Analysis of time-lapse logs to determine shale-related R factor
- Alejandro Jaramillo (Heriot-Watt University) | Maria-Daphne Mangriotis (Heriot-Watt University) | Colin MacBeth (Heriot-Watt University)
- Document ID
- Society of Exploration Geophysicists
- 2018 SEG International Exposition and Annual Meeting, 14-19 October, Anaheim, California, USA
- Publication Date
- Document Type
- Conference Paper
- 2018. Society of Exploration Geophysicists
- Log analysis, Shale, 4D, Geomechanics
- 0 in the last 30 days
- 23 since 2007
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Time-lapse changes in the overburden can be related to pore pressure variations in the underlying reservoir. The geomechanical changes observed are independent of fluid flow given the impermeable nature of the caprock, however, such deformation has the potential of causing a significant impact on the 4D signal. A physical model widely used to couple geomechanics and time-lapse seismic signatures, relates the fractional change in velocity and the vertical strain of reservoir and surrounding rocks via a constant factor R. This study presents improvements in understanding and predictability of the overburden R factors for future seismic interpretation. Here, we compare two different methods to investigate the complexity of the R factors using the well log data of two Jurassic shales from Central North Sea. A time-lapse analysis on repeated well logs is carried out to reveal the velocity response to porosity and pressure change that results into dilation in the overburden. The results are compared to estimates from a theoretical model that describes the unloading process in shales.
Presentation Date: Wednesday, October 17, 2018
Start Time: 1:50:00 PM
Location: Poster Station 17
Presentation Type: Poster
|File Size||794 KB||Number of Pages||5|
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