Proxy-Enabled Stochastic Interpretation of Downhole Fluid Sampling Under Immiscible Flow Conditions
- Morten Kristensen (Schlumberger) | Nikita Chugunov (Schlumberger) | Koksal Cig (Schlumberger) | Richard Jackson
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- Publication Date
- October 2018
- Document Type
- Journal Paper
- 633 - 648
- 2018. Society of Petrophysicists & Well Log Analysts
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- 142 since 2007
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The increasing complexity of downhole fluid sampling and the need for optimizing the sampling process call for a model-based approach in planning and interpretation applications. Efficient planning of fluid sampling requires quantitative evaluation of sampling hardware performance over a wide range of deployment conditions. For real-time contamination monitoring, recent work demonstrates that a model-based approach improves contamination estimates, especially in difficult sampling environments and for complex tool geometries (e.g., focused probes). Finally, both real-time and post-job interpretation of formation properties often require a model-based approach, in which parameters of a reservoir model are inverted using downhole fluid analysis (DFA) measurements.
The objective of this study is to develop a comprehensive set of forward models of filtrate contamination cleanup, including methods for speeding up model evaluation to enable applications in real-time inversion and uncertainty quantification.
Building on previous work in this area, we present numerical forward models for immiscible (e.g., oil sampling in water-based mud) filtrate cleanup. The models cover both conventional and focused sampling tools, and account for complex tool operating modes. Exploiting cloud-based simulation, we demonstrate how accurate proxy models can be constructed from a large number of precomputed numerical simulations. The resulting proxy models enable rapid interpretation workflows. An example of such a workflow is presented for relative permeability inversion from wireline formation tester measurements of water cut and pressure. This recently developed methodology complements laboratory measurements of relative permeability on core samples. The time required for inversion workflow execution is greatly reduced by using fast proxy models instead of full numerical simulations.
|File Size||13 MB||Number of Pages||16|