# No assumptions needed to simulate petroleum reservoirs

June 05, 2019Hidden deep below our feet, petroleum reservoirs are made up of hydrocarbons like oil and natural gas, stored within porous rock. These systems are particularly interesting to physicists, as they clearly show how temperature gradients between different regions affect the gradients of fluid pressures and compositions. However, because these reservoirs are so hard to access, researchers can only model them using data from a few sparse points, meaning many of their properties can only be guessed at. In a new study published in

*EPJ E*, physicists from France and Vietnam, led by Guillaume Galliero at the University of Pau, have found that this guesswork actually isn't necessary. They show that if the right choices are made when constructing models, no assumptions are needed in order to calculate the impact of temperature gradients on pressure and composition gradients.

Ultimately, Galliero's team developed an equation that fully expresses the pressure gradient of petroleum reservoirs, which they then used to determine variations in hydrocarbon composition throughout the mixture. Drawing on this main equation, they were able to identify several special cases where the pressure gradient is influenced by other properties, including the residual entropy of the fluid - the point at which the permeability of the rock becomes lower than a certain threshold. When this happens, temperature gradients generate pressure gradients which are proportional to this residual entropy. This implies that the pressure gradients across small parts of the fluid are generated by the balance between their own residual entropy, and that of the fluid as a whole.

Galliero and his colleagues started from basic principles of thermodynamics, then validated their conclusions using computer simulations. Their work could prove invaluable to petroleum engineers and geoscientists exploring the intriguing thermodynamic properties of petroleum reservoirs.

-end-

**Reference**

F. Montel, H. Hoang, G. Galliero (2019), Linking up pressure, chemical potential and thermal gradients,

*Eur. Phys. J. E*42:65. DOI 10.1140/epje/i2019-11821-0

Springer

**Related Thermodynamics Articles:**

Holographic cosmological model and thermodynamics on the horizon of the universe

A holographic cosmological model with a power-law term has been proposed by a Kanazawa University researcher to study thermodynamic properties on the horizon of the Universe.

A holographic cosmological model with a power-law term has been proposed by a Kanazawa University researcher to study thermodynamic properties on the horizon of the Universe.

APS tip sheet: Ultimate strength of metals

A new model is able to accurately determine the peak strength of polycrystalline metals.

A new model is able to accurately determine the peak strength of polycrystalline metals.

How sensitive can a quantum detector be?

Measuring the energy of quantum states requires detecting energy changes so exceptionally small they are hard to pick out from background fluctuations, like using only a thermometer to try and work out if someone has blown out a candle in the room you're in.

Measuring the energy of quantum states requires detecting energy changes so exceptionally small they are hard to pick out from background fluctuations, like using only a thermometer to try and work out if someone has blown out a candle in the room you're in.

A new model of metabolism draws from thermodynamics and 'omics'

Scientists at EPFL have developed an algorithm that can model biochemical reactions from metabolism down to RNA synthesis with unprecedented accuracy.

Scientists at EPFL have developed an algorithm that can model biochemical reactions from metabolism down to RNA synthesis with unprecedented accuracy.

Samara Polytech scientists has developed a new concept of mathematical modeling

Scientists at the Samara Polytech are developing a new area of mathematical modeling of locally nonequilibrium transfer processes and methods for their study.

Scientists at the Samara Polytech are developing a new area of mathematical modeling of locally nonequilibrium transfer processes and methods for their study.

Theorem explains why quantities such as heat and power can fluctuate in microscopic system

Brazilian researchers participate in theoretical study that could have practical applications in nanoscale machine optimization.

Brazilian researchers participate in theoretical study that could have practical applications in nanoscale machine optimization.

Scientists recalculate the optimum binding energy for heterogeneous catalysis

In a discovery that could lead to the development of novel catalysts that do not rely on expensive rare metals, scientists from the RIKEN Center for Sustainable Resource Science have shown that the optimal binding energy can deviate from traditional calculations, which are based on equilibrium thermodynamics, at high reaction rates.

In a discovery that could lead to the development of novel catalysts that do not rely on expensive rare metals, scientists from the RIKEN Center for Sustainable Resource Science have shown that the optimal binding energy can deviate from traditional calculations, which are based on equilibrium thermodynamics, at high reaction rates.

Team discovers polymorph selection during crystal growth can be thermodynamically driven

Lehigh University's Jeetain Mittal and his collaborators provide solid calculation to demonstrate the structural transformation in colloidal crystallization can be entirely thermodynamic, in contrast to the kinetic argument, from both theoretical and computational perspectives.

Lehigh University's Jeetain Mittal and his collaborators provide solid calculation to demonstrate the structural transformation in colloidal crystallization can be entirely thermodynamic, in contrast to the kinetic argument, from both theoretical and computational perspectives.

When kinetics and thermodynamics should play together

Research from the McKelvey School of Engineering suggests that without considering certain factors, researchers may overestimate how fast calcium carbonate forms in saline environments.

Research from the McKelvey School of Engineering suggests that without considering certain factors, researchers may overestimate how fast calcium carbonate forms in saline environments.

No assumptions needed to simulate petroleum reservoirs

New research published in EPJ E shows that if the right choices are made when constructing models of petroleum reservoirs, no guesswork is required to calculate the impact of their temperature gradients on their pressure and chemical gradients.

New research published in EPJ E shows that if the right choices are made when constructing models of petroleum reservoirs, no guesswork is required to calculate the impact of their temperature gradients on their pressure and chemical gradients.

## Trending Science News

**Current Coronavirus (COVID-19) News**

## Top Science Podcasts

We have hand picked the**top science podcasts of 2020**.

**Now Playing: TED Radio Hour**

**Teaching For Better Humans 2.0**

More than test scores or good gradeswhat do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.

**Now Playing: Science for the People**

**#556 The Power of Friendship**

It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.

**Now Playing: Radiolab**

**Space**

One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.