Pitfalls of 3D Saturation Modelling in the Middle East
- Daniel J. O'Meara (Geo2Flow)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Characterisation and Simulation Conference and Exhibition, 17-19 September, Abu Dhabi, UAE
- Publication Date
- Document Type
- Conference Paper
- 2019. Society of Petroleum Engineers
- saturation-height modelling, permeability, transition zone, saturation modelling, reservoir compartmentalization
- 2 in the last 30 days
- 133 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 28.00|
This paper shows how greater scientific rigor in discussions of modelling 3D saturations in the Middle East can lead to better understanding of the reservoirs. It demonstrates with examples how vocabulary limits ability to solve problems related to saturations, compartmentalization, and permeability. It raises the bar on technical discussions of saturation.
"Saturation-height modelling", "transition zones", and "Thomeer hyperbolas" are examples of terms that repeatedly confuse discussions of modelling 3D saturations in the Middle East. Vocabulary exposes a lack of scientific rigor, impedes progress, and leads to notable failures. Saturation is not merely a function of height. At the very least, it also depends on porosity, permeability, fluid densities, interfacial tension, and contact angle. Limiting it to height requires adding in all of these other functionalities as afterthoughts rather than incorporating them naturally through dimensional analysis. Most glaringly, it obscures the very useful role that saturations have in constraining permeability modelling and identifying reservoir compartments.
"Transition zones" focus on saturation and take emphasis away from relative permeability and fractional flow. Bimodal pore systems (abundant in the Middle East) can have such low relative permeability to water at high saturations that even 70% water saturation can produce dry oil. In such cases, talk of a transition zone is counterproductive as it implies high water production.
"Thomeer hyperbolas" reveal biases in how to fit capillary pressure curves. Force-fitting all data with a single model is inadequate. It takes emphasis away from understanding pore systems of rocks in favor of promoting a single-minded view. These examples and their implications are discussed in detail.
The existing literature is replete with incomplete explanations and misunderstandings that lead to notable failures in modelling Middle Eastern fields. Understandings predicated on simplified descriptions of homogeneous reservoirs are no longer sustainable. A more scientifically rigorous methodology is presented.
|File Size||1 MB||Number of Pages||28|
Adams, S.J. 2016. Saturation-Height Modelling for Reservoir Description: Including Capillary Pressure Interpretation. Auckland: The Petrophysicist Limited (www.petrophysicist.com).
Amaefule, Jude O., Mehmet Altunbay, Djebbar Tiab, David G. Kersey, and Dare K. Keelan. 1993. "Enhanced Reservoir Description: Using Core and Log Data to Identify Hydraulic (Flow) Units and Predict Permeability in Uncored Intervals/Wells." 68th Annual Technical Conference and Exhibition of the Society of Petroleum Engineers. Houston, Texas.
Clerke, E. A., H. W. Mueller, E. C. Phillips, R.Y. Eyvazzadeh, D.H. Jones, R. Ramamoorthy, and A. Srivastava. 2008. "Application of Thomeer Hyperbolas to decode the pore systems, facies and reservoir properties of the Upper Jurassic Arab D Limestone, Ghawar field, Saudi Arabia: A ’Rosetta Stone’ approach." GeoArabia 13 (4).
Spearing, M., M.K. Abdou, G.A. Azagbaesuweli, and M.Z. Kalam. 2014. "ransition Zone Behaviour: The Measurement of Bounding and Scanning Relative Permeability and Capillary Pressure Curves at Reservoir Conditions for a Giant Carbonate Reservoir." Abu Dhabi International Petroleum Exhibition and Conference. Abu Dhabi.
Yarin, L. P. 2012. The Pi-Theorem: Applications to Fluid Mechanics and Heat and Mass Transfer. Berlin: Springer-Verlag. doi:https://doi.org/10.1007/978-3-642-19565-5.