1. Andy Martin, Alexis Marmol & Abdullah Khan IPS-15-8
12/27/2018
Beyond Penetration: How Shot Density Variation can be used to Modify Production or Injection Profiles
Andy Martin, Alexis Marmol &
Abdullah Khan
IPS-15-8

2. Agenda
Perforating Analysis
Cross Flow
Water Injector
Oil Producer

3. Perforation Analysis Software

4. Perforating Analysis Penetration Model Based Stressed Rock
Skin Model for Combinations of Different Static and Dynamic Conditions
Multi-zone Analysis Based on Mechanical Earth Model

5. Productivity from New Software
Multiple Gun Strings
Multiple Casing Analysis
Multiple Zone Analysis

6. Productivity Comparison
DUB
Rock Optimized
12%
Deep Penetrating
Non-DUB
30%
Karakas & Tariq model
Lc/L = 0.8 for DUB, 0.1 for non-DUB
8 in. of damage
Additional penetration increases effective wellbore radius
More important for deep damage
More important for dirty perforations
Perfect combination is DUB & Rock Optimized

7. Example—Single Zone
2 7/8” gun shot in 7” casing
Estimate flow rate:

8. Same Gun Two Zones 6 spf for both intervals Same flow from both
Modify flow rates by adjusting shot density:
Top 12 spf
Bottom 1 spf

9. Cross Flow

10. Case Study—Cross Flow Add perforations to high pressure zone
Expect cross flow—but how much?
Can this new interval be perforated safely on Wireline?
Cross flow

11. Tool Lift Summary Low flow rate: Tool lift acceptable High flow rate:
Head tension up
Head tension down
Tool lift force
High flow rate:
Tool lift too high

12. Reducing Cross Flow Reduce shot density to choke back production
Reduce interval
Flow rate reduced to ~10%
Dynamic underbalance
Balanced perforating
Partial penetration
If we take the 26% increase in penetration and input the Berea data (8200 psi UCS, 5000 psi confining) we can compute productivity for different types of perforating. (Note that the actual penetration in rock was used in this study.)
In this case we looked at on balance, non-PURE perforating and 80% PURE perforating. (PURE perforating was discovered by Schlumberger and reported in SPE Since then more than 30 papers have been written on PURE perforating.)
As we can see, the productivity is increased by shooting deeper. In both cases PowerJet Nova out performs PowerJet Omega. The contrast is greater with more formation damage.
PURE perforating is better than non-PURE of course, but the contrast between the two types of shaped charge is less with cleaner perforations.
The highest productivity is delivered with PowerJet Nova and PURE.
As a side note, a section 4-type CFE series of tests were performed to measure the performance of PowerJet Nova vs PowerJet Omega. Both non-PURE and PURE conditions were used for the tests. Results showed similar CFE numbers indicating similar damage for non-PURE and similar cleanup for PURE. We conclude that PowerJet Nova charges behave in a similar way to PowerJet Omega charges in terms of perforation tunnel damage and clean up.
Now safe to perforate on Wireline

13. Water Injector

14. Case Study—Water Injector
10 zones
Permeability range:
3300 mD to 2.3 mD
Minimum requirement:
40,000 bwpd
Ideally:
38,000 bwpd into zones 3 & 4
70 bwpd into 7 & 8
6200 bwpd into 9 & 10

15. All Intervals Shot the Same Way
Total injection rate achieved—62,000 bwpd
Injection into 3 & 4, 7 & 8 achieved
Can we increase rate into 9 & 10?

16. Modified Shot Density Choke back production on 1, 2, 5 & 6
Increase shot density on 9 & 10
Better but not perfect!

17. Final Job Design Dynamic underbalanced used for all zones
Cut clean up period from program
Perforate bottom low permeability intervals first:
(7, 8, 9 & 10)
Injection test above frac pressure
40,000 bwpd achieved
Complete perforation of upper intervals
Final injection rated
60,000 bwpd limited by rig capacity

18. Oil Producer

19. Modified Perforating—SPE 103070
Production log before
Most of the flow coming from unit 6
Flow efficiency estimated at 20%
Skin 36

20. Theoretical Flow—SPE 103070 Adjust reperforation strategy
Use latest generation charges
Combination of adjusting spf and dynamic underbalance to balance flow profile

21. Production After—SPE 103070 Total skin reduced from 36 to 3.1
Vertical flow efficiency increased from 19 to 80%—optimizing drainage

22. Questions? Perforating Perforating Analysis Cross Flow Water Injector
Oil Producer
Questions?
* Mark of Schlumberger