A Fast and Accurate Upscaling of Transmissivities for Field Scale Reservoir Simulation

Guérillot, Dominique; Bruyelle, Jérémie

doi:10.3997/2214-4609.20141863

“…No-flow boundary conditions are considered hereafter. Other very interesting methods based on transmissibility upscaling exist, but they are not used in this paper [30].…”

Section: Upscaling Techniquesmentioning

confidence: 99%

Selecting an Appropriate Upscaled Reservoir Model Based on Connectivity Analysis

Preux

¹

,

Ravalec

²

,

Enchéry

³

2016

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

-Reservoir engineers aim to build reservoir models to investigate fluid flows within hydrocarbon reservoirs. These models consist of three-dimensional grids populated by petrophysical properties. In this paper, we focus on permeability that is known to significantly influence fluid flow. Reservoir models usually encompass a very large number of fine grid blocks to better represent heterogeneities. However, performing fluid flow simulations for such fine models is extensively CPU-time consuming. A common practice consists in converting the fine models into coarse models with less grid blocks: this is the upscaling process. Many upscaling methods have been proposed in the literature that all lead to distinct coarse models. The problem is how to choose the appropriate upscaling method. Various criteria have been established to evaluate the information loss due to upscaling, but none of them investigate connectivity. In this paper, we propose to first perform a connectivity analysis for the fine and candidate coarse models. This makes it possible to identify shortest paths connecting wells. Then, we introduce two indicators to quantify the length and trajectory mismatch between the paths for the fine and the coarse models. The upscaling technique to be recommended is the one that provides the coarse model for which the shortest paths are the closest to the shortest paths determined for the fine model, both in terms of length and trajectory. Last, the potential of this methodology is investigated from two test cases. We show that the two indicators help select suitable upscaling techniques as long as gravity is not a prominent factor that drives fluid flows.Résumé -Sélection de méthodes d'upscaling par analyse de connectivité -Les ingénieurs de réservoir construisent des modèles de réservoir pour comprendre les écoulements de fluides dans les réservoirs d'hydrocarbures. Ces modèles se composent de grilles en trois dimensions peuplées par des propriétés pétrophysiques. Dans cet article, nous nous concentrons sur la perméabilité qui est connue pour influencer de manière significative l'écoulement du fluide. Les modèles de réservoir ont généralement un très grand nombre de mailles fines afin de mieux représenter les hétérogénéités. Cependant, les simulations d'écoulement sur ces modèles fins sont très coûteuses en temps CPU. Une pratique courante consiste à convertir les modèles fins en modèles grossiers avec moins de mailles : c'est le processus de mise à l'échelle. De nombreuses méthodes de changement d'échelle ont été proposées dans la littérature qui mènent à des modèles grossiers différents. Le problème est de savoir comment choisir la méthode de mise à l'échelle appropriée. Différents critères ont été établis pour évaluer la perte d'information due à l'upscaling, mais aucun d'entre eux ne s'intéresse à la connectivité. Dans cet article, nous nous proposons d'abord d'effectuer une analyse de connectivité pour les modèles fins et grossiers. Cela nous permet d'identifier les chemins les plus courts reliant l...

show abstract

“…Figure6.11 Typical shale-adsorbed gas content, showing differences between lean, normal and rich shale in relation to adsorbed gas(Guérillot and Bruyelle, 2014).…”

mentioning

confidence: 99%

Shale Oil/Gas: A New Opportunity for New Zealand?

Filho¹

0

View full text Add to dashboard Cite

<p>Within New Zealand the East Coast Basin encompasses the primary shale oil and gás (unconventional) play areas in which both the Waipawa and Whangai formations are widespread. These formations are oil and gas prone and prevalent throughout a large area of the East Coast Basin. To characterise these two formations and evaluate their shale oil and gas potential, existing analytical results were supplemented by a set of new sample analyses of organic and inorganic geochemistry, and rock properties. Thus, some 242 samples from the Whangai Formation have organic geochemical analyses and 40 have inorganic geochemical analyses; for the Waipawa Formation there are 149 organic and 9 inorganic geochemical analyses. In addition, downhole logs from three exploration wells have been used to calculate the brittleness index of the Whangai Formation. All these data have been grouped by structural block and used to determine where the sweet spots are in each formation. Both basic and more robust statistical analysis (machine-learning) is applied to identify the best prospective area. The Rakauroa Member (Whangai Formation) and the Waipawa Formation have the best rock characteristics as unconventional reservoirs, based on quantity and quality. Maturation appears to be an issue for these formations, although there are some localised areas where the Whangai Formation has better maturity. The brittleness index is calculated only for the Rakauroa Member, given the lack of data available for other members of the Whangai Formation and the Waipawa Formation, and yielded promising results. The Motu block appears to be the best area in which to explore for unconventional oil and gas. The prospective resource volumes for the best case scenario for the Whangai (Rakauroa Member) and Waipawa formations combined in the Motu Block are 17% higher (713MMbbl) than the 2P (proved + probable) reserves of New Zealand for oil and condensate (588MMbbl) and 26% (2.1TCF) of the 2P (proved + probable) reserves of natural gas (7.8 TCF). Economic analysis shows feasibility to explore these unconventional reservoirs for both shale oil or shale gas with an oil price of US$60 for both methodologies tested. However, the methodology applied using standard shale oil and gas assessments shows feasibility only for shale oil. Shale gas would not be economic, unless a higher oil prices, lower costs or a technology was developed to improve the recovery factor of these reservoirs. These results indicate a minimum economic field size of 4.5 km² for this area.</p>

show abstract

“…Figure6.11 Typical shale-adsorbed gas content, showing differences between lean, normal and rich shale in relation to adsorbed gas(Guérillot and Bruyelle, 2014).…”

mentioning

confidence: 99%

Shale Oil/Gas: A New Opportunity for New Zealand?

Filho¹

0

View full text Add to dashboard Cite

<p>Within New Zealand the East Coast Basin encompasses the primary shale oil and gás (unconventional) play areas in which both the Waipawa and Whangai formations are widespread. These formations are oil and gas prone and prevalent throughout a large area of the East Coast Basin. To characterise these two formations and evaluate their shale oil and gas potential, existing analytical results were supplemented by a set of new sample analyses of organic and inorganic geochemistry, and rock properties. Thus, some 242 samples from the Whangai Formation have organic geochemical analyses and 40 have inorganic geochemical analyses; for the Waipawa Formation there are 149 organic and 9 inorganic geochemical analyses. In addition, downhole logs from three exploration wells have been used to calculate the brittleness index of the Whangai Formation. All these data have been grouped by structural block and used to determine where the sweet spots are in each formation. Both basic and more robust statistical analysis (machine-learning) is applied to identify the best prospective area. The Rakauroa Member (Whangai Formation) and the Waipawa Formation have the best rock characteristics as unconventional reservoirs, based on quantity and quality. Maturation appears to be an issue for these formations, although there are some localised areas where the Whangai Formation has better maturity. The brittleness index is calculated only for the Rakauroa Member, given the lack of data available for other members of the Whangai Formation and the Waipawa Formation, and yielded promising results. The Motu block appears to be the best area in which to explore for unconventional oil and gas. The prospective resource volumes for the best case scenario for the Whangai (Rakauroa Member) and Waipawa formations combined in the Motu Block are 17% higher (713MMbbl) than the 2P (proved + probable) reserves of New Zealand for oil and condensate (588MMbbl) and 26% (2.1TCF) of the 2P (proved + probable) reserves of natural gas (7.8 TCF). Economic analysis shows feasibility to explore these unconventional reservoirs for both shale oil or shale gas with an oil price of US$60 for both methodologies tested. However, the methodology applied using standard shale oil and gas assessments shows feasibility only for shale oil. Shale gas would not be economic, unless a higher oil prices, lower costs or a technology was developed to improve the recovery factor of these reservoirs. These results indicate a minimum economic field size of 4.5 km² for this area.</p>

show abstract

A Fast and Accurate Upscaling of Transmissivities for Field Scale Reservoir Simulation

Cited by 4 publications

References 5 publications

Selecting an Appropriate Upscaled Reservoir Model Based on Connectivity Analysis

Selecting an Appropriate Upscaled Reservoir Model Based on Connectivity Analysis

Shale Oil/Gas: A New Opportunity for New Zealand?

Shale Oil/Gas: A New Opportunity for New Zealand?

Contact Info

Product

Resources

About