Application of broadband 2D and 3D seismic reflection surveys for improved delineation of the Lake Okeechobee area Floridan Aquifer System hydrostratigraphy

Abstract

In support of the South Florida Water Management District (SFWMD) Floridan Aquifer System (FAS) and Aquifer Storage & Recovery (ASR) groundwater development & management programs, high resolution broadband seismic test data was acquired and processed in the Lake Okeechobee area. As part of the FAS and ASR development plans SFWMD identified the need for improved delineation and characterization of the FAS in terms of stratigraphic and hydro-geologic structure. High resolution 2D and 3D seismic acquisition, data processing & modeling, and integrated well log analysis, originally developed for deep oil and gas exploration, have been successfully adapted for high-definition geomorphologic and intra-stratigraphic characterization of the Floridan Aquifer System to depths in excess of 3,000 feet (bgs). In addition, the seismic survey programs were designed to evaluate the potential for identifying zones of deep karst structures that can provide hydro-geologic information concerning vertical and lateral flow of groundwater between major permeable zones within the Floridan aquifers. Based on results from the 2D and 3D seismic test surveys it is shown that the required seismic bandwidth of processed seismic data to identify complex FAS faults and fracture systems is approximately 10 Hz to 120 Hz. The required broadband seismic data is also essential for additional attributes processing to identify zones of intra-stratigraphic karst structures that can affect the long term migration and/or containment of groundwater within FAS confined aquifers. Location and seismic attributes knowledge of faults and fractures systems, augmented with detailed borehole and well log information, is critical to the future placement and installation of deep injection and groundwater production wells. In this presentation, we identify the areas of investigation and local FAS geology, summarize aspects of the seismic surveys, and present modeling and interpretation examples from the 2D and 3D data. From the SFWMD Lake Okeechobee seismic test program we present a summary review of other seismic methods and applications for future development and adaptation to similar groundwater exploration and aquifer investigation projects.