Offshore Heavy Oil Development SPE 2009

8/9/2019 Offshore Heavy Oil Development SPE 2009

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Best Practices

in Offshore Heavy Oil Development

Cesaltino Matias Pedro

Petroleum Engineer

AcknowledgmentDr. William John LeeDr. Jerome. J. Schubert

Dr. Ben D. Welch

18th February 2009, Angola SPE Section - Luanda


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Background Motivation


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Background Motivation


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Background MotivationAbundant heavy oil resources discovered.

Only +/- 8% of production is from heavyoil.

Over 90% of heavy oil production is fromonshore heavy oil fields.

Increasing demand of fossil fuel leadingto oil price increases.

Continuous technological advancements.


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Background Challenge Offshore Environment.

Remote locations Challenging water depths Reduce space

Fluid properties. High viscosity High sulfur content High TAN number

Reservoir properties. Low reservoir pressure Low reservoir temperature

Unconsolidated formation


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Background Offshore

EnvironmentComplex and expensive producing and

processing facilities.Challenging wells geometry.

Flow assurance problems. Low temperature of flow lines

Oil/water emulsions Solids production

Limited deck space.


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Background Fluid PropertiesLow fluid mobility.

Challenging gas and/or waterfloodPoor well productivity.

Low product price.Reduced market.

Flow assurance problems. Temperature drop in wellbore

Oil/water emulsions


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Background Reservoir

PropertiesChallenging wells to drill.

Well control

Extended reach

Horizontal and/or multilateral

Challenging well completion.

Poor lifting mechanism

Sand production

Low recovery.


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Best Practices Best practices are those practices that members of the industry

agree add significant value to projects and have been in use by the

Project Management teams;(they may have not been validated through IPAs statistical methods).

The recognition and implementation of existing best practices inoffshore heavy oil developments improves the probability of asuccessful development.

Offshore heavy oil developments have been around for over 50years and past experiences showed that some can be economically

developed, when we are able to: Reduce the project implementation cost, Improve well productivity Market opportunities (location and/or high prices).


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Best Practices 3D SeismicIntegrate 3D Seismic interpretation with

local geological understanding

Generate correlations between seismiccharacteristics and reservoir properties.

Critical for reservoir characterization

Main source of data for reservoir simulation


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Best Practices Extended Well

TestPerform extended well test to mitigate

the uncertainty and risk to develop thefield and investigate future producingsystem

Mitigate risk and reduce uncertainty

Determine reservoir and fluid properties Understand producing system

Basis of design for the development plan


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Best Practices Heavy Oil

CharacterizationCapture oil samples in every well during

appraisal phase, measure PVT phasebehavior at reservoir and lowertemperature conditions, and pay special

attention to viscosity determination

Determine fluid properties Understand viscosity temperature

relationship

Production and processing system design


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Best Practices Heavy Oil

Characterization Viscosity: In a light oil reservoir, one sample may adequately

define a reservoir. In a biodegraded reservoir, this is not the case.

20% variation on a single oil sample has been recorded usingcurrent viscosity techniques

Heavy oil reservoirs are generally created by biodegradation/waterwashing of light oil. Since this process is dependent upon fluid

flow within the reservoir, the degree of contact and the amount ofbiodegradation within a reservoir is not uniform, thus, differencesin API gravity, viscosity, and other oil properties can be created.

Sometimes there are general trends in oil property changes withina reservoir. However, the non-uniform water contact generallycauses significant additional heterogeneities which overlay anygeneral trend which may exist, and make localized predictionsdifficult.


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Best Practices Extended Reach

Horizontal and/or Multilateral wellDrill extended reach horizontal and/or

multilateral wells

Increase well productivity

Optimizing the number of barrels producedby drilling-dollars spent

Optimized reduced number of wellbores

Manage pressure drop


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Best Practices Electric

Submersible PumpInstall electric submersible pumps as the

lifting system in the well completion

Enable wells to flow

Manage start up requirements

Lift high quantities of fluids (oil and water)

Allow some production of solids


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Best Practices Upgrade Heavy

OilMix light oil to the heavy oil by injecting

downhole or in the processing facilities

Modify heavy oil viscosity

Improve heavy oil properties

Increase product price

Increase well productivity


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Best Practices Water InjectionWater injection is the most successful

secondary (cold) recovery method

Improve sweep efficiency

Provide pressure support

Improve reserves recovery


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Key Challenges

Water Management

Sand management

Personnel on Board (POB)

Drilling costs

Slot constrained

Rig availability for workovers

Case History Captain

Best Practices

Performed extended well test

Horizontal wells

Water injection

Creative local solution Use of polymer toaugment waterflood results

Located offshore United Kingdom estimated to contain956 million barrels of 19oAPI oil, viscosity 88 cp

C


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Key Challenges

Thin reservoir sands

Distance to producing facilities

Regional weather Drilling costs

Case History Grane

Best Practices


Horizontal wells

Detailed study of reservoir fluids

Water and Gas injection

Creative local solution Oil stored in caverns

Located offshore Norway, 405 ft water depth, reservoirpressure of 2,466 psi, estimated to contain 755 millionbarrels of 19oAPI oil


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Key Challenges

Large bottom aquifer

Sand management

Tarmat layer

Drilling costs and smaller pools of reserves

High oil viscosity

Case History Jubarte

Best Practices


Horizontal wells

3D seismic interpretation

3D geological and simulation model

Phased development

Creative local solution Value of Information

Located offshore Brazil, over 3,500 ft water depth, reservoirpressure of 2,600 psi, estimated to contain 600 million barrels of 17o

API oil (dead oil viscosity 3,000 cp)


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What works

CO2 gas injection

Gas lift Progressive Cavity Pump

Viscosity modification by addition of heat High well density

Regular pigging of production lines

Polymer flood

Logging while drilling

Open hole wells


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Opportunities

Microbial application to upgrade oil downhole

Downhole catalytic upgrade 4D seismic cost reduction

Increase capacity to handle fluids duringextended well test

Open hole fracpack completion

Increase ESP tolerance to sand production Downhole fluids separation

Thermal bundled flowlines and well completions


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Acronyms

SAGD Steam Assisted Gravity Drainage

CSS Cyclic Steam Stimulation & Steamflood HOSGD Heavy Oil Solution Gas Drive

Vapex Vapor Assisted Petroleum Extraction MEOR Microbial Enhanced Oil Recovery

SARA Saturated Aromatic Resins & Aspalthenes

CHOPS Cold Heavy Oil Production with Sand

THAI Toe to Heel Air Injection


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Conclusions1. Successful development plans of heavy oil fields are

site specific, depending upon oil properties, possibility

to blend with light oil, price scenario, and availabilityof refinery and market for the product.

2. Completing producing wells with electric submersible

pumps is the most efficient lifting method for offshoreheavy oil developments.

3. Interpretation and integration of 3D Seismic with local

geology understanding is the most reliable source ofdata for reservoir and property characterization.


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Conclusions4. During the appraisal phase of a heavy oil offshore

development, extended well test is crucial to mitigate

risk and reduce uncertainties.5. Fluid identification and characterization is essential to

design extended well tests and producing and

processing facilities.

6. Drilling extended reach horizontal wells is thepreferred alternative to improve well deliverability for

offshore heavy oil developments.

7. To date Waterflood is recognized by the industry asthe most successful enhanced heavy oil recoverymethod.

Documents

Offshore Heavy Oil Development SPE 2009