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WELCOME 2004 PLUNGER LIFT SEMINAR PRESENTED BY. TOPIC. The Theory of Plunger Lift. Plunger Lift = method of artificial lift that uses well’s gas energy as the prime mover of liquids that have caused loading. Theory of Operation. Plunger acts as interface between liquids and gas energy
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TOPIC The Theory of Plunger Lift
Plunger Lift = method of artificial lift that uses well’s gas energy as the prime mover of liquids that have caused loading Theory of Operation • Plunger acts as interface between liquids and gas energy • When surface control parameters are met, sales valve opens and exhausts pressure to create differential pressure across plunger • Differential Pressure then lifts liquids & plunger to surface • Sensors record plunger’s arrival, sales time starts • When sales time parameters are met, surface valve closes; plunger goes to off cycle and falls • Cycle repeated • Necessary GLR for 2 3/8” TBG-300scf/BBL/1000’ depth • Necessary GLR for 2 7/8” TBG-450scf/BBL/1000’ depth
TOPIC Gas well loading
GAS WELL LOADINGFalling Below Critical Velocity • Critical Velocity = Velocity of the Gas flowing up the production Tubing. • Falling Below CV -causes the liquids to start to fallback and start the liquid loading process • Liquid Loading creates hydrostatic head pressure on the formation • Result - loss in production due to hydrostatic head pressure (back pressure) created on formation.
GAS WELL LOADINGThe Production Loss • Hydrostatic head pressure experienced from liquid loading can calculated from fluctuations in FBHP or CP • The Fluctuation in FBHP or CP can be used in a calculation with PI ( Productivity Index) or placed in relationship with an IPR (Inflow Performance Ratio) to analyze the production loss
1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 2-7/8” Tbg 2-3/8” Tbg Flow Rate - MCFD 2-1/16” Tbg 1-1/2” coil 0 100 200 300 400 500 600 Flowing Tubing Pressure - psig CRITICAL VELOCITY of TUBING
TOPIC EVALUATION and DESIGN
EVALUATION • IDENTIFYING LIQUID LOADING and EVALUATING • Production Decline Curves • Lift Pressure Requirements • Calculating Lift Capabilities • Flowing Gradient Surveys • Calculating Uplift Capabilities • Single Point Slope N =1 • Multi Point Slope N = ?
IDENTIFYING A CANDIDATEUsing Production Decline Curves • PRODUCTION DECLINE CURVES • 1st—Identify the Following • Flow above Critical Velocity • Need Well bore Schematic • Flowing Well Conditions and Rates (FTP---MCF/D) • Calculate CV of Production Tube and Liner • Locate These Points on Decline Curve
TOP NORMAL DECLINE LOADING DEVIATION WELL PRODUCTION PLUNGER INSTALLED CUMULATIVE PRODUCTION INCREASE TIME Typical Gas Well Production Decline Curve
Lift CapabilitiesMore FluidMore Pressure More Gas Required to Lift
CALCULATING LIFTING GAS AVAILABLE • Example: Tubing Depth 10000’ Casing Pressure 800# 2 3/8” Tbg. Factor 1.5 • Formulae: TBG Depth 1000 X CP X Tbg Factor = SCF 10 X 800# X 1.5 =12000 • Rule of Thumb= 300SCF per BBL per 1000’ lift 300 SCF X 10 =3000SCF Per BBL 12000/3000 =4 BBL LIFT Capable
DESIGN • ·Tubing Size • ·Tubing Pressure – Discuss • ·Casing Pressure – Discuss • ·Tubing Depth vs. Perforations • · Fluid Height – Casing and Tubing
TUBING PRESSURE • TUBING PRESSURE IS A RELEVANT POINT of MEASURE IN ALMOST EVERY FORM of ARTIFICIAL LIFT. • Tubing Pressure is measured to indicate real time Flowing and Shut In conditions • TP is subtracted from the CP to calculate Hydrostatic Fluid Column pressure • PLUNGER LIFT SHUT IN CYCLE • TP can be used to initiate an Open Cycle to try and lift a plunger and it fluid column to surface • When the Annulus is not communicated (Pkr Set) • When Production Tubing is cemented in (Slim Hole) • When TP exceeds fluctuating Line Pressure by a sufficient amount
CASING PRESSURE • CASING PRESSURE is used as a direct indicator of BHP • Casing Pressure • Used in the Calculation of • Hydrostatic Fluid Column in the Tubing • Lift Capabilities • BHP • PLUNGER LIFT SHUT IN CYCLE
TUBING DEPTH vs. PERFORATIONS • TUBING PLACEMENT in WELLS with MULTIPLE PERFORATED INTERVALS or MASSIVELY THICK RESEVOIRS is CRITICAL • TUBING PLACED TO DEEP CAN CAUSE • Excessive Fluid Transfer from the Annulus when plunger Open Cycle is initiated can cause • Hydrostatic Fluid Column Pressure Behind the Plunger • Loss of Gas Differential Pressure Interface on Plunger causing it to no arrive • Tubing to Load Up
GRADIENT to FLUID HEIGHT • FLUID GRADIENT’S ARE USED TO CALCULATE FLUID HEIGHTS • GRADIENTS ARE USED IN CONJUCTION WITH PRESSURES OBTAINED • BHP TESTING • SURFACE PRESSURE RECORDING • TYPICAL GRADIENT’S • CONDENSATE .20 PSI PER FOOT • OIL .33 PSI PER FOOT • FRESH WATER .43 PSI PER FOOT • SALT WATER .50 PSI PER FOOT
GRADIENT to FLUID HEIGHTSurface Pressure Example • SITP = 300# • SICP = 600# • CP-TP = DP = 300# • Liquid Being Produced = 100% Oil = .33 Gradient • 300# DP / .33 Grad. = 909 ft of Liquid in Tubing
Import Tool – Plunger Lift APPLICATION
Solar Panel Lubricator Catcher Controller Dual “T” Pad Plunger Bumper Spring Plunger Lift SystemsApplications • Unload Wells That Continue to Load Up With Produced Wellbore Fluids • Reduce Fallback in Wells Being Produced by Intermittent Gas Lift • Increase Production in Wells With Emulsion Problems • Enhance Production in High Gas/Liquid Ratio Wells • Clean the Tubing I.D. in Wells Experiencing Paraffin Problems
Typical Range Maximum* OperatingDepth8,000’ TVD19,000’ TVD OperatingVolume1-5 BPD 200 BPD OperatingTemperature120° F 500° F Wellbore N/A 60°Deviation Corrosion Handling Excellent Gas HandlingExcellent Solids HandlingPoor to Fair GLR Required300 SCF/BBL/1000’ Depth Servicing Wellhead Catcher or Wireline Prime MoverTypeWell’s Natural Energy Offshore ApplicationN/A at this time System Efficiency N/A Solar Panel Lubricator Catcher Controller Dual “T” Pad Plunger Bumper Spring *Special Analysis Required Plunger Lift System Application Considerations
Solar Panel Lubricator Catcher Controller Dual “T” Pad Plunger Bumper Spring Plunger LiftSystem Advantages • Requires No Outside Energy Source - Uses Well’s Energy to Lift • Dewatering Gas Wells • Rig Not Required for Installation • Easy Maintenance • Keeps Well Cleaned of Paraffin Deposits • Low Cost Artificial Lift Method • Handles Gassy Wells • Good in Deviated Wells • Can Produce Well to Depletion
Solar Panel Lubricator Catcher Controller Dual “T” Pad Plunger Bumper Spring Plunger LiftSystem Limitations • Specific GLR’s to Drive System • Low Volume Potential (200 BPD) • Solids • Requires Surveillance to Optimize
Types of Wells Needing Plunger Lift • Intermitted • Soaped • Shut in and Blown • Gas locking pumping wells • Flowing wells with wide differentials between tubing and casing • Remove Solids Build Up ( Scale, Salt, Paraffin, Ice) • High line pressure • Gas Lift • Velocity Strings