USING SEISMIC ATTRIBUTES TO VISUALIZE SUBTLE FEATURES: A CASE STUDY OF A WAULSORTIAN MUD-MOUND WITHIN THE MISSISSIPPIAN AGE ULLIN LIMESTONE

Author

PRESTON MICHAEL PRICE, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2022

Degree Name

Master of Science

Department

Geology

First Advisor

Potter-McIntyre, Sally

Abstract

Acquisition of 2D seismic profiles often serves as a prerequisite to the acquisition of the more robust and more expensive 3D seismic volumes. However, in basins such as the Illinois Basin where production is operated by small scale, often family-owned operators, 2D seismic data is relied upon as the primary source of an exploration program. This thesis is a case study of two 2D seismic profiles that were acquired in the Illinois Basin over an inferred carbonate mud-mound. In an effort to enhance the geologic interpretation of these commonly hydrocarbon-rich features, this thesis focuses on producing effective processing and interpretation workflows utilizing 2D seismic reflection data.A detailed processing workflow utilizing a standard processing sequence as well as advanced processing techniques designed to enhance the signal-to-noise ratio, vertical resolution, reflection sharpness, and reflection continuity of the 2D seismic data is conducted to prepare the data for interpretation. Interpretation techniques included a seismic-to-well tie where a good match was generated using an extracted wavelet from the two seismic profiles and the bulk density / sonic curves from an offset well. Seismic signal, complex trace, and stratigraphic seismic attributes were also computed using Schlumberger’s Petrel Seismic Interpretation package. The computation of seismic attributes on two seismic reflection profiles to reveal the subtle, inferred mud-mound appears useful in terms of a qualitative interpretation. Mound like structures frequently contain chaotic reflections, lateral and vertical variations in lithology, and draping of overlying strata. The following attributes computed on both seismic reflection profiles are determined to have value in terms of qualitative interpretation applications: the first derivative of amplitude, the second derivative of amplitude, reflection intensity, instantaneous phase, cosine of instantaneous phase, dominant frequency, and sweetness. The RMS amplitude, apparent polarity, instantaneous bandwidth, instantaneous frequency, and envelope (reflection strength) all have little qualitative value and/or produce the relatively same results as the aforementioned useful attributes.