Category: Monthly Articles

Lost volumes in MPSR fluid sampling bottles, and the impact on fluid properties

This article was written in collaboration with Gerardo Seri from Wintershall DEA. The decision to sample downhole fluids using single phase (SPMC) bottles vs multiphase (MPSR) bottles is often based on the potential problem of “lost volumes in the MPSR bottles, that may introduce an error into the GOR and saturation pressure measurements”. What many […]

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How to quality check a developed EOS?

Author: Sissel Martinsen Whether you receive an EOS or you yourself have developed an EOS, it is always a good idea to quality check the EOS. You want to make sure that the EOS calculates physically consistent properties and thermodynamic valid solutions, and that it does not give any non-physical three-phase solutions that will slow […]

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Decreasing CGRs above Saturation Pressure in “Shales”

Author: Mathias Lia Carlsen * This is a snippet from SPE-199982-MS that was presented on the SPE Canada Unconventional Resources Conference held virtually in 2020. The full manuscript can be found attached to this blog post. Decreasing CGRs are observed while flowing bottomhole pressures are above the (apparent) saturation pressure in several unconventional basins throughout […]

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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 […]

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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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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 […]

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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