It’s the Cracks that Matter: DFN Modeling of Everything Rock

It’s the Cracks that Matter: DFN Modeling of Everything Rock

Paul La Pointe Golder Associates Inc. 27 June 2012

ARMA, Rock Mechanics & DFN Modeling

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R esearch in to rock m echan ics & fractu res have been linked th roughout the centuries, and A R M A m em bers have grea tly con tribu ted to th is anc ien t body o f know ledge.

To s tea l ideas from one person is p lag ia rism ; to s tea l ideas from m any peop le is scho la rsh ip & research .

Acknowledgments: Bill Dershowitz, Thomas Doe, Steve Rogers, Chris Barton

Divine Guidance – The Oracle of Delphi

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Geology of the Delphic Oracle By Andrew Alden, About.com Guid

Turns ou t the O rac le a t D e lph i saw the Future because o f pe tro leum vapors e ffus ing th rough fractu res in the earth “She entered an exalted state of mind and gave advice as if in a trance. Sometimes she didn't make much sense; sometimes her answers went over her questioner's head. On at least one occasion, she went into seizures and died.” P rophetic u tte rances about fractu res & pe tro leum are s till one o f the m a in uses o f D iscre te F ractu re N etw ork M ode ling (D FN )

D iodorus S icu lus 1 st C en tu ry B C ), te lls o f a goa t herder nam ed C ore tas, w ho no ticed one day tha t one o f h is goa ts , w ho fe ll in to a crack in the earth , w as behav ing s trange ly . O n en te ring the chasm , he found h im se lf filled w ith a d iv ine p resence and cou ld see ou ts ide o f the p resen t in to the past and the fu tu re . E xc ited by h is d iscovery he shared it w ith nearby v illagers . M any s ta rted v is iting the s ite to experience the convu ls ions and insp ira tiona l trances, though som e w ere sa id to d isappear in to the c le ft due to the ir frenz ied s ta te . A shrine w as e rected a t the s ite

Image of a fresco in the Sistene Chapel by Michaelangelo

Recognizing the importance of fractures

D E TA IL

M in ing

Fractures are important in many areas of rock mechanics…

Septem ber 15, 2012 6

Block Caving


Strength & Stability


Water Influx & Corrosion


Oil


Recovery of Oil, Gas & Water

11

http://www.southeastwaterproductions.com/hydrofracturing.html http://www.drillingahead.com/

new-jersey-governor-vetos-fracking-ban-legislation


W ater

TASS tunnel within the Äspö Hard Rock Laboratory, Oskarshamn, Sweden

Septem ber 15, 2012 13 Photo: Anders Pettersson, Golder Associates AB

Test various h igh-flow and low -flow grou ting techn iques

E xcava tion D am age Zone (E D Z) study, w here la rge b locks o f the tunne l w a lls w ere rem oved using saw cu ts to s tudy the fractu re pa tte rns crea ted by d rilling and b lasting

Rock Slopes


http://www.rgj.com/viewart/20120614/LIV08/306140037/Rock-risk-forces-Yosemite-closures

Military


http://trendsupdates.com/super-bunker-buster-bombs-on-fast-track-for-u-s-military/

Some Definitions


F ractu re – a generic d iscontinu ity Jo in t – A M ode I crack Fau lt – A M ode II c rack

The Odd Thing About Joints… (with apologies to Chris Barton)


“Jo in ts” a re the p lanes o f separa tion w here the rock b reaks apart, ye t the E ng lish w ord “jo in t” com es from the La tin w ord “jungere”, w h ich m eans to jo in o r un ite . Th is w ou ld appear to be a paradox.

Words to Describe “Joints” in Other Languages


K lu ft (G erm an): fissure , gap or c le ft D iac lase (F rench, S pan ish from G reek): to b reak in tw o Трещ ина (R ussian): crack, c le ft o r fissure

S o w hy is “jo in t” used in E ng lish to describe som eth ing tha t is “d is-jo ined”?

Usage of the Term “Joint” in English – Same as Today


The O xfo rd E ng lish D ictionary (from 1899-1901): "5 . G eo1. A crack o r fissure in te rsecting a m ass o f rock; usua lly occurring in se ts o f para lle l p lanes." A .J. G iek ie (1882): "A ll rocks a re traversed m ore o r less d is tinctly by vertica l o r h igh ly inc lined d iv is iona l p lanes te rm ed jo in ts. “ R .I. M urch ison (1839): "[M aste r Jo in ts] They a re na tu ra l fissures o ften travers ing a ll the stra ta in s tra igh t and w e ll de te rm ined lines “ J . P h illips (1836): "A ll the apparen t d iv is iona l p lanes o f rocks w h ich a re no t co inc iden t w ith surfaces o f s tra tifica tion , o r lam inae o f deposition , m ay in genera l be ca lled jo in ts."

Earlier Usage


John M acC ulloch (1821) uses the te rm fo r partings transverse to basa lt co lum ns w h ich d issect the co lum ns in to tabu la r p rism s:

“...tha t the m ost perfect and num erous jo in ts occur in the m ost regu la rly fo rm ed co lum ns. In the jo in ts , the surfaces in con tact a re som etim es uneven,a t o thers fla t, and o thers aga in , a lte rna te ly , concave and convex… ”

Fractures - the font of mythology and religion, then and now…

Legend has it tha t the Irish w arrio r w arrio r F ionn m ac C um hau il (F inn M cC oo l) bu ilt the causew ay to w a lk to S co tland to figh t h is S co ttish coun te rpart, B enandonner.

The G iant’s C ausew ay

Early Usage in Mining & Water


R obert B akew ell (1815): "C oa l s tra ta a re genera lly sp lit o r d iv is ib le in to rhom boida l b locks, by vertica l jo in ts ,… "

W illiam S m ith (1815), in h is Memoir to the Maps of the Strata of England w rites: “… the co llection o f w ater from those na tura l sub terraneous reservo irs , the caverns o f h ills and jo in ts o f rocks, fo r the supp ly o f cana ls ."

Back to the 18th Century…


C a tco tt (1761) in h is T rea tise on the D e luge: "These Jo in ts o r O pen ings be tw een the s tone in the upper parts o f R ocks ought to be d is tingu ished from the na tura l fissures in the body o f the rock, and are d is tingu ishab le there-from by various m arks, -be ing genera lly fa r m ore num erous… "

H ooson (1747) in h is M iners D ic tionary: "Joyn t. They are o f severa l sorts , and is a parting in the R ock, R ider, O re . o r any o ther S ubstance in the M ines, the ir various k inds are D is tingu ished ‘d by the ir severa l N am es,… ”

Even Earlier…


M orton (1712) in h is N ortham ptonsh ire re fe rs to quarrym en 's use o f the te rm : “… uprigh t-jo in ts , thorough-jo in ts and gu lfe jo in ts… ”

Lhw yd (1691) p resents an early usage in a le tte r to R ay: "O ne naked prec ip ice [on the G lyder M ounta in , N . W ales] is adorned w ith num erous equ id is tinct p illa rs , and these aga in s ligh tly cross 'd a t certa in joyn ts ."

The earliest known usage…mining once again!


The earliest geo log ic usage o f the w ord joint, ye t found, appears in H o lland 's trans la tion o f P liny 's N atura l H is to ry (1601): “The B actrian E m erauds ...be in ch inks o r joints (as it w ere) o f rock… and ga thered… w hen the N ortheast E tes ian w inds do b low … "

W hy m igh t have H o lland chosen the w ord “jo in t”?

Bactriani. in commissuris saxorum colligere eos dicuntur etesiis flantibus (Book 37, Chap 17:65)

C onsider the o rig ina l La tin :

Pliny


B orn 23 C E C om o, Ita ly

D ied A ugust 25 , 79 (aged 55–56) S tab iae , near P om pei, Ita ly

C ause o f death D ied in the eruption tha t destroyed P om peii

B ody d iscovered B y friends, under the pum ice

Source: http://en.wikipedia.org/wiki/Pliny_the_Elder

E ngineers shou ld no t ignore geo logy except a t the ir ow n peril…

The Final Answer?


P liny uses the w ord commissuris, m ean ing to b ind , join o r com bine . F rom La tin usage the princ ipa l m ean ing o f commissuris is a joining o r connecting together. W hy P liny chose to use commissura is no t know n, bu t w e can now deduce w hy H o lland used the w ord joint. H o lland m ust have recogn ized P liny 's in ten t o f a gap or ho le and thus he used the w ord ch ink to convey tha t m ean ing . B u t so as to be as lite ra l as possib le and to convey the essence o f P liny ‘s in ten t in commissura, H o lland adds: “ch inks o r jo in ts (as it w ere)."

“Joints” in the Modern World


Why Are So Many Papers Still Being Written About Fractures?


They ex is t in a lm ost every rock a t som e sca le a t som e tim e They are rea lly hard to sam ple and pred ic t They in fluence, o ften s ign ifican tly , rock p roperties such as: s trength , de form ab ility , flow , transport The w ay tha t they in fluence these properties is hard to w rite dow n in an equation

A fte r 2000 years o f w orry ing about fractu res, how do w e try to dea l w ith them now ?

The New Oracle: Discrete Fracture Network (DFN) Modeling


W hy th is approach?

“Instantaneous”

20 hours

4 days

No other breakthroughs were observed for two months

The Bromide Tracer Experiment at the Circle Ridge Field, Wind River Basin, WY

Flow in Fracture Networks Occurs in Mysterious Ways

• What is the permeability of this house?

• What is the most important thing to know about this house if you “drill” from the roof to find water?

• Are the pipes and bathtubs random? What controls their location and geometry?

ANALOGIES: Tubs = Matrix Storage Pipes = Fractures Faucets = Wells

The Paradigm of Fracture Flow

S lide courtesy o f Tom D oe

Streets – 10mDRoads – 100mDHighways – 1,000mD

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© Golder Associates

U nderstand ing & M ode ling the P lum bing is the K ey

Slide courtesy of Tom Doe & Steve Rogers

DFN models help us to understand the plumbing of the rock mass. Continuum methods cannot match the discrete geological pathways!


Where Does the Data Come From?

G eophysics

D ow nho le im age logs & core

O utcrops


Propagation of Waves - AVAZ


QUANTIFYING FRACTURE NETWORKS FROM ACOUSTIC ENERGY (AE) CLOUDS

Septem ber 15, 2012 44 http://www.globalgeophysical.com/docs/MICROSEISMIC_TFI%20Brochure%20%5B0711%5D.pdf

Borehole Image Logs


O utcrops

Finding the Elusive Fracture!


Celebration! We have found fractures!


Example Applications

O il & G as

N uclear W aste

M in ing

W ater

O ther


Oil & Gas Applications of DFN


D FN M ode ls a re use fu l fo r sorting ou t m ysteries and legends about reservo ir-sca le factu re flow

Satellite Image of the Field

M any o f the g ross structu ra l fea tu res a re consisten t w ith th is com m on tecton ic m ode l, bu t the reservo ir sca le fractu ring is fa r m ore com plex, and cou ld no t be pred icted from th is s im p le m ode l.

G reen V a lley S trike -S lip Fau lt

M a in R ed G u lly Thrust Fau lt

Building a Field-Scale Geomechanical DFN Model for the Circle Ridge Field, WY

Geological Framework Model

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F ie ld w ork w as com bined w ith w e ll da ta to c rea te geo log ica l c ross-sections in key a reas.

After Smith (2000)

3D S tructu ra l reconstruction is figuring ou t how to go from th is…

to th is…

Tensleep & P hosphoria as orig ina lly deposited

W hat the reservo ir looks like today a fte r fo ld ing and fau lting

Fracture Conceptual Model

Trap

R eservo ir in up thrust and dow nthrust b locks

Undeforming the Rock Layers

G E TTIN G TO TH IS U N D E FO R M E D S TA TE M E A N S TH A T W E H A V E TH E R IG H T FA U LT G E O M E TR Y , TH E R IG H T FA U LT M O V E M E N T H IS TO R Y , A N D TH E R IG H T FO LD IN G H IS TO R Y

Geologic Reconstruction

WE CAN COMPUTE THE FORWARD DEFORMATION HISTORY OF THE ROCK & SEE HOW THAT RELATES TO FRACTURES IN THE RESERVOIR

Understanding Fractures and Faults

We measured fracture orientations and intensity in many different locations and structural positions on rock outcrops & compared them to the calculated strain field.

These stra in o rien ta tions, w h ich ind ica te the m axim um d irection o f extension during the early fo ld ing o f the fie ld…

Th is and m any o the r com parisons show ed strong ev idence tha t the s tra in p roduced by the in itia l fo ld ing o f the fie ld w as a good p red ic to r o f fractu re o rien ta tion & in tens ity

S hosho ne 6 5-37

S hosho ne 66-07

Sho sh one 66-14

F ractu re Im age Logs V a lida tion W ells

C orrespond perfectly in a geom echan ica l sense w ith these fractu re o rien ta tions found in the im age log da ta…

Conceptual Model Validation

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“broken and busted”

H igh S tra in Low er

S tra in

R ed G u lly Fau lt T race

The b lue dashed lines show the dow n-d ip flexu re zones tha t m ay have fo rm ed due to the doub le p lunge o f the an tic line .

S om e o f these h inge zones link up across s tructu ra l b locks to ind ica te the m a jo r upw arp flexu re zone during the in itia l fo ld ing o f the fie ld .

Theory

F lexure Zone

R ea lity

Is there field evidence that horizontal flexure zones exist?

E xam ple o f a rad ia l (d ip -para lle l) h inge zone. N ote the change o f d ip be tw een pane ls , and the rubb le iza tion and consequent e ros ion in the h inge zone.

The G reen V a lley Fau lt separa tes B lock 6 (g reen) from B lock 8 (pu rp le ), w h ile the Y e llow F la ts Fau lt separa tes B lock 8 from B lock 9 (cyan)

The Bromide Tracer Experiment Showed Large-Scale Validation of the Model & the Development of Fracture SuperHighways Along Hinge Zones

Not all fractures are equally hydraulically important

Well Test Matching

C O N D U C TIV E vs. N O N -C O N D U C TIV E FR A C TU R E S

… com es from a s ing le fractu re ! A ll o f th is ...

W ell test s im u la tion is a m eans o f ca lib ra ting the D FN to the hydrau lic geom etry a t the sca le o f in te rest

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F ina l C a lcu la tion o f F lu id F low P roperties Through D FN T ransien t W ell Test M atch ing

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DFN Model of 3 Imbricate Blocks

Upscaling

The goa l o f upsca ling is to trans la te the geo log is t’s m ode l o f a fractu red reservo ir in to the eng ineer’s m ode l.

G eo log ist’s V iew o f a F ractu red R eservo ir

E ng ineer’s V iew o f a F ractu red R eservo ir

Transformation of a DFN model into Upscaled Properties

F irs t, w e use the s tra in va lues ca lcu la ted th rough the reconstruction o f genera te the fractu re se ts

N ext, the D FN m ode l is c lipped aga inst reservo ir surfaces

C lipped D FN m ode l w ith reservo ir bound ing surfaces rem oved

A geoce llu la r o r reservo ir s im u la tion g rid is superim posed over the D FN m ode l

The process o f ca lcu la ting e ffective reservo ir p roperties

E ffective fractu re -re la ted param eter va lues are ca lcu la ted fo r each grid ce ll

Before adjusting for conductive intensity (too permeable)

After adjusting for conductive intensity (on the order of 30% of previous)

How Reliable Is it?

In jecto r S hoshone 65-02

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P ressure M agn itudes in R espond ing W ells

V iew is look ing dow n on the s tructu re from the sou thw est to the northeast. S ize o f c irc les ind ica tes m agn itude o f p ressure response . The la rgest responses w ere seen in tw o w e lls on flexu re co rrido rs c lose to the in jecto r. M ost o f the respond ing w e lls a re e ithe r in the cyan-co lo red pod above and le ft (no rthw est) o f the in jecto r, o r a long the dow nd ip flexu re co rrido r to the righ t (sou theast) o f the in jecto r.

O verv iew o f N itrogen Test in O verth rust B lock

W ells w here n itrogen breakth rough w as ind ica ted a re show n; s ize o f ye llow c irc le a t w e ll top ind ica tes the tim e o f b reakthrough (la rge c irc le ind ica te s low response; sm all c irc les ind ica te rap id response).

F lexure zones a re ind ica ted by dashed o range (s trike -para lle l) and b lue (d ip -para lle l) lines

Hydrofracturing: Horn River Example

93

FracMan Technology Group

S teve R ogers

D oug B earinger

How Do Natural Fractures Influence Hydrofracture Development?

Im portance o f na tu ra l fractu res fo r a successfu l w e ll com ple tion known

E ffective u tiliza tion o f the na tu ra l fractu re system by the hydrau lic fractu re C A N a llow the w e ll to connect to a s ign ifican tly enhanced d ra inage vo lum e.

H ow ever uncerta in ty ex is ts w ith respect to the hydrau lic fractu re & na tu ra l fractu re in te raction

In a reservo ir w ith a com plex fractu re system , the resu ltan t s tim u la ted vo lum e is go ing to be h igh ly com plex

H ow can w e address th is?

Through DFN Modeling


Dilly Creek Work flow

W ith lim ited da ta , fractu re ne tw ork uncerta in ty is h igh

D anger o f fo rc ing a “h is to ry m atch” w ith an uncerta in m ode l

Instead vary key fractu re p roperties w ith in sensib le bounds and observe s im u la ted m icro-se ism ics

C om pare actua l and s im u la ted se ism ic response to see w h ich fractu re geom etries m ost like ly

P roperties to V ary Fracture In tens ity Fracture S ize Fracture S hape In jection flu id e ffic iency

DFN Work flow

1. C onstruct a D FN m ode l fo r reg ion surround ing w e ll

2 . Inc lude in fo rm ation about the w e ll’s hydrau lic fractu re

– P um p ra te , p ressure and dura tion o f each s tage

3 . M ode l hydrau lic fractu re and in te raction w ith o rig ina l fractu re ne tw ork fo r each stage based on :

– S tress fie ld and m ateria l p roperties– M ateria l ba lance o f in jected flu id and propant

4 . V a lida te m ode l w ith m icro -se ism ic da ta

M easured M icrose ism ic

M ode led and M easured M icrose ism ic

stubby Narrow Elongate

Broad Elongate Isotropic

Example Responses

Effects of Transmissivity

Transmissivity low Transmissivity high

C om bined D FN /E lfen S im ula tion

Network Connectivity

One Joint Set Two Joint Sets

Impact of Fracture property on Stimulated Volume

P roperty Increas ing P roperty D ecreasing P roperty

F racture in tens ity

S horter w ider s tim u la ted zone Longer narrow er s tim u la ted zones

F racture S ize W hen it increases connectiv ity it resu lts in a w ider s tim u la ted vo lum e

W hen it reduces connectiv ity , the s tim u la ted vo lum e w ill be narrow er

F racture C onnectiv ity

S horter, m ore c ircu la r and iso trop ic s tim u la ted vo lum e

E longate and an iso trop ic s tim u la ted vo lum e

F lu id E ffic iency

E xtends the hydrau lic frac and lim its the la te ra l exten t

B roadens the response and reduces the H F length

A spect R atio If connectiv ity increased, la rger s tim u la ted vo lum e

If connectiv ity decreased sm alle r s tim u la ted vo lum e

Estimating Stimulated Volume and EUR

102 15 Septem ber 2012 (c) G o lder Associa tes Inc., 2011

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Example Value Proposition

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Stimulated fractures 4 laterals

Stimulated volume 4 laterals

Same potential production from ½ the number of wells

Stimulated volume of the outer two laterals is approximately equal to the total

stimulated volume for the four laterals

Investigating Conceptual Models of Flow

Cumulative Production

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10415 Septem ber 2012(c) G o lder Associa tes Inc., 2011

T im e, D ays

Gaining insight into a mystery: Use of DFN models to explore which conceptual model helps explain the dynamic observations the best

Visualise the Pressure Field

15 Septem ber 2012(c) G o lder Associa tes Inc., 2011

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Matrix, Lineaments, Hydrofracs

Matrix, Lineaments

Matrix, Hydrofracs

Nuclear – Design & Performance Assessment

Septem ber 15, 2012 106

Lim, D-H., M Uchida, K. Hatanaka and A. Sawada (2007). Modeling of Radionuclide Migration through Fractured Rock in a HLW repository with Multiple Canisters, MRS Symposium on the Scientific Basis for Nuclear Waste Management XXXI, Sheffield, UK, Sep., 2007

Cs-135 Movement

Septem ber 15, 2012 107

Lim, D-H., M Uchida, K. Hatanaka and A. Sawada (2007). Modeling of Radionuclide Migration through Fractured Rock in a HLW repository with Multiple Canisters, MRS Symposium on the Scientific Basis for Nuclear Waste Management XXXI, Sheffield, UK, Sep., 2007

D FN M ode l

H ydrau lic H ead

D arcy F low V e loc ity

R esidence T im e

Modeling Where Radionuclides May Go

Septem ber 15, 2012 108

D FN M ode l

P athw ays

Environmental Applications – CO2 Sequestration

Septem ber 15, 2012 109

Loca tion o f the S E C A R B B lack W arrio r test s ite in D eerlick C reek F ie ld , B lack W arrio r B asin , A labam a.

Jin, G. and J. C. Pashin (2008). Discrete fracture network models of the SECARB carbon sequestration test site, Deerlick Creek Field, Black Warrior Basin, Alabama. 2008 International Coalbed and Shale Gas Symposium, paper #0821.

CO2 Sequestration – Deerlick Test

Septem ber 15, 2012 110

Jo in ted D FN m ode l based on s tra tig raph ic re la tionsh ips in the Jobson 24-14 #11 w e ll and observa tions o f fractu res in core and ou tcrop .

Compartmentalization & High-Grading

Orientations inferred from FMI data; intensity based on seismic attributes Analysis shows that the fractures form compartments

(The compartments in the model are shown by different colored groups of fractures)

“S w eet S pot”

CO2 Sequestration – Deerlick Test

Septem ber 15, 2012 112

R esu lts o f com partm enta liza tion ana lys is. N ote tha t sha llow coa l zones are in a com partm ent tha t is separa te from the reservo ir coa l zones and tha t sm a ll, s tranded jo in t com partm ents a re stranded be tw een the m a jo r reservo ir com partm ents.

Mining

Septem ber 15, 2012 113

Pillars

Mining- DFN Used to Better Characterize Pillar Strength

Septem ber 15, 2012 115

Elmo, D. and D. Stead (2009). An Integrated Numerical Modelling–Discrete Fracture Network Approach Applied to the Characterisation of Rock Mass Strength of Naturally Fractured Pillars. R ock M ech R ock E ng

Failure as a Function of Fracturing

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CA

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Block Caving

The F ragm enta tion o f the rock m ass during caving has a trem endous im pact on a num ber o f cave , m in ing and p rocessing design decis ions inc lud ing : D raw po in t spacing ; E qu ipm ent S e lection ; S econdary b reakage

requ irem ents; M ill se t up & energy requ irem ents

S. Rogers†, D. Elmo†, G. Webb† & A. Catalan‡A DFN based approach to defining in situ, primary and secondary fragmentation distributions for the Cadia East panel cave. Caving 2010 – Perth 20th-22nd April 2010

Caving-Pit Interaction

Pit OnlyPit + Block Caving

0-90 Joints 30-60 Joints

Caving-Pit Interaction

50° D ipp ing O rebody

Civil/Geotechnical Engineering

G routing

S lope S tab ility

121

Grouting

Trevor G . C arte r, W illiam D ershow itz , D aw n S hu ttle and M ichae l Je ffe ries, Im proved M ethods o f D esign fo r G rou ting F ractu red R ock, C om pan ion paper to : “Towards Better Injection Control and Verification of Rock Grouting” Bonin et.al. (2012 proceedings)

Frac

ture

tran

smis

sivi

ty:

m2 /s

ec

Efficiency of Grouting – can be checked

Septem ber 15, 2012

U se B ingham m odel to approx im ate grout flow

M odel fractures us ing D FN representa tion In ject to p roposed G routing In tens ity C heck/s im ula te groundw ater flow th ru

curta in R erun to op tim ize – ho le spacing etc

Aperture: mm

Travel Distance: mD

epth

: m

Evaluate Effectiveness of Grouting

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0.0

0.2

0.4

0.6

0.8

1.0

0.1 1 10

Gro

uti

ng

Eff

icie

ncy

(-)

Normalized Grouting Intensity: Vsimulated/ Voptimum (-)Normalized Grouting Intensity

Gro

utin

g Ef

ficie

ncy

Grouting Efficiency: E = 1 – (KGrouted / Kformation)

C om pute g roundw ater flow across g rou t curta in

th rough rem ain ing ungrou ted frac tu res in the

ne tw ork

90%

Design Curve = Optimum Volume

or Penetration Distance

Twice the effort

80%

C om pute g roundw ater

Grouted Fracture Set

0

Injection Time

1000+ Steps

Grouthole

Simulated Injection into Fracture Network

Visualized to evaluate “Penetration”

0.0m

Distance

10.0m

Slope Failures – Beichuan (2008)

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Rock Slopes

Groundwater

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Journal of Contaminant Hydrology Volume 38, Issues 1–3, May 1999, Pages 281–322 Alternative concepts and approaches for modeling flow and transport in thick unsaturated zones of fractured rocks K. Pruess B. Faybishenko, G.S. Bodvarsson

Calculating Permeability Tensors for Groundwater Flow

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V aria tion o f d irectiona l hydrau lic conductiv ity in 3 -D space

M. Wanga, P.H.S.W. Kulatilakea,*, J. Uma, J. Narvaizb (2002). Estimation of REV size and three-dimensional hydraulic conductivity tensor for a fractured rock mass through a single well packer test and discrete fracture fluid flow modeling. Int. J. Rock Mechanics & Mining Sciences 39, 887–904

…and a monumental application

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E xcava tion S im u la tion

Crazy Horse Memorial

Conclusions

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F ractu res in rock have been im portan t to hum an ity fo r a t least tw o m illenn ia , and p robab ly m ore in the a reas o f m inera ls , energy, w a te r supp ly and env ironm ent D esp ite tw o thousands years o f scho la rly investiga tions, m any im portan t questions regard ing na tu ra l fractu res have s till no t been fu lly answ ered D iscre te F ractu re N etw ork (D FN ) m ode ling has been a use fu l too l in the past tw o o r th ree decades, and p rom ises to be a too l o f ever-increas ing im portance in the a rsena l o f rock m echan ics p ractitioners. A nd the fu tu re?

Only creativity limits what can be modeled

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D FN M ode l by Tom D oe

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Thanks!

Edward Lhwyd Had Some Other Strange Ideas…On The Origin of Fossils

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“H e suggested a sequence in w h ich m ists and vapours over the sea w ere im pregnated w ith the ‘seed ’ o f m arine an im a ls . These w ere ra ised and carried fo r considerab le d is tances be fore they descended over land in ra in and fog . The ‘inv is ib le an im acu la ’ then penetra ted deep in to the earth and there germ ina ted ; and in th is w ay com ple te rep licas o f sea organ ism s, o r som etim es on ly parts o f ind iv idua ls , w ere reproduced in s tone.”

http://www.oum.ox.ac.uk/learning/pdfs/lhwyd.pdf

K eeper o f the A shm olean M useum a t O xford (an unpa id position , ra is ing m oney by en tic ing o thers to see h is curios ities). F ractu res a re still cu rios ities tha t a ttract a tten tion , and m any peop le w ho study them have strange ideas…

O rien ta tions o f m ost passages

D irection o f m axim um extens ion

Map annotation and photos courtesy of Laird Thompson, MOBIL

Understanding the Reservoir from the Inside Out - Engineers: Ignore Geology at your Peril!

… S O M E S O LU TIO N -E N H A N C E D FR A C TU R E S A R E N O T P E R M E A B LE TO LA R G E O B JE C TS

EXPLORING THE APERTURE DISTRIBUTION OF A FRACTURED RESERVOIR

Y ellow P assage R ed P assage

O rien ta tions o f m ost passages

D irection o f m axim um extens ion

Map annotation and photos courtesy of Laird Thompson, MOBIL

Understanding the Reservoir from the Inside Out

Braving dangers in the jungle…

It’s the Cracks that Matter: DFN Modeling of Everything Rock

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