Applying a Consistent Evaluation Approach to Thin-Bedded Sands in a Gulf of Mexico Deepwater Field
- Sarita Salunke (BP America Inc.) | Jeffry Hamman (BP America Inc.)
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- Publication Date
- October 2015
- Document Type
- Journal Paper
- 511 - 520
- 2015. Society of Petrophysicists & Well Log Analysts
- 0 in the last 30 days
- 196 since 2007
- Show more detail
Formation evaluation in thinly bedded sands has always been a challenge especially as individual sand beds thin below the resolution of logging tool measurements. Evaluation of these reservoirs is often further complicated since the various log measurements have differing vertical resolutions and depths of investigations and the wells normally have somewhat disparate log datasets.
In this study of a field located in the Gulf of Mexico (GoM) deep water we demonstrate how a consistent and crossverified approach was taken to evaluate thinly bedded sands, which resulted in increasing interpretation confidence and a more realistic net pay when compared with prior techniques that use conventional log interpretations.
The field used in this study has a total of five wells, including one well with whole core, three wells with nuclear magnetic resonance (NMR) logs, including the cored well, and two wells with standard log suites. The methodology applied begins with creating a continuous sand-count curve from the visual evaluation of whole-core photographs. This sand-count curve is then compared with the net-to-gross (NTG) curve obtained from a Thomas- Stieber analysis and then crossverified via NTG obtained from a NMR log. The calibration from the three wells with whole core or NMR was applied to the Thomas-Stieber analysis performed on the two wells with standard suites of logs. Whole-core porosities and water saturations are then used to constrain the log-derived porosity and water saturation values. Finally saturation-height modeling has been performed using porous-plate capillary pressure data and compared to log-derived water saturations.
|File Size||25 MB||Number of Pages||10|