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Drillbench® Dynamic Well Control

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Page 1: Dynamic Well Control_Slide printing.pdf

Drillbench® Dynamic Well Control

Page 2: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved11

History

Multiphase flow model

– Model originates from Rogaland Research

– Modeling has been supported by extensive verification work with

fullscale data; both experiments and real wells

– Continuous development by Schlumberger Integrated Solutions

(SIS)

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Copyright ©2001-2012 NExT. All rights reserved2

Dynamic Well Control

Kick Circulation

Kick Tolerance

Kill Sheet

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Type of Kick

Kick while drilling

Pore Pressure > ECD

– Formation pore pressure is higher than the dynamic bottomhole pressure

Kick during connections/pumps off

ECD > Pore Pressure > ESD

– Formation pore pressure is lower than the dynamic bottomhole pressure, but higher than the

static bottomhole pressure

Swab kick

ESD > Pore Pressure

– Formation pore pressure is lower than the static bottomhole pressure

Page 6: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved5

Circulating the Kick

2 method:

– Driller’s Method

– Wait & Weight Method

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Dynamic Well Control - Model Basic

Dynamic model

– A kick enters the well

– The well is closed in and well pressures stabilises

– The kick is circulated out

– A heavy kill mud is placed into the well

Conservation of mass and total momentum

– Mud

– Free gas

– Dissolved gas

– Formation oil

Equation set is solved by a finite difference technique with

– A set of sub models for physical properties

– Boundary conditions defined for various modes

Circulation

Closed in well

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Copyright ©2001-2012 NExT. All rights reserved7

Kick Tolerance

The maximum volume of influx that can be circulated out without breaking down the weakest

formation (Presumed to be at the last casing shoe, if no other information is available).

Page 9: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved8

SLB IPM Standards

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Kick Tolerance Consideration

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Kick Tolerance Consideration

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A dynamic model will disperse akick over a much longer section ofthe annulus whilst drilling ascirculation continues.

The dynamic model also accountsfor absorption of the gas into anyoil based fluid systems.

Dynamic Kick ToleranceCalculations result in a morerealistic design and allows casingsetting depths to be optimized.

Dynamic Kick Tolerance

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Copyright ©2001-2012 NExT. All rights reserved12

Dynamic Kick Tolerance Calculations result in a flatter line for volumes allowing larger kick volumes to be controlled.

5800

5900

6000

6100

6200

6300

6400

6500

0 10 20 30 40 50 60 70 80

Pre

ssu

res (

psi)

Kick Size (bbl)

Kick Tolerance for 14-3/4" hole at 2215m MDDF (drilled kick)

ECD at TD of Section (psi)

LOT Equivalent Pressure (psi)

Mud Weight in use (ppg)

Dynamic Kick Tolerance (psi)

Kick Tolerance Single Bubble Model (psi)

Mud Weight 15.50 ppg

ECD 15.91 ppg

LOT 16.50 ppg

Dynamic Kick Tolerance

Page 14: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved13

Dynamic Kick Tolerance Calculations result in a flatter line for volumes allowing larger kick volumes to be controlled.

Dynamic Kick Tolerance

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In well control simulations we provide the simulator which gives you a dynamic kill sheet and it allows to look at the possible scenario’s in minutes.

Whilst the well is being killed results of pressures and flow rates can be followed using the simulator.

Dynamic Simulations

Page 16: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved15

Facts to remember:

Concentration depends on operation – drilling will give a more

distributed kick than if it is swabbed in

– Influx rate

– Mud circulation rate

Gas dissolution process is transient

The conditions in HPHT wells are far above critical point

– One phase

– Infinite solubility

Page 17: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved1616

Pressure Losses

Frictional pressure drop

– Laminar and turbulent flow

– Rheology models

– Pressure loss

Flow area changes

BHA / Bit

Choke valve / choke line

– Two-phase flow

Page 18: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved1717

Geometry

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Copyright ©2001-2012 NExT. All rights reserved1818

Geometry

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Geometry

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Copyright ©2001-2012 NExT. All rights reserved2020

Geometry

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Surface Equipment

Delay: The time it takes to initiate theclosure/shutdown of a unit. Human factor.

Duration: The time it takes to for theunit to close/shutdown. Mechanical factor.

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Kick Detection Evaluation

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Reservoir – Influx Model

Two Model:

– Reservoir Model

– Constant Influx Model

Page 25: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved2424

Reservoir Model vs. Constant Influx

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Copyright ©2001-2012 NExT. All rights reserved2525

Choke Pressure During Kill

Gas Breakout

Methane

WBMMethane OBM

Black Oil

OBM

Comparison among different scenarios.

Page 27: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved26

Exercise

Setting up Input file

and do calculation

Page 28: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved27

PVT Models

Black Oil

– Correlations (several) – model gas & liquid

– Not very accurate

– May not be valid for HPHT conditions

Compositional– Base oil composition

Predefined alternatives Measured data

– Reservoir fluid composition

Predefined influx alternatives Measured data

– Equation of State

– Physical modeling

Measured Data (Tabular)

– Accurate

– Data is often unavailable

Predefined or custom fluid composition

Page 29: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved28

PVT Models

How to select the most appropiate one?

• Black Oil

– A system with liquid and gas where the composition of the liquid and the gas phase is thesame. You have one phase envelope describing the transition/equilibrium point.Gas/multiphase/oil regions. The important part is that the compositions does not change andeven if more gas is released as free, the remaining oil has the same composition.

Compositional

– In principle one phase transition curve for each component. You are referring to an equilibriumconstant for transition between phases for each component.

Note:

Compositional is to be used as default setting as all calculations will be done based on the «Equation of

State» while Black Oil is based on measurements of PVT properties at low to moderate pressures and

temperatures and to extrapolate to HPHT conditions is not recommended.

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Copyright ©2001-2012 NExT. All rights reserved2929

Degasser Input

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Verification

Experimental work at Rogaland Research– Full scale research drilling rig– Laboratory tests

Tested a large number of HPHT muds – Field muds– Base fluids– Various fluid compositions

Max pressure 1500 bar Max temperature 220 °C Measured– Compressibility– Thermal expansion– Rheology– Solubility of gas

Page 32: Dynamic Well Control_Slide printing.pdf

Copyright ©2001-2012 NExT. All rights reserved3131

Pressure

Flow

0 10 20 30 40 50 60 70

Time (min)

125

130

135

140

145

150

Pr e

ss

ur e

(ba

r )

Simulated

Measured

0 10 20 30

Time (min)

0

500

1000

1500

2000

Flo

wo

ut

(l/

in) Simulated

Measured

Verification

Flo

w o

ut

[l/m

in]

Pre

ss

ure

[b

ar]

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Copyright ©2001-2012 NExT. All rights reserved3232

Applications

All wells

Kick tolerance

Casing design

– Setting depths

– Pressure

Surface capacity

Well control procedures

Post analysis

Education / training