Category: Monthly Articles

Single Phase Labeling in Compositional Simulators

Author: Bilal Younus The term “single phase labeling” means to determine whether the given total composition zi (in a specific grid cell in the model) exists as single-phase “oil” or single-phase “gas” when the grid cell pressure is higher than the saturation pressure ps = f(zi,T), where T is the temperature in the model. A […]

Condensate Blockage – a short introduction to gas condensate well modeling

Author: Erlend Torheim It is important to understand and model the reduction in well deliverability due to condensate blockage in gas condensate wells. Failing to do so can lead to inappropriate design of (a) well completion, (b) number of wells required for development, and (c) compression requirements – all having a significant bottom-line impact on […]

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What is an Equation of State?

Author: Markus Hays Nielsen Most petroleum engineers understand that engineering calculations require the properties of fluids. “Fluid” is a term used to describe gases and liquids. An equation of state (EOS) is nothing more than a fluid model. Specifically, an EOS is a fluid model that takes a molar composition (z) and predicts the phase […]

Gas EOR Processes in Tight Unconventionals

Author: Stian Mydland *This is a short-version of SPE-200396-MS to be presented at SPE Increased Oil Recovery Conference 2020, Tulsa, OK, USA. Gas-Based EOR in Tight Unconventionals Gas-based EOR is currently being pilot-tested extensively in liquid-rich North-American tight unconventionals with the majority of projects using the Huff-n-Puff (HnP) method. This method differs from conventional displacement […]

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CGR Normalization – Convert Rates to a Common Surface Process

Author: Mathias Lia Carlsen * This is a short-version of SPE-199982-MS that will be presented on the SPE Canada Unconventional Resources Conference 18 March 2020 in Calgary, Canada. The manuscript can be found attached to this blog post. CGR Normalization – What is it?Black oil tables are generated assuming a fixed surface process, but in […]

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Separator optimization

Why is it important? Why do we want to maximize oil production in our processing plants? Do we get the same value whether we sell our produced hydrocarbons as part of a liquid phase or a gas phase? The short answer is no! For any given component, a mole of that component sold as part […]

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LBC Viscosity Correlation for Gas Condensate Reservoirs

Author: Sissel Martinsen The Lohrenz-Bray-Clark (LBC) correlation is the compositional viscosity correlation most used in the upstream petroleum industry. It is a relatively simple model, consistent for both gas and oil phases (also near critical conditions). With proper application of the LBC model involving (a) careful selection of component critical volumes for C7+ fractions and […]

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Gridding in Reservoir Simulation

Author: Ilina Yusra One of the key questions that reservoir engineers come across in their work is how to determine the minimum number of grid blocks required in a reservoir model. Whether it is a full-field model or a simpler model, determining the number of grid blocks needed is not necessarily trivial, and failing in […]

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Global Component Lumping for EOS Calculations

Author: Ahmad Alavian Did you develop a detailed equation of state (EOS) model and you do not know how to lump the components? Here is how we do it! The EOS model must provide an accurate prediction of phase and volumetric behavior of relevant mixtures flowing through a given system being modeled. Properties of density, […]

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Estimating In-Situ Reservoir Fluid Compositions

Author: Markus Hays Nielsen Having a good estimate for the in-situ fluid composition is crucial for modeling and forecasting surface gas and oil rate (GOR) behavior, resulting in enhanced reserves estimation. Moreover, if we have in-situ compositions for all wells, it is possible to generate a compositional map which can be used for optimizing the […]

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