Seismic attenuation values based on inverse Q-filtering are useful in enhancing seismic data resolution for quantitative interpretation. However, as field attenuation estimations are often contaminated by noise and overburden effects, an inverse Q-filter may reduce the signal-to-noise ratio. To help reservoir mapping with seismic resolution enhancement, we use well logs and surface seismic data to estimate the attenuation of a depth interval composed of several carbonate oil reservoirs onshore the Arabian Peninsula. From applying a prestack Q inversion on τ-p gathers from a large 3D seismic survey, the estimated effective attenuation values show spatially coherent patterns, likely corresponding to changes in the petrophysical and fluid properties. The patterns of the estimated effective attenuation values correlate considerably with the anticline geometry, with higher values on its crest than its flanks. The small percentage of the negative effective attenuation values indicates that the apparent attenuation and overburden effects are insignificant. At well locations, the effective attenuation values show a good correlation with the average porosity of the main reservoir, verifying that they are related to changes in petrophysical properties in the analysis interval. We propose an extended inverse Q-filter with two additional parameters to make it more robust and flexible and test it with synthetic and field datasets. We estimate a multiple-scattering attenuation value from well logs and use it in the proposed filter for the field dataset. The compensation for the multiple-scattering effects suppresses the overprints of the data components unrelated to the target interval, hence benefitting the quantitative data interpretation.
Wheelchair tray tables offer a convenient way for wheelchair users to carry out daily tasks such as eating, reading, and using mobile devices. However, most tray tables are made to serve the majority of wheelchair users and are inaccessible to some with a limited range of motion. In our work, we address this issue by exploring the ergonomic problems and possible solutions. In this paper, we describe the human factors in the design and development of powered wheelchair tray tables. The process of humanistic co-design relies on the direct involvement of the targeted demographic in the design process. This ensures the outcome is centered around the specific needs of the individual. Our approach employs user research studies (e.g., interviews, questionnaires, and actively working with a wheelchair using co-designer) as a means towards gleaning valuable insight into the needs of wheelchair users. In these studies, we sought to explore their experiences with using tables made for wheelchairs. We also collected data about whether the tray tables required external assistance to stow and use, and the problems they faced using existing solutions. We then highlighted the various specific needs presented by the codesigners and questionnaire respondents. These needs are embodied into scenario-based personas in which they may find themselves in need of a table for use with their wheelchairs. Deriving these personas from our survey results provides an effective method of keeping the insight gathered present throughout the design process. Implications for design are discussed.
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