Gas Well Deliquification Workshop Sheraton Hotel, February 29 March 2, 2016 Enriched Inflow Performance Relationship (EIPR) Curves for Simultaneous Selection of Target Rate & Pump Setting Depth While Visualizing Free Gas Conditions MSc. Sergio Caicedo, Artificial Lift Specialist
Introduction Pumping methods worldwide represents 75% of well population. However, the pump setting depth procedure has not been clearly determined Pumping methods: - Electro Submergible Pump (ESP) - Progressive Cavity Pump (PCP) -Sucker Rod Pumping (SRP) -Jet Pump (JP) Even though they have different working principles there are common issues when designing any pumping method Reservoir Inflow Performance must be considered Free gas has different effects & Limits in each method The Pump Setting Depth must be defined The Pump Setting Depth, Target Rate and Free Gas are interrelated There is a trade-off related to Setting Depth 2
Introduction The Setting Depth Trade-off The deeper the pump s setting depth 1. the lower the free gas into the pump (Fixed Production Rate) 2. the higher the maximum rate that could be produced 3. the higher the temperature (PCP, ESP) 4. the higher the expected failure rate 5. the higher the cost 6. the higher the risk (specially in horizontal wells) 7. the higher the rod weight and stresses (PCP, SRP) 3
Introduction Essentials concepts to keep in mind The real problem is the free gas percentage that actually is passing through the pump after downhole separation (if any) The free gas into the pump is mainly affected by: GOR Pump Intake Pressure (PIP) Bubble Point Pressure (Pbub) Water cut Downhole Gas separation efficiency (if any) THE PROBLEM IS NOT ONLY GOR Do not confuse gas handlers (handling capacity) with gas separators (separation capacity). 4
Introduction Gas uses space which requires higher pump capabilities. For example 50% of free gas to pump 2000BPD liquid will require 4000BPD of pumping capacity (regardless ESP, PCP, SRP, JP) The determination of free gas limit handling capacities for each method (ESP, PCP, SRP, JP) and effects it is not in the scope of this presentation. Notice that Manufacturer s limit could be different than the field engineer s limit. The free gas limit should be an input value imposed by the AL engineer as a design parameter. 5
Introduction INPUT DATA FOR PUMP DESIGN Reservoir data PVT data or Correlations Completion data Production Conditions data Target Rate, GOR,Water%... Pumping design preference parameters Pump setting depth OUTPUT DATA FOR PUMP DESIGN: Pump specifications Operational conditions Oil, water and gas rates at surface Rates at downhole conditions Power consumption Free gas percentage into the pump INPUT DATA FOR GAS LIFT DESIGN Reservoir data PVT data or Correlations Completion data Production Conditions data Target Rate*, GOR, Water % Gas Lift design preference parameters OUTPUT DATA FOR GAS LIFT DESIGN: Valves specifications Valves specifications: diameter, calibration pressure Operational conditions Oil, water and gas rates at surface Gas Lift injection.. Mandrel depths
Theoretical Background 4000 ft 6000 ft T u b i n g P u m p PIP = 1000PSI TIP=174F 20%Free Gas Qgas=600 BPD Qliq=3000BPD PWF = 3000 PSI T=250F The deeper the pump the lower the free gas into the pump (Fixed Production Rate) 7
Theoretical Background T u b i n g 2000 ft 8000 ft P u m p PIP = 2000PSI TIP=202F 10%Free Gas Qgas=300BPD Qliq=3000BPD PWF = 3000 PSI T=250F The deeper the pump the lower the free gas into the pump (Fixed Production Rate) 8
Theoretical Background 4000 ft 6000 ft T u b i n g P u m p PIP = 0PSI TIP=174F 75%Free Gas Qg = 15000 BPD Q=5500BPD PWF = 2000PSI T=250F Maximum Rate due to Reservoir Inflow The deeper the pump the higher the maximum rate that potentially could be produced Maximum Rate due to Pump setting depth 9
8000 ft 2000 ft Theoretical Background T u b i n g Maximum Rate due to Reservoir Inflow P u m p PIP = 0PSI TIP=202F 75%Free Gas Qgas=22000 BPD Q=7200BPD PWF = 1000PSI T=250F The deeper the pump the higher the maximum rate that potentially could be produced Maximum Rate due to Pump setting depth 10
Theoretical Background Typical Pumping Lift design procedure Guess an initial Pump Setting Depth Select Target rate from IPR Calculate Intake Conditions (Free Gas into the pump) Select Pump/Other Components Feasible? Yes.. Many people stop the design here. BUT Can the Target Rate be increased? How much? Can the pump be installed shallower? How Much? Feasible? No Can Target Rate be decreased? How much? Can the pump be installed deeper? How Much? Take another guess in Pump setting depth/target Rate and try again Time consuming procedure that depends on AL engineer experience/skills to find a solution (if any) No visualization about the situation or procedure!!! 11
Theoretical Background Schematic Gas Flow for No Packer & Packer pumping Completions T u b i n g T u b i n g P u m p S e p Downhole Gas Separation Most Gas Through Casing Remaining Gas Through Pump No downhole Packer Separation Efficiency Rotary 60%-90% (ESP) Static 40%-70%(PCP,SRP) Very high when pump below Perforations P u m p T u b i n g No Downhole Gas Separation No Gas Through Casing All Gas Through Pump Downhole Packer Separation efficiency = 0% Jet Pump (Mandatory) ESP,PCP,SRP optional 12
Free Gas percentage into pump T u b i n g P u m p S e p Fregas (1 Freegas sep ( GOR RS @ Pip, Tip) 14.7 (460 TIP ) Z@ Pip, Tip (1 sep) Q 5.615freegas Pip@ Pip 14.7, Tip 520 ( QGOR RS @ Pip, Tip) 14.7 fregas@ Pip, Tip Q(460 TIP ) Z@ Pip, Tip ) O@ Pip, Tip ( Q fw BO @ WPip, Tip @ Pip, TipB 5.615 P 14.7 520 1 f IP OBSERVATIONS ABOUT FREE GAS EQUATION x100% W @ Pip, Tip x100% ) Depends on Pip, Tip, Pbubble, GOR, Rs, %Water, Separation efficiency Requires good knowledge of PVT to predict solution gas Rs @ Pip, Tip Requires good knowledge of Downhole gas separation efficiency - Using a low value to be conservative - Using existing models [Alhanatti 1994] - Most of this models tested with lab data shows that the separator efficiency decreases when rates increases due to liquid dragging - Separation efficiency changes for each method The result must be compared with the Limit of the AL pumping system w Let s see the Free gas values obtained with this equation for different GOR, PIP, %Water, Separation Efficiency with Pbubble 3200 PSI, TIP = 150 F 13
GOR (SCF/STBL) GOR (SCF/STBL) GOR (SCF/STBL) GOR (SCF/STBL) GOR (SCF/STBL) GOR (SCF/STBL) 0%Water 0%Sep 50%Water 0%Sep 95%Water 0%Sep PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 16% 38% 65% 450 0% 0% 0% 0% 5% 20% 36% 55% 75% 600 0% 0% 0% 9% 21% 34% 48% 64% 81% 750 0% 0% 12% 22% 33% 44% 57% 70% 84% 900 0% 0% 22% 31% 41% 52% 63% 75% 87% 1050 0% 0% 30% 38% 48% 57% 67% 78% 89% 1200 0% 0% 36% 44% 53% 62% 71% 80% 90% 1350 0% 0% 42% 49% 57% 65% 74% 82% 91% 1500 0% 0% 46% 53% 61% 68% 76% 84% 92% 1650 0% 0% 50% 57% 64% 71% 78% 85% 93% 1800 0% 0% 53% 60% 66% 73% 80% 86% 93% 1950 0% 0% 56% 62% 69% 75% 81% 87% 94% 2100 0% 0% 59% 65% 71% 77% 82% 88% 94% 2250 0% 0% 61% 67% 72% 78% 84% 89% 94% 2400 0% 0% 63% 69% 74% 79% 84% 90% 95% 2550 0% 0% 65% 70% 75% 80% 85% 90% 95% 2700 0% 0% 67% 72% 76% 81% 86% 91% 95% 2850 0% 0% 68% 73% 78% 82% 87% 91% 96% 3000 0% 0% 70% 74% 79% 83% 87% 92% 96% PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 4% 11% 27% 450 0% 0% 0% 0% 1% 5% 10% 19% 38% 600 0% 0% 0% 2% 5% 9% 16% 26% 46% 750 0% 0% 3% 5% 9% 14% 21% 32% 52% 900 0% 0% 5% 8% 12% 18% 25% 37% 57% 1050 0% 0% 8% 11% 15% 21% 29% 41% 61% 1200 0% 0% 10% 14% 18% 24% 33% 45% 64% 1350 0% 0% 12% 16% 21% 27% 36% 48% 67% 1500 0% 0% 15% 19% 24% 30% 39% 51% 69% 1650 0% 0% 17% 21% 26% 33% 42% 54% 71% 1800 0% 0% 19% 23% 28% 35% 44% 56% 73% 1950 0% 0% 20% 25% 30% 37% 46% 58% 75% 2100 0% 0% 22% 27% 32% 39% 48% 60% 76% 2250 0% 0% 24% 29% 34% 41% 50% 62% 77% 2400 0% 0% 26% 30% 36% 43% 52% 63% 78% 2550 0% 0% 27% 32% 38% 45% 54% 65% 79% 2700 0% 0% 29% 34% 39% 47% 55% 66% 80% 2850 0% 0% 30% 35% 41% 48% 57% 68% 81% Feb. 27 - Mar. 2, 2011 3000 0% 0% 31% 36% 42% 49% 58% 69% 82% Gas Separation increases free gas decreases PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 9% 25% 49% 450 0% 0% 0% 0% 3% 12% 23% 39% 61% 600 0% 0% 0% 6% 13% 22% 33% 48% 68% 750 0% 0% 7% 13% 21% 30% 41% 55% 73% 900 0% 0% 14% 20% 28% 37% 47% 61% 77% 1050 0% 0% 19% for 26% 33% PIP 42% 52% > 65% 80% 1200 0% 0% 24% 31% 38% 47% 56% 68% 82% 1350 0% 0% 29% 35% 42% 51% 60% 71% 84% 1500 0% 0% 33% 39% 46% 54% 63% 73% 85% 1650 0% 0% 36% PSI) 42% 49% 57% 65% 75% 86% 1800 0% 0% 39% 45% 52% 59% 68% 77% 87% 1950 0% 0% 42% Regardless 48% 55% 62% 70% 78% 88% 2100 0% 0% 45% 51% 57% 64% 71% 80% 89% 2250 0% 0% 47% GOR, 53% 59% 66% PIP, 73% 81% 90% 2400 0% 0% 49% 55% 61% 67% 74% 82% 90% 2550 0% 0% 51% %Water, 57% 63% 69% 76% 83% 91% 2700 0% 0% 53% 58% 64% 70% 77% 84% 91% 2850 0% decreases 0% 55% Separation 60% 66% 71% 78% 85% 92% 3000 0% 0% 57% 62% 67% 73% 79% 85% 92% Free gas = 0% Pbubble (3200 GOR 450 SCF/STBL &PIP 400 PSI HAS MORE Water FREE increases GAS THAN free gas GOR 3000 SCF/STBL & PIP 2800 PSI Efficiency PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 2% 6% 16% 450 0% 0% 0% 0% 1% 3% 6% 11% 24% 600 0% 0% 0% 1% 3% 5% 9% 16% 30% 750 0% 0% 1% 3% 5% 8% 12% 20% 36% 900 0% 0% 3% 5% 7% 10% 15% 23% 40% 1050 0% 0% 5% 7% 9% 13% 18% 27% 44% 1200 0% 0% 6% 8% 11% 15% 21% 30% 48% 1350 0% 0% 7% 10% 13% 17% 23% 33% 51% 1500 0% 0% 9% 11% 15% 19% %Sep 25% 35% 54% 1650 0% 0% 10% 13% 16% 21% 28% 38% 56% 1800 0% 0% 11% 14% 18% 23% 30% 40% 58% 1950 0% 0% 13% 16% 19% 24% 31% 42% 60% 2100 0% 0% 14% 17% 21% 26% 33% 44% 62% 2250 0% 0% 15% 18% 22% 28% 35% 46% 64% 2400 0% 0% 16% 20% 24% 29% GOR 37% 48% 65% 2550 0% 0% 17% 21% 25% 31% 38% 49% 67% 2700 0% 0% 19% 22% 26% 32% 40% 51% 68% 2011 Gas 2850 0% Well 0% Deliquification 20% 23% 28% 33% 41% Workshop 52% 69% 3000 0% 0% 21% 24% 29% 35% 42% 54% 70% PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 1% 3% 9% 450 0% 0% 0% 0% 0% 1% 3% 6% 14% 600 0% 0% 0% 1% 2% 3% 5% 9% 18% 750 0% 0% 1% 2% 3% 4% 7% 11% 22% 900 0% 0% 2% 3% 4% 6% 9% 14% 26% 1050 0% 0% 3% 4% 5% 7% 10% 16% 29% 1200 0% 0% 4% 5% 6% 9% 12% 18% 32% 1350 0% 0% 4% 6% 7% 10% 14% 20% 35% 1500 0% 0% 5% 7% 9% 11% 15% 22% 37% 1650 0% 0% 6% 8% 10% 12% 17% 24% 40% 1800 0% 0% 7% 8% 11% 14% 18% 26% 42% 1950 0% 0% 8% 9% 12% 15% 20% 28% 44% 2100 0% 0% 8% 10% 13% 16% 21% 29% 46% 2250 0% 0% 9% 11% 14% 17% 22% 31% 47% 2400 0% 0% 10% 12% 15% 18% 23% 32% 49% 2550 0% 0% 11% 13% 15% 19% 25% 34% 51% 2700 0% 0% 11% 14% 16% 20% 26% 35% 52% 2850 0% 0% 12% 14% 17% 21% 27% 36% 54% 3000 0% 0% 13% 15% 18% 22% 28% 38% 55% 0%Water 80%Sep 50%Water 80%Sep 95%Water 80%Sep For a fixed PIP < Pbubble And fixed %Water & Free gas increases with PIP (PSI) 3600 3200 2800 2400 2000 1600 1200 800 400 300 0% 0% 0% 0% 0% 0% 0% 1% 2% 450 0% 0% 0% 0% 0% 0% 1% 1% 3% 600 0% 0% 0% 0% 0% 1% 1% 2% 4% 750 0% 0% 0% 0% 1% 1% 1% 3% 5% 900 0% 0% 0% 1% 1% 1% 2% 3% 6% 1050 0% 0% 1% 1% 1% 2% 2% 4% 8% 1200 0% 0% 1% 1% 1% 2% 3% 4% 9% 1350 0% 0% 1% 1% 2% 2% 3% 5% 10% 1500 0% 0% 1% 1% 2% 2% 3% 5% 11% 1650 0% 0% 1% 2% 2% 3% 4% 6% 12% 1800 0% 0% 1% 2% 2% 3% 4% 7% 13% 1950 0% 0% 2% 2% 3% 3% 5% 7% 13% 2100 0% 0% 2% 2% 3% 4% 5% 8% 14% 2250 0% 0% 2% 2% 3% 4% 5% 8% 15% 2400 0% 0% 2% 3% 3% 4% 6% 9% 16% 2550 0% 0% 2% 3% 4% 5% 6% 9% 17% 2700 0% 0% 3% 3% 4% 5% 7% 10% 18% 2850 0% 0% 3% 3% 4% 5% 7% 10% 19% 3000 0% 0% 3% 3% 4% 5% 7% 11% 20% 14 14
The Enriched Inflow Performance Relationship (EIPR) Concept What is the traditional tool to select the Target Rate? Inflow Performance Relationship Curve (Vogel or equivalents) at perforations Only Reservoir considerations No AL considerations for feasiility Some programs AFTER DESIGN show IPR at pump intake and report the corresponding free gas for the selected target rate 15
The Enriched Inflow Performance Relationship (EIPR) Concept How to visualize simultaneously the target rate, the pump setting depth and the free gas? IN THE PROPOSED METHOD NO SETTING DEPTH DECISION HAS BEEN TAKEN AT THIS TIME!!!! First step to reach our goal is to plot the IPR at different setting depths, so let s plot IPR at 6000, 7000, 8000, 9000, 10000 and 11000 ft. 16
The Enriched Inflow Performance Relationship (EIPR) Concept The IPR at different setting depth provides Pip, Tip to be introduced in free gas equation while showing consistent Rates. Each setting depth has a different Maximum rate BUT still pending free gas display 17
The Enriched Inflow Performance Relationship (EIPR) Concept By adding points with colour scale for free gas to the corresponding rate and setting depth curve the EIPR curves are obtained 18
The Enriched Inflow Performance Relationship (EIPR) Concept The EIPR curve not only provides useful information but also proposes a new paradigm design for pumping methods. So instead of guessing a target rate and a setting depth and check if it is possible, then it is much better to start with the free gas percentage the engineer considers is feasible and then check which are the possible rates and setting depths having this condition. 1200 BPD @ 7000 ft Example Maximum 10% free gas 3000 ft above perforations 3500 BPD @ 10000 ft perforations 3000 BPD @ 9000 ft 7800 BPD @ 11000 ft 1000 ft above perforations 1000 ft below perforation 2000 BPD @ 8000 ft 2000 ft above perforations @ 6000 ft not possible to produce with 10% or less free gas 19
The Enriched Inflow Performance Relationship (EIPR) Concept EIPR curves provide an easy concept to explain and communicate with non-al specialists Reservoir Engineer. Feasible Maximum Rates Completion Engineer. Packers effects Drilling Engineer. Effects of restrictions in depths: Liners, Doglegs, Rat holes, Trajectories. 20
EIPR Sensitivity Cases As matter of visualization how sensitive is the EIPR Sensitivity variables (one change per Base Case case) GOR = 1500 scf/stbl Water=50% SEP=70% Reservoir Pressure = 4000 PSI Productivity Index = 3 BPD/PSI P bubble = 3000 PSI GOR = 500 scf/stbl Water=90% SEP=0% & rate dependent 30% - 90% Reservoir Pressure = 3000 PSI Productivity Index = 1.5 BPD/PSI 21
EIPR GOR & Water Sensitivities GOR = 500 scf/stbl Water=0% SEP=70% GOR = 500 scf/stbl Water=90% SEP=70% GOR = 1500 scf/stbl Water=0% SEP=70% GOR = 1500 scf/stbl Water=90% SEP=70% 22
EIPR Preservoir & PI Sensitivities Productivity Index=3 BPD/PSI Productivity Index=1.5 BPD/PSI Reservoir Pressure=4000 PSI Reservoir Pressure=3000 PSI
EIPR Gas Separation Efficiency Sensitivity Gas Separation Efficiency=70% Gas Separation Efficiency=0% (no separator and downhole packer) Variable Gas Separation (High at low rates Low at High rates)
EIPR to understand pumping constrains and challenges Production Constrain Water Coning Surface Facilities Asphaltene Natural Flow 1500 BPD Gas Lift Best Design 4000 BPD 25
Conclusions The EIPR concept is an innovative, useful and feasible idea that allows the simultaneous selection of target rate & pump setting depth while visualizing free gas and pump/reservoir conditions that applies for ESP, SRP, PCP and JP. The EIPR curve allows and proposes a new approach to design for pumping methods that starts with the free gas pumping capacity and then selecting a feasible production rate and corresponding pump setting depth. The EIPR idea can be extended to show other parameters such as total downhole rate and estimated power that complement the initial objective of displaying simultaneously free gas percentage. EIPR curves provide an easy concept and tool to explain and communicate with non-al specialists about the target, pump setting depth and free gas conditions as well as other parameters such as total rate and estimated power. 26
Recommendations Use EIPR curves to communicate with non-al specialists Since to plot the EIPR colour scale requires intensive computations then it is recommended to AL engineers to develop own software or to request software providers to develop this feature in their programs at the design stage rather than in the output stage. EIPR is sensitive to some parameters, then it is recommended that when having uncertainties on reservoir pressure, productivity index, water cut, separation efficiency the lower value should be taken to have a conservative design. 27
Thanks for your valuable Time and attention Questions? 28
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Back Up Slides 31
Introduction The AL available options are divided in two groups: The Pumping Methods The Gas Lift Methods Even pumping methods worldwide represents 75% of population, the pump setting depth procedure has not been clearly determined 32
Introduction Free Gas effects Gas uses space which requires higher pump capabilities. 50% for 2000BPD liquid will require 4000BPD pump capacity (regardless ESP, PCP, SRP, JP) Each method has its own free gas limits and effects Method Maximum Effects Free Gas Limit ESP radial flow impeller A % Gas Lock. Trip- Motor Burned. Low production and efficiency ESP mixed flow impeller B % Gas Lock. Trip-Motor Burned. Low production and efficiency ESP gas handlers C % Gas Lock. Trip- Motor Burned. Low production and efficiency ESP axial flow impeller D% Gas Lock. Trip-Motor Burned. Low production and efficiency PCP E % Elastomer overheating. High stresses. Shorter Pump run life HRPCP F % Elastomer overheating. Shorter Pump run life SRP G% Lower Compression ratio. Temporally Gas Lock. Energy waste. Low production JP H % Requires Higher volumes and higher pressures in the power fluid. 33
Theoretical Background INPUT DATA FOR PUMP DESIGN Reservoir data Pressure, Temperature, Depth Productivity index, IPR curve PVT data or Correlations Completion data Casing/Liners diameters & depths Trajectory Survey,Tubing Diameters & depths Production Conditions data Target Rate, GOR, Water Cut,Well Head Pressure Pumping design preference parameters Pump setting depth Pumping speed range (Hz/ESP, RPM/PCP, SPM/SRP) Safety factors; Load Stresses, limits Downhole gas separator efficiency OUTPUT DATA FOR PUMP DESIGN: Suitable system specifications Pump model: minimum and maximum rates, pressures Name plate specification for other Components ESP (Motor, seal, cable) PCP (Rod, Well drive head) SRP (Rod, Beam Unit) Operational conditions Oil, water and gas rates at surface Rates at downhole conditions Free gas percentage into the pump Power consumption Qliquid vs Pumping Speed Pump and motor load,pump and motor efficiencies Intake and discharge pressures Exact speed to match the target rate INPUT DATA FOR GAS LIFT DESIGN Reservoir data Pressure, Temperature, Perforations depth Productivity index, IPR curve PVT data or Correlations Completion data Casing/Liners diameters & depths Trajectory Survey,Tubing Diameters & depths Production Conditions data Target Rate*, GOR, Water Cut,Well Head Pressure Gas Lift design preference parameters Kick-off pressure Safety factors; Pressure drops, limit GLRI minimum distance between Mandrels OUTPUT DATA FOR GAS LIFT DESIGN: Suitable system specifications Mandrel depths Valves: diameter, calibration pressure Intermittent: Cycle Time Plunger: Cycle Time, Lubricator, Plunger type Chamber: Cycle Time, Chamber length Operational conditions Oil, water and gas rates at surface Gas Lift injection Operational Pressure Casing pressures that would open the unloading valves Qliquid vs Qgi curves 34
Theoretical Background T u b i n g Free Gas percentage into pump definition (GVF gas volume fraction) Fregas Q Q fregasintopump@ Pip, Tip freegasintopump@ Pip, Tip Q O@ Pip, Tip Q W @ Pip, Tip x100% P u m p S e p Freegas PIP,TIP Freegas (1 (1 sep ) Q O sep ) Q (1 ( GOR R (1 sep ) Q GasRes@ Pip, Tip sep ) Q S @ Pip, Tip O ) GasRes@ Pip, Tip Q ( GOR R @ Pip, Tip ( Q O@ Pip, Tip S @ Pip, Tip O B ) O@ Pip, Tip @ Pip, Tip Q Q O W @ Pip, Tip fw 1 f w B x100% W @ Pip, Tip x100% ) Separation efficiency = Natural Separation & Separator device Solution gas (Rs) Helps Final step Include real gas equation 35