applied mathematics in the oil & gas industry: metocean...

Company name appears here

Town and Gown Mathematics Department,

Covenant University

Ota, Nigeria

Applied Mathematics in the Oil & Gas

industry: Metocean Engineering

Dr. Emmanuel Osalusi, CSci, CMarSci

Senior Metocean Engineer The Shell Nigeria Exploration and Production Co.

Lagos, Nigeria

1 05/11/2017


Covenant University

Vision Statement:

To be a leading World-Class Christian Mission University,

committed to raising a new generation of leaders in all fields of

Human endeavour.

Mission Statement:

To create knowledge and restore the dignity of the black man via

a Human Development Total Man Concept driven curriculum

employing innovative, leading-edge teaching and learning

methods, research and professional services that promote

integrated, life-applicable, life-transforming education,

relevant to the context of Science, Technology and Human

Capacity Building’ 2 05/11/2017


Applied Mathematics

Applied Mathematics:

a combination of mathematical science and specialized knowledge

Beyond numbers

Uncertainty Quantifications. e.g.

1. ….they were about 600k men on foot, besides women and children (Exo.

12:37)

2. …and they that did eat were 5000 men, besides women & children - Mathew

14:21

3 05/11/2017


OUTLINE

1. Safety moment

2. Background

3. Introduction to Metocean Engineering

4. Metocean Considerations for Offshore Oil/Gas Development

5. Specifying the Offshore Environment

6. Metocean and its implications for offshore design and operations

1. Impact on Design Criteria

2. Impact on Operations

7. Q&A

4 05/11/2017


Safety Moment

5 05/11/2017

Company name appears here 6 05/11/2017

Institutions Attended

Academic

Qualifications

PhD Petroleum Engineering (Institute of Petroleum

Engineering, Heriot-Watt University, UK)

MSc Applied Mathematics (University of Limpopo, South

Africa

PgDip, Mathematical Sciences, (African Institutes for

Mathematical Sciences – www.aims.ac.za ), University of Cape

Town, South Africa

BSc (Hons), Mathematical Sciences, Ondo State University

(now Ekiti State University, Ado-Ekiti), Nigeria

Professional

Qualifications

Lead Auditor /Auditor Course, Quality Management System

(ISO 9001:2008)

Member, The Institute of Marine Engineering, Science &

Technology (MIMarST - UK)

PRINCE2 – (Project Management - UK)

Chartered Scientist (CSci), Science Council (UK),

Chartered Marine Scientist (CMarSci), IMarEST (UK)

QUALIFICATIONS


Year Institutions Attended

1997 - 2000 Computer Officer/QA&QC officer, SPIE Enertrans S.A., Nigeria.

Shell/Total/NNPC LNG contract, Bonny Island, Rivers State.

2000 - 2001 Document Control Officer, Titan Engineers & Constructors, Nigeria.

Shell/Total/NNPC LNG contract, Bonny Island, Rivers State.

2001 - 2002 Administrative Officer/Document Control Officer, Hyundai Heavy

Industries, Nigeria, Shell/Total/NNPC LNG contract, Bonny Island,

Rivers State.

2006 Research Associate, International Centre for Theoretical Physics

(ICTP), Italy (CNR-ITAE).

2006 - 2009 Research Associate, Heriot-Watt University, Edinburgh.

2009 - 2010 Numerical Hydrodynamic Engineer, Total Gas & Power Ltd.,

London

2010 - 2011 Senior Oceanographer, Partrac Ltd., Glasgow

2011 - 2013 Senior Global Analyst, GE Oil & Gas, Newcastle, UK

2013 ongoing Senior Metocean Engineer, SHELL, Nigeria

CAREER PATH


Peer Reviewed Publications

1) E. Osalusi, J. Side, R. Harris. Structure of turbulent flow in EMECs tidal energy test

site, Int. Comm. Heat and Mass Transfer, 36, 5,422-431, (2009)

2) E. Osalusi, J. Side, R. Harris. Reynolds stress and turbulence estimates in bottom

boundary layer of Fall of Warness, Int. Comm. Heat and Mass Transfer, 36, 5, 412-

421, (2009)

3) E. Osalusi, J. Side, R. Harris. Thermo-Diffusion and Diffusion-Thermo effects on

combined heat and mass transfer of a steady MHD convective and slip flow due to a

rotating disk with viscous dissipation and Ohmic heating, , Int. Comm. Heat and Mass

Transfer , 35, 908-915 (USA), (2008)

4) E. Osalusi, J. Side, R. Harris. Ohmic heating and viscous dissipation effects on

unsteady hydromagnetic flow and heat transfer over a porous rotating disk with variable

properties, hall and ion-slip currents, Far East Journal of Applied Mathematics, In

press, (2008) etc

5) ( 17 – Fluid Mechanics, 2 on Oceanic Turbulence)

8 05/11/2017


Metocean Engineering

9 05/11/2017


Metocean Engineering and the business

The impact of metocean engineering applies across all phases with the

potential to add value at each phase ([Opportunity Realisation Process

(ORP) phases]

10


High cost of getting metocean wrong

11 05/11/2017


Marine

12 05/11/2017


Aviation Nigeria: 322 fatalities in about a 14 months

13 05/11/2017


Squalls: formation

LiVe IMAGE

14 05/11/2017

Aviation: Turbulent wind - Squalls

http://www.sat24.com/foreloop.aspx?type=1&continent=afrika


Aviation: Squalls


Airfrance 477: 228 fatalities – all lost!

X

The aircraft encounters point X, where it enters the microburst zone, and a headwind causes

it to rise above the normal glideslope. At the center of the microburst, point Y, there is a

downdraft causing the aircraft to sink. The aircraft now enters the most dangerous zone,

point Z, where a sudden tailwind causes the aircraft to lose airspeed and potentially crash.

F-7-14-54 (AF477)

Y

Z

Microburst zone Most dangerous zone

2:14:28 Hrs 2:06 Hrs

16 05/11/2017


The cost of getting it wrong!

17 05/11/2017


Metocean = Meteorological + Oceanographic

What is metocean

Abbreviation came in 40 years

ago

Metocean is a discipline covering

meteorology and physical

oceanography, and is concerned

with quantifying the impact and

effect of weather and sea

conditions on a wide range of

activities in the onshore and

offshore oil & gas and renewables

18 05/11/2017


Metocean

Metocean = meteorological + oceanographic

19 05/11/2017


The role of Metocean Engineer

Provide optimal/suitable and innovative Metocean solutions and guidance for

offshore/onshore projects:

Extreme design criteria for ultimate strength

Fatigue criteria

Operational criteria for construction/tow/installation

Meteorological and oceanographic instrumentation and measurement

systems

Weather and ocean modeling and forecasting

Renewable ocean/wind energy

Ice management planning

Iceberg and sea ice tracking

Research/technology development

Industry/regulatory liaison 20 05/11/2017

http://sww.wiki.shell.com/wiki/index.php/File:KANUMAS_Ice_Breaker_Odin.bmphttp://sww.wiki.shell.com/wiki/index.php/File:Groundediceberggreenland3.JPG


Engineering Requirements

Metocean Conditions

Metocean Data

Acquisition

Weather Forecasts/ Hindcasts

Metocean Design

Criteria & Operational Statistics

Metocean cycle Challenges

• Cross-discipline awareness

• Early interaction

• Appropriate time & budget for deliverables

21 05/11/2017


Institute of Petroleum Engineering, Heriot-Watt

University, UK

Research works

Ocean Turbulence – Wave-Current Interactions

22 05/11/2017

There is no branch of mathematics, however abstract, which may not

some day be applied to phenomena of the real world. Nikolai Lobachevsky

http://www.azquotes.com/quote/586908?ref=applied-mathematicshttp://www.azquotes.com/quote/586908?ref=applied-mathematicshttp://www.azquotes.com/quote/586908?ref=applied-mathematics


Motivation

23 05/11/2017

goal

…the understanding of the flow

due to short-term fluctuations in

stream velocity, at a typical tidal

stream site, will assist in the

modelling of a tidal test site and

improve design optimisation of

tidal stream turbine design.


Inline force

t

XρVCX(t)|X(t)|ρAC(t)F mdx

2

1

'uUX

Morison’s Equation

2'''

2

1||

2

1)( UAC

t

uVCuuACtF dmdx

Oscillatory Force Steady Force oscillatory drag coefficients

24 05/11/2017

Inertia Force Drag Force

'''

cw uuu


Ocean turbulence

Multimodal directional seas

affects stability,

fatigue loading and

response

25 05/11/2017


Boundary layer

26

Uc

CBL

MWS

Uw

h

0 WBL w

Boundary-layer-induced turbulence fluctuations:

Creates unequal forces on the turbine

Cyclic loads on the blade

Fatigue damage

Excitation of roll response

In physics and fluid

mechanics, a boundary

layer is the layer of fluid

in the immediate vicinity

of a bounding surface

where the effects of

viscosity are significant.

05/11/2017


Boundary layer

27

Interaction btw WBL & CBL creates transient &

nonlinear flow ….. transient load

CBL

WBL

05/11/2017


Boundary layer

28

The ability of the offshore structure to cope with short-term stream velocity variations such as those resulting from turbulence or wave–current interactions is a concern in

offshore industry

'uUX

05/11/2017


Turbulence

w

wc

c

Total Bed Shear Stress = Mean Bed Shear Stress + Maximum Oscillatory Bed Shear Stress

2

2

ln130

ln12

2

1

b

A

Nc

ccc

k

k

ek

h

f

uf

29 05/11/2017


Analysis Method – Flow Chart

30 05/11/2017

ADCP Raw

Data

Pytho

n

Raw Binary

Waves Data

Raw

Binary

Current

Data

Turbulence

Estimates

Prime Flowchart

Preprocess


Directional

Wave

Spectra Input

Record Length [FN: RunDirSp, specCompute2]

Compute: Cross Power

Spectrum Wavenumber

Transfer parameter

Directional Spectra Wave

parameters (Hs, Tp, DTp, Dp) [FN: specCompute3, specCompute4]

Plotting:

S(f,Q), Hs, Tp, DTp,

Dp [FN: specPlot1, specPlot2]

Save:

S(f,Q), Hs, Tp, DTp, Dp [Folder: waveplots_{starting date} ]

[FN: specCompute2]

Directional

Wave Spectra

Smooth?

Smooth Spec

with

resolution Yes

No

Preprocess



Raw

Current Data

Structure of Measured Data

+

Configuration [FN: runCurrent1]

Plotting:

*10-min mean current velocity Vs time

*Water level Vs mean (over depth) current velocity

*Depth-time current velocity magnitude

*Tidal height Vs time [FN: runCurrent2]

Current Profiles Preprocess



QC: Data must undergo extensive quality control analysis in order to ensure that the

uncertainties in the output are reduced to the minimum.

Before the deployment

thresholds are set in order to ag bad data

that fall outside of broad error specifications or against a narrower range of error

specifications

Error due to strong reflections from the water surface that overcome the sidelobe

suppression

Pre-processing

some data may be questionable.

Such suspected data, called spikes, are not removed; rather, they are detected

and possibly replaced.

Spikes in the data may corrupt, overestimate wave spectra or skew smoothed

estimates. Spikes in the ADCP data are mainly caused by fish, ship, turbulence and

floating debris.

Data QC – Noise Removal


Data QC – Noise Removal

35 05/11/2017

(1) Detecting

(2) Removing

(3) Replacing erroneous data

Methods:

1. Acceleration Threshold Methods

2. Phase-Space Threshold Method (PTM) (3D

Poincare map Method)


Data Quality Control

36 05/11/2017

2222

Dumt

Voulgaris & Trowbridge

(1998)

Sampling error related to

Phase shift (independent

of flow)

Error variance due

to mean velocity

shear (flow related)

Doppler noise related to

Doppler band width

broadening (flow related)

Total vel. Error

variance

[dominate noise term

due to turbulence and

the mean shear error,

becomes significant

close to the seabed]

The total source of

noise in ADCP

beam

velocity is given as:

ADCP=Acoustic Doppler Current Profiler


3D Poincare Method

37 05/11/2017

These methods are based on the

observation that the derivative of a signal

amplifies the high-frequency components

(the spikes domain). The separation of

these erroneous data is amplified as the

order of derivative increases.

),(),(

),(),(),(

tt

t

ttXty

j

j

k

j

kkk

=Fourier series transformed of u(t) – instantaneous velocity,

w(t) the radial frequency and j positive index

),( tk

)sin(22

2

tt

)cos(

)sin(

tt

t


3D Poincare map

Method

38 05/11/2017


TKE- Reynolds stress

39 05/11/2017


Metocean Considerations for Offshore Oil &

Gas Development Projects

40 05/11/2017


Field development concept selection

Offshore Field Development Concept Selection influenced by: • Field characteristics • Water depth • Metocean conditions……

41 05/11/2017


Fixed platform

Limited to ~ 300 m Piled steel jacket & concrete gravity platform

Loading: waves and currents on substructure winds on topsides

Deck elevation Sufficient air gap to allow for wave crests, tide & storm surge

Scouring Near bed currents

42 05/11/2017


Towing and installation

Metocean Impact on: Installation method Barge selection Design of sea fastenings Tow route

Hazards Long period waves Wave height Cross seas Strong currents Wind/wave/current offsets

43 05/11/2017


Floating production systems Various Types: TLP, Semi-Sub, Spar, FPSO

Advantages over fixed structures Deep water Small fields/short field life Re-use other location

44 05/11/2017


Floating production platform

Metocean needed for: Feasibility appraisal Floater selection, modification or new design Product export – tanker offloading or pipeline Subsea installation Floater installation Operation Decommissioning/re-use Cost Benefits: Metocean + Response Based Design For feasibility & selection of appropriate system Metocean statistics for vessel motion, Operational windows for FPSO shuttle tanker Metocean conditions Assessment of fatigue life

45 05/11/2017


Subsea, pipelines & cables

Metocean Hazards: Strong near-bed currents Wave motions (shallow water) Seabed scouring Unsupported spans Bottom temperatures Turbidity currents Hydrate formation Ice

46 05/11/2017


Jetty Coastal Protection

Marine Cooling Water and

Desalination Systems Coastal Facilities

Coastal facilities

47 05/11/2017


Offshore operations

Applications: Offshore Oil & Gas Production Aviation Marine vessels Oil spill contingency

Metocean deliverables: Metocean Operational Planning Statistics Real-Time Metocean Measurements Weather Forecasts Oil spill modeling and contingency plan

48 05/11/2017


Metocean requirements for each development phase

49 05/11/2017


Metocean desktop study process map

Deliverables

Technical Review

(TA Sheet)

Request

Define SOW,

Approaches and

deliverables

Report

Memo

Data Sources

Analysis

Assign TA/TR

Brief the work

Q/A

Status

50 05/11/2017


Data sources

Sea Surface

Seabed

300khz ~ 100m range

75khz ~ 500m range

38khz ~ 1000m range

Seabed or BOP-mounted 75khz ~ 500m range

RovADCP ~ 6000m range

51 05/11/2017

http://www7320.nrlssc.navy.mil/GLBhycom1-12/navo/globalsshnowcast.gif


SQUALL

52 05/11/2017


SOLITONS

53 05/11/2017


Metocean data consideration

54 05/11/2017


Metocean data consideration - annual variation

55 05/11/2017


Design criteria – design philosophy

Goal: design offshore facility to withstand extreme environmental conditions that will

occur during its lifetime with “optimum” risk level

Weigh consequences of failure against cost of over-designing

For facilities with 20-30-year lifetime, generally use 100-year metocean criteria

With typical implicit and explicit safety factors, annual probability of failure ≈ 10-3 to 10-4

Procedure:

Analyze historical environmental conditions

Assume future exposure will have the same statistics of extremes as past exposure

Global climate change:

Effect on extreme conditions is not yet known, and is generally neglected

Assume design safety factors will accommodate any increase in environmental severity

that may occur

56 05/11/2017


SPECIFYING THE OFFSHORE

ENVIRONMENT

57 05/11/2017

Applied mathematics will always need pure

mathematics just as anteaters will always

need ants. Paul Halmos

http://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/quote/1255760?ref=applied-mathematicshttp://www.azquotes.com/author/28949-Paul_Halmoshttp://www.azquotes.com/author/28949-Paul_Halmos


Structural response to extreme conditions

58 05/11/2017


Marine operability assessment

59 05/11/2017

Measurement

Modeling (hindcasting)

Continuous time-series

Acceptable motions criteria

Analysis (available windows)

Modeling (berthing simulator)

Modeling (vessel responses)

Metocean Environment

Vessel particulars

Floating System

Basin testing


Side-by-side offloading

60 05/11/2017

FENDERS

MOORING LINES


Solitons impact

Impact

Fatigue – risers, subsea equipment

Operations – ROV

In mathematics and physics, a soliton is a self-reinforcing solitary wave

packet that maintains its shape while it propagates at a constant velocity.

1. It must maintain its shape when it moves at constant speed.

2. When a soliton interacts with another soliton, it emerges from the

"collision" unchanged except possibly for a phase shift.

61 05/11/2017

https://en.wikipedia.org/wiki/Mathematicshttps://en.wikipedia.org/wiki/Physicshttps://en.wikipedia.org/wiki/Wave_packethttps://en.wikipedia.org/wiki/Wave_packet


Metocean delivers a broad range of products

Example Product Delivery List

Seismic data acquisition criteria

Drilling criteria

Rig orientation

Riser fatigue

Mooring criteria

Host/Site design criteria

SURF design criteria

Tow criteria

Installation/construction criteria

Waiting on Weather statistics

Environmental sensors for MAS/MIS

62 05/11/2017


THE METOCEAN CHALLENGE

Risk

Costs

Risk

Costs

Improvements through:

63 05/11/2017


OCEANOGRAPHIC PARAMETERS FOR DESIGN

Criteria need to address

multiple parameters in space

and time

Wind, wave, and current are

vectors with magnitude and

direction

Wind/wave have broad

frequency components

Some conditions drive

ultimate strength, some drive

fatigue

64 05/11/2017


Characterizing random seas

65 05/11/2017


Conclusions

66 05/11/2017


The cost of getting it wrong !

67 05/11/2017


68



69



High cost of getting metocean wrong

71 05/11/2017


“If you stop at general math, you’re only going to

make general money.” – Snoop Dogg

Thank you!!

72 05/11/2017

applied mathematics in the oil & gas industry: metocean...

Documents