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Collaborating Authors
Wyoming
Summary Geohazards such as the abnormal pore-pressure, fracture gradient, and shallow water flow are important conditions to detect and analyze when planning (or drilling) a well. The most reliable tool, which can provide such information are the seismic waveform data, and inverting seismic data is the only way to retrieve subsurface lithology, which can then be linked to such geohazards ahead of the drill-bit. Here, we develop a hybrid seismic inversion method, combining a prestack waveform inversion (PWI) with an amplitude-variation-with-offset/angle (AVO/AVA) inversion. Applying our method to real data from the Rock-Springs uplift, Wyoming, USA we demonstrate that the method is capable of predicting the three-dimensional (3D) model ahead of the drill-bit. Although we use this inverted 3D model to identify the lithological and fluid properties for potential targets for carbon dioxide (CO2) storage, we also show how the methodology outlined here could be applicable in predicting zones of hydrocarbon accumulations and detecting possible geohazards.
- Geology > Geological Subdiscipline > Geomechanics (0.51)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.48)
- North America > United States > Wyoming > Sand Wash Basin (0.99)
- North America > United States > Wyoming > Bighorn Basin > Phosphoria Formation (0.99)
- North America > United States > Utah > Sand Wash Basin (0.99)
- (3 more...)
Summary In recent years new methods and tools were developed in seismic survey design to address the increasing complexity of geophysical and geological problems that seismic exploration is faced with. In this paper we discuss three of these new developments: the application of point-spread functions for seismic resolution analysis, seismic survey design based on Bayesian methodology, and the generation of the seismic response for a fractured reservoir using 3D elastic general anisotropic finite-difference modeling. We demonstrate that these methods can be used effectively for seismic survey design.
Summary In this study, we develop a composite 3D seismic attribute workflow to identify areas of high open-fracture intensity. The composite attribute incorporates measures of 3D seismic discontinuity and directional curvature. Discontinuities and directional curvature were computed in depth. Discontinuities were extracted from the 3D seismic using post-stack processing to enhance resolution and reflection irregularities. Maximum directional curvature was computed in the direction orthogonal to the dominant (N76ยฐW) open fracture trend. Maximum curvature orthogonal to the dominant open fracture trend may enhance fracture aperture. Discontinuity and directional curvature were upscaled into a reservoir grid and combined to form a composite fracture driver. The driver reveals the potential for reservoir compartmentalization and areas where fracture intensity is likely to be highest. Distribution of predicted high intensity areas is consistent with the distribution of oil production in the field. The dominant N76ยฐW (hinge-oblique) set coincides with the N75.5ยฐW orientation of SHmax (maximum horizontal compressive stress) inferred from drilling induced fractures. We recommend that enhanced oil recovery operations employ lateral wells oriented in the ~N20ยฐE direction through areas of predicted high fracture intensity and approximately normal to the SHmax trend. This strategy offers the possibility to maximize recovery and CO2 storage.
- North America > United States > Wyoming > Powder River Basin > NPR-3 > Teapot Dome Field > Wall Creek Formation (0.99)
- North America > United States > Wyoming > Powder River Basin > NPR-3 > Teapot Dome Field > Tensleep Formation (0.99)
- North America > United States > Wyoming > Powder River Basin > NPR-3 > Teapot Dome Field > Sussex Formation (0.99)
- (6 more...)
Summary We present the results of interferometry applied to three passive downhole microseismic data sets acquired in the hydrocarbon-bearing Niobrara, Eagle Ford, and Bakken formations. Although the available three-component (3C) data make it theoretically possible to recover full elastic Greenโs tensors for any receiver pair, we choose to restrict the scope of our paper to single, along-the-well component of the 3C records. Depending on the survey geometry, crosscorrelations of this component retrieve either P- or S-waves traveling between the receivers and allowing one to estimate the velocities useful for building models for microseismic data processing.
- North America > United States > North Dakota (0.67)
- North America > United States > South Dakota (0.49)
- North America > United States > Montana (0.49)
- North America > United States > Texas (0.46)
- North America > United States > Wyoming > Laramie Basin > Niobrara Formation (0.99)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- (8 more...)
Abstract The key for characterization of fractured reservoir is to obtain the fracture density and orientation information of the formation. In this paper, on the basis of the azimuthal anisotropic feature of seismic attributes, ellipse fitting method is presented to predict fracture density and orientation. The ellipticity of the ellipse is used to represent the fracture intensity, while the direction of the longer axis of the ellipse represents fracture direction. The method is applied using P-wave wide azimuth attributes in the study area. The inversion results could reflect the fracture distribution characteristics through the contrast verification to well logging data, FMI data and production data in the well location.
- North America > United States (0.47)
- Asia > China (0.30)
- North America > United States > Wyoming > Manderson Field (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
- North America > United States > Texas > East Texas Salt Basin > East Texas Field > Woodbine Formation (0.98)
Summary Moving sensitivity domain that varies with frequency was implemented and tested in a parallel magnetotelluric (MT) integral equation inversion. This approach reduces computation time and memory requirements. We assess the robustness of the approach by model tests and apply it to the inversion of EarthScope MT data collected over the Northwestern US. Prominent features obtained by this inversion include resistive structure associated with the Juan de Fuca slab subducting beneath the northwestern United States and the conductive zone of partially melted material above the subducting slab corresponding to the Cascade volcanic arc. We also observe extensive areas of moderate-to-high conductive asthenosphere below 100 to 200 km and high-conductive body associated with the Yellowstone mantle plume.
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.90)
- Geology > Geological Subdiscipline > Volcanology (0.87)
- South America > Argentina > Noroeste Basin (0.99)
- North America > United States > Wyoming > Great Basin (0.99)
- North America > United States > Utah > Great Basin (0.99)
- (6 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (0.90)
- Information Technology > Mathematics of Computing (0.63)
- Information Technology > Hardware > Memory (0.34)
SUMMARY We retrieve reflected plane waves by applying seismic interferometry to the recorded ground motion from a cluster of earth- quakes. We employ upgoing/downgoing P/S wavefield decomposition, time windows, time reversal, and multi-dimensional deconvolution (MDD) to improve the quality of the extraction of reflected waves with seismic interferometry. Because MDD interferometry requires the separation of wavefields depending on the direction of wave propagation, almost no studies apply this technique to earthquake data observed at the surface to extract body waves. The wavefield separation and seismic interferometry based on MDD allow us to reconstruct PP, PS, SP, and SS reflected waves without unwanted crosstalk between P and S waves. From earthquake data, we obtain PP, PS, and SS reflected plane waves that reflect off the same reflector, and estimate P- and S-wave velocities.
SUMMARY This 3D-3C seismic survey greatly improves the structural model of the Soda Lake, Nevada geothermal system. The goal of determining a "geothermal indicator" in the seismic signal is approached here by looking at seismic anisotropy in a smoothed version of the 3D converted-wave data. Processing of the 3D converted-wave data was limited due to both a high near-surface VP=VS ratio which under-sampled shear-wave energy and the maximum geophone offset which limited the incidence angles. The 3D converted-wave data that we can image shows encouraging similarity to the deep structural features in the P-wave sections, but has little resolution of shallow structures. Smoothing the absolute value of seismic amplitudes along these deep reflections allows for time shift analysis of the diffuse reflections. The reflections that demonstrate higher than 1% anisotropy appear to be controlled by shallow structural features and occur in areas with longer more continuous faults that strike N-S. A correlation is observed between varied fault strike and geothermal production. This study demonstrates the potential for future studies to map out brecciated zones with multiple fault strikes for geothermal resource development.
- Geology > Structural Geology > Fault (0.94)
- Geology > Rock Type (0.70)
- Geology > Geological Subdiscipline (0.69)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.69)
- Energy > Renewable > Geothermal > Geothermal Resource (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Wyoming > Great Basin (0.99)
- North America > United States > Utah > Great Basin (0.99)
- North America > United States > Oregon > Great Basin (0.99)
- (4 more...)