Arran Field Case Study: From conceptual model to Reservoir ... Field Case... · DEVEX 2011 - Arran...

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Dana Petroleum

Arran Field Case Study:Arran Field Case Study: From conceptual model From conceptual model

to reservoir modelto reservoir modelJamie CollinsJamie Collins

Dana PetroleumDana Petroleum

DEVEX 2011DEVEX 2011

DEVEX 2011 - Arran Field Case Study: From conceptual model to reservoir model 2

Dana Petroleum

15 June 2011

Contents

Acknowledgments

Arran field introduction and project objectives

Project strategy

Conceptual model

Key data observations

Core

Outcrop analogues

Seismic

Static reservoir modelling

Conclusions


Dana Petroleum

15 June 2011

Acknowledgments

Partners

Esso Exploration & Production UK

Shell UK

Dyas

E.On Ruhrgas UK E&P

Dana team

Natalie Bordas-Le Floch

Jamie Collins

Brian Cullen - Reservoir Associates North Sea

John Downey

Steve Kenyon-Roberts

Paul Mattson - Logios Consulting

Jason White


Dana Petroleum

15 June 2011

Arran Field located 240km east of AberdeenCentral Graben - Blocks 23/11 & 23/16

Gas condensate field

Palaeocene Forties Sst Member reservoirMedial Forties turbidite system

Eastern margin on-laps onto Jaeren High

StructureArran North - reservoir pierced by

Zechstein salt diapir

Arran South – Stratigraphic pinch-out to east, with local low relief four way dip closure

Project objectivesIncorporation of new 2010 3D seismic data

– Reinterpretation of all existing data

Support detailed well planning

– 3 well development

Arran Field Introduction

ArranRedrawn from Fraser et al., 2003

Petrostrat Regional Study

Northern North Sea

Moray Firth

Central North Sea

East Shetland Platform

Horda Platform

Central Graben

West Central Shelf

Utsira High

Witch Ground Graben

North

Vik

ing

Gra

ben

Cen

tral

Vik

ing

Gra

ben

Sout

h Vi

king

G

rabe

n

Jaeren High

Inner Moray Firth

Outer Moray Firth

Tail End GrabenMid North Sea High

Fladen Ground

Spur

Redrawn from Fraser et al., 2003

Redrawn from Petrostrat Regional Stufy

Arran Field


Dana Petroleum

15 June 2011

Forties Sst pinch-out marginArran North

Arran South

Arran Field located 240km east of AberdeenCentral Graben - Blocks 23/11 & 23/16

Gas condensate field

Palaeocene Forties Sst Member reservoirMedial Forties turbidite system

Eastern margin on-laps onto Jaeren High

StructureArran North - reservoir pierced by

Zechstein salt diapir

Arran South – Stratigraphic pinch-out to east, with local low relief four way dip closure

Project objectivesIncorporation of new 2010 3D seismic data

– Reinterpretation of all existing data

Support detailed well planning

– 3 well development

Arran Field Introduction


Dana Petroleum

15 June 2011

Base UK

HordaSeleForties Fm

Ekofisk

BCUTop TriassicTop saltRotliegend / Base Salt

Base Forties

Triassic

S

1 km

Salt

23/16b-10

Arbitrary Line 1992 23/16 3D Shell Reprocessed 2003 PSTM

Forties Seismic Pinchout

W E

LineLocation

Forties

Arran Seismic Cross Section

CGGV Quad 22 Regional Survey 2008


Dana Petroleum

15 June 2011

Arran Field Data

Well data6 wells in immediate area, ~50% of

reservoir interval in wells cored

– Core coverage over entire Forties stratigraphy

– Wells located along axis of Forties fairway

Biostratigraphic, log & MDT data

– Limited DST data

CGG Veritas Quad 22 Regional 3D Survey 2008 Reprocessed 2010 to PreSDM

– Seismic inversion fluid cube

– Seismic Vshale volume

Partner analogue data from nearby fieldsTechnical and production experience

Reservoir connectivity


Dana Petroleum

15 June 2011

Project Strategy

Seismic

Outcrop Analogues

Core

Seismic Attributes

Conceptual Model

Knowledge Sharing

Stratigraphic Framework


Dana Petroleum

15 June 2011

Forties Reservoir Conceptual Model

Arran Field depositional settingsMedial parts of Forties turbidite systemEastern margin thins and pinches out

against Jaeren High

Preliminary core interpretations showStacked amalgamated and non-

amalgamated fairway sandstone bodies– High density turbidites

Extensively interbedded with – Heterolithic low density turbidite fringe

deposits – Slumps & debris flows– Hemipelagic and turbiditic shales

Moderate NTG system with poor reservoir qualityThin heterolithic faciesAvg. net porosity ~15%Avg. net permeability ~5mD

From Hempton et al, 2005 – Sele Fm Reservoirs

Arran


Dana Petroleum

15 June 2011

Central fairway submarine channels and amalgamated sands `

Non amalgamated sands passing laterally into lobe margins

Thin bedded lobe fringes passing laterally into interlobe / abandonment shales

Forties Reservoir Conceptual Model

Tabular elongated turbidite lobe bodies - high density turbidites

Axial amalgamated lobe bodies, passing laterally towards heterolithic lobe fringes

Lateral migration of lobes over time

Conceptual model evolved through project life cycle, along with field interpretations


Dana Petroleum

15 June 2011

Sandy Debrites & Slumps, 4

Interlobe / Abandonment Shale, 15

Channels & Amalgamated, 12

Non Amalgamated, 22

Thin Bedded Lobe Fringe, 10

Muddy Debrites, 14

Lobe Margin,24

Arran Core & Facies Interpretations

~50% of Arran reservoir interval coredDetail core facies interpretation7 key facies identifiedGrouped into depositional units to assist

with reservoir modelling

Moderate NTG system dominated by non amalgamated and lobe margin faciesLack of large erosive channel unitsAverage bed thickness dependent on

facies– Typically <50cm due to heterolithic

facies– Low energy lobe environment

Consistent with medial but marginal location within Forties turbidite systemPoorer average reservoir quality than

typical Forties fieldsDominated by thin heterolithic reservoir

units

High proportion of thin

heterolithic facies


Dana Petroleum

15 June 2011

Non-Amalgamated Facies

• Massive and dewatered high density turbidites

• Beds are discrete depositional units, separated by preserved low energy bed tops

Non-Amalgamated & Lobe Margin Facies

Lobe Margin Facies

• Interbedded high density turbidites

• Linked debrites with muddy debrites

• Thin-bedded turbidites and slumps

Implications for static modelling and reservoir performance?

A

B

2ft cell

A

B

A

B

2ft cell

A

B


Dana Petroleum

15 June 2011

Outcrop Analogue Data – Gres d’Annot

Vicinity of Col de Cayolle

• Key observations:

• 3D appreciation for reservoir distribution and architecture

• Lateral and vertical facies transition

• Reservoir connectivity

~ 10m Thick-bedded submarine sandlobe

Lateral and vertical facies transition


Dana Petroleum

15 June 2011

A) Amalgamated thick bedded high density sand-lobe – Arran field.

B) Thick-bedded high density turbidites of slightly channellised depositional sandlobes

A

B

C

D

D) Lobe-fringe low density turbidites

C) Thin-bedded lobe- fringe - Arran field.

Core - Outcrop Analogue Data

Col de la Moutiere Col de la Moutiere


Dana Petroleum

15 June 2011

B D

Seismic - Outcrop Analogue Data

Chalufy - Gres d’Annot


Seismic scale architecture

Bed scale architectures


Dana Petroleum

15 June 2011

Seismic Interpretations

CGGV 2008 seismic data

Seismic Vshale volume

Detailed integration of all data

Seismic & attributes

Stratigraphic framework

Outcrop analogue

Vshale data clearly identifies low Vshale regions

Sand rich reservoir intervals

Used to assist with reservoir characterisation

Lateral migration of seismic lobe units with time

Consistent with conceptual model

2010 CGGV VShale BL

Top Forties

Base Forties

Top Forties

Base Forties


Sand rich lobes identified from

Vshale data


Dana Petroleum

15 June 2011

Seismic Attribute Data

Seismic Vshale volumeSpatial relationship and distribution of

turbidite units

Proportional slices through Vshale volumeElongated lobe bodies identified

Northwest-southeast orientation

Possible slump bodies derived from Arran North diapir

Vshale volume controls reservoir facies distribution during static modellingSpatial relationships

Palaeoflow azimuth data

Lobe dimensions

Vshale volume used to assist with well planning optimisation


Dana Petroleum

15 June 2011

Palaeoflow Azimuth Data

Upper Forties-Vshale slice

Lower Forties-Vshale slice

Lateral migration of lobe towards

field margin

Local deflection of lobesForties turbidite

palaeoflow data


Dana Petroleum

15 June 2011

Static Modelling

Non Amalgamated Facies

Vshale

Prob

abili

ty

Facies Probability Grid

Good correlation of Vshale vs Facies

Vshale used to condition facies model


Dana Petroleum

15 June 2011

Arran Facies Modelling

Vshale facies probability data applied

Used to control reservoir distributions, proportions & lobe azimuths

Analogue and well data used to determine reservoir dimensions

Maintain facies spatial relationship

Amalgamated sand rich axis passing laterally into marginal heterolithic lobe fringes

Slumps / debrites derived from

Arran North diapir

Andrew High trend

Salt diapir

Andrew High trend


Dana Petroleum

15 June 2011

Arran Facies Model-2ft slice

Slump bodies sourced from diapir

Moderate reservoir passing downdip and laterally into poorer

heterolithic reservoir

Arran Facies Modelling

Vshale facies probability data applied

Used to control reservoir distributions, proportions & lobe azimuths

Analogue and well data used to determine reservoir dimensions

Maintain facies spatial relationship

Amalgamated sand rich axis passing laterally into marginal heterolithic lobe fringes

Slumps / debrites derived from

Arran North diapir

Andrew High trend


Dana Petroleum

15 June 2011

Low Vshale resulting in good reservoir quality

23/16b-1st

23/16b-1stTransition from poor to good reservoir captured in Vshale and facies model

Arran Facies – Vshale Cross Section

Moderate Vshale indicating heterolithic reservoir facies

• Reservoir model consistent with • Conceptual model• Core & outcrop observations• Seismic characterB


Dana Petroleum

15 June 2011

Model Uncertainties

Key uncertainties include

Seismic scale reservoir characterisation

– Is it sufficient to predict detailed reservoir performance?

– Facies distribution & connectivity – especially towards field margin

– Kv/Kh permeability

Limited well test data to quantify reservoir uncertainties

Knowledge sharing with partners proved critical to quantify uncertainties

Adjacent Forties field analogue data and production experience

Vertical and lateral connectivity

– Facies distribution

– Permeability


Dana Petroleum

15 June 2011

Conclusions

Successful integration of cross discipline subsurface data

Detailed reservoir model constructed

Key uncertainties captured

Study supports detailed well planning

Close collaboration of all disciplines from start to finish

Objectives and uncertainties of various disciplines captured early in project lifecycle

Support from Joint Venturers

– Technical and production experience from analogue fields utilised

Lessons learnt from project captured to feed back into future model builds

Reservoir connectivity due to modelling parameters

Ongoing evolution of conceptual model and field interpretations

– Must allow flexibility for an evolving and iterative approach


Dana Petroleum

15 June 2011

Project Strategy

Seismic

Outcrop Analogues

Core

Seismic Attributes

Conceptual Model

Knowledge Sharing

Stratigraphic Framework

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