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expensive computation, such as a flow simulation, using the streamline sensitivities,
calculated per geomodel grid block and per production well.
Generate model realizations
Generate model realizations
Calculate exact likelihood
Calculate exact likelihood
Generate new proposal
Generate new proposal
Calculate approximate
likelihood with sensitivities
Calculate approximate
likelihood with sensitivities
Proposal
accepted?
Proposal
accepted?
no
no
yes
yes
Forward simulation
(response & sensitivities)
Forward simulation
(response & sensitivities)
Calculate exact likelihood
Calculate exact likelihood
no
no
Proposal
accepted?
Proposal
accepted?
yes
yes
Promote proposal
Promote proposal
no
no
Convergence
achieved?
Convergence
achieved?
yes
yes
Collect proposal
Collect proposal
Fig. 11. Flowchart of the streamline-based, two-step MCMC algorithm as implemented in
AHM workflow (Maučec et al. 2007; Maučec et al. 2011a; Maučec et al. 2011b).
The streamline-based, two-step MCMC history-matching workflow represents an integral
component of the new prototype technology for Quantitative Uncertainty Management
(QuantUM) (Maučec and Cullick, 2011) that seamlessly integrates the next-generation Earth
Modeling API, VIP ® and/or Nexus ® reservoir simulators and the code DESTINY (MCERI
Research Group, 2008), used as a generator of streamline-based sensitivities. The workflow
was validated by reconciling the dynamic well production data with a completely synthetic
model of the Brugge field (Maučec et al. 2011a). The stratigraphy of Brugge field combines
four different depositional environments and one internal fault with a modest throw. The
dimensions of the field are roughly 10x3 km. In the original (referred to as the “truth-case”)
high-resolution model of 20 million grid cells essential reservoir properties, including
sedimentary facies, porosity and permeability, Net-To-Gross (NTG), and water saturation
were created for the purpose of generating well log curves in the 30 wells (Peters et al. 2009).
Multiple realizations of high-resolution (211x76x56, i.e., approximately 900k grid cells) of
facies-constrained permeability model (referred to as “initial”) were generated using the
information on the structural model, well properties and depositional environments based
on the “truth-case” model.
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