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Beam Pump Artificial Lift Optimization

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Some good practices and rules of thumb for optimizing beam pump applications, as well as other artificial lift troubleshooting techniques

Beam Pump Artificial Lift Optimization

  1. 1. Beam Pump Artificial Lift Optimization Putting All The Pieces Together Daryl Curtis Drilling & Production Co. September 24 th & 25 th , 2008
  2. 2. Artificial Lift Optimization – What Does It Mean? <ul><li>Webster’s defines optimize as “to make as perfect, effective, or functional as possible” </li></ul><ul><li>You should know what your desired outcome or goal is when optimizing a unit – optimize means many things to many people </li></ul><ul><ul><li>maximize production </li></ul></ul><ul><ul><li>minimize loading on the rods or unit </li></ul></ul><ul><ul><li>optimize electrical costs </li></ul></ul><ul><ul><li>sand control </li></ul></ul>
  3. 3. Artificial Lift Optimization – What Does It Mean? <ul><li>Optimizing a beam pump requires more than optimizing the pumping unit itself. It requires knowledge of the whole pumping system, from the reservoir to the pumping unit. </li></ul><ul><li>Optimization does not require the use of expensive software packages or unique tools </li></ul><ul><li>Optimization is best when a “big picture” perspective is incorporated into the design </li></ul>
  4. 4. Artificial Lift Optimization – Required Information <ul><li>Reservoir Data </li></ul><ul><ul><li>Reservoir Pressure </li></ul></ul><ul><ul><li>Deliverability / Inflow Rate, Q </li></ul></ul><ul><ul><li>Fluid Data – GOR, Water Cut, Fluid Gravities/ Densities, Paraffinic?, CO2 / H2S content </li></ul></ul><ul><ul><li>Rock / Formation Type – consolidated, friable, clays, migrating fines *** </li></ul></ul><ul><li>*** Not necessary – good to know </li></ul>
  5. 5. Artificial Lift Optimization – Required Information <ul><li>Well Design </li></ul><ul><ul><li>Total Depth </li></ul></ul><ul><ul><li>Perforation Intervals </li></ul></ul><ul><ul><li>Casing Design – shoe depths, ID, liner top, ect. </li></ul></ul><ul><ul><li>Gyros or Deviation Surveys – directional, horizontals, doglegs, ect. (if available) </li></ul></ul>
  6. 6. Artificial Lift Optimization – Required Information <ul><li>Production String Design </li></ul><ul><ul><li>Pump – depth, type, size, design, ect. </li></ul></ul><ul><ul><li>Rods – length, size, design (taper) , grade (C, D, High Strength, ect) , guides (type and material) , couplings (type and material) </li></ul></ul><ul><ul><li>Tubing – type, size, anchor depth </li></ul></ul>
  7. 7. Artificial Lift Optimization – Required Information <ul><li>Pumping Unit </li></ul><ul><ul><li>Unit Type – Conventional, Mark II, Air Balance </li></ul></ul><ul><ul><li>API Specs – i.e.C 320-210-100 </li></ul></ul><ul><ul><li>Stroke Length – current </li></ul></ul><ul><ul><li>Strokes per minute (SPM) – current </li></ul></ul><ul><ul><li>Motor size </li></ul></ul><ul><ul><li>Rod rotator / Tubing rotator? </li></ul></ul><ul><ul><li>Timer / Pump Off Controller? </li></ul></ul>
  8. 8. Artificial Lift Optimization – Required Information <ul><li>Production Files </li></ul><ul><ul><li>Production History </li></ul></ul><ul><ul><li>Pull tickets </li></ul></ul><ul><ul><li>Dynos </li></ul></ul><ul><ul><li>Fluid Levels </li></ul></ul><ul><ul><li>Pump repair tickets </li></ul></ul><ul><ul><li>Well work programs – workovers, stimulations, ect. </li></ul></ul>
  9. 9. Artificial Lift Optimization – Required Information <ul><li>Initially this is a lot of information, but it is essential for analyzing the current conditions and for making the best recommendations. </li></ul><ul><li>This data will be important for any future work or measurements – such as dynos, fluid levels </li></ul><ul><li>Develop a record keeping system that is efficient and allows you access to this information in one place – i.e. file folder </li></ul>
  10. 10. Artificial Lift Optimization – Typical Design Situations <ul><li>New well </li></ul><ul><ul><li>good understanding of well deliverability </li></ul></ul><ul><ul><li>deliverability unknown </li></ul></ul><ul><li>Existing well </li></ul><ul><ul><li>currently producing, have production history and pull history </li></ul></ul><ul><ul><li>No unit, have production history and pull history </li></ul></ul><ul><ul><li>No unit, no history </li></ul></ul>
  11. 11. Artificial Lift Optimization – Optimization Considerations <ul><li>First step in optimizing your artificial lift system is to simulate the current conditions </li></ul><ul><ul><li>Use Rodstar, a vendor’s simulation program (SROD), or the following free programs </li></ul></ul><ul><ul><ul><li>Qstar ( www.Echometer.com ) </li></ul></ul></ul><ul><ul><ul><li>SRP Calculator ( www.unicous.com/oilgas/srpcalc.php ) </li></ul></ul></ul><ul><li>If necessary, run a dynomometer to determine – </li></ul><ul><ul><li>Pump condition </li></ul></ul><ul><ul><li>Loads on the rod string and pumping unit </li></ul></ul><ul><ul><li>System efficiency </li></ul></ul><ul><ul><li>Balance the unit </li></ul></ul><ul><ul><li>*** Dynos are more critical when dealing with loads, especially on wells deeper than 1500 feet </li></ul></ul>
  12. 12. Artificial Lift Optimization – Simulate / Measure Initial Conditions <ul><li>When simulating current conditions and/or when running a dyno, it is critical that the following information is correct / accurate – </li></ul><ul><ul><li>Check to insure that the input information is accurate / correct </li></ul></ul><ul><ul><li>Check to make sure that the production value calculated by the dyno or simulation program matches, within a few bbls, the actual production. </li></ul></ul><ul><ul><li>When comparing a simulation to a dyno, make sure the structure, gearbox, and rod loads are similar. Polish rod horsepower and Peak Polish Rod Load should also be similar </li></ul></ul>
  13. 13. Artificial Lift Optimization – Pump Condition <ul><li>NOTE: Do not run a dyno for measuring load conditions if you know the pump is slipping or bad </li></ul><ul><li>In almost all dynos, pump efficiency is calculated from the card </li></ul><ul><ul><li>The pump efficiency will be correct if the pump size, stroke length, and SPM values were correct </li></ul></ul><ul><li>If a well has fluid over the pump, the dyno may calculate an inaccurate fluid level. Either get a fluid level or a fluid gradient when the dyno is run </li></ul><ul><li>Check the pump condition by valve checks </li></ul><ul><li>Note: A pump can have 100% fillage, but less than 100% pump efficiency </li></ul>
  14. 14. Artificial Lift Optimization – Structure Loading <ul><li>Check the unit’s structure loading by dividing the peak polish rod load (lbs) by the unit structure rating (100 lbs) </li></ul><ul><ul><ul><li>Unit size is a C 320-256-120 </li></ul></ul></ul><ul><ul><ul><li>Structure rating is 256 (100 lbs), or 256 x 100 = 25,600 lbs </li></ul></ul></ul><ul><ul><ul><li>The peak polish rod load = 17,111 lbs </li></ul></ul></ul><ul><ul><ul><li>Maximum Structure Loading = 17,111 lbs / 25,600 lbs = .67 or 66.8% </li></ul></ul></ul><ul><li>Don’t trust the load value if there is significant pump slippage </li></ul>
  15. 15. Artificial Lift Optimization – Gearbox Loading <ul><li>You can calculate a gearbox loading, or you can run a Torque Analysis when you run your dyno. A gearbox torque analysis will predict a balanced maximum gearbox loading. </li></ul><ul><li>Check the gearbox load by dividing the peak upstroke torque by the gearbox rating </li></ul><ul><ul><ul><li>Unit size is a C 320-256-120 </li></ul></ul></ul><ul><ul><ul><li>Gearbox rating is 320,000 in-lbs </li></ul></ul></ul><ul><ul><ul><li>The peak upstroke torque = 525,304 in-lbs </li></ul></ul></ul><ul><ul><ul><li>Maximum Gearbox Loading = 525,305 in-lbs / 320,000 in-lbs </li></ul></ul></ul><ul><ul><ul><li> = 1.64 or 164% <OVERLOADED> </li></ul></ul></ul><ul><li>It is possible that the unit needs to be balanced, which would lower the peak load value. The unit can be balanced with an amp meter or based on the Torque Analysis recommendations </li></ul>
  16. 16. Artificial Lift Optimization – Miscellaneous Notes <ul><li>Dyno’s and simulation programs will calculate rod loading </li></ul><ul><ul><li>Make sure you know the grade of rod and taper design </li></ul></ul><ul><li>Dyno’s and simulation programs will calculate motor sizes based on depth and production </li></ul><ul><li>Beam Balanced Units – dyno’s do not accurately measure the structure and the gearbox loads of beam balanced units </li></ul><ul><ul><li>The programming was designed for conventional, Mark II, or air balanced units </li></ul></ul>
  17. 17. Artificial Lift Optimization – Design Guidelines – Pump Efficiency <ul><li>0% to 60% </li></ul><ul><li>60% to 90% </li></ul><ul><li>> 90% </li></ul><ul><li>Reduce the production capacity of the pumping system </li></ul><ul><li>Ideal Range – no need to do anything </li></ul><ul><li>Increase the production capacity of the pumping system </li></ul>
  18. 18. Artificial Lift Optimization – Design Guidelines – Structure Loading <ul><li>15% to 40% </li></ul><ul><li>40% to 70% </li></ul><ul><li>70% to 100%+ </li></ul><ul><li>The unit is too big for the current application. The unit could be downsized, but should not be a problem if left unchanged. This condition will reduce the system efficiency and increase electrical usage and cost. </li></ul><ul><li>This is the optimum unit structure load range </li></ul><ul><li>The unit is too small for the current application. The options available for increasing production are limited because there is little room to increase the structure load without exceeding the structure rating. </li></ul>
  19. 19. Artificial Lift Optimization – Design Guidelines – Gearbox Loading <ul><li>< 85% </li></ul><ul><li>85% to 95% </li></ul><ul><li>95% to 115% </li></ul><ul><li>> 115% </li></ul><ul><li>Good, safe range to be in </li></ul><ul><li>Should consider new unit design if the loads can’t be reduced. Before increasing production capacity, run simulation to determine if unit can handle the loads </li></ul><ul><li>Gearbox can probably withstand the load, but should replace with unit with higher gearbox rating when feasible. Not recommended as a long term solution </li></ul><ul><li>The gearbox life will be reduced. A bearing will probably fail </li></ul>
  20. 20. Artificial Lift Optimization – Case 1: Increase Capacity <ul><li>Run a dyno </li></ul><ul><ul><li>make sure pump is in good condition before spending $$$ for dyno; </li></ul></ul><ul><ul><li>If pump is not in good condition, make sure you know what the pump efficiency is for the simulation – either pull and replace the pump, or simulate with worn pump </li></ul></ul><ul><li>Obtain operating and static fluid levels </li></ul><ul><li>Calculate max production from well (Vogel’s method) </li></ul><ul><li>Simulate well using Rodstar, QStar, SRod, etc. </li></ul><ul><li>Once simulation accurately reflects the current situation, then you are ready to size the unit *** see notes regarding how to check for accuracy </li></ul><ul><li>Use the peak polish rod load from the dyno to calculate structure loading (Determines minimum API unit structure #) </li></ul><ul><li>Use the maximum torque from the dyno to calculate gearbox loading (Determines minimum API unit gearbox rating #) </li></ul><ul><li>Choose a Unit Size based on min loads and “Rules of Thumb” – Vendor spec books, available units in bone yard, units in vendor’s yard </li></ul>
  21. 21. Artificial Lift Optimization – Case 2: Size unit for well w/no unit <ul><li>Obtain static fluid level </li></ul><ul><li>Must know deliverability of well, or best guess </li></ul><ul><li>Simulate well using Rodstar, QStar, SRod, etc. </li></ul><ul><li>Once simulation accurately reflects the current situation, then you are ready to size the unit *** see notes regarding how to check for accuracy </li></ul><ul><li>Use the peak polish rod load from the simulation to calculate structure loading (Determines minimum API unit structure #) </li></ul><ul><li>Use the maximum torque from the simulation to calculate gearbox loading (Determines minimum API unit gearbox rating #) </li></ul><ul><li>Choose a Unit Size based on min loads and “Rules of Thumb” – Vendor spec books, available units in bone yard, units in vendor’s yard </li></ul>
  22. 22. Artificial Lift Optimization – Dialing in your design <ul><li>Once a unit is chosen, re-run the simulation program using the stroke length options (i.e. if you have three stroke length options, run three simulations, each run at a different stroke length). Remember, do not change pump size, rod design, or SPM’s. </li></ul><ul><li>Check to see what the calculated loads are. Make a comparison table that shows calculated loads (gearbox, structure, rod) vs. variables (i.e. SPM, stroke length, pump size) </li></ul><ul><li>You may have to vary pump size combinations and SPM’s to zero in on a design. Pump sizing reaches a point where you don’t gain any more production due to increases in rod stretch – deep wells </li></ul><ul><li>Make sure that you stay within the physical parameters of the unit that you chose. </li></ul><ul><li>You may not be able to vary anything except surface components – i.e. no $$$ for rig. Factor that in but don’t let it override good design technique. Choose the unit size and design for the long term objectives, not short term </li></ul><ul><li>Utilize the “Design Rule of Thumb” guidelines to help </li></ul>
  23. 23. Artificial Lift Optimization – Unit Sizing “Rules of Thumb” <ul><li>Always design for worst case conditions (i.e. pumped off, 100% pump efficiency) </li></ul><ul><li>Don’t use min unit size if recommended by simulation program (i.e. Rodstar) </li></ul><ul><li>Try to achieve a system efficiency of 50% </li></ul><ul><li>Try to use the slowest SPM and the largest pump combination possible </li></ul><ul><li>For wells that produce more than 75 bbls per day, use a unit with three crank holes </li></ul><ul><li>Design unit so that the longest stroke length doesn’t overload the gearbox or the structure </li></ul><ul><li>Design for min and max production rates </li></ul><ul><li>Don’t forget that rod designs have a big effect on loading, as do pump sizes </li></ul>
  24. 24. Artificial Lift Optimization – Sucker Rod Design <ul><li>Rod designs seem to be misunderstood on a regular basis, or forgotten </li></ul><ul><li>You may have the luxury of pulling your well and replacing the rod string – or you may not. </li></ul><ul><li>Some simulation programs (such as Rodstar) will give you a design based on your simulated condition. If you are not careful and lock in the design, the design will always change as your conditions change. Lock in a design and stick with it. </li></ul><ul><li>Quick and accurate way to design a rod string without a simulation program is the rod design tables (handout) – utilizes percentages </li></ul>
  25. 25. Artificial Lift Optimization – Sucker Rod Design <ul><li>Once you’ve decided on a rod design, plug it into your simulation program and re-calculate loads. Check against the physical parameters of your unit and rules of thumb design guidelines. </li></ul><ul><li>As a final design consideration, make sure your rod design will handle worst case scenarios – i.e. highest loads, SPM’s, production, ect. This may not be the most efficient rod design, but it keeps you out of trouble if conditions change downhole or on the surface. You are covered in all situations. </li></ul>
  26. 26. Artificial Lift Optimization – Rod Guides <ul><li>Rod guides are an integral component in a good design in wells that have deviations, doglegs, or are directional / horizontal. Directional surveys or gyros become very helpful in a guide design </li></ul><ul><li>Guides come in many shapes, sizes, materials, and for many applications. Know what your application or conditions are in order to properly choose a guide for your well </li></ul><ul><li>In wells that have rod / tubing wear problems, guides can significantly improve tubing and rod life, and run times </li></ul><ul><li>Always run a rod rotator in rod / tubing wear situations – cheap insurance and gives a longer run time </li></ul>
  27. 27. Artificial Lift Optimization – Rod Guides – Snap Ons <ul><li>On pretty straight holes, with low production rates (< 75 bpd) snap on guides (either hard rubber or nylon) should be sufficient for protection. Guide with a minimum of three guides per rod </li></ul><ul><li>If the well produces a lot of gas with the fluid, use nylon guides. The hard rubber material will swell and tear up </li></ul><ul><li>Snap on guides are fine if you need to make a quick decision and run the well back on but want some extra wear protection. </li></ul><ul><li>Snap on guides are not a long term solution for any conditions that do not represent #1 or #2 </li></ul>
  28. 28. Artificial Lift Optimization – Rod Guides – Molded Guides <ul><li>If you have high fluid rates (> 75 bpd) and a deviated / dog leg / directional well, it is highly recommended to spend the money on molded on guides. </li></ul><ul><li>Molded on guides come in many different materials – need to know the operating conditions to correctly choose the right material (i.e. fluid composition, temperature, deviation, side loads, ect.) </li></ul><ul><li>Do not guide more than 4 guides per rod, or less than 3 guides per rod. More than 4 guides per rod is almost never needed – but, there may be special circumstances where that is OK. Too much turbulance (corrosion) and rod stiffness created which could cause premature failures. </li></ul><ul><li>Rod guides do not help with removing wax buildup in a well that has significant wax problems – just compounds the issue. </li></ul><ul><li>If you install a new guided rod string, make a habit to caliper the guides the first few times the well is pulled, top to bottom. The info will help in understanding side loads, wear areas, and improve on the future designs </li></ul>
  29. 29. Artificial Lift Optimization – Final Thoughts <ul><li>In almost every case, the rod string will have some of the highest compression right above the pump </li></ul><ul><li>Run a stabilizer bar on top of the pump to prevent premature failures at the pump – a stabilizer bar is basically a 1” rod that is 4’ to 6’ in length, guided with 4 molded on guides. Also helps keep the pull rod centralized </li></ul><ul><li>Sometimes it is better to run a 1-taper rod string instead of a 2-taper rod string. Example – a 7/8” string vs. a ¾” and 7/8” string. The 7/8” string is stiffer and will have less issues due to compression. Of course this is only if the unit can handle the additional loads. </li></ul><ul><li>Consider tubing rotators, poly lined tubing, or corod for wear issues </li></ul><ul><li>Work very closely with the pump shop, the rod / tubular vendor, and the pumping unit vendor to come up with the best design for your application. Often times their input will save you $$$, and remember that they rely on you to be the expert on your well. </li></ul>

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