FRAC BALLS TESTING Report Prepared for: Bruce Diamond Corporation Prepared by: Rapid Design Group Inc. (Original Signed by) (Original signed by) Mohammad Nauman Technical Services Engineer, E.I.T. Serg Arabsky President, CEO August 14, 2012 Nisku, Alberta
1. INTRODUCTION The purpose of this report is to provide a detailed analysis on the pressure test results of Frac Balls provided by Bruce Diamond Corporation. Rapid Design Group Inc. uses its expertise in testing Frac Balls and rating them according to their performance under hydraulic pressures. The Frac Balls are divided into different batches with each batch labeled under different materials. Those batches are further divided into batches of different sizes and thus, compared to the exact same size batch in different materials. And the Frac Balls are rated under size batch which comes under the category of material batch. 1.1 TEST GOALS Frac Balls are tested to determine: 1. Ball Failure/Maximum Pressure in each batch 2. Ball performance at Failure/Maximum Pressure 3. Ball performance at Holding Pressure 4. Back Pressure after the Holding Pressure 5. Pressure rating due to performance 1.2 TERMINOLOGY 1.2.1 Failure/Maximum Pressure: The pressure testing equipment is rated to a maximum pressure of 10,000 psi. Therefore, a Frac Ball is tested until it fails under the hydraulic pressure, Failure Pressure, or until the maximum pressure is attained if it does not fail. 1.2.2 Ball Failure: Frac Balls are placed in such a way inside the pressure testing equipment that they create a seal on the ball sleeve creating a differential pressure i.e., Pressure is applied on the top side of a Frac Ball while the bottom side is open to atmosphere. A Frac Ball fails if the pressure escapes the seal created by the Frac Ball. 1.2.3 Holding Pressure: Once a Frac Ball has been tested, another Frac Ball of the same batch is tested until the pressure inside the equipment reaches ~85% of the Failure/Maximum Pressure. The Frac Ball is held at that pressure for 5-10 minutes. 1
1.2.4 Back Pressure: Depending upon the material and size of a Frac Ball, some either extrude through the ball sleeve while some crack at the sealing location into 2 halves or break into several smaller pieces. After the Holding Pressure, the equipment is flipped 180 such that the bottom side becomes the top side. Pressure is applied, Back Pressure, in order to determine the pressure required to eject the ball off the ball sleeve. This pressure corresponds to Bottom Hole Pressure, BHP, in the Downhole Completions industry on field. 2. EQUIPMENT 2.1 Ball Batches for Testing: - 5 X 3.750 BDC INJECTION MOLDED PEEK - 1 X 3.750 Extruded PEEK - 1 X 3.750 Controlled G10 2.2 Testing Apparatus: - 3 5/8 Seat - Pressure Testing Unit with ¼ NPT fittings on the end caps - Stand-alone pressure pumping unit - Pressure recording system 3. TESTING PROCEDURE 3.1. Initial Failure/Maximum Pressure Test: - Start pressuring up until the maximum pressure of 10,000 psi is attained or the ball fractures before reaching the maximum pressure inside the fixture - Upon fracturing, the bottom end cap with atmospheric relief valve will start leaking - Record the ball failure/maximum pressure 3.2 Holding Pressure Test: - Use Frac Ball of a sample that has undergone Initial Failure/Maximum Pressure Test - Pressure up to ~85% of the Failure/Maximum Pressure and hold for 5-10 minutes - Record the holding pressure and the pressure drop 2
3.3 Back Pressure Test: - Flip the fixture 180 such that the bottom side becomes the top side and interchange the fittings - Pressure up to ~85% of the Failure/Maximum Pressure and hold for 5-10 minutes - Record the holding pressure and the pressure drop 3.4 CF PEEK Balls Placement - Place the ball dimple facing up on the sleeve and perform 3.1, 3.2 and 3.3 in this orientation - Place the ball dimple facing sideways on the sleeve and perform 3.1, 3.2 and 3.3 3.5 Controlled G10 Balls Placement - Place the ball dimple facing up on the sleeve and perform 3.1, 3.2 and 3.3 in this orientation - From experience and considering the quantity of balls, dimple on the ball represents the weak orientation and therefore; the weak orientation must be tested first 3.6 Extruded PEEK Placement - The ball is homogeneous therefore the orientation doesn t matter 3
Output (psi) FRAC BALL TESTING REPORT 4. RESULTS AND DISCUSSIONS 4.1 BDC INJECTION MOLDED PEEK 4.1.1. Failure/Maximum Pressure Dimple up Break 1 4500 4000 3.750" BDC INJECTION MOLDED PEEK - DIMPLE UP BREAK 1 3500 3000 Ball Fail = 4,173 psi 2500 2000 1500 1000 500 0 10:55:05 10:55:14 10:55:23 10:55:33 10:55:42 Time Figure 1-3.750" BDC injection molded PEEK - Dimple up Break 1 @ 4,173 psi The ball had a sharp break establishing its failure at 4,173 psi, Figure 1. The ball came off the seat easily with very little effort, Figure 2. 4
Output (psi) FRAC BALL TESTING REPORT Figure 2-3.750" BDC injection molded PEEK Break @ 4,173 psi 4.1.2. Failure/Maximum Pressure Dimple up Break 2 4500 4000 3.750" BDC INJECTION MOLDED PEEK - DIMPLE UP BREAK 2 3500 Ball Fail = 3,762.8 3000 2500 2000 1500 1000 500 0 11:06:24 11:06:31 11:06:37 11:06:44 11:06:51 11:06:58 Time Figure 3-3.750" BDC INJECTION MOLDED PEEK - Dimple up Break @ 3,763 psi 5
The ball had a sharp failure dimple up, like before, at 3,763 psi. The ball came off the seat easily with very little effort. Figure 4-3.750" BDC INJECTION MOLDED PEEK Ball Dimple up break @ 3,763 psi 6
Output (psi) FRAC BALL TESTING REPORT 4.1.3. Failure/Maximum Pressure Dimple on side Break 1 9000 3.750" BDC INJECTION MOLDED PEEK BREAK - DIMPLE ON SIDE 1 8000 7000 6000 5000 Ball Fail = 4,878 psi 4000 3000 2000 1000 0 11:17:27 11:17:49 11:18:12 Time Figure 5-3.750" BDC INJECTION MOLDED PEEK Ball - Dimple on side break @ 4,878 psi When the ball was tested in the orientation when the dimple faced the side wall of the sleeve, the ball broke at higher pressure i.e., 4,878 psi, Figure 5. However, instead of the ball losing pressure it started to gain pressure. The fixture was flipped 180 and was back pressure however; the pressure could not be built up. Upon inspection, it was noticed that the ball was broken in half and the bottom half flipped inside the sleeve getting stuck which explained the uncommon pressure graph. The ball had to be pressed out of the seat on a hydraulic press. 7
Output (psi) FRAC BALL TESTING REPORT Figure 6-3.750" BDC INJECTION MOLDED PEEK Dimple on side break @ 4,878 psi 4.1.4. Failure/Maximum Pressure Dimple on side Break 2 9000 3.750" BDC INJECTION MOLDED PEEK - DIMPLE ON SIDE BREAK 2 8000 7000 6000 Ball Fail = 4,892.8 psi 5000 4000 3000 2000 1000 0 12:03:09 12:03:20 12:03:31 12:03:43 12:03:55 Time Figure 7-3.750" BDC INJECTION MOLDED PEEK Dimple on side break @ 4,893 psi 8
Figure 8-3.750" BDC INJECTION MOLDED PEEK dimple on side break @ 4,893 psi The ball was tested in this orientation again and similar results were noticed. It was further noticed that the bottom half was stuck at the dimple ends against the sleeve walls. Also, the crack occurred at the plane parallel and slightly above the two dimples. One of the reasons could be that the manufacturing induced pressure traps at the dimple locations and as soon as cracks appeared at that plane, pressure traps got released and the ball slightly extruded outward. Hence, the ball got stuck at the two end points surfaces. The ball bottom half flipped at about 45, crack plane with the vertical axis. This could be understood such that there were two actions happened simultaneously. Firstly, as the first crack appeared at the sealing location which also happened to be roughly at the same plane explained above, it propagated across the diameter of the ball. Secondly, the escaping pressure flipped the bottom half inside the seat getting stuck. The top half remained in the same orientation after the test as it was placed before the test. The two different orientation tests show that the ball has a weak and strong orientation, and pressure-wise the ball is non-homogeneous. Therefore, dimple up is weak orientation. 9
Output (psi) FRAC BALL TESTING REPORT 4.1.5. Holding Pressure Dimple up 4000 3500 3.750" BDC INJECTION MOLDED PEEK BALL - HOLDING PRESSURE Holding Pressure = 3,360.81psi Δ = 335.65 psi 3000 2500 2000 1500 1000 500 0 11:43:42 11:44:50 11:46:00 11:47:10 11:48:20 Time Figure 9-3.750" BDC INJECTION MOLDED PEEK Ball Holding Pressure It can be seen that the ball holding pressure plateaued at around 3,000 psi on its weak orientation, Figure 9. Had the ball been held at 3,500 psi it would have shown similar results, Figure 10. Hence, the ball can be rated between 3200-3500 psi. 10
Figure 10-3.750" BDC INJECTION MOLDED PEEK after Holding Pressure 11
Output (psi) FRAC BALL TESTING REPORT 4.2 3.750 Extruded PEEK 4500 3.750" EXTRUDED PEEK Failure/Maximum Pressure Chart 4000 3500 Max = 3,840 psi 3000 2500 2000 1500 1000 500 0 17:12:46 17:13:03 17:13:21 17:13:38 17:13:55 17:14:12 17:14:30 17:14:47 17:15:04 17:15:22 Time Figure 11-3.750" Extruded PEEK failure @ 3,840 psi 12
Figure 12 - Extruded PEEK failure @ 3,840 psi It can be seen From Figure 11 that the failure pressure for the ball is 3,840 psi. Due to limited quantity the ball could not be tested for holding pressure. The ball extruded into the seat as compared to the 3.750 BDC injection molded PEEK balls. The ball came off the sleeve at city water pressure. 13
Output (psi) FRAC BALL TESTING REPORT 4.3 3.750 G10 4.3.1 Failure/Maximum Pressure 4500 3.750" G10 Failure/Maximum Pressure Chart - Weak Side 4000 3500 3000 Max = 3,958 psi 2500 2000 1500 1000 500 0-500 15:43:21 15:43:29 15:43:38 15:43:47 15:43:55 15:44:04 15:44:12 Time Figure 13-3.750" G10 failure pressure @ 3,958 psi It can be seen from Figure 13 that the ball failed at 3,958 psi and the ball breaks into a sharp 2 halves break. 14
Figure 14-3.750" G10 failure @ 3,958 psi 15
5. COMPARISON 5.1 3.750 Ball Lowest Failure Pressure 4,000 3.750" Ball Lowest Failure Pressure (psi) 3,958 3,968 3,950 3,900 3,850 3,840 3,800 3,750 Extruded PEEK Controlled G10 BDC injection molded PEEK Figure 15-3.750" Ball Lowest Failure Pressure Chart It can be seen from Figure 15 that the BDC INJECTION MOLDED PEEK ball has highest pressure of all. The pressure shown is the average of the two break pressures at its weak orientation. The Controlled G10 breaks into 2 halves, which could create problems downhole by getting stuck into the seat. In the 2 halves break, the bottom half quickly turns 90 due to high pressure force and thus getting stuck. Once the ball is stuck sideways, pressure can t build up on the ball sleeve and therefore, the ball might need to get milled. The BDC INJECTION MOLDED PEEK may have getting stuck and milling problems if the ball landed at its strong orientation. Also, since the ball built up pressure after the break it can throw off pumping personnel suggesting something getting stuck other than the ball. Extruded PEEK yields into the seat losing seal therefore, pressure can t build up on the ball such that it gets pushed through the seat therefore, milling may be required. In this test however, due to high ductility of the material the ball extruded in such a way that it came out the other end. More tests may be needed to be done to confirm consistency. 16
BDC INJECTION MOLDED PEEK ball shows consistency in terms of break pressure, holding pressure, break and the back pressure. Since the ball outperforms G10 ball therefore, it is a better ball and has higher pressure rating. The ball is also better because it is lighter than the G10 ball. 6. CONCLUSION - BDC INJECTION MOLDED PEEK is a better ball in 3.750 category. It is light and takes higher pressure. However the dimple side getting stuck into the sleeve could create problems. - Extruded PEEK extrudes through the seat and it has slightly lower pressure than BDC INJECTION MOLDED PEEK. More tests are needed to be done on this material to confirm extrude through exit consistency. However, there is a chance that the ball may get stuck into the seat. 17