Optimizing Rod Lift in High Water Cut Resource Plays: A Divide County North Dakota Three Forks Case Study

Transcription

1 Optimizing Rod Lift in High Water Cut Resource Plays: A Divide County North Dakota Three Forks Case Study Danny Green Production Operations Engineer SM Energy Company July 16, 2014

2 Scope and Purpose Ø As resource play development expands outward from sweet spots, operators are forced to evaluate areas with higher water cut Ø In these economically sensitive areas, appropriately designed artificial lift can be the difference between success or failure 2

3 Gooseneck Area Overview Ø Gooseneck ~36,000 acres 3

4 Gooseneck Statistics Ø Primarily upper Three Forks play Ø 7,800 to 8,800 true vertical depth Ø ~14 thick, ~8% porosity, ~35% water saturation upper TFS target, ~4,250 psi reservoir pressure Ø 1280 acre spacing units (10,000 laterals) Ø Multi-stage open hole completions (primarily swelling packers and ball actuated sleeves) Ø 48,000 bbls (hybrid fluid) and 2,500,000 lbs (20/40 & 40/70 sand) frac jobs Ø Stabilized water cuts range from 27% to 68% Ø Produced water density around 9.70 ppg to 9.95 ppg 4

5 Rod Lift Design Origins Ø Started with conventional pump units Ø 86 taper rod string with guided K sinker bars Ø 2.00 x26 RHBM rod pump Ø Pump intakes set at 7,200 to 8,100 Ø AJAX (single cylinder gas engine) prime mover Ø Designed to move ~450 BPD at 6.5 spm (100% efficiency) 5

6 Rod Lift Design Origins Ø Evaluated several rod lift dynamometer analyses Ø Assessed inflow performance relationships Ø Wells appeared to have the potential to produce additional fluid 6

7 Gooseneck Rod Lift Design Progression Ø As co-op electricity and natural gas generators became available (allowing for electric prime movers), a new rod lift design was initiated Ø Rotaflex (long stroke) pumping unit Ø 100 hp electric prime movers with VSDs and rod pump controllers Ø Same rod string & intake depth Ø 2.25 x36 THM tubing pump Ø Designed to move ~600 BPD at 3.7 spm (100% efficiency) Ø Lift design borrowed and adapted from SM s Madison water flood unit Ø Recently advanced the design to included a 2.75 THM pump in 3-1/2 tubing 7

8 Rod Lift System Comparison ; 2.00 x26 RHBM ; 2.25 x36 THM Ø 144 net downhole stroke Ø 85.7% of surface gross stroke Ø Fast unit speed creates different velocities along the rod string, reducing net stroke & causing gas interference issues Ø 287 net downhole stroke Ø 93.8% of surface gross stroke Ø Slow pumping speed reduces rod string harmonics & increases the percent of stroke surface stroke transmitted to the pump 8

9 Longevity and Reliability Comparison Rod Lift Design Type ; 2.00 x26 RHBM Well Count ; 2.25 x36 THM Date of First Installation 5/27/2010 3/17/2011 Rod Lift Failures 10 9 Average Failures per Well per Year Mean Time Between Failure (years) Average Pumping Unit Speed (spm) Average System Cycles per Year 3,416,400 1,944,720 Average Cycles Before Failure 8,332,600 15,557,760 9

10 Fluid Production Comparison 10

11 Oil Production Comparison 11

12 Additional Comparisons Rod Lift Design Type ; 2.00 x26 RHBM Well Count ; 2.25 x36 THM Designed Rate 450 BPD 600 BPD Pumping Unit Speed 6.5 spm 3.7 spm Gross Surface Stroke Net Downhole Stroke (Designed) Average Six Month Fluid Recovery 88,436 bbls 115,820 bbls Average Six Month Oil Recovery 43,699 bbls 59,163 bbls Average One Year Oil Recovery 72,404 bbls 97,670 bbls Average Year and Half Oil Recovery 93,220 bbls 127,950 bbls Average Stabilized Water Cut 41.6% 45.3% Ø Long stroke system averages 35.4% more oil in six months, 34.9% more oil in one year, and 37.3% more oil in 1.5 years Ø Increased recovery appears to be long term - not simply rate acceleration 12

13 Economic Comparison Ø ~57,000 more barrels of oil recovered in 3.17 years with the average ; 2.25 x36 design Ø Rate of return is 100% at $80/bbl oil Ø ROR remains over 100% until prices approach $21/bbl 13

14 Divide County Recovery Analysis Ø Only 34 wells in SM operated evaluation Ø Expanded evaluation to include production from 271 other Divide County wells Ø Majority of other wells in the county using conventional geometry pumping units 14

15 Divide County Fluid Evaluation 68% increase at year two 15

16 Divide County Oil Evaluation 126% increase at year two 16

17 Advantages and Disadvantages ; 2.00 x26 RHBM ; 2.25 x36 THM Ø Benefits ü Low capital cost ü Can use natural gas prime mover ü Pump barrel retrievable on rods ü Very standard system Ø Drawbacks ü Low fluid rate ü High pumping unit speed ü Poor gas handling ü Short net downhole stroke ü Increased failure frequency Ø Benefits ü Long & slow unit stroke ü Extended run time ü Increased production rate ü Great gas handling ü No apparent negative reserve impact Ø Drawbacks ü Expensive capital cost ü Require electric prime mover ü Pump barrel retrieval requires tubing pull ü Relatively uncommon lift design 17

18 Key Takeaways and Conclusions Ø The long stroke unit with tubing pump lift design has: Ø Increased run times Ø Reduced workover expenses Ø Improved oil rates and recovery Ø These value adding factors have contributed to favorable economics in the Gooseneck play Ø This added profitability has allowed SM to pursue higher water cut resources that may have otherwise been uneconomical if lifted with traditional methods 18

19 Discussion Ø Questions? Ø Comments? Thank You! 19