Frac-to-Frac Gas EOR—The Future of Unconventional Gas EOR?

Author: Ilina Yusra, Stian Mydland & Mathias Lia Carlsen After EOG Resources reported uplift results from their Eagle Ford Huff-n-Puff (HnP) activities, gas injection has gained significant traction in tight unconventionals. The success in the Eagle Ford has led companies to pursue gas HnP in other basins including Permian, SCOOP/STACK, Bakken and Montney. The HnP […]

Using Contaminated PVT samples

Authors: Ahmad Alavian & Curtis Hays Whitson A contaminated sample is collected in an openhole formation testing tool (OFT) like MDT or RCI. The well has been drilled with oil based mud (OBM), where some percentage of the collected sample being OBM and the remainder being in-situ reservoir fluid. Finding a good estimate of the […]

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EOS Component Lumping Optimization

Author: Arnaud Hoffmann To reduce CPU time in compositional petroleum simulation models (e.g. compositional reservoir simulations), a minimum number of components should be used in the equation of state (EOS) to describe the fluid phase and volumetric behavior. A ″detailed” EOS model often contains from 20 to 40 components, with the first 10 components representing […]

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Answers to Questions at SPE IOR 2020

SPE-200396: Gas EOR Processes in Tight Unconventionals Q1) Why did you select the “minimum dimension” instead of “surface to volume ratio” to explain the dependence of the oil-recovery results on sample size. Hassan Dehghanpour (University of Alberta) We believe that the minimum dimension is easier to understand and relate to than the surface-to-volume ratio (S/V). […]

Black-Oil and Compositional Reservoir Simulation of Gas-Based EOR in Tight Unconventionals

Author: Stian Mydland *This is a short-version of URTEC-2020-2765-MS presented at Unconventional Resources Technology Conference (URTeC) 2020. Paper can be downloaded in the end of this article. Reservoir simulation requires a fluid model to describe the volumetric behavior of gas and oil. When initiating a reservoir simulation study, we have to choose whether to use […]

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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 […]

Collaborating with ResFrac on Advanced Black Oil PVT

Author: Mathias Carlsen Most reservoir engineering analysis in the petroleum industry is performed utilizing black oil tables. In general, there are three different types of black oil tables: (1) traditional, (2) modified and (3) extrapolated. These are visually presented in the figure above and becomes more “sophisticated” as we move from left to right. Traditional […]

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 […]