This paper focuses on the geophysical challenges encountered during reservoir characterization and quantitative interpretation phases, particularly with regard to porosity estimation. Porosity prediction becomes challenging in low-porosity or tight sand reservoirs as the propagating seismic waves become less sensitive to changes in porosity. Consequently, a novel approach is followed to predict reservoir porosity.
Objectives
This study presents the following three distinct workflows implemented as part of this project:
- Use of regional well data to generate a prognosis for the target reservoir, which subsequently is employed to project hypothetical well tops in wells that do not penetrate the target reservoir.
- Application of local corrections to seismic interpretation that removes velocity-pullup structures caused by the overlying channel system, thereby enhancing the accuracy of the interpretation.
- Implementation of post-stack inversion for porosity prediction, accompanied by a range of quality-control (QC) measures to ensure the reliability and validity of the results.
To maintain confidentiality, the target reservoir will be referred to as Formation A, while the overlying formation will be designated as Formation B.
Methodology
Data Preparation. The seismic data used in this study consists of a reprocessed prestack time-migrated 3D volume. Before conducting seismic interpretation, a comprehensive data collection and QC process was undertaken, encompassing all relevant data, including well coordinates, well logs, check shots, and well tops.
