analysis of sand transportability in bekapai pipelines (presentation)

Balikpapan, July 2010

Analysis of Sand Transportability in Pipelines

Laras Wuri Dianningrum

Chemical Engineering Program of Study

Faculty of Industrial Technology

Bandung Institute of Technology

Contents

2 - Reference, date, place

Background of Study

Objectives

Methodology

Main Finding

Recommendation


Background of Study

Bekapai pipelines

Surface corrosion by bacteria under sand layers

Sand accumulation

How to manage

?

Analysis of sand

transportability

-WHY

-WHEN

-HOW

Objectives


FLOW REGIME

FLOW CRITICAL VELOCITY

SAND BEHAVIOR

Methodology (1)


Sand Transportation in Pipeline

(critical flow velocity and sand behavior)

Holdup

Fluid properties

(Vsl,Vsg,ᵨ,σ,

µ)

Inclination

(θ)

Particleproperties

(Dp,ᵨ)

Sand Production

Rates

Pipeline properties

(D,roughness)

Flow regime

Further

analyze in

this study

MULTIPHASE FLOW

Actual liquid and

gas velocity, liquid

holdup comparison

FLOW REGIME

Experimental Correlation

Horizontal Pipe

(Mandhane Map)

Vertical Pipe

(Aziz Map)Beggs & Brill

Mechanistic Model

(all inclinations)

OLGA

SAND BEHAVIOR

Methodology (2)


Oil-gas-water flow oil-gas & water-gas flow

VERTICAL and

HORIZONTAL

flow

1 2 3 4

Critical velocity

(Salama, 1989) and

Chien, 1994)

1 3

3

32

4

Vs

Vs

Vs

COMPARATIVE

STUDIES

Particles

Methodology (3)


Assumptions used:

a.Steady state flow

b.There is not an inter-phase mass or energy transfer

c.Temperature and pressure are constants along pipeline

OLGA Spesifications:

a. 100 horizontal & 10 vertical sections

b. Run period: 48 hours

c. No slip: OFF

d. Steady-State: ON

Pipeline d (inch) Length (m) Wall thickness

(mm)

BB-BP 12 1660 9.52

BH-BG 6 1900 9.52

BF-BL 6 1000 9.52

BJ-BB 6 850 9.52

BK-BP 8 1900 9.52

BL-BA 6 1530 9.52

Pipeline P(bar) T (oC)Q Oil

(STBD)Q Gas

(MSCFD)Q Water (BWPD)

8 inch BK-BP1 10 60 1 960 68

6 inch BJ-BB 56 60 0 1302 1

12 inch BB-BP1 10 60 339 1608 2152

6 inch BF-BL 11 60 175 1712 1177

6 inch BH-BG 13 60 422 1239 478

12 inch BL-BA 10 60 5011 9540 4263

Beggs & Brill correlation

CL, L1,L2,L3,L4,Fr

Flow regime

(segregated, distributed, intermittent, transition)

Main Finding (1)


Mandhane’s Map

Horizontal pipe1 3Vs

vsg (ft/s) vsml (ft/s)Regime

(Mandhane) Regime (BB)

3.64 0.0134 Stratified segregated



10.48 0.4616 Slug segregated


16.09 0.7916 Slug segregated

Sand

Behavior

Ruano,2008

Stratified

Slug

Pipeline

8 inch BK-BP1

6 inch BJ-BB

12 inch BB-BP1

6 inch BF-BL

6 inch BH-BG

12 inch BL-BA

Stratified:

-constant behavior

-high concentration in liquid

phase

-sand dune formation

Slug:

-smaller D pipe, more effective

sand transport

-slug body--turbulence


Main Finding (2)

Vertical Pipe32 Vs

Beggs & Brill correlation

CL, L1,L2,L3,L4,Fr

Flow regime

(segregated, distributed, intermittent, transition)

Pipeline

Regime

Aziz

Beggs &

Brill

8 inch BK-BP1 Slug Segregated

6 inch BJ-BB Slug Segregated

12 inch BB-BP1 Slug Segregated

6 inch BF-BL Slug Segregated

6 inch BH-BG Slug Segregated

12 inch BL-BA Slug Segregated

Sand

Behavior

Annular-Segregated

(very high gas-liquid ratio, high gas flow rate, annular film on the wall is thickened

at the bottom of pipe)

Slug-Intermittent

(medium gas-liquid ratio, high liquid flow rate)

Annular:

-Entrained sand in gas and liquid

phase

-Increase pressure drop and

erosion risk

Slug:

-more complex behavior

-depends on slug frequency, slug

length, pipe diameter, etc.

Aziz et al. Map


Main Finding (3)

34 VsFlow regime, holdup, fluid actual velocity

50th section

(H)

Riser bottom

(101th section) (R)

Outlet (110th

section) (O)

Pipe geometry

Pipeline H R O H R O

8” BK-BP1 1 1,2,3,4 Mostly 2 1 2 Mostly 2

6” BJ-BB - - - 1 2 2

12” BB-BP1 1 1,2,3,4 Mostly 2 1 1,2,3,4 1,2,3,4

6” BF-BL 1 2 2 1 2 2

6” BH-BG 1 2 2 1 2 2

12” BL-BA 1 2 2 1 2 2

1

2

3

4

Stratified

Annular

Dispersed

Slug

OIL BLOCKAGESLUG 8”BK-BP1 and 12”BB-BP1

WATER BLOCKAGESLUG12”BB-BP1OLGA

Gas-Oil flow Gas-Water flow

50th section(horizontal line)

Beggs & Brill (horizontal)

101th section(riser bottom)

110th section(pipe outlet)

Beggs & Brill (vertical)

FLOW REGIME

Stratified Segregated

Stratified, annular, slug,

dispersed

Mostly annular, slug, dispersed Segregated

HOLDUP 0.2-0.52 (fluctuating)

0.12 0-1 (slug) 0-0.25 (slug) 0. 15

ACTUAL LIQUID VELOCITY

-0.79-2.25 m/s (fluctuating, closer

to zero)0.08 m/s

Too low (assumed zero),

except in slug regime (reach

1.5 m/s

0-(-1.5) m/s 0.14 m/s

ACTUAL GAS VELOCITY

0.8-2.9 m/s(fluctuating)

0.93 m/s(-4)-8 m/s

(back flow)-1.3-2.2 m/s(back flow)

2.18 m/s


50th section(horizontal line)

Beggs & Brill (horizontal)

101th section(riser bottom)

110th section(pipe outlet)

Beggs & Brill

(vertical)

FLOW REGIME Stratified Segregated Annular Annular SegregatedHOLDUP 0.17 0.02 m/s 0 0 0.03

ACTUAL LIQUID VELOCITY

Too low, fluctuating, back

flow0.01 m/s back flow

Too low, fluctuating, back

flow 0 m/s

ACTUAL GAS VELOCITY

Too low, fluctuating, back flow

0.57 m/sToo low,

fluctuating, back flow

Too low, fluctuating, back flow

0.58 m/s

Main Finding (4)

12” BB-BP1

(OIL-GAS

FLOW)

6” BJ-BB

(WATER-GAS

FLOW)


Main Finding (5)

Critical VelocityHorizontal Pipe--Salama (1989)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

8.22E-05 9.38E-02 1.41E-01

cri

tical velo

cit

y (

m/s

)

liquid superficial velocity (m/s)

Particle A

Particle B

Particle C

Particle D

Particle E

Particle F

Particle G

Particle H

minimal velocity to avoid sand settling (Vm)

sand settling flow velocity<Vm affected factors:

1. particle properties

2. fluid properties

3. pipe properties

Investigation

by Salama

(1989)

Bekapai case

Sand particle

size

100, 280,

and 500 micrometer

x<38 micrometer until x>600 micrometer

Pipe diameter4 in 6, 8, 12 in

MediaWater, gas

(CO2, N2,

air), oil,

inhibitors, sand

Water, oil, gas, sand

Water cut1%, 10%,

50%, and 100%

46%, 53%, 86%, 87%, 98%, and 100%

Pressures 4 and 8 bara 11, 12, 14 , 57 bara

Temperature Ambient Wall (60oC)

NO SAND SETTLING OCCURS IN ALL INVESTIGATED PIPELINES!


Main Finding (6)

Critical VelocityVertical Pipe--Chien (1994)

SAND SETTLING IN 6”

BJ-BB

0

5

10

15

20

25

30

35

40

45

50%

weig

ht

critical velocity (m/s)

particle B

particle C

particle D

particle E

particle F

particle G

particle H

38 µm<d<63

µm

355µm<d<600 µm

250

µm<d<355 µm

150

µm<d<250 µm

106

µm<d<150 µm

63

µm<d<106 µm

d>600 µm

d<38 µm

affected factors:

1. particle properties

2. fluid properties


Recommendation

take a precaution over sand accumulation, especially at the riser bottom or another

transition section of pipelines due to analysis results. Fluid mixture velocity should be

enhanced until exceed the critical flow velocity to prevent initial sand bed formation.

Routine pigging should be done in pipelines that have been detected to experience sand

settling. Some pipelines which have low fluid mixture velocity (6” BJ-BB, 8” BK-BP1, and 12”

BB-BP1) should be placed at top priority.

Because sand settling phenomena strongly depends on the present data of fluid volumetric

rate in pipelines, this analysis is recommended to be routinely updated.

use OLGA instead of Beggs & Brill and experimental correlation in application to determine

multiphase flow properties, especially flow regime and dynamic behavior of each parameter

included.

do further study and analysis about this topic, especially about the other parameters

correlation that affecting sand behavior (e.g. pipe geometry and fluid properties).

use real model of Bekapai pipelines and fluid in order to be applied in the future.

Balikpapan, July 2010

Thank you for your attention……………

Laras Wuri Dianningrum

Chemical Engineering Program of Study

Faculty of Industrial Technology

Bandung Institute of Technology

analysis of sand transportability in bekapai pipelines (presentation)

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