# A case study of reservoir characterization and modeling for tidal-dominated estuary reservoir in Ecuador

## TL;DR

This study improves reservoir modeling in a tidal-dominated estuary in Ecuador by combining well and seismic data to better understand sediment patterns.

## Contribution

A new reservoir model for tidal-dominated estuaries using integrated electrofacies and seismic facies analysis.

## Key findings

- Four electrofacies were identified to characterize lithology combinations in the estuary setting.
- Seismic facies analysis revealed spatial sedimentary patterns in the LU layer.
- Bottom-water reservoirs were reinterpreted as a combination of upper and lower reservoir types.

## Abstract

The Oriente Basin, as part of the retro-arc foreland basin system, develops tidal-dominated estuary, where the LU layer exhibits complex sedimentary characteristics in lateral that brings great uncertainty to reservoir characterization using only wells. As a result, it is essential to investigate the sedimentary characteristics of the tidal-dominated estuary by incorporating seismic data. First, four electrofacies are established to characterize the logging response of various lithology combinations in an estuary setting. The seismic facies are then studied by establishing the relationship between seismic waveforms and logging response. Finally, a reservoir model of the LU layer is built by quantitatively characterizing the spatial distribution of sedimentary facies based on the electrofacies and seismic facies. Bottom-water reservoirs are reinterpreted as a combination of the upper edge-water reservoir and the lower bottom-water reservoir based on the characterization results, which are verified by the new drilling wells.