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Pcp operating issues final


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Pcp operating issues final

  1. 1. Operating Issues and Concerns Prof. SSP SINGH
  2. 2. Operating Concerns Heavy Oil <ul><li>Flow Losses </li></ul><ul><li>Due to high viscous fluid. </li></ul><ul><li>Increases; horsepower, torque, discharge pressure. </li></ul><ul><li>Solution </li></ul><ul><li>Use large diameter tubing (Note: if producing sand, flow velocities must be maintained) </li></ul><ul><li>Inject diluents to decrease fluid viscosity. </li></ul>
  3. 3. Operating Concerns Heavy Oil <ul><li>Sand Production </li></ul><ul><li>Important part of production </li></ul><ul><li>Abrasive action accelerates wear of pump, tubing & rod string </li></ul><ul><li>Increased H.P. & Torque requirements </li></ul><ul><li>Restricts pump inlet </li></ul><ul><li>Tubing blockage due to low transport velocities </li></ul><ul><li>Design system to allow for slugs </li></ul>
  4. 4. Operating Concerns Heavy Oil <ul><li>Solution </li></ul><ul><li>To increase tubing flow velocities </li></ul><ul><li>– decrease tubing size </li></ul><ul><li>– inject fluid down annulus & pump @ higher rates </li></ul><ul><li>To reduce wear to pump </li></ul><ul><li>– decrease rotor stator interference fit </li></ul><ul><li>– increase number of pump stages </li></ul><ul><li>– use softer more resilient elastomer </li></ul><ul><li>– operate at lower speeds </li></ul><ul><li>To dissipate sand slugs </li></ul><ul><li>– extend rotors, run booster pump </li></ul>
  5. 5. Operating Concerns Heavy Oil <ul><li>High Viscosity Fluid </li></ul><ul><li>Pumps operate @ rates which are higher than fluid can flow into the pump cavity </li></ul><ul><li>Solution </li></ul><ul><li>To decrease flow velocities through pump </li></ul><ul><li>– use large displacement pumps </li></ul><ul><li>– reduce speed @ which cavities open and close (rpm) </li></ul><ul><li>Reduce fluid viscosity by injecting diluents down the annulus </li></ul>
  6. 6. Operating Concerns Medium Oil <ul><li>Aromatics (benzene, toluene, xylene) </li></ul><ul><li>Swelling, softening and decline in mechanical properties of the elastomer. </li></ul><ul><li>Swelling results in tight rotor/stator interference fit and decrease in volumetric efficiencies </li></ul><ul><li>Tight interference fit results in high pump friction, torque and horsepower requirements </li></ul><ul><li>Solution </li></ul><ul><li>Custom fit, match elastomer to wellbore fluids </li></ul>
  7. 7. Operating Concerns Medium Oil <ul><li>H 2 S and CO 2 </li></ul><ul><li>Creates weak acids that accelerate corrosion </li></ul><ul><li>Extended vulcanization in elastomer causes: </li></ul><ul><li>– decline in mechanical properties </li></ul><ul><li>– high pump torque and decrease in volumetric efficiency </li></ul><ul><li>CO 2 oxidizer, affects mechanical properties </li></ul><ul><li>Solution </li></ul><ul><li>Match elastomer to wellbore fluids </li></ul><ul><li>Use corrosion inhibitor (elastomer compatible) </li></ul>
  8. 8. Operating Concerns Medium Oil <ul><li>Gas Production </li></ul><ul><li>Incomplete pump fillage. </li></ul><ul><li>High operating temperatures </li></ul><ul><li>Solution </li></ul><ul><li>Sump pump below perforations </li></ul><ul><li>Use downhole gas separation equipment </li></ul>
  9. 9. Operating Concerns Light Oil <ul><li>Highest Aromatic, H 2 S and CO 2 Concentrations </li></ul><ul><li>High G.O.R’s </li></ul><ul><li>Same operating concerns as medium oil </li></ul>
  10. 10. Operating Concerns Water <ul><li>Abrasive Solids </li></ul><ul><li>Frac. & coal fines damage stator </li></ul><ul><li>Fluid velocities must transport solids </li></ul><ul><li>Large particles can seize pump. </li></ul><ul><li>Solution </li></ul><ul><li>Sand screens and slotted tag bars reduce amount and size </li></ul><ul><li>of solids entering pump </li></ul>
  11. 11. Operating Concerns Water <ul><li>Dissolved Solids </li></ul><ul><li>Precipitant, forms scale on production equipment </li></ul><ul><li>Scale build-up creates restrictions in tubing and </li></ul><ul><li>flow lines </li></ul><ul><li>– increased horsepower and torque requirements </li></ul><ul><li>Solution </li></ul><ul><li>Chemicals to stop precipitation of dissolved solids </li></ul><ul><li>– Note: Should be compatible with elastomer </li></ul>
  12. 12. Operating Concerns Water <ul><li>Gas Production </li></ul><ul><li>Same concerns as other applications </li></ul><ul><li>H 2 S and CO 2 </li></ul><ul><li>Same concerns as other applications </li></ul>