Marginal Reservoirs

8/17/2019 Marginal Reservoirs

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Pushing the Envelope:Proven Technologies for Exploiting New Opportunities in

Marginal Reservoirs

NIGERIAN ASSOCIATION OF PETROLEUM EXPLORATIONISTS

September 2014 Monthly Technical Meeting

17th September 2014


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⁄ Placing “small/marginal” accumulations in context

⁄ Key challenges in Marginal field/reservoir development

⁄ SEPLAT Fields & Discoveries – An Overview

⁄ Subsurface Overview and Technology Application (Okporhuru and Oben fields)

-Target reservoirs depositional setting and key development challenges

-Smart Well Technology - Okporhuru field

-Periscope Technology - Oben field

Principle, Planning, Execution and Results

⁄ Conclusions

OUTLINEOutline


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Niger Delta Oilfields and “small/marginal accumulations” context


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SEPLAT’s OPERATED ASSETS MAP

OBEN & OKPORHURU FIELDS LOCATION


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OKRU V2000 - V7000 Reservoir Correlation

OWC(-11173)

- 1 1 7 5 0

-11750-11750

- 1 1 2 5 0

- 1 1 2 5 0

-

- 115 00

-115

-

-1 -1

-

- -1 5 - 1 2 2

- 1

-1 25

-1 5

- 1

5

-1 2 75

- 1 2 7

-11162

OKRU-001

-11208

OKRU-003

-11099

OKRU-004

-11142

OKRU-007-11097

OKRU-007-ST1

377000 378000 379000 380000

2 0 7 5 0 0

2 0 8 0 0 0

2 0 8 5 0 0

2 0 9 0 0 0

2 0 9 5 0 0

0 100 200 300 400 500m

1:12500

SEPLAT etroleum evelpment

Block

OkporhuruFieldTopStructuralDepthMap

Horizonname

V7000_top

Scale

1:12500Contourinc

50 AssetDevelopment

W E


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Okporhuru Facies

Offshore shelf

Shoreface

Back-barrier

Lagoon/tidal flatsTidal

Inlet

Lower delta

plain

Prodelta/Shelf

Tidal Flat/Lagoon

Shoreface/Beach

Most Likely Model – Fitting all Observations at all Levels

Okporhuru-4 Core


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Reservoir Development Challenges

O W C ( - 10 47 7 ) O W

C ( - 1 0

4 7 7 )

O W C ( - 1 0 4 7 7 )

O W C ( - 1

0 4 7 7 )

-11000- 110 0 0

- 1 0 5 0 0

- 1 0 5 0 0

-

- - 10 7 5 0

-

-

-

-

- 1 1

-

-

-10433

OKRU-001

-10475

OKRU-003

-10397

OKRU-004

-10392

OKRU-006

-10447

OKRU-007

-10398

OKRU-007-S T1

377000 378000 379000 380000

0 1 00 2 00 3 00 4 00 5 00 m

1:12500

SEPLAT Petroleum Development Co

Block

OkporhuruFieldTopStructuralDepthMap

Horizonname

V2000_top

Scale

1:12500Contourinc

50 AssetDevelopment

1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600

1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4600

- 1 1 3 6 0

- 1 1 2 8 0

- 1 1 2 0 0

- 1 1 1 2 0

- 1 1 0 4 0

- 1 0 9 6 0

- 1 0 8 8 0

- 1 0 8 0 0

- 1 0 7 2 0

- 1 0 6 4 0

- 1 0 5 6 0

- 1 0 4 8 0

- 1

0 4 0 0

-1 1 3 6 0

-1 1 2 8 0

-1 1 2 0 0

-1 1 1 2 0

-1 1 0 4 0

-1 0 9 6 0

-1 0 8 8 0

-1 0 8 0 0

-1 0 7 2 0

-1 0 6 4 0

-1 0 5 6 0

-1 0 4 8 0

-1 0 4

0 0

0 1 00 2 00 3 00 4 00 5 00 m

1:10000

A A’

A’

A

⁄ DPR Well spacing vs limited pool size

⁄ Small Ultimate Recovery: < 1MMstb per reservoir

⁄ Small area extent < 1.5sqkm

⁄ Several stacked reservoirs

⁄ Lateral sand continuity and connectivity

⁄ Aquifer strength

V2000

V3000

V7000


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What is a Smart or Intelligent Well?

⁄ Exploitation of marginal reserves through controlled

commingling of reservoirs

⁄ Remotely monitor and control well inflow or injection

down-hole at the reservoir


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Candidate Selection Criteria

⁄ Stacked reservoirs

⁄ Continuous shale separating sands

⁄ Reservoirs with similar pressure regimes

⁄ API variance within Regulatory limits

⁄ Remote location

⁄ Minimal security Issues


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Reservoir Technical data

TECHNICAL FIELD/RESERVOIR DATA

Structure

Reservoirs

Sands

Fluid properties

⁄ API: 38/-43; Rsi: 15 - 2200 scf/stb

⁄ Bo:1.015 -2.22 (FVF); Oil viscosity: 0.5- 4 cp

⁄ Mostly channel and shoreface sands

⁄ Simple rollover anticline, Four way dip

dependent closure

⁄ Depth: 8500 -11,300 ftss;

⁄ Porosity: 15-20%;

⁄ Perm: 225-580 md

⁄ Average thickness 70ft

Favourable

Conditions

⁄ Stacked Reservoirs, similar reservoir pressures

⁄ Minimal Security Issues


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Reservoir Production profile (Smart vs Individual Well Completion)

Commingled Smart WellIndividual Reservoir Completion


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Test Results and Model Calibration

⁄ Good match between actual vs model gross production

⁄ FTHP within 10% of prediction

⁄ Samples sent to PC Lab for analysis

⁄ Established that there was no flow domination or crossflow during static conditions.

⁄ Established that daily production allocation could be performed from the network model

0

10

20

30

40

50

V2000 V3000 V7000

OKRU-07 Prediction vs Actual

Prediction Actual

%

C o n t r i b u t i o n


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Oben Field – Overview

⁄ The Oben Field is situated in OML-4 some 60 km NNE of Warri.

⁄ The field was discovered in 1972

⁄ 42 wells drilled encountering over 50 hydrocarbon bearing sands

⁄ HC were encountered from depth 6,600 ftss to 10,500 ftss.

⁄ The field came on stream in 1974 and attained a maximum oil production

of 40,000 bopd in 1985.


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A A’

E2000 Reservoir Cross Section (Strike Section)

A

A’


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E2000 Reservoir Cross Section (Dip Section)

M t Lik l M d l Fitti ll Ob ti t ll L l


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Most Likely Model – Fitting all Observations at all Levels

Prodelta/Shelf

Tidal Flat/Lagoon

Shoreface/Beach

R i D l t Ch ll


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Reservoir Development Challenges

⁄ Thin reservoir


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Periscope Basic Principle and Application

⁄ PeriScope* maps bed boundaries in real-time using the 360°

directional and deep distance-to-boundary measurement up to 4m

away from the borehole.

Applications:

⁄ Maximizing Production*

⁄ Precise well placement in thin complex reservoir targets*

⁄ Water detection and sidetrack avoidance

⁄ Refining reservoir models

Benefits:

⁄ Increased production rates and recovery

⁄ Less or delayed water production

⁄ Access to reserves considered economically marginal*

Principles:


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Periscope Demo


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Well Placement Components - Workflow

Off t W ll D t S l ti


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Offset Well Data Selection

3D View of E2000 with offset wells and well tops

SW-NE Cross Section View of E2000 Reservoir NNW-SSE Cross Section View of E2000 Reservoir

E2000 Map View with Planned OBEN-38 well

OB-6

OB-32

OB-5OB-9

OB-3

OB-20

SW

NE

NNW

SSE

Ob 38 P i HD I i M d l R lt b Ob 32


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Oben-38 Periscope-HD Inversion Model Result base on Oben-32

⁄ Log response forward modeling to complete several PeriScope distance to boundary Inversions

⁄ To ascertain best quality inversion response to the formations and maximum distance to boundary

⁄ Pre-job modeling indicates that the E2000 Top can be resolved by HD inversion when well path is inside

the reservoir at a varying distance up to maximum of 8ft TVD


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Oben-38 Drain hole: Real time Monitoring /Optimization


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E2000 Dynamic Model Results

Target oil rate = 800 stb/d

Actual oil rate = 1050 stb/d

Horizontal Vertical

Well Reserves: 1.1 MMstb 0.28 MMstb


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Oben 38 PeriScope HD Highlight

⁄ Oben-38 entire drain length was placed within 1-3ft TVD below the

E2000 target sand top achieving our objective.

⁄ PeriScope HD mapped the target E2000 sand top from the beginning of

the drain section to total depth.

⁄ Reduced possible gas cusping in horizontal well through optimized

trajectory.

C l i


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Conclusion

⁄ Smart Intelligent well technology enabled the exploitation of marginal

reserves and acceleration of hydrocarbon production through controlled

commingling of stacked reservoirs.

⁄ Use of Periscope was critical to maintaining drain-hole section within 1-3ft

TVD below the target sand top on a real time basis.

⁄ The application of both technologies have proven that marginal reserves

can be efficiently exploited to achieve production offtake goal.


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THANK YOU

Marginal Reservoirs

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