MENAPS 13-25 A Comparative Study of Carbonate Matrix ... · Design for Acidizing –SPE165141 A previous laboratory study showed that acid injectivity could be impacted by initial

International Perforating ForumInternational Perforating Forum

2013 2013 Middle East and Middle East and North AfricaNorth AfricaPerforating SymposiumPerforating Symposium

MENAPS 13-25

A Comparative Study of Carbonate

Matrix Acidizing after Perforation with Matrix Acidizing after Perforation with

Reactive and Non-reactive Shaped

Charges

A. Rabie and Hisham A. Nasr El-Din, Texas A&M

University, J.T. Hardesty and N. Clark, Geodynamics,

Inc. SPE165141

Perforation Geometry

MENAPS 13-25 GEODynamics Carbonate Matrix Acidizing – Charge Design

2-3 December, 2013 Middle East and North Africa Perforating Symposium

2

Background

Conventional 25g Reactive 25g



3

Background

Advantages:

• Improve injectivity and flow performance.

• Enhance stimulation job’s efficiency .



4

• Increase productivity to a point that would

offset cost.

SPE116226, SPE122174, SPE125901, SPE144167, SPE149453

Reactive Perforating

� Not an end in itself, but a tool to produce improved

tunnel geometry

� Intermetallic reaction between charge liner

materials, triggered by detonation pressure

� Exothermic reaction



� Exothermic reaction

• Heats tunnel volume & near-tunnel pore space

• Consumes supporting liner material

� Breaks up and expels debris from tunnel

� Effect occurs in each tunnel, independently

� Clean tunnels with less reliance on surge

5

Design for Acidizing – SPE165141

� A previous laboratory study showed that acid injectivity could be impacted by initial

perforation geometry caused by perforating conditions. (SPE 105022)



� Reactive shaped charges, introduced in late 2007, exploits an exothermic secondary

reaction in the perforation tunnel during the perforation event.

� The reaction generates radial energy which drives the break up and expulsion of crushed

zone material and compacted debris into the wellbore resulting in profoundly cleaner, more

effective tunnels, which enhance the ease and reliability with which the perforated

formation can be stimulated. (SPE 122174)

6

Design for Acidizing

� A previous laboratory study showed that acid injectivity for matrix acidizing was found to

be higher for cores perforated with reactive liner shaped charges, however target size and

therefore charge size were limited. (SPE 138434)



7

Objectives

(1) Investigate the effect of using reactive liner shaped charges on

the outcome of matrix acidizing treatments with multiple charge

designs.

(2) Compare the performance of stimulations performed after



(2) Compare the performance of stimulations performed after

perforating with reactive liner and conventional shaped charges

through complete fluid analysis and CT-scan imaging before and

after the acidizing treatments.

8

Experimental Method

• Perforate a set of 7” x 24” cream chalk cores using

conventional and reactive charges (15g and 23g, two

designs) at 7000 psi OB, 3000 pore, 3000 wb.

• Evaluate the geometry of reactive charges in



9

• Evaluate the geometry of reactive charges in

carbonate rocks.

• Acidize perforated core with 15% HCl at 200F, 1200

psi back pressure, and 50cc/min

• Evaluate the effect of charge design on acid

wormholing.

Experimental Studies

Perforation Flow Cell




Acidizing LoopAcidizing LoopAcidizing LoopAcidizing Loop



11




12


Porosity, Porosity, Porosity, Porosity, Initial Initial Initial Initial (pre(pre(pre(pre----shot) shot) shot) shot) PermeabilityPermeabilityPermeabilityPermeability, , , , PostPostPostPost----shot Permeabilityshot Permeabilityshot Permeabilityshot Permeability, and , and , and , and

Tunnel Tunnel Tunnel Tunnel LLLLength ength ength ength of the Cream Chalk of the Cream Chalk of the Cream Chalk of the Cream Chalk Cores.Cores.Cores.Cores.

Run #Run #Run #Run #Core Core Core Core

NumberNumberNumberNumber

Porosity, Porosity, Porosity, Porosity,

vol.%vol.%vol.%vol.%

InitialInitialInitialInitial

Permeability Permeability Permeability Permeability

mDmDmDmD

PostPostPostPost----shot shot shot shot

Permeability Permeability Permeability Permeability

mDmDmDmD

Tunnel Tunnel Tunnel Tunnel

LengthLengthLengthLength, in., in., in., in.

1111 CTS 09 27.2 12.3 21.2 17.1



2222 CTS 11 27.4 14.4 23.8 15.8

3333 CTS 15 28 15.3 34.8 17.6

4444 CTS 16 27.7 14.6 16.3 14.0

5555 CTS 20 27.5 14.3 19.9 18.6

6666 CTS 22 28 14.0 15.6 18.2

13

Results & Discussion

Summary of All Acidized Cores in the Current StudySummary of All Acidized Cores in the Current StudySummary of All Acidized Cores in the Current StudySummary of All Acidized Cores in the Current Study

Run #Run #Run #Run #Core Core Core Core

NumberNumberNumberNumberType of ChargeType of ChargeType of ChargeType of Charge

Charge Charge Charge Charge

Weight, Weight, Weight, Weight, gmgmgmgm

5555 CTS-20 Reactive − GH 23Group



2222 CTS-11Conventional −

GH23

3333 CTS-15 Reactive − DP 23

1111 CTS-09 Conventional − DP 23

6666 CTS-22 Reactive − DP 15

4444 CTS-16 Conventional − DP 15

Group

#1

Group

#2

Group

#3

14


Group #1: GoodGroup #1: GoodGroup #1: GoodGroup #1: Good----Hole DesignHole DesignHole DesignHole Design

CTSCTSCTSCTS----20, Reactive Charges20, Reactive Charges20, Reactive Charges20, Reactive Charges----23 gm Load23 gm Load23 gm Load23 gm Load

Acid

Breakthrough



Acid Flow through

the Core

15

Group #1: GoodGroup #1: GoodGroup #1: GoodGroup #1: Good----Hole DesignHole DesignHole DesignHole Design

CTSCTSCTSCTS----20, Reactive Charges20, Reactive Charges20, Reactive Charges20, Reactive Charges----23 gm Load23 gm Load23 gm Load23 gm Load



Before Acidizing After Acidizing

16

Group #1: CTSGroup #1: CTSGroup #1: CTSGroup #1: CTS----11, Conventional Charges11, Conventional Charges11, Conventional Charges11, Conventional Charges----23 gm23 gm23 gm23 gm



Before Acidizing After Acidizing

17


Summary of the Results of Group #1Summary of the Results of Group #1Summary of the Results of Group #1Summary of the Results of Group #1

Run Run Run Run

####

Core Core Core Core



Weight, Weight, Weight, Weight,

gmgmgmgm

Length of Length of Length of Length of

PerforationPerforationPerforationPerforation

Tunnel, in.Tunnel, in.Tunnel, in.Tunnel, in.

CumulativCumulativCumulativCumulativ

e Acid e Acid e Acid e Acid

PorePorePorePore

Volume, Volume, Volume, Volume,

PVPVPVPVtbtbtbtb

5555 CTS-20 Reactive − GH 23 18.6 0.050.050.050.05



5555 CTS-20 Reactive − GH 23 18.6 0.050.050.050.05


GH23 15.8 0.300.300.300.30

18

CTSCTSCTSCTS----15, Reactive15, Reactive15, Reactive15, Reactive CTSCTSCTSCTS----09, Conventional09, Conventional09, Conventional09, Conventional

Group #2: DeepGroup #2: DeepGroup #2: DeepGroup #2: Deep----PenetrationPenetrationPenetrationPenetration----23 gm Load23 gm Load23 gm Load23 gm Load

CTCTCTCT----Scan Images After AcidizingScan Images After AcidizingScan Images After AcidizingScan Images After Acidizing



19



Run Run Run Run

####

Core Core Core Core




gmgmgmgm






PorePorePorePore

Volume, Volume, Volume, Volume,

PVPVPVPV



PVPVPVPVtbtbtbtb

3333 CTS-15 Reactive − DP 23 17.6 0.070.070.070.07


DP23 17.1 0.370.370.370.37

20

CTSCTSCTSCTS----22, Reactive22, Reactive22, Reactive22, Reactive CTSCTSCTSCTS----16, Conventional16, Conventional16, Conventional16, Conventional

Group #3: DeepGroup #3: DeepGroup #3: DeepGroup #3: Deep----PenetrationPenetrationPenetrationPenetration----15 gm Load15 gm Load15 gm Load15 gm Load

CTCTCTCT----Scan Images After AcidizingScan Images After AcidizingScan Images After AcidizingScan Images After Acidizing



21


Run Run Run Run

####

Core Core Core Core




gmgmgmgm






PorePorePorePore

VolumeVolumeVolumeVolume, , , ,




gmgmgmgm Tunnel, in.Tunnel, in.Tunnel, in.Tunnel, in. VolumeVolumeVolumeVolume, , , ,

PVPVPVPVtbtbtbtb

6666 CTS-22 Reactive − DP 15 18.2 0.180.180.180.18


DP15 14.0 0.200.200.200.20

22

Design for Acid Conclusions, (1)

1- Initial perforation geometry produced by different charge design

has a significant effect on the effectiveness of subsequent stimulation

treatments for the targets and conditions within this study.

2- Reactive liner shaped charges created tunnels with more effective

(open) length when compared to conventional charges, with notable

improvement in tunnel quality at the tip of the tunnel.



3- Acid consumption, expressed in cumulative PV, was higher in cores

perforated with conventional charges.

4- Effluent fluid analysis showed higher calcium, magnesium, and

metal ion concentrations in effluent samples when a conventional

charge was used, indicating dissolution of greater amounts of

perforation debris and formation material was required to achieve

breakthrough for conventional charges.

23

Design for Acid Conclusions, (2)

5- CT-scan images confirmed the preceding results by showing a

dominant wormhole generated from the tunnel tip when reactive liner

shaped charges were used.

6- Multiple and deviated wormholes originating before the tunnel tip

when conventional charges were used.



7- Perforation of carbonate formations with properly designed

reactive liner shaped charges rather than conventional shaped

charges should result in more effective matrix acid stimulation as

dominant wormholes will be created from the tip of each perforation

tunnel, resulting in greater effective wellbore radius for a given

volume of acid stimulation.

24

References

• Bartko, K.M., Chang, F.F., Behrmann, L.A., and Walton, I.C.: “Effective Matrix Acidizing in Carbonate Reservoir-Does Perforating Matter?”, SPE 105022, 15

th SPE Middle East Oil and

Gas Show, Bahrain, 11-14 Mar 2007.

• Bell, M.R.G., Hardesty, J.T., Clark, N.G.: “Reactive Perforating: Conventional and

Unconventional Applications, Learnings and Opportunities”, SPE 122174, SPE European

Formation Damage Conference, Netherlands, 27-29 May 2009.

• Behrmann, L.A., Hughes, K., Johnson A.B. and Walton, I.C.: “New Underbalanced

Perforating Technique Increases Completion Efficiency and Eliminates Costly Acid

Stimulation”, SPE 77364, SPE Annual Technical Conference and Exhibition, Texas, 29

September-2 October 2002.

• Lloyd Stutz, H., Behrmann, Larry A., “Dynamic Under Balance Perforating Eliminates Near

Wellbore Acid Stimulation in Low-Pressure Weber Formation”, SPE 86543, SPE International



25

Wellbore Acid Stimulation in Low-Pressure Weber Formation”, SPE 86543, SPE International

Symposium and Exhibition on Formation Damage Control held in Lafayette, Lousiana,18-20

February 2004.

• Cocanower, R.D., “Perforating Assumes New and Greater Importance in Well Stimulation”,

SPE 799, Mechanical Engineering Aspects of Drilling Production Symposium in Fort Worth,

Texas, 23-24 March 1964.

• Williams, Bert B., Gidley, John L., and Schechter, Robert S., “Acidizing Fundamentals “,

Jun 1979.

• Economides, Michael J., Hill, Daniel A., and Economides, Christine E., “Petroleum

Production Systems”, December 1993.

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Documents

MENAPS 13-25 A Comparative Study of Carbonate Matrix ... · Design for Acidizing –SPE165141 A previous laboratory study showed that acid injectivity could be impacted by initial