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

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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

11

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

27

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

30

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

33

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

36

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