Acquisition Geometry-Related Noise Reduction for a Crooked-Line Seismic Reflection Profile in White County, Illinois

• Main Author: Smelker, Jacob
• Format: Others
• Published: OpenSIUC 2017
• Online Access: https://opensiuc.lib.siu.edu/theses/2146; https://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=3160&context=theses

The Indian Creek seismic reflection profile located in White County, Illinois is a crooked seismic line with four 90 degree bends in the line, but otherwise it is generally straight. Data acquisition geometry-related noise is present on shot records as well as final stacked records. The purpose of this thesis is to process the Indian Creek seismic data using industry standard seismic reflection processing software in various attempts to reduce the noise associated with the profile geometry. Methods applied were based on three different data acquisition binning geometries and five different line geometry acquisition scenarios selected from the complete 120 channel dataset. Binning geometries used include crooked-line, curved slalom-line and straight line processing of the data. The acquisition geometry-related scenarios used to produce final stacked records include: 1.) Elimination of very high fold cmp data 2.) Careful selection of velocity function locations 3.) Variation of the number of velocity functions 4.) Reduction of the number of channels used 5.) Use of individual sides of the split spread array Results from these processing scenarios are presented in the thesis. ii The original stacked record produced by a professional data processing company was used for quality control and comparisons to the stacked records produced for this thesis. The stacked records compared were created using the straight slalom line binning method, which produced the best results of the three binning geometries used for this thesis. The stacked records produced compared favorably with the professionally processed records, however additional process experimentation was done for this thesis. The survey profile was interpreted using a synthetic seismogram based on a sonic log and drill hole geology data from a well adjacent to the survey line. An older seismic profile located approximately one mile north of the Indian Creek profile and an associated synthetic seismogram was also used for the geological interpretation. Five major reflectors were identified on the Indian Creek reflection records, they include: the Golconda Formation, The Barlow Limestone, The New Albany Shale, the Knox Supergroup, and the Eau Claire Formation. In one area on the western part of the thesis record a subtle localized geological structure is interpreted to be a fault. It was not clearly observed on the professionally processed record, probably due to the use of too few velocity functions, resulting in a lack of resolution of the structure. One of the important conclusions of this thesis is that in areas where small and subtle structures may exist, it is necessary to use more velocity function to resolve such features.