Influence of Shaped Charge Design on Target Penetration.Ballistic Performance Modelling in Rock

MENAPS 2016-5

AUTHORS: Liam McNelis, Dr. Joern Loehken, Bernd Fricke DynaEnergetics

NOV 13TH, 2016

MUSCAT, OMAN

• Ballistic Indicator Function Model

and simplified variations

• Rock Core Overview

• Stressed Rock Lab Testing

• Influence of DoP on Productivity

and other factors

• Summary

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OUTLINE & INTRODUCTION

Fluorescent Dye Flow

INTRODUCTION: WHY PENETRATION MODELLING?

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Why do we need to model on stressed

rock?

• Concrete penetration data is insufficient

• Depth of penetration must exceed the

drilling damage – (reduced permeability

caused by mud/drilling fluid invasion)

• Section II & IV Testing for every scenario

can be very time consuming and

expensive

• Test/lab equipment or cores may be

limited to simulate downhole conditions

(HP wells)

PENETRATION MODELLING

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4

Drawbacks of some penetration models used

for oilfield shaped charges:

• Overreliance on concrete penetration data

• Tendancy to overpredict DoP in downhole

environment

• Different models provide considerably

different results for same shaped charge

• Inadequate consideration of rock specific

parameters – porosity, pore pressure,

effective stress, EOS (sonic Velocity)

limited UCS range

API 19b Section I

Concrete

Stressed Rock

API 19b Section

IV

WHY PENETRATION MODELLING

DoP in Concrete vs DoP in Stressed Rock

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0

5

10

15

20

25

30

35

40

45

Charge A Charge B Charge C Charge D Charge E

Ro

ck p

enet

rati

on

/ A

PI 1

9B

co

ncr

ete

pen

etra

tio

n [

%]

Hard Rock (UCS >35 kpsi)

Sandstone (UCS 11-15kpsi)

Sandstone (UCS 8-11kpsi)

Sandstone (UCS 6-8kpsi)

Charges Developed

in Concrete

LAB TEST CONFIGURATION

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Overburdon/confining psi

Pore-Pressure psi

Wellbore psi

General Section II/IV Hardware Set-Up

TEST CORES OVERVEW

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7“ OD Cores

with a wide

range of UCS

values

Weißer Roter Bentheimer Roter Piesberger

Main Main Bunt

TEST CORES OVERVIEW

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Name Type UCS (psi)Porosity

(%)

Fluid

Permeability

(mD)

Bulk Density

(g/cm3)Visual

Roter Bunt, Batch T14 Sandstone8.200 –

9.40013-16 7-13 2,16-2,25 red, visible bedding

Roter Bunt, Batch T16 Sandstone10.000-

11.00011-12 1-3 2,26-2,29 red, visible bedding

Weißer Main Sandstone 5.000-7.500 15-18 13-97 2,12-2,19 white, strong bedding

Roter Main Sandstone11.000-

15.00012-15 2-27 2,19-2,31 red, no bedding visible

Sander Schilf Sandstone 5.000-7.000 15-20 1-76 2,12-2,20 green, no bedding visible

Bentheimer Sandstone 3.400-4.500 20-22 800-1300 1,97-2,02grey to yellow, no bedding

visible

PENETRATION MODELLING

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Ballistic Indicator Function Model (SPE Paper – 151846)

combines UCS & stress function of target, including charge and target coefficients

ln ( DoP/ DoPref ) = α0 ( FBI, ref - FBI )

FBI = UCS + b.Peff

Peff = Pc – a.Ppore

a(ø) = 0.0967 ø0.428

b(UCS) = 0.7336 -1.813 x 10-5. UCS (for UCS < 30,000psi)

α0 = Exponential Charge Coefficient (constant for charge design)

FBI = Ballistic Indicator Function of Formation (psi)

FBI, ref = Ballistic Indicator Function of Test Formation (10,000psi)

Peff = Ballistic Effecitve Stress (psi)

Pc = Confining Stress (psi)

Ppore = Pore Pressure (psi)

a = Ballistic Pore Pressure Coefficient (Porosity dependent)

b = Stress Influence Coefficient (UCS dependent)

UCS = Unconfined Compressive Strength of Formation (psi)

ø = Porosity (%)

PENETRATION MODELLING

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 5000 10000 15000 20000 25000 30000 35000 40000

No

rmal

ise

dT

TP V

alu

es

[%]

Ballistic Indicator Function [psi]

Ballistic Indicator Function (FBI) Exponential Fit

4 1-2 inch

3 3-8 inch

3 1-8 inch

2 7-8 inch

2 inch

𝐷𝑜𝑃~𝑒−𝑎0𝐹𝐵𝐼coefficient of determination R²=0,96

y = 9,28E+01e-3,40E-05x

R² = 9,30E-01

BALLISTIC INDICATOR FUNCTION MODELLING

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0 5000 10000 15000 20000 25000 30000 35000 40000

No

rmal

ise

dT

TP V

alu

es

[%

]

Ballistic Indicator Function [psi]

Ballistic Indicator Function (FBI) Power Function Fit

4 1-2 inch

3 3-8 inch

3 1-8 inch

2 7-8 inch

2 inch

𝐷𝑜𝑃~𝐹𝐵𝐼−∝0

coefficient of determination R²=0,98

y = 16872x-0,574

R² = 0,9872

SIMPLIFIED ITERATIVE PENETRATION MODELS

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

2.10 2.20 2.30 2.40 2.50 2.60 2.70

No

rmal

ise

d T

TP V

alu

es

[%

]

Saturated Target Density [g/cm3 ]

Rock Penetration vs Target Density4 1-2 inch

3 3-8 inch

3 1-8 inch

2 7-8 inch

𝐷𝑜𝑃~𝜌𝑠𝑎𝑡−𝛽0

coefficient of determination R²=0,93

y = 1,36E+04e-2,28E+00x

R² = 9,65E-01

SIMPLIFIED ITERATIVE PENETRATION MODELS

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

2500 3000 3500 4000 4500 5000

No

rmai

lse

d T

TP V

alu

e [

%]

Sonic Velocity [m/s]

Rock Penetration vs Sonic Velocity

4 1-2 inch

3 3-8 inch

3 1-8 inch

2 7-8 inch

𝐷𝑜𝑃~𝑣𝑠𝑜𝑛𝑖𝑐−𝛾0

coefficient of determination R²=0,96

y = 6,196E+02e-6,784E-04x

R² = 9,612E-01

DIRECT COMPARISON OF CHARGE DESIGNS

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0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

2700 2900 3100 3300 3500 3700 3900 4100 4300

No

rmal

ize

d P

en

etra

tio

n

Sonic Velocity (m/s)

Rock Penetration vs Target Sonic Velocity

Charge A

Charge B

Charge C

• 3 x charge designs with 22,7g HMX-St

DIRECT COMPARISON OF CHARGE DESIGNS

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0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

26000 28000 30000 32000 34000 36000

No

rmal

ise

dP

en

etra

tio

n

Ballistic Indicator Function (psi)

Rock Penetration vs FBI (3x Charge Designs for 3 1/8" Gun)

Charge A

Charge B

Charge C

• 3 x charges have very similar average EHD

• Charges A&B have similar concrete penetration

• Charge C has ~30% less concrete penentration

CORRELATION BETWEEN DEPTH OF PENETRATION & PRODUCTIVITY RATIO ?

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0

0.2

0.4

0.6

0.8

1

1.2

5000 7000 9000 11000 13000 15000 17000 19000

No

rmal

ise

dR

ock

Pe

ne

trat

ion

Ballistic Indicator Function (psi)

Charge #1

Charge #2

4x different charges designs for one gun size (same gram weight)

0

0.5

1

1.5

2

2.5

0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Pro

du

ctiv

ity

Rat

io (

Pre

-FLo

w/P

ost

FLo

w)

Normalized Penetration

General Trend

CORRELATION BETWEEN DEPTH OF PENETRATION & PRODUCTIVITY RATIO ?

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Based on Section IV results:

an increased DoP generally will

support an increase in Productivity

PR is also strongly influenced by

• Clear Tunnel Depth/Ratio

• Perforation Skin

• Tunnel Geometry & Volume

• EHD in Casing

• Porosity

• Bedding plane orientation

COMPUTER MODEL FOR PENETRATION IN STRESSED ROCK

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12“ Target Length

Identical Charge & Identical Target

2900psi

Confining

Pressure

14500psi

Confining

Pressure

• RHT Material Model

describes the material

behavior of rock under stress

• Model is implemented in the

Hydro-Code of Ansys-

Autodyn

(dynamic numerical

simulation) for penetration

• Results model are highly

dependent on the accuracy of

the material parameters (>30

parameters to describe the

rock material)

SUMMARY OF RESULTS

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• Every perforation model does needs to be verified with sufficient & reliable lab data:

– a good shaped charge design workflow needs reliable input from the models used,

laboratory testing, and field data – core samples, reservoir data & field trials

• FBI Model requires sufficient Section II/IV data input to acquire the penetration curve

• FBI appears to provide a fairly accurate method of prediction for penetration depth in

stressed sandstone targets – does not tend to overpredict penetration

• Allows also for charge optimization on stressed rock using the DoPref and α0

• The extent of the difference in DoP (rock to concrete) is not only dependent on the rock

properties but also the shaped charge design itself.

• API Section IV testing confirms that there are more factors than just DoP which contribute

to the Productivity Ratio

REFERENCES

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• Harvey.J, Grove.B, Zhan.L, SPE 151846 „Stress Rock Penetration Depth

Correlation“ - 2012.

• Harvey.J, Kokel.P, Zhan.L Grove.B, Huang.H, Atwood.D, SPE 143993 Schlumberger

„ Determining Perforation Parameters from Single-Shot Tests Radial vs Axial Flow“ -

2011

• Ott. R.E, Bell.W.T, Harrigan J.W. Golian.T.G, , SPE 27424,

„Simple Method Predicts Downhole Shaped Gun Performance“ - 1993.

• Harvey.J, Grove.B, Zhan.L, SPE, Schlumberger; Behrmann.L, Consultant , SPE

127920 „ New Predictive Model of Penetration Depth for Oilwell-Perforating

Shaped Charges“ - 2010

• Grove.B, Heiland.J, Walton.I, Atwood.D, SPE, Schlumberger , SPE 111778

„ New Effective-Stress Law for Predicting Perforation Depth at Downhole Conditions“

- 2009

Thank you for your attention.

MENAPS 2016-521