The Norne Field Case - A Unique Comparative Case Study

Rwechungura, Richard Wilfred; Suwartadi, Eka; Dadashpour, Mohsen; Kleppe, Jon; Foss, Bjarne A.

doi:10.2523/127538-ms

Cited by 11 publications

(17 citation statements)

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“…Hence, the objective function is an expected value (average) of NPV from the realizations. We use a real reservoir geometry, from the Norne field case [33] as shown in Fig. 9.…”

Section: Numerical Casementioning

confidence: 99%

Nonlinear output constraints handling for production optimization of oil reservoirs

2011

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Adjoint-based gradient computations for oil reservoirs have been increasingly used in closed-loop reservoir management optimizations. Most constraints in the optimizations are for the control input, which may either be bound constraints or equality constraints. This paper addresses output constraints for both state and control variables. We propose to use a (interior) barrier function approach, where the output constraints are added as a barrier term to the objective function. As we assume there always exist feasible initial control inputs, the method maintains the feasibility of the constraints. Three case examples are presented. The results show that the proposed method is able to preserve the computational efficiency of the adjoint methods.

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“…Hence, the objective function is an expected value (average) of NPV from the realizations. We use a real reservoir geometry, from the Norne field case [33] as shown in Fig. 9.…”

Section: Numerical Casementioning

confidence: 99%

Nonlinear output constraints handling for production optimization of oil reservoirs

2011

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“…Example 4, Norne field case Recently, Rwechungura et al (2010) published data from the E-segment of Norne Field on the Norwegian continental shelf. This is a real-field benchmark case made available to the petroleum research community as download from the Norne benchmark website.…”

Section: Example 3 2-d Reservoir Case With Heterogeneitiesmentioning

confidence: 99%

Planning and Interpretation of Offshore-Field Tracer Tests Using Accurate and Refined Tracer Simulations

et al. 2010

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Tracers are chemical compounds or radioactive isotopes used to label injection water and gas in petroleum reservoirs. In inter-well tracer tests (IWTTs), well connections and fluid patterns can be established when the tracer appears in production wells. Tracer simulation is an invaluable tool to ease the planning or interpreting results of IWTT. In this paper we introduce a novel tracer simulation methodology which is based on a decoupling from the underlying reservoir simulation. The methodology ensures accurate and very fast tracer simulation; with CPU times in the order of a few percent of ordinary reservoir simulation. The method is based on solving the tracer equations on a grid separated from the underlying reservoir simulation. The separate tracer grid can be refined, with significant improvements in the accuracy of the tracer solution, without affecting the speed of the reservoir simulation. Accurate refinement as well as localized tracer grid refinement is introduced and investigated. Local refinement is compared to global refinement, and we demonstrate that local refinement can be a valid strategy in many cases. We demonstrate the methodology on a real reservoir case, and show that predicted breakthrough times are significantly affected by the accuracy of the solution. The method improves accuracy by overcoming numerical diffusion through separate tracer-grid refinement. In our specific real case, the breakthrough time was underestimated by about one year in the solution obtained using standard methods. This was corrected using the new methodology. The large difference in simulated breakthrough time between the improved and corrected solution has important consequences for the planning and interpretation of IWTT. IntroductionTracer testing in petroleum reservoirs is a mature technology, where fluid movement is tracked by tagging injection fluids by inert chemical or radioactive compounds (for a review see Zemel, 1994). One application of tracers is the inter-well tracer test (IWTT), which is used to obtain information on well-to-well communication, heterogeneity and fluid dynamics (Dugstad, 2007). One of the appealing features of IWTT is that at the first tracer breakthrough in a producer, immediate and unambiguous information on the injector -producer communication is given. In cases with several sources of injection fluids, tracers yield unique information on the origin of fluids. During IWTT, injected fluids are labeled using unique radioactive or chemical tracer compounds, which are then subsequently used to trace the fluids as they move through the reservoir. Many compounds may a priori be candidates for tracer application. However, compounds are subject to harsh temperature and pressure conditions, biodegradation, scaling reactions, ion exchange, adsorption to the solid phase etc. Modeling of these effects would require a detailed description of the chemical and physical conditions in the reservoir, conditions that are generally not known. Rather than attempting to model such effects, it is custom...

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“…These indicate a successful data fitting for the model ensemble. (Rwechungura et al, 2010). These figures show that the gas reservoir, the Garn sand formation, is located around 2.45 s and is characterized by a relatively lower V p , density and acoustic impedance (eg.…”

Section: Case Study Using An Oilfield Data Norne Field North Seamentioning

confidence: 99%

“…The reservoir is sealed by the Melke shale formation and it consists of four sand formations from top to base: Garn, Ile, Tofte and Tilje of Lower to Middle Jurassic age. A gas reservoir is mostly situated in the Garn formation of nearshore facies, the oil reservoir is mainly located in the Ile and Tofte formations which are shallow marine deposits with channelized sandstones, and the Tilje formation is mostly sand with some clay and conglomerates (Rwechungura et al, 2010).…”

Section: Case Study Using An Oilfield Data Norne Field North Seamentioning

confidence: 99%

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Seismic inversion and uncertainty analysis using a transdimensional Markov chain Monte Carlo method

Zhu

Gibson

2016

SEG Technical Program Expanded Abstracts 2016

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We use a transdimensional inversion algorithm, reversible jump MCMC (rjMCMC), in the seismic waveform inversion of post-stack and prestack data to characterize reservoir properties such as seismic wave velocity, density as well as impedance and then estimate uncertainty. Each seismic trace is inverted independently based on a layered earth model. The model dimensionality is defined as the number of the layers multiplied with the number of model parameters per layer. The rjMCMC is able to infer the number of model parameters from data itself by allowing it to vary in the iterative inversion process, converge to proper parameterization and prevent underparameterization and overparameterization. We also use rjMCMC to enhance uncertainty estimation since it can transdimensionally sample different model spaces of different dimensionalities and can prevent a biased sampling in only one space which may have a different dimensionality than that of the true model space. An ensemble of solutions from difference spaces can statistically reduce the bias for parameter estimation and uncertainty quantification. Inversion uncertainty is comprised of property uncertainty and location uncertainty. Our study revealed that the inversion uncertainty is correlated with the discontinuity of property in such a way that 1) a smaller discontinuity will induce a lower uncertainty in property at the discontinuity but also a higher uncertainty of the location of that discontinuity and 2) a larger discontinuity will induce a higher uncertainty in property at the discontinuity but also a higher ''certainty'' of the location of that discontinuity. Therefore, there is a trade-off between the property uncertainty and the location uncertainty. To our surprise, there is a lot of hidden information in the uncertainty result that we can actually take advantage of due to this trade-off effect. On the basis of our study ii using rjMCMC, we propose to use the inversion uncertainty as a novel attribute in an optimistic way to characterize the magnitude and the location of subsurface discontinuities and reflectors. important it is to estimate the uncertainty, and I used another method for two years but it turned out that method was unsuccessful for solving my research problems because it couldn't answer the question for uncertainty assessment. This is one of the biggest mistakes that I have ever made because I wasn't aware of the importance of my advisor's words and questions. Indeed, research is not always successful and smooth and I did encounter failures, but I didn't give up.

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The Norne Field Case - A Unique Comparative Case Study

Cited by 11 publications

References 0 publications

Nonlinear output constraints handling for production optimization of oil reservoirs

Nonlinear output constraints handling for production optimization of oil reservoirs

Planning and Interpretation of Offshore-Field Tracer Tests Using Accurate and Refined Tracer Simulations

Seismic inversion and uncertainty analysis using a transdimensional Markov chain Monte Carlo method

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