DHI/AVO best practices
methodology and applications

28

The use of resolution matrices in geophysical model appraisal

Thanksgiving Recess

Anisotropy estimation and fracture characterization of tight-gas sandstones at Rulison Field, CO

Modeling the sonic log response fractures

New methods of computing elastic parameters for laboratory samples and
verification of experimental data outputs and commercial software

Abstract
In this presentation we discuss full waveform inversion from a practical computational point of view. We empirically demonstrate the conditions under which full waveform inversion can be a practical tool for direct and essentially automatic estimation of an Earth model. We show both synthetic and real examples of the kinds of issues that must be dealt with if full waveform technology is to become a routine part of seismic data processing.

We demonstrate the need for both full source-receiver reciprocity and extremely low frequencies in measured data. We then compare the full waveform approach to the inverse scattering approach and demonstrate that like its, perhaps, better understood counterpart, inverse scattering has similar problems that also compromise its potential in
the current computation environment. Finally we speculate on the future of high technology seismic processing and argue that emerging hardware developments may create a environment for emergence of a seismic "silver bullet."

Biography
After receiving a Ph.D. in Mathematics from the University of Texas at Austin, Bee did research in Anti-Submarine Warfare and taught Mathematics at Drexel University and the University of Tulsa. He was Manager of Seismic Research at Cities Service Company and later became Manager and then Director of Geophysical Sciences at Amerada Hess, where he was instrumental in development of distributed seismic processing software and lead Amerada to the forefront of prestack depth imaging and computer assisted interpretation. He has participated in over 100 prestack depth imaging and interpretation projects and has published over 75 papers in mathematics, electrical engineering, geophysics, and computer science. After retiring from Amerada Hess, he became Vice President of Research and Development at Advanced Data Solutions where he was instrumental in introducing LINUX based cluster computers to the energy industry. He founded 3dBee Tech in 1997 to perform consulting and geophysical software development. He is currently one of the founders of Panorama Technologies Inc where he is Senior Executive Vice President. He still consults for companies engaged in the exploration for and production of hydrocarbons and manages the development of geophysical software on modern cluster computers.

Abstract
Microgravity surveys of a stream flow augmentation project at the Tamarack Ranch Wildlife Refuge on the South Platte River in NE Colorado were conducted to test the precision of water mass estimates and specific yields obtained from gravity surveys. At the Tamarack site, groundwater is pumped from alluvial wells near the river during periods of high flow. The water is discharged into ponds located in surrounding upland areas approximately 1 km away from the river. Water returns to the river through infiltration and groundwater flow to augment stream flow during periods of peak irrigation need. Key issues in managing the flow augmentation project are quantifying the water mass budget and the specific yield of the unconfined aquifer, which consists of a 13-20 m-thick layer of poorly sorted gravel, sand, and minor clay sediments deposited in a braided fluvial environment. The recharge ponds are located in a roughly 7-m thick layer of well sorted fine eolian sand that overlays the aquifer. A shale unit underlies the aquifer at depths that range from 13 m near the river to 47 m beneath the recharge ponds.

Gravity surveys were conducted over a 3.2 km 2 area at common station locations during the pumping phase (March, 2005) and six weeks after pumping had ceased. Water table monitoring in roughly 20 wells in the study area indicates that these survey times capture the steady-state condition of the aquifer during pumping and the natural condition without pumping. The gravity surveys were conducted using a Scintrex CG-5M meter, which has a nominal precision of <5 m Gals. A base station located on a stable concrete well platform that showed minimal change in water table depth between surveys was used to reference the two surveys. After correcting for Earth Tides, instrument drift, and instrument height, the difference in gravity between the two surveys was inverted to estimate the change in the depth of the water table. The inversion assumed a density contrast at the water table surface of 0.20 g/cc based on prior estimates of a specific yield of 0.2. Changes in the water mass predicted from the gravity data compared to changes in water table depth measured in the wells predicts a specific yield of 0.20 +/- 0.06, consistent with estimates obtained from hydrogeological data.

Biography
Dr. Dennis Harry is the Edward M. Warner Professor of Geophysics in the Department of Geosciences at Colorado State University. Dr. Harry earned his Ph.D. in geophysics from The University of Texas at Dallas, and M.S. and B.S. degrees in geophysics from Texas A&M University. He did his post-doctoral work at Rice University before accepting a faculty appointment at The University of Alabama, which he held until he joined CSU in 2003. He teaches Physical Geology for Scientists and Engineers, Applied Geophysics, Subsurface Geophysical Mapping, and Exploration Seismology. Dr. Harry's research focuses on understanding the geodynamics of continental rift systems and passive continental margins, and on hydrogeophysics. Dr. Harry is a member of the American Geophysical Union, The Society of Exploration Geophysicists, The Geological Society of America, The Environmental and Engineering Geophysical Society, and the Rocky Mountain Association of Geologists. He serves as an officer on several committees in those societies and is an Associate Editor of the journal Geosphere.

Abstract
The simplest way of measuring the size of an earthquake would be to estimate the energy carried in seismic waves. Accurately measuring seismic energy is, however, a challenging problem. Traditionally the size of an earthquake was measured using the amplitude of different seismic waves, and indirectly using seismic moment. With the advent of broadband seismometers direct calculation of seismic energy became possible. We now have two measures of earthquake size – seismic moment, a static measure and seismic energy, a dynamic measure – the relationship between the two can be used to understand the dynamic processes that occur in earthquake rupture. Seismic energy is only a part of the total energy released in an earthquake, so we would like to know what fraction of the total energy released is used to generate seismic waves, i.e., what is the seismic efficiency of an earthquake? If seismic efficiency varies systematically with fault type, geology, tectonic environment or earthquake size, it is important that we understand this variation.

Radiated energy along with other macroscopic seismic parameters can be related to the partitioning of energy in earthquakes using a simple slip-weakening model. Of the large earthquakes we studied, tsunami earthquakes and some deep earthquakes are less “brittle” as compared to other subduction zone events. The highly faulted rocks at the subduction trench in tsunami earthquakes could dissipate a large amount of energy in fracture processes. The rupture behavior of deep earthquakes, on the other hand, depends on the temperature of the subduction zone leading to the suggestion that deep earthquakes that occur in younger (and thus warmer) slabs dissipate a greater fraction of their energy in thermal processes in the fault zones.

Another important problem in seismology is the growth of rupture in small and large earthquakes. Insights into this problem can be obtained by understanding the scaling of seismic efficiency with size. Our analysis of micro-earthquakes recorded on a high-density surface and borehole network in Japan shows a breakdown in spectral similarity with earthquake size; this suggests that macroscopic source parameters such as static stress drop and/or rupture velocity do not scale with earthquake size. With the increasing availability of borehole data, we can quantify these macroscopic parameters over a range of sizes in different tectonic environments and start to interpret the physics of the processes that control the final rupture size.

Biography

Anupama Venkataraman completed a B.Sc. and M.Sc. at the Indian Institute of Technology, Kharagpur and a Ph.D. in geophysics at the California Institute of Technology (2002). From 2002 until 2005 she was the George A. Thompson Postdoctoral Scholar at Stanford University. Anupama is currently employed by ExxonMobil Upstream Research Company, conducting research in quantitative interpretation of seismic and microseismic data to determine reservoir rock and fluid properties that would be important in reservoir management. Her role and responsibilities include processing seismic and microseismic data, developing new algorithms and procedures suitable for the analysis of the data, and communicating her research with her peers at the Research Company, other ExxonMobil affiliates and external audiences. She is working in a multi-disciplinary team that is involved in reservoir monitoring and 4D seismic studies.

Abstract
In 1997, ExxonMobil developed a company wide best practice to evaluate and understand the risk for DHI-dependent plays. Within this best practice, a robust controlled amplitude/phase processing stream, rigorous analysis, and a calibrated DHI-rating system using both data quality and observed DHI characteristics were designed. The methodology is not dependant on evaluating just a single DHI attribute; e.g. AVO, but on a multitude of seismic characteristics. The rating system provides a consistent approach for evaluating DHIs and data quality and integrating it with risk analysis. Two case histories from different geologic and business settings illustrate the application of the best practice. The data used in both cases were processed with the prescribed controlled amplitude, controlled phase stream which was a key factor for our analysis.

The first example is from an exploration setting. The example shows how applying best practices can help identify the risks correctly and set expectations prior to drilling the first well in a frontier basin. By using our best practice methodology the main risk identified here was low gas saturation, even though no low gas saturated sands had previously been encountered in the area. Subsequent drilling confirmed this prediction.

The second example is from a development setting. This example illustrates application of an emerging technology, Spectral Decomposition to high-grade an anomaly not observed on traditional seismic data. Identification of the anomaly with the correct DHI attributes enabled us to successfully position and drill a key development well. The well results helped us gain confidence in the reserve estimate for the field and develop an optimized depletion plan.

In summary, for each case history we will present our pre-drill analysis and predictions and share the learnings from the post well drilling results. Also, as an audit of the process, we will show the overall statistics of how the best practices have fared since its implementation.

Biography

Bill A. Fahmy received a B.S. in Geophysics from the University of the Pacific in Stockton, California in 1979 and a M.S. in Geophysics from the University of Wyoming in 1988. Prior to getting his Masters Degree, Bill spent his early career working for Western Geophysical Company as a Seismic Crew Assistant Manager and Manager. In 1988, he joined Exxon, which later became ExxonMobil. Bill is currently a Geophysical Advisor for ExxonMobil Exploration Company. His primary role includes assisting and advising the Angola/Congo exploration teams on technical needs and issues as well as providing perspectives for upper management on all drill wells, resource assessment, and acreage capture opportunities. Bill is a member of SEG, AAPG, and HGS.

Abstract
The permeability of porous media is of wide-ranging and critical importance in many areas of science and engineering. Knowledge of the permeability of the granular materials used in fluidized-bed reactors, catalysts and certain types of distillation columns is important for their design. The permeability of ground-water aquifers and oil and gas reservoirs is required knowledge for planning production and treatment facilities as well as for planning future development (and its limitations!). Permeability has enormous economic implications: we should understand it. To investigate the basics, we will restrict this discussion to absolute permeability and single phase flow in the laminar or potential flow regime: the simplest case.

The empirical Darcy equation establishes the meaning of permeability, but does not explain it. To gain additional insight into the meaning of permeability, we can address the issue of how the pore geometry of rocks influences permeability. Electrical currents and fluid flow in rocks are governed by the same volumetric and geometric aspects of pore geometry. The complexity of pore geometry can be minimized by considering the pore-space as a large number of stream-tubes, thereby eliminating the need for describing pore-connectivity. Electrical and fluid fluxes share the same type of flow equation as well, making their direct comparison possible. The difference between the flow of fluids and electric currents is the way each interacts with pore surfaces. Interaction of fluids with pore surfaces can be very strong and is propagated throughout the fluid by viscous forces. In contrast, interaction of electric currents with pore surfaces is localized to within a few angstroms of the surface and does not affect conduction in the remainder of the pore water. Using this information, permeability can be expressed as the product of volumetric, geometric and surface interaction terms. Separating the variables which determine permeability in this way permits the investigation of each independently and permits the identification of the two pore-geometric parameters that control permeability and the single geometric parameter that determines electrical conductivity.

Biography

Dr. David C. Herrick is a Visiting Associate Professor in the Geophysics Department, CSM, temporarily replacing Professor Max Peters (as if that were possible!) during his absence this fall semester. Dave is on leave from the Science Department of the Houston Technology Center of Baker Hughes where he is Chief Petrophysicist.

Dave was trained in chemistry and geochemistry at Indiana University (B.S.) and Penn State (Ph.D.). He has conducted research, training, and technical service during his thirty years in the petroleum industry for Conoco, Amoco, Mobil and Baker Hughes in geochemistry, petrology and petrophysics. He has been an SPWLA Distinguished Speaker with over fifty presentations on the theory and interpretation of resistivity and permeability given world-wide. He has been an organizing committee member for five SPWLA Topical Conferences and SPE Forums. In 2002 SPWLA awarded Dave its Technical Achievement Award. His publications include new and fundamental work on interpretation theory and methodology for resistivity data.

 

Abstract
Global changes are normal and have been with us since before our species emerged from the slime long ago. Our data sets indicate that global changes have been abrupt and dramatic in the past. Data also suggest that ongoing changes are likewise dramatic. In fact, it is
being suggested that after gaining an appreciation of the depth of geologic time and recognizing the role of plate tectonics, that today's paradigm shift leading to an acceptance of catastrophism as a significant geological theme represents one of the most significant
steps in understanding earth's behavior. This talk will review climate changes from a geologic perspective, bring it home to Colorado to examine changes that are manifest on our own landscape, and finally develop some thought experiments that may be answerable by geophysical means. The latter will be in the realm of groundwater quantification in areas south of Denver where our vital groundwater resources are recognized to be dwindling at extremely rapid rates.

Biography

Dr. Bob Raynolds works as a Research Associate at the Denver Museum of Nature & Science and has taught geology, worked for the USGS, the oil industry, and now raises yaks in Longmont.

Abstract
The recognition of the significance of seismic geometries and the depositional sequence concepts derived from them has provided a more predictive framework for carbonate platform development. New insight into carbonate platform evolution has been gained from outcrops by describing subseismic geometric and facies relationships within a larger seismic-scale chronostratigraphic framework. Until recently, seismic analysis of carbonate strata has focused on building a more accurate understanding of large-scale carbonate platform architecture. Delineating the depositional sequence framework provides a predictive way to map reservoir (e.g., grainstone shoals, reefal buildups, etc.), source, and seal lithofacies, and to qualitatively delineate the early diagenetic history of a platform (e.g., subaerial exposure at sequence boundaries). Outcrop dimensional data, and forward seismic models are helping to validate seismic predictions of stratigraphy and lithofacies, and are helping to quantitatively populate geometrically constrained stratigraphic models.

The sequence framework also provides constraints for geologic modeling in exploration and production settings. The introduction of 3-D seismic, seismic attributes (e. g., amplitude, frequency, phase), and visualization technology integrated with rock physics, core, and outcrop lithofacies dimensions provide new opportunities to delineate meter to decimeter-scale stratigraphy. Attribute and seismic facies can be mapped in 3-D volumes and provide spatial distributions of individual stratal bodies. Low impedance contrasts within platforms can be due to subtle porosity changes and are detectable with seismic inversion. Carbonate pore systems are, however, complex and record both depositional and diagenetic controls. Quantifying porosity distribution is a significant challenge. This is area that is increasingly attracting research efforts in industry, because of the globally significant volume of hydrocarbons trapped in carbonate reservoirs (over 60% of the world’s oil and gas).

Efforts to significantly improve seismic imaging of carbonate sequences and pore systems are critical to any advances in the area of volume and attribute interpretation. The unique aspects of carbonates, including high impedance, low impedance contrasts within platform successions, lack of bedding and complex pore systems in reefal lithofaces, the potential for steep depositional slopes, and the chaotic character of karsted terrain’s all can potentially diminish seismic quality and resolution. The intimate association with mobile evaporites in many basins produces complex structures and steep dips that present challenges to seismic acquisition and processing. Also, carbonates are commonly interbedded with siliciclastics that have much lower impedance, resulting in a strong susceptibility for multiple generation.

Biography

J.F. 'Rick' Sarg received his Ph.D. (1976) in Geology from the University of Wisconsin-Madison. Rick also holds an M.S. (1971) and a B.S. (1969) in Geology from the University of Pittsburgh. He has extensive petroleum exploration and production experience in research, supervisory, and operational assignments with Mobil (1976), Exxon (1976-90), as an Independent Consultant (1990-92), with Mobil Technology Company (1992-99) where he attained the position of Research Scientist, and with ExxonMobil Exploration (2000-05). Rick was a member of the exploration research group at Exxon that developed sequence stratigraphy, where his emphasis was on carbonate sequence concepts. He has worldwide experience in integrated seismic-well-outcrop interpretation of siliciclastic and carbonate sequences and has authored or co-authored 27 papers on carbonate sedimentology and stratigraphy. Rick achieved the position of Stratigraphy Coordinator at ExxonMobil Exploration Company, and since 2005, had been working as a senior advisor and instructor with William M. Cobb & Associates, Inc. In August of 2006, Rick joined the Colorado Energy Research Institute at CSM as a Research Professor. Rick has just completed a term as President of the Society for Sedimentary Geology (SEPM) (2004-05).

Abstract
Recent developments in down-hole seismic data acquisition, along with advancements in the field of seismic interferometry provide many opportunities for novel unconventional imaging applications with borehole sensors. Seismic interferometry retrieves the response between any two receivers as if a physical source were placed at one of the receiver locations. A current imaging challenge that presents itself as an opportunity to the use of interferometry is imaging in complex structural environments such as subsalt or in the presence of steeply dipping features. By applying interferometry to both active-shot and drill-bit VSP data, we propose novel imaging applications that may help subsurface characterization in areas where surface seismic can be compromised by structural complexity. In addition, to perform interferometry of wavefields excited by complex, continuous and incoherent excitations, we have developed the theoretical basis for performing interferometry with multi-dimensional data by the use of deconvolution. We will show numerical examples to illustrate these concepts. Using these interferometry tools, we present results from seismic-while-drilling data recorded at the San Andreas Fault Observatory at Depth (SAFD), in which we image waves reflected at the San Andreas Fault zone that could not have been imaged from conventional experiments. In yet another example, using the well-known Sigsbee velocity model we show that from recording internal multiples excited by sources close to the surface, we can use interferometry to reconstruct single-scattered data that illuminates the salt structure from beneath.

Biography
Ivan Vasconcelos joined CWP upon completing his honors B.Sc. in geophysics from the University of Sao Paulo, Brazil. Ivan’s research at CSM revolves around elastic wave propagation and scattering in heterogeneous, anisotropic and attenuative media. His current research is on interferometric imaging from down-hole acquisition geometries with applications to imaging faults and subsalt features, and to imaging from drill-bit noise recordings. Other interests lie in subsurface imaging and characterization from multicomponent seismic data; effective properties of microheterogeneous media; and anisotropy vs. heterogeneity in different signatures and experiments. During Summer 2004, Ivan interned with GX Technology, Axis Imaging Division, Denver, working on detecting azimuthal variations of attenuation in surface seismic data. Summer 2005, Ivan worked at Shell International E&P with Vladimir Grechka on seismic characterization of fractured media and on modeling effective fractured media. Fall 2006, he will intern with GXT's Imaging Research team in Houston.

Abstract
Borehole and surface ground penetrating radar (GPR) have been successfully used to detect and monitor the movement of dense non-aqueous phase liquids (DNAPL) experimentally and at contaminated sites. The radar systems employed typically range in frequency from 100 MHz to 900 MHz, with borehole radar systems at the lower end. This study shows how a 1.4 GHz borehole radar system was used to detect and quantify DNAPL saturation changes during a controlled spill of tetrachloroethylene (PCE). The Environmental Protection Agency sponsored the PCE spill experiment at the University of California, Berkeley’s Richmond Field Station. Over a period of 72 hours, 24 liters of PCE were spilled into a 2.4 m diameter tank filled with water saturated sand and clay mixtures. A layer of clay was placed within the saturated sand to contain the PCE, mimicking the function of a clay aquitard. Zero offset gather data were acquired between two wells (1.4 m deep) before the spill began, at 12 hour intervals during the spill, and regularly after the spill had stopped until the data traces appeared to stabilize. The times of the direct arrivals of the zero offset gathers were converted to velocity and permittivity. The Bruggeman Hanai-Sen mixing formula was then applied recursively to obtain values for the vertical distribution of porosity followed by PCE saturation. The results demonstrate that high frequency borehole GPR was sensitive to changes of just a few percent in PCE saturation.

Biography
Erin Wallin received her BS in Geophysical Engineering from Colorado School of Mines in 1999. She has worked for the United States Geological Survey’s Crustal Imaging and Characterization Team since 2000. Her PhD advisor is Gary Olhoeft.

Abstract
A method has been developed for obtaining formation compressional and shear velocities without using wave mode first breaks, stacking, or semblance techniques. This new technique uses frequency decomposition of thin bed reflection spectral tuning present in the coda section of the sonic full waveform to accurately determine formation velocities. This research first adapted frequency decomposition from the seismic trace to the sonic waveform domain, and then applied it to synthetic sonic waveforms that were generated with a 2 1/2 D, fully elastic, finite difference model based on Biot poroelastic wave propagation. Field data sonic logging full waveforms, acquired in a thinly bedded natural gas reservoir, were successfully processed with this technique and provided accurate thin bed velocities.

Biography
Lauri Burke is a PhD candidate in the Center for Petrophysics. Her advisor is Max Peeters. She is pictured here during a trip to Alaska.

Abstract
The pursuit of ever more obscure targets and reduced drilling risk continues to drive the seismic industry towards denser sampling of the seismic wavefield. The advent of MEMS (Micro-Electro-Mechanical Systems) based multi-component sensors has also renewed interest in point measurement of the full particle motion. We will discuss this new sensor technology and our experiences with the data it produces. We will also review a new acquisition system developed to significantly increase the density of land surveys and consider the implications for seismic processing.

MEMS technology evolved from techniques developed for chip making. Instead of etching circuitry, mechanical devices are carved out of the silicon. These sensors have been deployed in both marine ocean bottom cable and land surveys resulting in significant improvements in P-wave data quality and valuable PS-wave information when compared to standard acquisition.

Utilizing technology advances driven by the consumer electronics industry, a cableless land acquisition system using these MEMS sensors has been developed that will allow station counts and sampling density to be dramatically increased. Scheduled for field scale tests in November 2006, this new system together with LIDAR, GPS and field management software should also allow more efficient and environmentally friendly field operations. Dense broadband multi-component acquisition will permit more effective implementation of existing processing techniques such as offset vector tiling for azimuthal attribute analysis and hopefully stimulate development of new approaches.

Biography
Alex Calvert received a Ph.D. in Seismology & Geophysics from Cornell University in 1999 and a B.A. in Physics from Oxford University in 1993.  In 1999, he joined BP in Houston as a geophysicist for a deepwater Gulf of Mexico asset where he worked on field development and marine high resolution survey planning, acquisition & processing.  In 2001, he joined BP’s seismic imaging group to work on high resolution depth velocity model building and depth imaging.  In search of cooler climes, he moved to GXT in Denver in 2003 as a research geophysicist to work on wide azimuth land and converted wave processing. Since 2005, he has been responsible for GXT’s multi-component processing technology program.

Abstract
Large-scale, mine dewatering and petroleum production may produce subsidence patterns with widths of several kilometers and broad distributed vertical displacements of several to several 10’s of centimeters per year. Associated fissuring and compression deformation have the potential to disrupt surface hydrology, tailings storage areas, pipelines and structures. Early knowledge of areas with high surface strain accumulations could allow time to safely manage the potentially costly impacts.

Although, Satellite Interferometric Synthetic Aperture Radar (InSAR) has become a valued, tool for mapping dewatering subsidence patterns, the method’s off-vertical, line-of-sight displacement observations have presented an obstacle to estimating the horizontal displacements necessary for analysis of ground surface strains. We discuss how we have overcome that limitation and present a new InSAR post-processing methodology termed STRAIN-SAR (Strain Tensor Rate Analysis – InSAR), which recovers full horizontal strain rate tensor values from InSAR observations of subsidence features.

We apply this technique to multi-year InSAR measurements made over several large dewatering operations. We discuss signal recovery and the characteristics of the horizontal strain tensor and its rotational invariants as they pertain to mapping and understanding strain concentrations in the surface. An unexpected result is that the strain maps appear to delineate pre-existing geologic faults and contacts influencing fluid flow or separating domains of differing elastic properties, hence the surface strain mapping method offers utility as a site investigation geophysical tool as well. We compare the recovered strain results with known surface fissuring patterns to test the validity and predictive capability of the method.

Biography
Dr. Gary Oppliger is a Research Associate Professor at the Arthur Brant Laboratory for Exploration Geophysics, Mackay School of Earth Sciences and Engineering at the University of Nevada Reno since 1999. He earned his Ph.D. in Engineering Geoscience at the University of California, Berkeley in 1982 were he specialized electrical exploration methods under Professor H. F. Morrison. He also completed MS and BS degrees in Engineering Geoscience at U.C. Berkeley in 1977 and 1975, respectively. Dr. Oppliger worked as a research and exploration geophysicist in the mining industry for 17 years, first with Newmont Exploration Ltd’s geophysics research group (founded by Dr. Arthur Brant) in Tucson, Arizona between 1980 and 1989 and later with Western Mining Corporation and Kennecott Exploration 1989 through 1998. Dr. Oppliger’s research focuses on potential fields, electrical and radar imaging methods for resource applications and he teaches graduate courses in these subjects. He is an active member of the American Geophysical Union, the Society of Exploration Geophysicists, the Geological Society of America, the American Society of Photogrammetry and Remote Sensing and the Geothermal Resource Council.

Abstract
The twin Martian rovers, Spirit and Opportunity, landed in January of 2004 to carry out the mission of tracing the geological and geochemical evidence of water on the surface of Mars.  The landing sites, Gusev Crater and Meridiani Planum were selected based on orbital evidence of the potential for a "watery" past.  Over 2 years and more than 15 kilometers combined, these robot explorers continue to unveil the surface through optical and infrared spectroscopy, Moessbauer, APXS and magnetic studies, and a wealth of imagery from microscopic to panoramic scales.  Highlights of the mission include the discovery of hematitic spherules, "blueberries", in layered sediments at Meridiani, active dust devils at Gusev, and a wealth of information on aqueous alteration of surface materials dominated by the formation of iron oxides, oxyhydroxides, and sulfates, with limited evidence for phyllosilicates.  These results point to alteration in an acidic, water-limited environment, early in the planets history.  A summary of the missions accomplishments and major scientific findings to date will be presented.

Biography
Wendy Calvin is a Research Professor in the Dept. of Geological Sciences and Engineering at the University of Nevada in Reno.  She uses infrared spectroscopy to identify and map the surface composition of the solid planets in the Solar System.  She received her PhD in Geophysics from the University of Colorado in Boulder in 1991, and BS in Physics/Mathematics from the University of Denver in 1983.  Before joining UNR she was with the Astrogeology team of the USGS in Flagstaff, AZ.  Wendy was selected as a participating scientist for the rover mission in 2002 and is a co-I\investigator for the MARCI/CTX camera on the Mars Reconnaissance Orbiter, the newest in the fleet of orbital spacecraft at Mars.

Abstract
Increasing population in the Western United States has increased the need for sustainable water resources, especially in the Upper Arkansas River Valley where declining water tables threaten the area. Clearly an understanding of the groundwater resources is necessary for safe, sustainable development. However, before a comprehensive hydrologic model can be built, the basin geometry and macro-scale water flow must be determined. Working with the Geophysics Department Field Camp, I have compiled two years of field data into a working model of the complex basin using geologic observation, as well as reflection seismic, gravity, electrical, and electromagnetic data. Although the basin, which is up to two kilometers deep, appears to consist of domino-like fault blocks in cross section, I show that these are actually strongly rotated structures. The basin does not have the anticipated north/south symmetry, which has strong implications toward basin-scale groundwater flow patterns.

Biography
Andy Kass joined the Center for Gravity, Electrical, and Magnetic Studies while an undergraduate at CSM. Though his main research interest is in transient electromagnetics, his projects allow him to be a “Jack of all trades.” In addition to the Upper Arkansas River Valley project, Andy is working on rapid terrain corrections for filtered airborne gravity gradient data, as well as a time-lapse TEM survey of the Leyden artificial aquifer storage and recovery (ASR) project in Arvada, Colorado.

Abstract
Increasingly commonplace is the imaging of small-scale geophysical targets characterized by low noise levels and spatially balanced and dense sensor coverage. Such applications require precise resolution and variance analysis of the recovered models in order to provide a reliable diagnosis. Quantifying resolution of small-scale targets is generally the most critical of these tasks. While the concept of resolution matrices and operators dates back to the work of Backus and Gilbert in the late 1960’s, their study has been limited due to the intensive computation requirements and persistent non-linear relationships. The resolution matrix relates the recovered model to the true model; columns are then equivalent to the Backus-Gilbert point spread function and rows equivalent to averaging functions. Through this definition, a piecewise method of forming the explicit non-linear resolution matrix is developed and applied to several small-scale, non-linear, potential field problems. In this talk, I present the method of resolution-matrix construction, discuss the resulting statistical and scaling properties of the resolution matrix, and, based on these properties, show that construction of the partial matrix can quantify the local resolution in model space.

Biography
A Ph.D. candidate in Geophysics at the Colorado School of Mines, Barry is advised by Yaoguo Li and Gary Olhoeft. He is currently a staff scientist at Lawrence Livermore National Laboratory in California and has worked as an electrical engineer at Caterpillar Research in Illinois, a marine seismology technician at the Scripps Institution of Oceanography in California, and a bartender at the Table Mountain Inn in Colorado. Areas of professional interest include computational electromagnetics, model appraisal in geophysical inversion, geophysical instrumentation, and teaching.

Abstract
The Gulf of Mexico (GoM) has been a prolific basin for hydrocarbon discovery. To date approximately 165 billion barrels of oil equivalent (bboe) has been discovered in the onshore and shelf portion of the basin. In deep water (> 600m water depth) approximately 15 bboe have been discovered and the yet to find is estimated in the range of 25 to 30 bboe. The search for hydrocarbons in deep water is made challenging by the fact that the area is largely covered by allochtonous salt sheets, pushed outwards by the sediment load. The challenge in imaging strata under salt using seismic data is caused by the fact that salt is a partial mirror. The top salt produces a booming reflection, and transmission of energy below the salt is weak and highly focused. These effects and the resulting multiple scattering lead to poor illumination of sub-salt targets by the seismic waves, and to a very low signal to noise ratio in the sub-salt and intra-salt images.

Modern algorithms used to tackle the sub-salt problem are all of the pre-stack depth variety, including the one way or two way wave equation algorithms. These algorithms require massive computations and the output images are still low frequency. Producing images takes considerable time, upwards of a year for a typical project covering about 100 GoM blocks (about 2500 square kilometers), regardless of the quality of the final image.

When everything works well, images of the salt body and sediments below can be stunning. However, in the same survey one can run into difficulties, and fail to image either the base of salt or the sediments below the salt. This is a basic problem: the quality of the seismic images depends on the shooting direction of the seismic survey relative to salt bodies, namely the azimuthal direction of illumination. Acquisition techniques such as wide azimuths surveys attempt to eliminate that problem by brute force and show definite improvements.

While the top of the salt is usually well imaged, a common problem is the disappearance of the base of salt. The reason for that disappearance is generally poorly understood and usually attributed to an illumination issue, but can also be due to algorithmic limitations. If the base of salt cannot be imaged, imaging of the sediments below is simply impossible.

Another problem is imaging within the salt itself, which is not a generally a homogeneous halite body, but contain shale inclusions and suture zones which are potential severe drilling hazards. It is therefore important that we image them properly. However our low frequency algorithms and the illumination within the salt lead to very poor imaging of these events.

Another drilling hazard is the large overpressure that can occur sub-salt. Currently the best remote tool to predict overpressure is the seismic velocity. However current technology does not allow us to predict the sub-salt sediment velocity with the degree of accuracy required to predict the locations of these drilling hazards.

Progress is being made constantly in imaging, both in our acquisition and processing techniques, but currently the salt appears to be winning. As an industry we are scoring some points, although a step change may be needed in the way we approach the problem.

Biography
Jacques P. Leveille received a PhD in Theoretical High Energy Physics from Boston University in 1976. After post-doctoral appointments at Imperial College in London and the University of Wisconsin at Madison, he was on the research faculty at the University of Michigan in Ann Arbor until 1982. During those years, his research was on elementary particle physics. In 1982 he joined Shell Development Company at the Bellaire Research Center in Houston where he remained until 1994. He then joined the Hess Corporation, where he is currently a global geophysical advisor. His first assignment in geophysics was the development of a shear logging tool, both from the theoretical and experimental aspects. His other interests are in rock physics, wave propagation, seismic processing and imaging, especially pre-stack depth imaging. He is the author and co-author of over thirty publications in particle physics, of over 50 internal company reports and external publications in geophysics and three patents.

Abstract
Tight gas sandstones are important unconventional hydrocarbon resources that contain a quarter of natural gas proven reserves in the United States. Rulison Field, located in the Piceance Basin, Colorado, produces gas from a thick section (1700 to 2400 ft) of stacked, discontinuous sandstone channels interbedded with siltstones, shales, and coals. Typically small size of the sand channels (about 30 ft) makes them difficult to image with surface seismic data. Understanding anisotropy helps to reveal the rock heterogeneity and improve seismic imaging. We estimate the anisotropic parameters at Rulison using a variety of techniques and datasets, including conventional ultrasonic core plug measurements, well logs and 3C P-wave VSP data to derive local velocity and anistropy around the well. Using P-wave prestack data, we made a fracture characterization analysis at different intervals in the reservoir showing a correlation of the areas of high production with the areas of high fracture density.

Biography
Gerardo Franco is an MSc candidate in geophyiscs at the Colorado School of Mines. After receiving bachlor degrees in electronical engineering (2000) and geophysical engineering 92001) he worked for WesternGeco-Scholumberger as a geophysicist (2001-2005) in seismic acquistion and processing. His academic research focueses on anisotropy estimation and reservoir characterization of tight-gas sandstones.

Abstract
A finite-difference well bore modeling code based on a modified Biot’s theory is used to study the response of sonic tool designs to fractures encountered along the well bore surface. Designs include standard short-spacing and long-spacing borehole compensation, and sonic arrays. Fracture variables include effective fracture aperture, length and spacing.

The aim is to determine tool design sensitivity to fracture parameters with respect to acoustic attenuation. Inversely, the relationships among fracture parameters and attenuation are being investigated to determine whether quantitative fracture properties may be derived. This is particularly important in determining the petrophysical properties of fractured hydrocarbon reservoirs for simulation and management.

Biography
Cindy Arjoon received a B.Sc. degree in Physics in 1994 at the University of the West Indies in Trinidad and Tobago. She taught high school physics and math before returning to the university to conduct research in the field of Medical Physics for which she received a Masters of Philosophy degree in Physics in 2000. She then worked in QC/QA at the local steel plant before joining a marine oil and gas company Trinmar Ltd., which was later fully nationalized under the Petroleum Company of Trinidad and Tobago. She did seismic interpretation, well site sitting and pore pressure detection from seismic data, and was involved in the first multilateral well drilled offshore Trinidad. She entered CSM in 2004 to pursue an M.S. degree in Geophysics with the Center for Petrophysics. Since then she has had internships with Apache in 2005 investigating the AVO response of deep GOM sediments, and Anadarko’s Denver office working on pore pressure modeling using sonic logs. Her research focuses on modeling the effects of fractures on the sonic tool response and her main career interest is in “seismic petrophysics”. Cindy served as the executive treasurer for the Geological Society of Trinidad and Tobago from 2001-2004, and more recently as the treasurer of the SGGS at CSM

Abstract
We model the boundary of sandwich structures in terms of displacements by computing the top boundary conditions from sandwich structure theory and applying classic elastic theory to core deformation. This serves as a new method for computing elastic parameters for laboratory samples and a new way of verification of experimental data outputs and commercial software simulations.

Biography

Begoña Ruiz is a graduate from Madrid Polytechnic University ( Spain) and the Colorado School of Mines where she obtained the degrees of Engineering (BS and MS), and Engineering and Technology Management (MS). She worked for the Madrid School of Mines and European Union in Environmental Analysis and Control of human produced pollutants, and later joined the Center for Commercial Applications for Combustion in Space, working for the Johnson Space Center, DARPA, Bechtel, etc. Begoña's proudest accomplishment is having a wonderful daughter.