2. Categories:
What is Optimization?
Well Performance and System Analysis
Production System
Reservoir Fluid
How do we get hydrocarbons to surface?
Tubing Performance (Vertical Lift)
Tubing Size Selection
System Analysis (Using Nodal Analysis)
3. Understand the components of Inflow Performance
Understand the components of vertical lift Performance
Understand combination of Inflow & vertical lift
performance
Objectives
4. Production Optimization
Production Optimization means… Balance between Production rate /
Deliverability and demand
Production Optimization includes a good understanding about Production
Systems and Reservoir Fluid
10. Phase Behavior
The reservoir fluid can be classified into basically three types
i.e., single phase, two phases, or a combination.
Such information is used to determine the type of IPR equation
to be used.
From a technical point of
view, the various types of
reservoirs can be
defined by the location
of the initial reservoir
temperature and pressure
as commonly shown on
pressure-temperature …
(PT) phase diagrams.
11. Segments
Rock Properties & Reservoir character
Reservoir Fluid qualities
Reservoir flow paths
The effect of pressure drop and back pressure on fluid flow in the Reservoir
Fluid behavior in approach / entry to the wellbore
Lift type and Optimization of flow from bottom hole through the tubing
Operations effect on the flow rate…
Choke setting
Restrictions
Separator operations
Pipeline
Start up/ shut down operations, stabilizing
12. System AnalysisSystem Analysis
Well deliverability is
determined by a well’s inflow
performance.
The Inflow Performance
Relationship (IPR) is defined as
the functional relationship
between the production rate
and the bottom hole flowing
pressure.
Productivity Index (PI or J)
expresses the ability of a
reservoir to deliver fluids to the
wellbore.
Productivity Ratio (PR) is the
ratio of actual productivity
index to the ideal productivity
index where skin, s=0.
Reservoir Deliverability System
13. Inflow Performance & Productivity Index
A commonly used measure of the ability of the well to produce
…is Productivity Index
Defined by the symbol “J”, it is ratio of the total fluid flow rate to
the pressure drawdown….
Drawdown (∆P) = (Pr- Pwf)
In generally,
PI = J = Q/ ∆P
PI = Productivity Index
Q = Flow rate,
∆P = Pressure drawdown,
Pr = Average drainage pressure (static),
Pwf = bottom hole flowing pressure,
System Analysis
14. In Flow Performance Relationship - IPR Curves
The Inflow Performance Relationship (IPR) for a well is the
relationship between the flow rate of the well q and the flowing
pressure of the well Pwf.
In single phase flow this is a straight line but when gas is moving in
the reservoir, at a pressure below the bubble point, this in not a linear
relationship.
17. Tubing Performance (Outflow Performance)
Picture yourself at the bottom of the flowing well ……
Now this time …… Look up into the tubing ……
What would prevent flow from the well?
What would make this well produce more?
18. Tubing Performance (Outflow Performance)
The outflow system takes energy from the inflow system and
use that energy to get the total fluid rate to surface
For the outflow system, the higher the pressure at the bottom
of the well, the more fluid can be pushed from the well
( In order to overcome friction)
19. Tubing Performance (Outflow Performance)
Another convenient view of the Outflow is on a Depth Vs. Pressure
graph (These are pressure in the tubing)
24. IPR & TPR curves can be combined to find the
Stabilized Flow Rate (Point of Natural Flow)
Tubing shoe reaches the perforation depth****
Wellbore flowing pressure and tubing intake pressure
are considered at the same depth
At a specific rate when these two pressures are
equal, the flow system is in equilibrium and
flow is Stable
System Analysis (Combination of Inflow Vs. Outflow)
25. System Analysis (Combination of Inflow Vs. Outflow)
Flowing bottom hole pressure (Pwf) = Tubing intake pressure(Pwf e)
… the stable flow rate***
29. Production Optimization Using Nodal Analysis
Well deliverability is determined by the combination of well inflow
performance and wellbore flow performance.
This work focuses on prediction of achievable fluid production rates from
reservoirs with specified production string characteristics.
The technique of analysis is called ‘‘Nodal analysis’’.
Its application to well producing systems was first proposed by Gilbert
(1954).
30. Applications
Typical Applications include:
Estimation of flow rates
Selection of Tubing size
Selection of Flowline size
Selection of Wellhead pressure & surface choke
Artificial Lift Design
Estimation of the effects of reservoir pressure depletion
Identification of flow restrictions
31. Optimization Procedure
Identify the components in the system
Select one component to be optimized
Select the node location that will best emphasize the effect of change
Develop expression for inflow and outflow
Calculate pressure drop versus rate for all components
Determine the effect of changing the characteristics of the selecting
component
Repeat the procedure for each component
Optimize the production system
32. Start Select Model
Options
Set up and Match
PVT Model
Input System
Equipment & IPR
Yes
Match IPR &
VLP
Calculate System
Sensitivities
Performance
Acceptable?
Review
Design
Finish
33. Production
Optimization
Production
Optimization
Nodal Analysis
To simulate the fluid flow in the system, it is
necessary to ‘‘break’’ the system into discrete
nodes that separate system elements (equipment
sections). Fluid properties at the elements are
evaluated locally.
Nodal analysis is performed on the principle of
pressure continuity, that is, there is only one
unique pressure value at a given node regardless
of whether the pressure is evaluated from the
performance of upstream equipment or
downstream equipment.
The performance curve (pressure–rate
relation) of upstream equipment is called ‘‘inflow
performance curve’’;
the performance curve of downstream equipment
is called ‘‘outflow performance curve.’’
The intersection of the two performance curves
defines the operating point, that is, operating flow
rate and pressure, at the specified node.
40. Results
During the production, chosen well with tubing Size of 3.95" and 4.78" causes
restriction because of tubing. But the production rate increases at the production with
tubing Size of 6.18".
According to production potential of the well and reservoir and Capacity of surface
equipment Wellhead Pressure 2000 psi for the well is appropriate.
If the creation restriction in bottom hole completion or Formation damage, inflow
performance can be Improve using the Work Over Such as Hydraulic Fracturing or
Acidizing.
According to formation stability (type and structure of reservoir rock), completion by
the method of open hole is appropriate and there’s no need to mechanical integrity in
the junction.