Eureka DOF SIG Webinar, Session 1 Case Study:
Modeling and Control of an Underbalanced Well
Join the WebEx Meeting link in the announcement https://sisevents.webex.com/sisevents/j.php?ED=107020972&UID=0&PW=NOTczZTg1MGEy&RT=MTgjMjE%3D
NOTE: do not use WebEx for the audio (during WebEx startup just close the audio dialog box)
Join the BT Meet Me audio US: tel: +1 617 340 4082
UK: tel: +44 3301 230 834 Other countries: http://www.btconferencing.com/schlumberger/globalaccess/?bid=277
Participant passcode: 69401626 then #
Eureka DOF SIG Webinar, Session 2 Case Study:
Modeling and Control of an Underbalanced Well
Join the WebEx Meeting link in the announcement
https://sisevents.webex.com/sisevents/j.php?ED=107020987&UID=0&PW=NYmUwNzVkZDlm&RT=MTgjMjE%3D
NOTE: do not use WebEx for the audio (during WebEx startup just close the audio dialog box)
Join the BT Meet Me audio US: tel: +1 617 340 4082
UK: tel: +44 3301 230 834 Other countries: http://www.btconferencing.com/schlumberger/globalaccess/?bid=277
Participant passcode: 69401626 then #
Wyoming UBD
Modeling and control of an UBD well Kjetil Havre – Chief Scientist SPT Group
Wyoming
7
Project participants in Wyoming DAPC team
Shell International Exploration & Production
Project client
@Balance
Project Management
Powerchokes
Provider of automatic choke manifold & responsible for instrumentation of choke manifold
Onsite support to the DAPC team
Halliburton
Provider of Multiphase Meter to measure flow rates at wellhead
Scandpower PT / Prediktor
Provider of online models and automatic control of the well
Provider of online Industrial IT-platform
Data communication with rig and surface data (WITS)
Communication with Multiphase flow meter (Modbus)
8
Content of presentation
This presentation concerns the modeling and control
issues:
• Model setup
• Control of wellhead and bottom hole pressure
• Online controller results
9
Wyoming online simulator – main tasks
1. Online multiphase models for the UBD application.
Windows into the wellbore dynamics –
past, present and future
2. Bottom Hole & Wellhead Pressure Control –
to control and maintain the degreee of UB
3. Estimation of reservoir inflow
10
Wyoming - setup
Under balanced drilling application
Main process components
• closed system with
• coil tubing unit,
• automatic choke manifold,
• multiphase flow meter,
• wellhead separator unit
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Wyoming setup – Inlets and flow path
Mud injection pump.
Water based mud
CaCl2 is used. Gas injection,
N2 is used.
Kill fluid pump
12
Wyoming setup – Inlets and flow path
Flow path through the drill string down
to Bottom Hole Assembly BHA into
Annulus, through DAPC Valve Manifold,
through the Heater and the Multiphase
Flow Meter into the separator. Gas is
flared. Mud returns to storage.
Bottom Hole Assembly, consisting of
hydraulically driven motor, instruments,
steering devices. The BHA is equipped
with pressure and temperature
transmitters. Signals are transmitted
electrically back to surface.
13
Wyoming setup – DAPC manifold
The Dynamic Annular Pressure
Controller DAPC automatic choke
manifold consisting of two main chokes
and a two inch bypass line with a choke
in parallel. The Choke manifold is
instrumented with valve position signal
and pressure transmitters. The purpose
with the automatic chokes is to control
wellhead or bottom hole pressure
14
Wyoming setup – Downstream wellhead
Multiphase Flow
Meter to measure
gas, condensate and
mud flow rates.
Separation of gas
condensate and mud.
The gas exits to flare,
mud is returned to
storage for circulation
15
Wyoming setup – Wellbore
Status page with
measured and
calculated BHP,
number of well
sections drilled etc.
16
Wyoming – Controller tasks
1. Stable bottom hole pressure
in the event of reservoir
influx and kicks, changes in
pump flow rate and tripping
the hole, i.e. surge and
swab effects
2. Control of wellhead
pressure when the BHA is
out of the hole and when
deploying
17
Wyoming setup – BHP controller
Bottom Hole Pressure Controller
BHPC. The purpose with this
controller is to keep a constant
bottom hole pressure. The bottom
hole pressure can be either the
measured in the annulus at the
location of the BHA or a pressure
inferred by the OLGA real time
model. Such examples are the heel
or toe pressure or the pressure at
a drilled inflow section
18
Wyoming setup – WHP controller
Wellhead pressure
controller DAPC.
The purpose with
this controller is to
track the desired
wellhead pressure
calculated by the
BHPC controller.
Alternative wellhead
pressure sensors
and control valves
are included.
19
Wyoming setup – WHP controller in the RTM
Wellhead pressure
controller in the real
time model –
equivalent to the
plant DAPC
wellhead pressure
controller.
20
Wyoming setup – WHP controller
Controller parameters, gain Kp, integral
time Ti, derivative time, manual input
MI. Controller variables and calculated
output.
21
Wyoming setup – BHP controller
Controller responses;
red curve – process variable,
blue curve – calculated output
darker blue curve – controller set point
22
Wyoming setup – Wellhead controller
Feed forward action
to wellhead pressure
controller – purpose
is model matching
of wellhead pressure
23
Wyoming setup – Model inlet
Measurements:
Input flow rates and temperature of
injected fluids - mud and gas
Measurements are used to close the
model boundaries
Model is tuned to match measured
stand pipe pressure
24
Wyoming setup – Model outlets
Multiphase flow
measurements used
for reservoir inflow
estimation
Model tuned to match
separator pressure
25
Algorithms for tuning the model
Stand pipe pressure
Measured depth
On-line inflow estimation
26
Application outputs
Calculated and
measured values
Data trended and
stored in database
Result pages as tabs:
- Status
- Pressure
- Flows
- Separator
- Profiles
- Drilling
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Typical window into the annulus
Gas flow rate Mud flow rate
Liq. Vol. frac.
Wellhead
Bottom hole
TV
D
28
Controller performance
BHP “at” set-point
WHP “tracks” set-point
Gentle valve movements
29
Controller performance – Gas bubble escapes
Gas bubble escapes annulus –
flows through valve manifold Response in BHP
Response in WHP
Response in
modelled WHP
Response in
measured and
modelled BHP
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Pump starting
Response in
measured and
modelled BHP
31
Pulling up, pushing down
Response in BHP
32
A kick initial response
Initial response in BHP
Initial response in choke
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A kick wellhead pressure build-up
Response in BHP
Response in choke - choking
Wellhead pressure build-up
34
A kick – the complet response
Response in BHP
Initial response in BHP
Initial response in choke
Response in choke - choking
Wellhead pressure build-up
35
Inflow estimation is turned on
Inflow estimation
turned on and gas
comes to surface
Modelled BHP matches
measured BHP
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Inflow estimation is turned on
Inflow estimation
turned on and gas
comes to surface
Modelled BHP matches
measured BHP
With match in modelled and measured BHP:
Modelled BHP calculated by OLGA can
be used to control the degree of UB.
37
Summary
Multiphase modeling and OLGA
provides key results to:
1. Control the degree of under
balance in UB applications
2. Reservoir inflow estimation