P E T R O L E U M E N G I N E E R I N G

Numerical and Laboratory Study of Gas Flow through Unconventional Reservoir Rocks

RPSEA Piceance Basin Tight Gas Research Review

Xiaolong Yin, Assistant Professor

Petroleum Engineering, Colorado School of Mines

April 21 2011

P E T R O L E U M E N G I N E E R I N G

Presentation Outline

Challenges and our research activities

Our RPSEA project and collaborators

Preliminary results

Goals and objectives

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Background

In very tight reservoir rocks, both measurement techniquesand our understanding of the physics are being challenged

Our groups research activities focus on pore-scale physics and flow using direct simulation and experiments

Specifically, we investigate what makes unconventional rocks unconventional Surface interaction

Non-continuum slippage

Heterogeneity in pore structure and rock-fluid interactions

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Our RPSEA Project

RPSEA 09122-29 02/2011 02/2014 Use nanofluidic chips and single-molecule detection techniques to

visualize fluid flow in nano-sized pores

Combine core flooding test and SEM imaging to correlate fluid flow in tight rocks to pore structures

Develop pore-scale numerical models to provide information that cannot be easily obtained from experiments, such as three-dimensional motion of fluids

Our Team Missouri University of Science & Technology B. Bai (core flooding),

Y. Ma (single-molecule detection)

Colorado School of Mines X. Yin (pore-scale models), K. Neeves(nanofluidic chips)

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Traditional laboratory studies

Pulse-decay permeability measurement

Mercury porosimetry

Linear core flooding

Ultra-centrifuge

PVT (CSM)

These equipments allow us to study

Porosity and permeabilityStorage capacity and transportMultiphase flows and formation damage

A CMS-300 Pulse-Decay Permeameter

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Non-traditional laboratory studies

What makes flow in unconventional reservoir rocks unconventional? Surface interactions

Non-continuum slippage

Heterogeneity in surfaceproperties

Fractures and cracks

In-situ stress

Some of these effects can be studied using micro (right) and nano-scale (below) porous media analogs constructed on silicon / polymer chips

Photo courtesy of Keith Neeves

Chemical Engineering

Colorado School of Mines

This list is probably far from complete.

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Preliminary results from micro-chip experiments

Data and photo provided by Keith Neeves and Melissa Wu ,

Chemical Engineering, Colorado School of Mines

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

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Experiment LB Simulation

Permeability comparison

Air-water two phase flow test: Left: The geometry is initially saturated with water

Below: Air is injected in the lower left corner forcing water out of the channels

P E T R O L E U M E N G I N E E R I N G

Simulation of micro- and nano-scale flows

Numerical tools have been and are being developed to study fluid flow with non-continuum effects in nano-sized pores

Representative porous media geometry models

Experimentally measured and k and pore structure

Direct numerical simulation models:Lattice-Boltzmann (for Navier-Stokes)DSMC (for non-continuum flows being developed)

Pore structureRelative permeabilityEffect of stressAdsorption / Desorption

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Preliminary results from pore-scale modeling

Porosity-permeability relation is the key to rock typing and understanding geomechanical effects on fluid flow

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Porosity

Homogeneous Geometry

Heterogeneous Geometry

Ideal, channelized geometry porosity-permeability shows a strong correlation

More realistic, heterogeneous geometry porosity-permeability shows large scattering

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Preliminary results from pore-scale modeling

A universal porosity-permeability correlation can be developed by recognizing that the large pores do not contribute to permeability

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Conductive Porosity

Homogeneous Geometry

Heterogeneous Geometry

These data are from our scoping studies using 2D geometries

3D simulations and experiments are underway

Such a correlation can be used to determine the geometry of pores from bulk measurement without resorting to image analysis

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

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Porosity

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Parallelized, 3D pore-scale simulator

3D Representative Geometries

3D Porosity-Permeability Data

3D Simulator Parallel Speedup

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RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Goals and objectives

Simulations with controlled

geometries and assumed physics Micro- and nano-

fluidic experiments with controlled

geometries and real physics

Core-scale experiments with

real geometries and real physicsIncreasing level of

reality

The combined approach will significantly improve our understanding of fluid flow on nano-scale and unconventional reservoir dynamics

RPSEA Piceance Basin Research ReviewApril 21, 2011, Denver, Colorado

P E T R O L E U M E N G I N E E R I N G

Acknowledgements

Collaborators Baojun Bai, Yinfa Ma (MUST)

Keith Neeves (CSM, ChemE)

Qinjun Kang (Los Alamos National Lab)

Students Feng Xiao (PE)

Lei Wang (PE)

Melissa Wu (ChemE)

Funding RPSEA

P E T R O L E U M E N G I N E E R I N G

Simulated vs. measured permeability

Simulation of flow through digital cores from CT-scan

CT and experimental data from Imperial College

Numerical simulations are done in CSM

A1 BSS C1 F42A S1 S2

Porosity 42.9 19.6 23.3 33 14.1 24.6

Resolution 3.85 5.345 2.85 9.996 8.683 4.956

K (exp) 7,220 1,286 1,102 59,000 1,678 3,898

K (sim) 8,675 1,507 1,192 59,331 2,006 4,076

% error 20.2% 17.2% 8.1% 0.6% 19.6% 4.6%