Dear DPS member
Our next meeting will be on September 5th with the topic on
Saturation Height Modeling.
We have two speakers sharing their expertise on the topic:
Jan Lutgert (retired EBN) and lulian Hulea (Shell)
Talk 1
Title: From Plug Measurements to Dynamic Simulations: Upscaling Effects on Modeled Hydrocarbon Volumes
Speaker: Iulian Hulea, Shell
Abstract:
Building reliable subsurface models requires detailed knowledge of both the rock and fluids involved. One critical petrophysical property determining the viability of a development is the hydrocarbon saturation. In 3D geological models, the saturation is populated via saturation height models and free fluid levels. In populating a 3D model with meaningful properties, measurements at various scales are integrated. Core measurements acquired at resolution far superior to that used in the 3D models require a change of scale- upscaling step. The process of accurately predicting water saturation in the upscaled model is not trivial. Here we follow this process by employing a saturation height model (SHM) at different scales in relationship to various permeability realizations. Multiple choices available as inputs into the SHM in various ranges of sensitivity with respect to the free water level position as well as different rock quality are looked at. Various degrees of heterogeneity are studied by using synthetic data, the saturation prediction accuracy based on upscaled input rock properties (like arithmetic/geometric and harmonic upscaled permeability).
For homogeneous rocks a workflow is detailed with the purpose of detecting the upscaling limits highlighting the possible errors that might appear in the upscaling process. A counterintuitive result is that in the transition zone (the focus of this work) permeable rocks are more prone to errors than the less permeable ones.
We also conclude that no alteration of the SHM is necessary in the upscaling process. Given the fact that rock quality enters the SHM and that permeability upscaling follows a route that ultimately attempts to honor well performance, a natural question is what the relevance of such a permeability model as input for the SHM is. Our results highlight the best choices for an upscaled SHM input (upscaled) permeability- not necessarily the upscaled permeability used in history matching. Smallest errors are shown to be resulting from using geometrical or 1/3 power law upscaled permeability.
Speaker Bio:
Iulian N. Hulea is a Senior Petrophysicist working for Shell Global Solutions BV, Projects and Technology in the Netherlands, currently working on global reservoir studies. Before this position he held a Carbonate (field development planning) Petrophysicist and a Research Petrophysicist position (both in Shell). He holds a Master (Bucharest University, Romania) and a PhD (Leiden University, The Netherlands) in experimental physics. After completing the PhD (2004) he held a postdoctoral position at the Delft University of Technology, Kavli Institute for Nanoscience, also in the Netherlands.
Talk 2
Title: A Comparison of Saturation Height Models – Some Thoughts, Observations and Tests. Some Doubts Too …
Speaker: Jan Lutgert, Part Time Lecturer in Petrophysics at the University of Amsterdam (Netherlands) and Anton de Korn University (Suriname)
Abstract:
Saturation Height Modelling (SHM) is an important reservoir characterization method for estimating the water saturation, which is a fraction of the total (3D) reservoir fluid distribution in a porous medium. SHM can be applied to both core data and log-derived information. This presentation will focus on clastic reservoirs and measurements in the logging domain.
Industry-standard software provides a large number of methods for SHM mostly derived from empirical equations trying to match observations using a goodness-of-fit criterion. Background information on which method to use based on geological relevance usually is scarce or completely absent. This presentation addresses a number of exactly such issues and highlights the importance of properly understanding textural controls on porosity and water saturation when selecting an appropriate SHM method. Four frequently used SHM equations will be examined (Entry-height, Lambda, Sigmoidal and Fractal BVW) and results will be discussed, mostly in the context of textural controls. In the process the merits and deficiencies of these methods will be highlighted, which may provide you with some pointers about their practical applicability. Time willing a brief demonstration of their implementation in Excel will be provided.
Speaker Bio:
Jan Lutgert studied geology at Utrecht State University. He worked for TNO as a geoscientist from 1987 until 2010. Assignments involved geological and petrophysical R&D studies, advisory work for the MEA and international consultancy. From 2010 to 2018 he worked for Energie Beheer Nederland (EBN), predominantly focusing on and hydrocarbon exploration, the de-risking of tight reservoirs and reservoir unitizations. He retired in 2018 and currently he enjoys parttime lecturing petrophysics at the University of Amsterdam and the Anton de Kom University in Suriname.
We are looking forward to seeing you there,
DPS board