1. supervisors: Prof. Ali Moradzadeh
Dr. Peyman Pourafshary
Presented By: Farhad Orak
Shahrood University of Technology
October 2012 1
Shahrood
University of
Technology

2. Production Optimization using Nodal Analysis
Effect of Well Geometry on Production of Field Case Study
Field Geography Situation & Geology
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2
1
5 Results & Recommendations
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Application of Multilateral Wells in HC Reservoir
2

3. GeologyMultilateral Wells
Production
OptimizationWell Design
Advantages
Disadvantages
Risks
Benefits
• Higher productivity indexes(PI).
• Relatively thin layer drainage can be
accomplished(0.8m).
• Decreased water and gas conning.
• In secondary and EOR applications, long horizontal
injection wells provide higher injectivity rates.
• In heterogeneous reservoirs, more oil and gas
pockets can be exploited and an increased number
of fissures can be intersected.
• It definitely helps to reduce the drawdown that is
experienced on a single lateral leg
• High risk associated to drilling and completion may
take away the economic benefit.
• Remotely operated inflow valves to control flow
rates from well branches and zones.
• Debris when milling through casing in existing
completions.
• Highly sensitive to heterogeneities and anisotropies
(both stress and permeability).
• Very complicated drilling, completion and
production technologies are used.
• Interference of well branches may occur (Cross flow
may take place).
• Borehole instability
• Stuck pipe
• Drilling formation damage
• Staying in the productive zone
• Casing exit orientation
• Whipstock orientation in existing
wells
• Horizontal multilateral completion allows the placement
of the junction in the reservoir, reducing overburden
drilling, casing and cementing costs.
• These cost savings are in addition to the service capital
expenditure costs (structures, wellheads, pipelines) and
operating expenses.
Where these types of completions make sense:
• High-cost drilling markets (such as offshore or deep reservoirs)
• plays where increased reservoir exposure is required (such as
heavy oil)
• areas where geological structures produce segregated reservoir
targets.
Results
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4. Geology
Production
Optimization
Well Design
geography Situation
Results
South Pars gas field is located in Persian Gulf and known as the largest gas field in the world,
which has the 50% of entire Iran Gas supply and 8% of the world. It is also extended into Qatar
territorial water where it is called the North Field.
Multilateral Wells
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5. Geology
Production
Optimization
Well Design
Reservoir geology
Results
It consists of four producing gas layers K1, K2, K3 and K4 which are separated
by anhydrite layers.
Reservoir thickness is about 400 meters. The thickness of each layer is different
with others.
This reservoir is constructed of Kangan and Dalan formations with Lithology of
lime stone, dolomitic Lime stone, Anhydride and staked clay in the depth of 2700
meters.
More of the gas reserves are in Kangan and Dalan formations which are the main
layers of South Pars Gas Field, there are also other layers which Oil existence in
those layers are approved according to performed drilling .(Darian)
Multilateral Wells
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6. Geology
Production
Optimization
Well Design Results
Challenges
The ordinary trajectory of wells in this field is a 42˚ slant path that touches all of
these layers and it culminates in a commingled production after all.
But problem arises here, on the flanks, where the level of WGC is too high that
K3 and K4 are inundated with water, and there is no enough production from
this two layers, then it calls for finding another way to extend the production
period.
In this case the role of multilateral wells becomes highlighted and those
conventional wells can be substituted by their novel multilateral forms.
Multilateral Wells
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7. Multilateral
Wells
Geology
Production
Optimization
Well Design
Well Design
Results
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
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8. GeologyMultilateral Wells
Production
Optimization
Well Design
Results
Multilateral Well (Quadrilateral )
8

9. GeologyMultilateral Wells
Production
Optimization
Well Design
Results
IPR Plot IPR & VLP Plot
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’’ (a Schlumburger patent). 9

10. GeologyMultilateral Wells
Production
Optimization
Well Design
Results
Dual Opposed Multilateral Well IPR Plot
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11. GeologyMultilateral Wells
Production
Optimization
Results
Well Design 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. 11

12. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Used Procedure
1. Determine which components in the system can be changed. Changes are limited in some cases
by previous decisions. For example, once a certain hole size is drilled, the casing size and,
therefore, the tubing size is limited.
2. Select one component to be optimized ( in this work focus is on production pipe diameter, well
head pressure, skin effect and produced water effect).
3. Select the node location that will best emphasize the effect of the change in the selected
component. This is not critical because the same overall result will be predicted regardless of the
node location ( in this work the node is assuming at the well end and a the above of lateral
branch).
4. Develop expressions for the inflow curve and outflow curve (As plotted).
5. Determine the effect of changing the characteristics of the selected component by plotting
inflow curve versus outflow curve and reading the intersection (As plotted).
6. Repeat the procedure for each component that is to be optimized.
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13. GeologyMultilateral Wells
Production
Optimization
Results
IPR & VLP Plot
Before Optimization
Well Design
Multilateral Well
(Dual Opposed )
97 MMscf/day
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14. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Effect of tubing size
79 MMscf/day
91 MMscf/day
104 MMscf/day
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15. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Effect of Wellhead pressure
76 MMscf/day
94 MMscf/day
101 MMscf/day
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16. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Effect of water cut
97 MMscf/day
80 MMscf/day
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17. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Skin Effect
114 MMscf/day
84 MMscf/day
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18. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
After optimization
Specifications:
Tubing size: 6.18 inch
Wellhead pressure: 2000 psi
Assumptions:
Water Cut: 5%
Skin Factor: +1
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19. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Results
1. According to small ratio of Kv/Kh , it’s not suitable to drilling the horizontal branches
in this field although it’ll be more reservoir exposure . So drilling of slant branches
(Dual opposed multilateral wells) has the better efficiency.
Results
2. 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".
3. According to production potential of the well and reservoir and Capacity of surface equipment
Wellhead Pressure 2000 Psi for Dual Opposed Multilateral Well is Appropriate.
4. 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.
5. 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.
6. To avoiding of Cross flow in design of multilateral well, One-way Chock usage can lead to
increasing of Reliability in completing design.
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20. Geology
Multilateral
Wells
Well Design
Production
Optimization
Results
Recommendations
1. Considering the limits in production on the flanks (where the level of WGC is too
high that K3 and K4 are water invited), it’s suggested to use of multilateral wells with
horizontal branches and utilization of intelligent equipment's in reducing of water
production and reducing of Cross flow risqué and better and optimized production of
these zones.
2. Investigating of optimum length of horizontal branches and drilling appropriate angle for more
reservoir exposure.
3. Estimation of reservoir depletion time in different production condition with reservoir
simulation.
4. For more control during production and selective production from zones, it’s suggested to use of
PVT gauges and SSD in design of bottom hole equipment.
5. Above all, this study can be done for the great gas field that just explored in the deep waters
(712 m) in Caspian Sea.
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21. Thanks for your attention !
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