Browsing by Subject "geophysics"
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Item Airguns: Theory and operation of the marine seismic source(2010) Krail, Paul M.A detailed knowledge of the radiation field of seismic sources is essential to effective source design and source wavefield deconvolution. To understand the principles of airgun theory and operation it is necessary to follow the motion of the air bubble that is produced and released underwater by the airgun. An airgun is a mechanical device that releases a high pressure bubble of air underwater, the expansion of the air bubble generates seismic waves the water that are the source waves of the seismic waves used in reflection seismology. This monograph is about the motion of the bubble of air in the water that creates the seismic pressure wave called the airgun signature. The relevant physical principles for a single bubble are discussed first, then the dynamic behavior of the bubble is derived from the basic equations of fluid mechanics for the ocean and thermodynamics for the air. The surface ghost reflection part of the signature is derived and its behavior explained. Once the dynamics of a single bubble is understood, the behavior of an array of airgun bubbles is easy to understand, the reasons for an array are explained and detailed. The discussion then moves on to practical performance specifications in the field. The different types of airguns are discussed and their mechanical operation explained, this leads to the airgun system, a pneumatic-electrical computer controlled system on board the seismic vessel under the control of the GPS navigation system.Item Evaluation of Geophysical Techniques for Identifying Fractures in Program Wells in Deaf Smith County, Texas, Revision 1(1987) Gillespie, R. P.; Siminitz, P. C.Quantitative information about the presence and orientation of fractures is essential for understanding the geomechanical and geohydrological behavior of rocks. This report evaluates various borehole geophysical techniques for characterizing fractures in three Civilian Radioactive Waste Management (CRWM) Program test wells in the Palo Duro Basin in Deaf Smith County, Texas. Emphasis has been placed on the Schlumberger Fracture Identification Log (FIL), which detects vertical fractures and provides data for the calculation of orientation. Depths of FIL anomalies were compared to available core. It was found that the application of FIL results to characterize fracture frequency or orientation is inappropriate at this time. The uncertainties associated with the FIL information render the information unreliable. No geophysical logging tool appears to unequivocally determine the location and orientation of fractures in a borehole. Geologic mapping of the exploratory shafts will ultimately provide the best data on fracture frequency and orientation at the proposed repository site.Item Letter to George P. Woollard from H.B. Stenzel on 1955-06-20(1955-06-20) Stenzel, Henryk B.Item Letter to H.B. Stenzel from E.J. Smith, Jr. on 1939-06-14(1939-06-14) Smith, E.J., Jr.Item Letter to H.B. Stenzel from Ed W. Owen on 1955-06-10(1955-06-10) Owen, Ed W.Item Letter to H.B. Stenzel from Felix A. Vogel, Jr. on 1939-05-06(1939-05-06) Vogel, Felix A., Jr.Item Letter to H.B. Stenzel from George P. Woollard on 1955-07-19(1955-07-19) Woollard, George P.Item Letter to H.B. Stenzel from Hewlett A. Russell on 1945-01-29(1945-01-29) Russell, Hewlett A.Item Letter to H.B. Stenzel from Raymond C. Moore on 1968-03-27(1968-03-27) Moore, Raymond C.Item Letter to H.B. Stenzel from W.S. Levings on 1955-07-20(1955-07-20) Levings, W.S.Item Letter to H.B. Stenzel from William A. Berggren on 1967-11-13(1967-11-13) Berggren, William A.Item Letter to William S. Levings from H.B. Stenzel on 1955-06-20(1955-06-20) Stenzel, H.B.Item Microseismic Monitoring of Chocolate Bayou Texas The Pleasant Bayou No.2 Geopressured/Geothermal Energy Test Well Program(1981) Mauk, Frederick J.Commercial utilization of the geopressured brines underlying the Gulf Coast as unconventional geothermal-methane energy sources is dependent upon high volumetric production rates. The production requirements for effective withdrawal and disposal of these highly saline brines are believed to be near 3 X 10^4 bbl/day/well. Such high volumetric productions can substantially alter the ambient state of stress of the local geological column, potentially resulting in reactivation of preexisting zones of weakness as well as causing new fracture development. To investigate normal ambient seismicity as well as potentially enhanced seismic activity induced by brine production, Teledyne Geotech, with the authorization of the Texas Bureau of Economic Geology, has conducted a seismic monitoring program in the vicinity of the Chocolate Bayou geopressured test well (the Pleasant Bayou No. 2) since September 1978. The Pleasant Bayou No. 2 well has been completed and perforated at depths of 14,467 - 14,707 feet (4464.4 - 4482.7m). The brines produced from the Pleasant Bayou No. 2 well are reinjected at a depth of 6226 - 6538 feet (1897.7 - 1992.8m) in the Pleasant Bayou No. 1 well. This report describes the seismic monitoring network and results obtained from January through November 1981.Item Milestones in Geophysics: Five Decades of Progress (A Tribute to Arthur E. Maxwell)(Institute for Geophysics, 2018-06-10) Ganey-Curry, Patricia (editor)Item Seismic Evaluation and Reconnaissance TDEM Survey of the Southeast and Playa 3 Areas of the Pantex Plant, Carson County, Texas(2000) Paine, Jeffrey G.In response to a recommendation in the recent "Protecting the Ogallala Aquifer II" report, the Bureau of Economic Geology (the Bureau) evaluated the potential of seismic reflection and TDEM (Time-Domain Electromagnetic) methods to define the distribution and thickness variations of the Ogallala fine-grained zone (FGZ) that perches groundwater beneath the Pantex Plant. Bureau researchers briefly examined existing seismic reflection data collected at and near the Pantex Plant by the U.S. Army Corps of Engineers (COE) and by the Bureau, conducted TDEM modeling studies, and acquired reconnaissance TDEM data in the Pantex Southeast and Playa 3 areas. The existing seismic reflection surveys had broad objectives that extended from the Ogallala caprock to the base of the Ogallala Formation. These surveys provided basic data on the stratigraphic framework of playa and interplaya areas. Although the top of the FGZ appears to be a good seismic reflector in existing data, reprocessing the limited COE and Bureau seismic data in the Pantex Southeast area might enhance that reflection and reveal other associated reflectors in the same depth range. Further improvement in the seismic characterization of the FGZ would require acquisition of new seismic data that would benefit from the restricted target depth and recent advances in seismic equipment.Item Storage of Carbon Dioxide in Saline Aquifers: Physicochemical Processes, Key Constraints, and Scale-Up Potential(2021) Ringrose, Philip S.; Furre, Anne-Kari; Gilfillan, Stuart M.V.; Krevor, Samuel; Landrø, Martin; Leslie, Rory; Meckel, Tip A.; Nazarian, Bamshad; Zahid, AdeelCO2 storage in saline aquifers offers a realistic means of achieving globally significant reductions in greenhouse gas emissions at the scale of billions of tonnes per year. We review insights into the processes involved using well-documented industrial-scale projects, supported by a range of laboratory analyses, field studies, and flow simulations. The main topics we address are (a) the significant physicochemical processes, (b) the factors limiting CO2 storage capacity, and (c) the requirements for global scale-up.Although CO2 capture and storage (CCS) technology can be considered mature and proven, it requires significant and rapid scale-up to meet the objectives of the Paris Climate Agreement. The projected growth in the number of CO2 injection wells required is significantly lower than the historic petroleum industry drill rates, indicating that decarbonization via CCS is a highly credible and affordable ambition for modern human society. Several technology developments are needed to reduce deployment costs and to stimulate widespread adoption of this technology, and these should focus on demonstration of long-term retention and safety of CO2 storage and development of smart ways of handling injection wells and pressure, cost-effective monitoring solutions, and deployment of CCS hubs with associated infrastructure.Item Study Effects of Geopressured-Geothermal Subsurface Environment on Elastic Properties of Texas Gulf Coast Sandstones and Shales Using Well Logs, Core Data, and Velocity Surveys(1980) Gregory, A. R. (Alvin Ray), 1915-Relations between porosity and permeability for the Pleasant Bayou wells were determined from conventional core data. Porosities from the time-average equations required compaction correction factors of 1.9 in hydropressured sandstones and 1.0 in geopressured sandstones. Best average permeabilities in the geopressured zone were found in the primary production interval 14,687 to 14,716 ft (4,477 to 4,485 m). Average density gradients were 2.106 x 10-3 and 2.688 x 10-3 (gm/cm3)/100 ft in sandstones and shales, respectively. Compressional (P-wave) and shear (S-wave) velocities from the long-spaced sonic log and bulk densities from the formation density log were used to compute in-situ elastic moduli, Poisson's ratio, Vp / Vs, and bulk compressibility in two intervals of deep geopressured sandstone and shale in No. 2 Pleasant Bayou. Most computed values of these parameters seem reasonable. Improved accuracy of travel times from the long-spaced sonic log should permit more accurate depth-to-time correlation with seismic data. However, wave theory from Biot (1956) and Geertsma (1961) predicts dispersion at well-log frequencies that may introduce velocity errors of 1.5 to 3.6 percent in sandstones with high porosity and permeability. High reflection coefficients at interfaces between shales and brine-saturated sandstones indicate that seismic reflection methods may be able to detect high-quality reservoirs with enhanced dissolution porosity in deep Tertiary sandstones.