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Butterfield_Masters_Thesis_Final.pdf (27.9 MB)

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Characterization of a Utica Shale Reflector Package Using Well Log Data and Amplitude Variation with Offset Analysis

Butterfield, Andrei
http://rave.ohiolink.edu/etdc/view?acc_num=wright1401462908

Abstract Details

2014, Master of Science (MS), Wright State University, Earth and Environmental Sciences.
Using well logs and AVO gradient analysis, I identify and characterize a package of reflectors associated with the Utica Shale from vibroseis data collected by Wright State University at the Gabor Gas Storage field near Canton, Ohio. I also correlate TOC measurements from wells to densities and velocities at the same depths. On the seismic data, I interpret prominent reflections from the top and bottom of the Utica Shale and an intra-Utica reflector of varying frequency content associated with a velocity/density low in well log data. I investigate the possibility that the lateral variation in frequency content and change in wavelet character of these reflections is influenced by velocity gradients, termed Wolf Ramps. A Matlab software script was written in order to approximate this behavior using synthetic wavelets, and the resulting model matched well with the seismic data. Additionally, I note a possible reverse fault within the Utica that could create fracture porosity and a migration pathway. To model the AVO response, an AVA volume was created from prestack data and reflection coefficients up to 30 degrees of incidence were calculated using the two-term Aki-Richards approximation. Large negative normal incidence reflection coefficients attenuated at higher angles of incidence (Class IV anomalies) were observed at the top of Utica reflector, a response consistent with a change from silica-rich nonsource shale to black source shale. Large positive normal incidence reflection coefficients decreasing at higher angles of incidence (Class I anomalies) were noted at the bottom of Utica reflector, consistent with a shift from low impedance source shale to higher impedance calcareous shale. To perform forward modeling, I used geophysical well logs and NS-EW vibroseis line data. Using Hampson Russell commercial software, acoustic impedance and reflectivity were computed from sonic and density logs. An average wavelet at the Utica two-way travel time was extracted using Promax software and convolved with the reflectivity to create a synthetic seismogram for each well. Lastly, the Utica Shale and underlying formations were correlated in Petrel software using well logs in the vicinity of the seismic lines. The results of the correlation allowed me to make connections between the depositional processes that led to the formation of the Ohio Utica from the New York Utica, for which outcrops and a large number of well logs are available.
Doyle Watts, Ph.D. (Advisor)
Ernest Hauser, Ph.D. (Committee Member)
David Dominic, Ph.D. (Committee Member)
134 p.
Geology; Geophysics
AVO; shale; Utica; Point Pleasant; Trenton; Wolf Ramp; seismic interpretation; crossplot; shale petrophysics; well log; amplitude versus offset; amplitude variation with offset

Recommended Citations

Citations

  • Butterfield, A. (2014). Characterization of a Utica Shale Reflector Package Using Well Log Data and Amplitude Variation with Offset Analysis [Master's thesis, Wright State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401462908

    APA Style (7th edition)

  • Butterfield, Andrei. Characterization of a Utica Shale Reflector Package Using Well Log Data and Amplitude Variation with Offset Analysis. 2014. Wright State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=wright1401462908.

    MLA Style (8th edition)

  • Butterfield, Andrei. "Characterization of a Utica Shale Reflector Package Using Well Log Data and Amplitude Variation with Offset Analysis." Master's thesis, Wright State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401462908

    Chicago Manual of Style (17th edition)

wright1401462908
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This open access ETD is published by Wright State University and OhioLINK.