Application of instantaneous-frequency attribute and gamma-ray wireline logs in the delineation of lithology in Serbin field, Southeast Texas: A case study

Abstract

Although Serbin field in Southeast Texas was discovered in 1987, lithologic and petrophysical properties in the southeastern part of the field have not been fully evaluated. We have generated instantaneous frequency from 3D seismic data and predicted gamma-ray response volume from seismic attributes. By extracting maps of the instantaneous frequency and gamma-ray response along interpreted horizons, and crossplotting the instantaneous frequency against gamma-ray logs and integrating core data, we generated lithology maps to identify shale-prone zones that stratigraphically trapped hydrocarbons in the southeastern part of the field. We determine that Serbin field is separated into two areas: (1) a high-frequency, high-gamma-ray, and high-acoustic-impedance area in the northwest and (2) a low-frequency, low-gamma-ray, and low-acoustic-impedance area located in the southeast. By developing a lithologic map and relating it to the corresponding instantaneous-frequency map and log data, we also find that the southeastern part of the field can be divided into three zones: (1) zone 1, composed of approximately 0.7–2.7 m (approximately 2–8 ft) thick sandstone-rich beds of moderate frequency (25–30 Hz); (2) zone 2, composed of high-frequency (33–60 Hz) shale-rich zones that serve as stratigraphic-trapping-mechanisms; and (3) zone 3, composed of approximately 1.7–4 m (approximately 5–13 ft) thick sandstone-rich beds of low frequency (0–18 Hz) and relatively high porosity. These methods can be applied in other areas of the field with limited well control.