Gas Shale Fracture Optimization by Microseismic and Tracers

7/31/2019 Gas Shale Fracture Optimization by Microseismic and Tracers

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CORPORATIONCORPORATION

GeorgeKingGeorgeKing .

ove r 38 y ears o f exper ience . He s ta r t ed h is ca reer w i thAm oco in 19 71 . H is t echn ical backg rou nd in c ludes

energ ized f rac tu r in g , acid iz ing , com p lex fo rm at ion

.over 38 y ears o f exper ience . He s ta r t ed h is ca reer w i thAm oco in 19 71 . H is t echn ical backg rou nd in c ludes

energ ized f rac tu r in g , acid iz ing , com p lex fo rm at ion.

George has w r i t t en over 60 t echn ical papers , a book oncom p le t ion s and w ork overs , w as a 1985 SPE d is t ing u ishedlectu r e r and ad jun c t p r o fessor a t t he Un iver s i t y o f Tu l sa

.

George has w r i t t en over 60 t echn ical papers , a book oncom p le t ion s and w ork overs , w as a 1985 SPE d is t ing u ishedlectu r e r and ad jun c t p r o fessor a t t he Un iver s i t y o f Tu l sa

am o ng s m a ny on or s t r ou g ou t s car eer .

George i s cu r r en t l y a consu l t an t w i th Apache in t he a rea o fst i m u l at i o n a n d w o r k o v e r s.

am o ng s m a ny on or s t r ou g ou t s car eer .

George i s cu r r en t l y a consu l t an t w i th Apache in t he a rea o fst i m u l at i o n a n d w o r k o v e r s.

2009 EPT Plan Presentation.ppt 02/16/2009 1


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ShaleGasFracturing CombiningTracersandShaleGasFracturing CombiningTracersandMicroseismic to

Optimize

Fracture

NetworksMicroseismic to

Optimize

Fracture

Networks

GeorgeE.KingCompletionsConsultantGeorgeE.KingCompletionsConsultant

Based on SPE Paper 119,896 and other well data


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Areyourfracturesoptimized?Areyourfracturesoptimized? Can IP be tied to EUR? Onl if frac network sta s o en! Can IP be tied to EUR? Onl if frac network sta s o en!

Decline of 25% in 20 days in well w/ low rate frac (controlled frac h) - did notgenerate much frac network ?

Decline of 25% in 20 days in well w/ low rate frac (controlled frac h) - did notgenerate much frac network ?

w w ,

network , but didnt prop it had higher IP, but suffered faster decline andhigh water production!

w w ,

network , but didnt prop it had higher IP, but suffered faster decline andhigh water production!

, ,ramp for breakdown and faster sand ramp. Had flatter declines w/ low water.

, ,ramp for breakdown and faster sand ramp. Had flatter declines w/ low water.

Early High Rate Frac (70 bpm),500 bwpd Produced Water

one year ec ne o80%! WHY?

The feeder fractures

High ratefrac w/ hcontrol

.

Low Rate Frac (35 bpm),30 bwpd Produced Water


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SomeObservationsFrom200+BarnettFracStagesSomeObservationsFrom200+BarnettFracStages Tensile fracs & open natural fracs are easiest to extend. Can go out

of zone in slower fluid ramp, faster sand ramp, buildbarriers.

- .

- Mixtures of sand 100 mesh + 40/70 or 20/40 used to plug runaways.

- Rate of press increase of 1 to 8 psi/min is good, faster press increase

.

- Mixtures of sand 100 mesh + 40/70 or 20/40 used to plug runaways.

- Rate of press increase of 1 to 8 psi/min is good, faster press increasemay signal impending screenout . Press drop may signal out-of-zone

frac growth.

may signal impending screenout . Press drop may signal out-of-zone

frac growth.


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WellPerformancevs.FlowRegimefor

FWB

Barnett

Wells

WellPerformancevs.FlowRegimefor

FWB

Barnett

Wells Stress Anisotropy

An optimum frac should An optimum frac should6,000

NaturalFracture

Shear FracturesPresent Worth

it to maximize NPV andEUR.it to maximize NPV andEUR. 4,000

,

d)

Drainage

Only?

The performance of most

fracs in the Barnett are

The performance of most

fracs in the Barnett are

3,000

ate

(mcf

,still needed.

,still needed.

1,000

,

WellIP

ProppedFracture

frac performanceproblem that could showfrac performanceproblem that could show

0

0.0 2.0 4.0 6.0

Well EUR (BCF)

Drainage ONLY

Stress Anisotropy

EUR?

EUR?

Shear FracturesPresent Worth

Plot by Jim Shuss


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FracNetworkingwithFractureHeightControlFracNetworkingwithFractureHeightControl OK what is happening? OK what is happening?

- Natural fractures are being opened, but not effectivelypropped.- Natural fractures are being opened, but not effectivelypropped.

- a ura racs c os ng as reservo r pressure ec nes anwater is recovered.

-

- a ura racs c os ng as reservo r pressure ec nes anwater is recovered.

-

- Can frac closure be controlled?

-

- Can frac closure be controlled?

-

Formation stresses, pressures, saturations and shale fabricdominates.

Formation stresses, pressures, saturations and shale fabricdominates.


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AflowbackpatternfromonewellAflowbackpatternfromonewell

Lift

Days of Flow


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MoreTypical Asthewaterdrops,sodoesthegasMoreTypical Asthewaterdrops,sodoesthegas

Days

of

Flow CourtesyRimrock Energy


9/29

Whatmakesadifferenceinthewells?Whatmakesadifferenceinthewells? Classic shale gas candidate criteria

Where are the flow paths located?

Classic shale gas candidate criteria

Where are the flow paths located?

What factors affect well placement and design?

What factors affect well placement and design?

The way we operate the wells?

The way we operate the wells?


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RoughComparisonsofGasShales

Pay Barnett Marcellus Fayetteville Woodford Conasauga Devonian Antrim N Albany Lewis

Basin FW Appalachia Arkoma Arkoma BWB App Michigan Illinois San Juan

Location TX PA, WVA AR OK Ala, GA KY, NY, PA,WV

MI, IN, OH IN, KY CO, NM

Depth (ft) 6 to9000+

4 -10,000 1500 to 6000 6 to 12,000 4 to 8,000 2 to 8000+ 0.6 to 2K+ 0.5 to 2K+ 3 to 6000

H, thick:gross/net

250: 50% 50 to 300 50-550: 50% 200 to 350 3000:? 30 to 300: 40% 160: 40 -60

180: 40 to60

3000:?

Modulus, psi 7 to 9MM 4 to 7MM 3MM 3 to 5MM


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. ,value than pore gas NPV dominates.

2 M v m n f hr h h h l m rix l flesser importance its just too slow!

3. Recoverin the stored as in accessible naturalfractures is the major current value.

Graphics source: Ron McDonald, Schlumberger


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CORPORATIONCORPORATIONNaturalFractures PrimaryandSecondaryNaturalFractures PrimaryandSecondaryShaleoutcrop in

.

Note theprimary

secondary(yellow)naturalfractures. Athirdnatural frac

set can beseen at thebottom of

2009 EPT Plan Presentation.ppt 02/16/2009 12Gary Lash SUNY, AAPG

e p c ure.


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Whatarewetryingtodo?Whatarewetryingtodo?1. Possibilities in each part of the formation barriers,

faults, local variances. Take advantage.1. Possibilities in each part of the formation barriers,

faults, local variances. Take advantage.

. .

3. Increase frac path width (complex frac)

. .

3. Increase frac path width (complex frac)

5. Understand the treating pressure signature.

6. Understand how to use the treatment variables:

5. Understand the treating pressure signature.

6. Understand how to use the treatment variables: Where do you place the perfs?

Acid, ball sealers, hydraulic diversion

Where do you place the perfs?

Acid, ball sealers, hydraulic diversion

a , s urry vo umes an ramp-up spee Sand & liquid volumes what is needed and usable?

Rate both stable rate and corrective rate changes

a , s urry vo umes an ramp-up spee Sand & liquid volumes what is needed and usable?

Rate both stable rate and corrective rate changes

When and when not to push for isolation When and when not to push for isolation


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SettingupfracstagesandperfsSettingupfracstagesandperfs How to divide the wellbore?

- If natural fractures are regular, a regular spacing is OK.

How to divide the wellbore?

- If natural fractures are regular, a regular spacing is OK.

- If not, find where the nat. fracs are.

Methods of findin natural fracs assumin that is ood- If not, find where the nat. fracs are.

Methods of findin natural fracs assumin that is ood

- ROP and gas-shows from logs

- Ratios of methane-to-ethane resence of C3 and C4 as

- ROP and gas-shows from logs

- Ratios of methane-to-ethane resence of C3 and C4 as

- 3D seismic interpretation yes, it may indicate nat. fracs.

-

- 3D seismic interpretation yes, it may indicate nat. fracs.

-

- Tracers both tagged sand and water markers

-

- Tracers both tagged sand and water markers

-

Overlay all your data and look for patterns.

Overlay all your data and look for patterns.


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SomeWellDesignFactorsSomeWellDesignFactors Wellbore orientation relative to frac direction(s)? Wellbore orientation relative to frac direction(s)?

oes ma e a erence

Do you really want the wellbore at 90

oes ma e a erence

Do you really want the wellbore at 90degrees to the frac?degrees to the frac?

Primary

Frac

Secondary

Direction

NaturalFracs

Wellbore


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Microseismic capturedfromsequentialfracturedwells.Microseismic capturedfromsequentialfracturedwells.Notewellboreat a sli htangle toprimaryfracturedirectionkeeps

secondaryrac rom

followingwellbore.


ource mrocEnergy SPE

119896


17/29

WellDesign Vertical,SlantorWellDesign Vertical,SlantorHorizontal offers maximum contact but slant wells

,

several fracs and can fit on smaller leases.


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vertical for themost part, butma follow the

wellbore for ashort distance indeviated wells.

Fractureorientation isaffected btectonic stressesin the rock.

2009 EPT Plan Presentation.ppt 02/16/2009 18 DHVI?


19/29

Tracer tagged sands are used periodicallyto analyze proppant breakdown points and

near well communications.

Tracer tagged pad & frac waters determine: which intervals are broken down in each ?

which intervals are flowing back first;

whichstayopencomparedtoprodlog.

12001400

Stage 1

Candidate?

0200400600800

65 5 0 0

Stage 2

Stage 3

Stage 4

Stage 5

Stage 6LevelofUse?

1 4 69

98

125

148

1720

1935

2115

2295

2470

2620

3145

3490

3755

not

given

notgiven

Stage 7

Stage 8

Untilyouunderstand.


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What does micro-seismic reallytell you?What does micro-seismic reallytell you?

General location of sounds in/near the pay that are General location of sounds in/near the pay that area ove a certa n energy t e gate eve .

High and low energy events and high and low

a ove a certa n energy t e gate eve .

High and low energy events and high and low

A decent view of fracture extension, fracture

direction, fracture isolation, upper and lower frac

A decent view of fracture extension, fracture

direction, fracture isolation, upper and lower fracpenetration, and fracture flow path development.

In some cases, it can tell you the effect of near-field-

penetration, and fracture flow path development.

In some cases, it can tell you the effect of near-field- , .

And many sounds totally unconnected with a frac.

, .

And many sounds totally unconnected with a frac.


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WhatisavailablefromMicroseismic?WhatisavailablefromMicroseismic?Complexity, Frac Height, Direction, Length, Faults

Correlation to Treating Events (pressure, rate, proppant loading)


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CORPORATIONCORPORATIONMoreComplexity LimitedDownwardGrowthMoreComplexity LimitedDownwardGrowth

2009 EPT Plan Presentation.ppt 02/16/2009 22CourtesyRimrockEnergy


23/29


Thefrachadstayedinzoneuntilthis

point first

25%

of

events

and

the

chart

recordsaveryslow,steadypressurerise.

Thenpressurestartstodecreaseassand

concentrationisincreased..



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FracturegoesintotheEllenberger. This

correspondswith

a

drop

in

rate

and

a

rapidjumpbacktofullrate.



25/29


Pressurestartstoclimbandfracture

goesup

and

spreads



26/29

Microseismic verticalaccuracyMicroseismic verticalaccuracy Is MS accurate enough to depend on it? It can be. Is MS accurate enough to depend on it? It can be.The comparison wells are mile apart.

monitored from the

vertical section of anoffset producing well.

20% of events below pay.

Well produced 500 bwpd

of 100,000 ppm water.

Left and Right: a frac

unfractured wellbore.

2% of events below pay.

e pro uce wpof 35,000 ppm water.


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OperationsOperations

How fast do you recover the water?

How hard do you pull the pressure down on the well?

How fast do you recover the water?

How hard do you pull the pressure down on the well?

When do you use lift? What type?

When do you use lift? What type?


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ConclusionsConclusions

Spend the money early to understand the reservoir.

Place the wells to maximize the access to flow paths

Spend the money early to understand the reservoir.

Place the wells to maximize the access to flow pathswithin the reservoir

Monitor fracs cheapest way to improve fracs quickly.

within the reservoir

Monitor fracs cheapest way to improve fracs quickly.

- Cost of the science is about 10% of well cost.

- Frac optimization should take about 3 wells with science $

- Cost of the science is about 10% of well cost.

- Frac optimization should take about 3 wells with science $

- Frac optimization has taken 10 wells w/o science $

- The difference in production between optimized and

- Frac optimization has taken 10 wells w/o science $

- The difference in production between optimized and

unoptimized fracs is about 30 to 50%.unoptimized fracs is about 30 to 50%.

Documents

Gas Shale Fracture Optimization by Microseismic and Tracers