EFFECTS OF HIGH PORE PRESSURE ON PERFORATION TUNNELS IN BOTH HIGH AND MODERATE COMPRESSIVE STRENGTH ROCKS IPS 16-43

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1 2016 INTERNATIONAL PERFORATING SYMPOSIUM GALVESTON EFFECTS OF HIGH PORE PRESSURE ON PERFORATION TUNNELS IN BOTH HIGH AND MODERATE COMPRESSIVE STRENGTH ROCKS May 10TH, Halliburton. All Rights Reserved. AUTHORS: D. Haggerty, G. Craddock, and J. McGregor, Jet Research Center Halliburton

2 AGENDA/INTRODUCTION Testing Objectives Review Testing Conditions Discuss Results Conclusions 1

3 TESTING OBJECTIVES Run perforation tests at actual reservoir pressures, not just matching effective stress. Examine perforation penetration results as pore pressure is increased; compare moderate and high strength rock targets. View perforation tunnel images at increasing pore pressures. Review the shock wave physics simulation exercise. 2

4 TESTING CONDITIONS A. Charge: B. Lab gun scallop plate: C. Gun clearance: D. Casing plate: E. Cement coupon: F. Core: Net confining stress (effective stress): Temperature: 3 3/8-in. 25 g HMX DP in. w.t., scallop depth: in in in. w.t HT RC 20-24, simulating 7-in. 32 lb L in. Class A Portland Note: No gap is present between cement and core. Size / type / average unconfined compressive strength (UCS) / average porosity (%): 7 in. diameter, 24 in. length / (1) Indiana limestone / 14,700 psi UCS / 12.5% (2) Berea sandstone / 8,500 psi UCS / 19.8% 10,000 psi ~75 F 3

5 RESULTS: TABLE OF PENETRATION Test Sets (2 each) Applied Overburden Stress (psi) Pore Pressure (psi) Net Confining Stress (psi) 4 Core Type Tested Relative Depth of Penetration (fraction) 1A 9, Limestone B 10, ,000 Sandstone A 12,000 2,000 10,000 Limestone B 12,000 2,000 10,000 Sandstone A 18,000 8,000 10,000 Limestone B 18,000 8,000 10,000 Sandstone A 24,000 14,000 10,000 Limestone B 24,000 14,000 10,000 Sandstone A 30,000 20,000 10,000 Limestone B 30,000 20,000 10,000 Sandstone A 36,000 26,000 10,000 Limestone B 36,000 26,000 10,000 Sandstone A 42,000 32,000 10,000 Limestone B 42,000 32,000 10,000 Sandstone 0.618

6 RESULTS: ROCK PENETRATION VS. PORE PRESSURE Fit Linear Log Rock Intersect (psi) 15,935 13,005 R Limestone R Sandstone Normalized Penetration (fraction of max)

7 Hole Diameter, in. RESULTS: LOW PRESSURE TEST ARTIFACT Cement exit and core entry hole size: Without pore pressure, the contact between the core and the cement is separated briefly during the perforation event Cement Hole diameter, in. Casing EH diameter, in. 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 Pore Pressure, psi 6

8 PORE PRESSURE EFFECTS Average Penetration: 10.5 in. Tests run at 10,000 psi OB, 5,000 Pore pressure (NCS: 5,000 psi) Average Penetration: 7.15 in. Tests run at 25,000 psi OB, 20,000 Pore pressure (NCS: 5,000 psi) 7

9 RESULTS: CT IMAGES fraction of max. Limestone Sandstone Limestone Sandstone Limestone Sandstone normalized penetration Net Confining Stress: 10,000 psi Net Confining Stress: 10,000 psi Net Confining Stress: 10,000 psi Overburden: 9,500/10,000 psi Overburden: 12,000 Overburden: 18,000 Pore: 0/500 psi Pore: 2,000 psi Pore: 8,000 psi 8

10 RESULTS: CT IMAGES fraction of max. Limestone Sandstone Limestone Sandstone Limestone Sandstone Limestone Sandstone normalized penetration Net Confining Stress: 10,000 psi Net Confining Stress: 10,000 psi Net Confining Stress: 10,000 psi Net Confining Stress: 10,000 psi Overburden: 24,000 Overburden: 30,000 Overburden: 36,000 Overburden: 42,000 Pore: 14,000 psi Pore: 20,000 psi Pore: 26,000 psi Pore: 32,000 psi 9

11 SHOCK WAVE PHYSICS MODELING EXERCISE Modeling Exercise Setup 10

12 SHOCK WAVE PHYSICS MODELING EXERCISE 11

13 SHOCK WAVE PHYSICS MODELING EXERCISE 12

14 SHOCK WAVE PHYSICS MODELING EXERCISE 13

15 SHOCK WAVE PHYSICS MODELING EXERCISE 14

16 CONCLUSIONS Shaped charge penetration in the higher UCS limestone rock was less than in the Berea sandstone up to a pore pressure of approximately 12,500 psi. A linear fit of the penetration data showed a reduction of in. per 1,000 psi for the limestone core and in. per 1,000 psi for the sandstone core. CT images of the perforation tunnels proved to be much different than those observed at lower pore pressures. This was mostly observed in the lower UCS sandstone, where just a 2,000 psi pore pressure shot at balanced pore-wellbore conditions created an enlarged core entry hole. Subsequent higher pore pressures resulted in highly eroded perforation tunnels caused by dynamic underbalance-created turbulence with high erosion in approximately the upper one-third of the perforation tunnel. The limestone core tunnel geometry was less affected likely due to its higher strength. 15

17 CONCLUSIONS (Continued) The shock wave physics modeling simulations revealed that various sections near the middle of the perforation tunnels at elevated pore pressures showed an enlarged diameter, which were also observed in the CT images of the actual tests. The shock wave physics modeling simulations revealed that with higher pressures, the thickness of the crushed zone increases along with the crush zone density. Flow tests in subsequent high pressure perforation studies will help determine the significances of these phenomena. Testing adjustments at these high pressure conditions will help expand the understanding of expectations in deeper wells with different rocks, shaped charges, fluids, and wellbore conditions. 16

18 2016 INTERNATIONAL PERFORATING SYMPOSIUM GALVESTON Acknowledgement A special thanks to Halliburton management for permitting these tests and the APFL crew for conducting these tests. QUESTIONS? THANK YOU! Effects of High Pore Pressure on Perforation Tunnels in Both High