PET 524

Fluid Flow in Porous Media

Fall Semester 2010

Thomas W. Engler, Ph.D.,P.E.

Course objectives

1. to develop an understanding of the basic physical

characteristics of porous media and the fluids contained

therein,

2. to understand and appreciate the mechanisms that drive

fluid flow in porous media and

3. to apply this knowledge to some of the more complex

problems of fluid flow through porous media.

Course objective

1. to develop an understanding of the basic physical

characteristics of porous media and the fluids contained

therein,

Structure and Properties of Porous Materials

Porosity

Permeability

Static Properties of Fluids in Porous Media

Saturation

Multiphase phenomena

Course objective

2. to understand and appreciate the mechanisms that drive

fluid flow in porous media

Physical and mathematical theory of flow

Darcy’s Law

Course objective

3. to apply this knowledge to some of the more complex

problems of fluid flow through porous media.

Transient laminar flow of homogeneous fluids

Simultaneous flow of immiscible fluids

Simultaneous flow of miscible fluids

bV

pV

ebulk volum

volumePorePorosity

Pore spacematrix

Bulk volume

Path of fluid flow

Porosity

Total vs Effective porosity?

Porosity

Effective porosity –

Interconnected clean

Pore space

e = ?

e = ?

heterogeneous

homogeneous

microscopic macroscopic

volume

po

rosi

ty

0

1

Porosity

Porosity is an average property over a R.E.V.

Porosity

shss 1

ssLnR

shsnr

1*3

1*3

Csh *

ssC

1

1

1

sssh )1( 1

Dispersed

Laminated

Critical

Concentration

Sedimentary rocks

Clastics Carbonates

Grain size

Sorting

Packing

Shape

Framework

Fractures

vugs

channels

intergranular

intercrystalline

Porosity

Porosity textural parameters

(After Krumbein & Sloss)

Porosity textural parameters

Porosity textural parameters

Porosity textural parameters

(After Krumbein & Sloss)

Porosity textural parameters

Vb =

Vg =

=

Porosity textural parameters

The sphericity of a grain refers to the dimensions of the grain with respect to a

equi-dimensional sphere.

The roundness is related to the roughness of the grain from angular to smooth.

[After Pettijohn, et al.,1973]

The degree of sorting and packing are dependent upon two

final textural parameters; roundness and fabric of the grains.

Porosity textural parameters

fabric is the composite effect or

framework of the various grains

[After Pettijohn, et al.,1973]

Depth – 1492 ft., Field of view is ~80 microns.

Pore space is blue.

The yellow dye is a stain for potassium feldspar

Observations

• this is a fairly high porosity sandstone.

•Average grain size is less than 10 microns.

Depth – 1497, 100X mag, FOV ~90 microns.

Observations

• Sand grains are coarser and more

well-rounded,

• Less clay content, more anhydrite cement

• Note abundant feldspar (yellow stain, and

relative lack of porosity.

Porosity textural parameters

Porosity carbonates

[After Anderson,1975]

Porosity carbonates

Porosity carbonates

AL

fL

fh

fw

bV

pV

f

Schematic of a single fracture

f

hf

wf

nA

fh

fwA

fn

f

)(

2

mL

fL

Define fracture porosity,

or

Where

tortuosity

nf, number of fractures per unit area