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

Transcription

1 MUSCAT, OMAN Influence of Shaped Charge Design on Target Penetration. Ballistic Performance Modelling in Rock MENAPS NOV 13TH, 2016 AUTHORS: Liam McNelis, Dr. Joern Loehken, Bernd Fricke DynaEnergetics

2 OUTLINE & INTRODUCTION Ballistic Indicator Function Model and simplified variations Rock Core Overview Stressed Rock Lab Testing Fluorescent Dye Flow Influence of DoP on Productivity and other factors Summary MENAPS

3 INTRODUCTION: WHY PENETRATION MODELLING? 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) MENAPS

4 PENETRATION MODELLING Drawbacks of some penetration models used for oilfield shaped charges: Overreliance on concrete penetration data Tendancy to overpredict DoP in downhole environment Stressed Rock API 19b Section IV API 19b Section I Concrete 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 MENAPS

5 Rock penetration / API 19B concrete penetration [%] WHY PENETRATION MODELLING DoP in Concrete vs DoP in Stressed Rock Charges Developed in Concrete Hard Rock (UCS >35 kpsi) Sandstone (UCS 11-15kpsi) Sandstone (UCS 8-11kpsi) Sandstone (UCS 6-8kpsi) 5 0 Charge A Charge B Charge C Charge D Charge E MENAPS

6 LAB TEST CONFIGURATION General Section II/IV Hardware Set-Up Overburdon/confining psi Wellbore psi Pore-Pressure psi MENAPS

7 TEST CORES OVERVEW 7 OD Cores with a wide range of UCS values Weißer Roter Bentheimer Roter Piesberger Main Main Bunt MENAPS

8 TEST CORES OVERVIEW Name Type UCS (psi) Porosity (%) Fluid Permeability (md) Bulk Density (g/cm 3 ) Visual Roter Bunt, Batch T14 Sandstone ,16-2,25 red, visible bedding Roter Bunt, Batch T16 Sandstone ,26-2,29 red, visible bedding Weißer Main Sandstone ,12-2,19 white, strong bedding Roter Main Sandstone ,19-2,31 red, no bedding visible Sander Schilf Sandstone ,12-2,20 green, no bedding visible Bentheimer Sandstone ,97-2,02 grey to yellow, no bedding visible MENAPS

9 PENETRATION MODELLING Ballistic Indicator Function Model (SPE Paper ) combines UCS & stress function of target, including charge and target coefficients ln ( DoP/ DoP ref ) = α 0 ( F BI, ref - F BI ) F BI = UCS + b.p eff P eff = P c a.p pore a(ø) = ø b(ucs) = x UCS (for UCS < 30,000psi) α 0 = Exponential Charge Coefficient (constant for charge design) F BI = Ballistic Indicator Function of Formation (psi) F BI, ref = Ballistic Indicator Function of Test Formation (10,000psi) P eff = Ballistic Effecitve Stress (psi) P c = Confining Stress (psi) P pore = 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 (%) MENAPS

10 Normalised TTP Values [%] PENETRATION MODELLING Ballistic Indicator Function (F BI ) Exponential Fit y = 9,28E+01e -3,40E-05x R² = 9,30E inch inch inch inch inch DoP~e a 0F BI coefficient of determination R²=0, Ballistic Indicator Function [psi] MENAPS

11 Normalised TTP Values [%] BALLISTIC INDICATOR FUNCTION MODELLING Ballistic Indicator Function (F BI ) Power Function Fit y = 16872x -0,574 R² = 0, inch inch inch inch 2 inch DoP~F BI 0 coefficient of determination R²=0, Ballistic Indicator Function [psi] MENPAS

12 Normalised TTP Values [%] SIMPLIFIED ITERATIVE PENETRATION MODELS Rock Penetration vs Target Density inch y = 1,36E+04e -2,28E+00x R² = 9,65E inch inch inch DoP~ρ sat β 0 coefficient of determination R²=0, Saturated Target Density [g/cm3 ] MENAPS 2ß

13 Normailsed TTP Value [%] SIMPLIFIED ITERATIVE PENETRATION MODELS Rock Penetration vs Sonic Velocity y = 6,196E+02e -6,784E-04x R² = 9,612E inch inch inch inch DoP~v sonic γ 0 coefficient of determination R²=0, Sonic Velocity [m/s] MENAPS

14 Normalized Penetration DIRECT COMPARISON OF CHARGE DESIGNS Rock Penetration vs Target Sonic Velocity Charge A Charge B Charge C x charge designs with 22,7g HMX-St Sonic Velocity (m/s) MENAPS

15 Normalised Penetration DIRECT COMPARISON OF CHARGE DESIGNS 1.00 Rock Penetration vs F BI (3x Charge Designs for 3 1/8" Gun) Charge A Charge B Charge C x charges have very similar average EHD Charges A&B have similar concrete penetration Charge C has ~30% less concrete penentration Ballistic Indicator Function (psi) MENAPS

16 Normalised Rock Penetration Productivity Ratio (Pre-FLow/Post FLow) CORRELATION BETWEEN DEPTH OF PENETRATION & PRODUCTIVITY RATIO? 4x different charges designs for one gun size (same gram weight) 1.2 Charge #1 Charge #2 2.5 General Trend Ballistic Indicator Function (psi) Normalized Penetration MENAPS

17 CORRELATION BETWEEN DEPTH OF PENETRATION & PRODUCTIVITY RATIO? 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 MENAPS

18 COMPUTER MODEL FOR PENETRATION IN STRESSED ROCK Identical Charge & Identical Target 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) 12 Target Length 2900psi Confining Pressure 14500psi Confining Pressure MENAPS

19 SUMMARY OF RESULTS 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 F BI Model requires sufficient Section II/IV data input to acquire the penetration curve F BI 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 DoP ref and α 0 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 MENAPS

20 REFERENCES Harvey.J, Grove.B, Zhan.L, SPE Stress Rock Penetration Depth Correlation Harvey.J, Kokel.P, Zhan.L Grove.B, Huang.H, Atwood.D, SPE Schlumberger Determining Perforation Parameters from Single-Shot Tests Radial vs Axial Flow Ott. R.E, Bell.W.T, Harrigan J.W. Golian.T.G,, SPE 27424, Simple Method Predicts Downhole Shaped Gun Performance Harvey.J, Grove.B, Zhan.L, SPE, Schlumberger; Behrmann.L, Consultant, SPE New Predictive Model of Penetration Depth for Oilwell-Perforating Shaped Charges Grove.B, Heiland.J, Walton.I, Atwood.D, SPE, Schlumberger, SPE New Effective-Stress Law for Predicting Perforation Depth at Downhole Conditions MENAPS

21 Thank you for your attention. MENAPS