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WELL PERFORMANCE ANALYSISWELL PERFORMANCE ANALYSIS
P.O.G.CP.O.G.CSubject of ConferenceSubject of Conference
In The Name of God
OutlinesOutlines
IntroductionIntroduction Inflow performance relationship (IPR)Inflow performance relationship (IPR) Tubing performance relationship (TPR)Tubing performance relationship (TPR) Wellhead performance relationship (WPR)Wellhead performance relationship (WPR)
Goals of Well Analysis Determination of the flowrateDetermination of the flowrate
To determine under what flow conditions well will cease to To determine under what flow conditions well will cease to produce. produce.
To select the most economical time for the installation of artificial To select the most economical time for the installation of artificial lift lift
ToTo optimize the well conditions and system geometryoptimize the well conditions and system geometry
To analyze each component in the well systemTo analyze each component in the well system
5
porous media
vertical well
surface facility Separator
Stock tank
Sales Gas
production system
Inflow performance relationship (IPR) is defined as the relation Inflow performance relationship (IPR) is defined as the relation between the surface flowrate (q) and bottomhole flowing pressure between the surface flowrate (q) and bottomhole flowing pressure (P(Pwfwf). ).
Inflow Performance Relationship (IPR)
IPR curves are used to analyze the deliverability of wells by IPR curves are used to analyze the deliverability of wells by estimating the production rate for a given bottomhole flowing estimating the production rate for a given bottomhole flowing pressure and vice versa and also reflect the ability of the reservoir to pressure and vice versa and also reflect the ability of the reservoir to deliver fluid to the wellbore. deliver fluid to the wellbore.
IPR Curve
11 ( (Straight line (Constant PI)Straight line (Constant PI)
22 ( (A curve which shows that the PI is decreasing with rateA curve which shows that the PI is decreasing with rate
33 ( (A combination of 1 and 2A combination of 1 and 2..
Constant PIConstant PI
)( wfro PPJq • Production rate is proportional to the pressure drawdown
• Occurs for single phase liquid flow
IPR Equation for Multiphase FlowIPR Equation for Multiphase Flow
Vogel’s EquationVogel’s Equation
Fetkovich’s Equation Fetkovich’s Equation
Klins and Majcher EquationKlins and Majcher Equation
Pudjo Sukarno’s EquationPudjo Sukarno’s Equation
Fetkovich’sFetkovich’s EquationEquation
nwfro PPCq )( 22
Using data from multirate tests on 40 different oil wells in six fields, Using data from multirate tests on 40 different oil wells in six fields, Fetkovich showed that the following approach was suitable for predicting Fetkovich showed that the following approach was suitable for predicting performance:performance:
where 0.5 ≤ n ≤ 1.0where 0.5 ≤ n ≤ 1.0
n
r
wf
o
o
P
P
q
q])(1[
)(2
max
This can be expressed in a form similar to Vogel’s IPRThis can be expressed in a form similar to Vogel’s IPR..
))PP
rr22 – P
– P
wf
wf22
( (ps
iaps
ia
Flowrate ( q ) STB/dFlowrate ( q ) STB/d LogLog
LogLog
11//nn
IPR Curve for Multiphase FlowIPR Curve for Multiphase Flow
Effective Parameters on Inflow PerformanceEffective Parameters on Inflow Performance
Dow point and bubble point pressureDow point and bubble point pressure
Reservoir pressure depletionReservoir pressure depletion
Skin effectSkin effect
Tubing Performance Relationship (TPR or VFP)Tubing Performance Relationship (TPR or VFP)
Tubing performance may be defined as the behavior of a well in giving up the reservoir fluids to the surface .
Flowing bottomhole pressure (tubing intake pressure) for each production rate equals total pressure drop through the tubing and any
bottomhole restriction and wellhead pressure.
Pwh
Q
Pw
f
relation between the surface flowrate (q) and relation between the surface flowrate (q) and tubing intake ressure(Pwf).(Pwf).
Pressure Drop In the Vertical WellPressure Drop In the Vertical Well
Hydrostatic pressure dropHydrostatic pressure drop
Friction pressure dropFriction pressure drop
Vertical Two-Phase Flow PatternVertical Two-Phase Flow Pattern
Bubble flow (A)Bubble flow (A)
Slug flow (B)Slug flow (B)
Transition flow (C)Transition flow (C)
Annular-mist flow (D)Annular-mist flow (D)
Flow Regimes
Change in phase behavior in the production tubing
Natural flowNatural flow Accrue when the wellbore flowing pressure and tubing intake pressure
(at perforation depth) are equal, TPR and IPR curves intersect together. The intersection of TPR and IPR curves called natural flow
point.
Variables that Effects on Natural FlowVariables that Effects on Natural Flow
Wellhead pressureWellhead pressure
Gas/liquid ratio Gas/liquid ratio
Tubing sizeTubing size
Static pressure &…Static pressure &…
Effect of Wellhead PressureEffect of Wellhead Pressure
Effect of Gas/Liquid RatioEffect of Gas/Liquid Ratio
Effect of Tubing DiameterEffect of Tubing Diameter
Effect of the SkinEffect of the Skin
BHSP
59005500500045004100
Wellhead PerformanceWellhead Performance By using of the wellhead performance can show in which range of flowrate By using of the wellhead performance can show in which range of flowrate
in the well column, the hydrostatic pressure drop is more than friction in the well column, the hydrostatic pressure drop is more than friction pressure drop. pressure drop.
26
porous media
Separator
Stock tank
Sales Gas
production system
vert
ical w
ell
IPR & TPR & WPRIPR & TPR & WPR
PPwhwh
TPRTPR
WPRWPR
RateRate
Pre
ssu
reP
ress
ure
IPRIPR
Choke PerformanceChoke Performance The main function of a choke is to dissipate large amounts of potential The main function of a choke is to dissipate large amounts of potential
energy (i.e., pressure losses) over a very short distanceenergy (i.e., pressure losses) over a very short distance . .
Two types of two-phase flow can exist in a chokeTwo types of two-phase flow can exist in a choke: :
Critical flowCritical flow
Subcritical flow Subcritical flow
PP1 1 = Wellhead ( upstream) pressure= Wellhead ( upstream) pressure
PP2 2 == downstream pressuredownstream pressure
P2/P1 ≤ %50 = RC
P2/P1 > %50 = RC
CPR and WPRCPR and WPR
The intersection of the WPR and choke performance curve defines the The intersection of the WPR and choke performance curve defines the rate of natural flow for the given choke size. rate of natural flow for the given choke size.
Gilbert and RosGilbert and Ros
CBL dGLRAqDP )(1
RecommendRecommend
Basic requirement for well performance Basic requirement for well performance analysis is the ability to determine , so it is analysis is the ability to determine , so it is required to determine BHP using surface datarequired to determine BHP using surface data
Determine the best correlation to predict the Determine the best correlation to predict the fluid behavior in well column same as fluid behavior in well column same as culender smite or duckler &…culender smite or duckler &…
Examine the quality of separator tests using Examine the quality of separator tests using daly reports of SPGC daly reports of SPGC
Thanks for your Thanks for your attentionattention