speleothems in the Carlsbad Caverns: West Texas Geological Society Fall Symposium, p. 35-42. 

Nagihara, S., in press, Three-dimensional inverse modeling of refractive heat flow anomaly associated with salt diapirism: Amer. Assoc. Petrol. Geol. Bull.

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