Replacing OBM with WBM?

Ole Iacob Prebensen,

Technology Manager, European Technical Center

Agenda

• Background

• Norwegian Continental Shelf

• Technical Challenges of Mature Fields

• Customers challenges in the future

• Vapour from base oils• Vapour from base oils

• New water based drilling fluid

• WBM versus WBM, from an environmentalperspective

Challenges - the NorwegianContinental Shelf

&Customer Questionnaire

&Customer Questionnaire

Background

• Technical challenges in the oil industry are becomingmore complex each day:

• Ten kilometer wells

• Ultra high-temperature high-pressure wells

• Wells with very limited hydraulic window

• These scenarios are no longer the exception, ratherthe standard.

• Different drilling methods to deal with suchenvironments include managed pressure drilling andcasing drilling operations.

Norwegian Continental Shelf

• The NCS consists ofthe North Sea, theNorwegian Sea and theBarents Sea.

• The North Sea isregarded as a matureregarded as a maturearea, where mostreservoirs are depleted.

Norwegian Continental Shelf

• As drilling operations expands to the northern partsof Norway and into the Barents Sea and most likelybeyond, the impact of drilling operations to theenvironment is a very sensitive topic.

Man

Algae

(Skeletonema sp.)

Sediment Reworker

(Corophium sp.)

Zooplankton

(Acartia sp.)

Fish

(Scophthalamus sp.)

Bioaccumulation

Aerobic Biodegradation

Anaerobic Biodegradation

Water soluble?

Water insoluble?

Customers Questionnaire

“The technical challenges we face in ourindustry are becoming more complex andwe would like your opinion in this matter,we would like your opinion in this matter,

especially were you see tomorrow’schallenges within your own group / rig.”

Challenges in the industry

TOPFIVE

TODAY

1 ECD Limitations

2 Losses to theformation

TOMORROW

ECD Limitations

Depleted reservoir

3 Depleted reservoir

4 Hole Cleaning Issue

5 Transfer ofExperience

Losses to theformation

Hole Cleaning Issue

Transfer ofExperience

”Runners-Up”

• Environmentally accepted chemicals

• Wellbore strengthening

• Zero Discharge

• Slop / Waste handling

• Vapour• Vapour

__________________________________________

Focus:

Develop drilling fluid systems that meet thesechallenges......!!!

Solution?

• No single solution exist that will deal with all ofthese topics at the same time.

• As an example, by nature there is a conflictbetween using very low viscosity base oil forreduced viscosity in the drilling fluid and at thesame time have low vapor from the same base oil.

• A compromise must be met.

Conventional WBM

Bit balling

Accretion

Stuck pipe Stuck pipe

Hole cleaning

Bit trips – accretion

Development of a new WBM system

Goals set for the new WBM system

1. Develop a water based alternative with the samebenefits as experienced with oil based treatedmicronized weight material (TMWA).

2. Create a highly inhibitive water based drilling fluidsystem in order to replace existing high-performance systems.performance systems.

Applications

• Intermediate sections where high-performancewater based drilling fluids or conventional oil baseddrilling fluids are being used.

• Narrow operating windows are experienced & ECDmanagement is needed.

• Long section where WBM’s have been used and• Long section where WBM’s have been used andtorque is an issue.

• Rigs where vapour is an issue.

• Limitation to the CRI unit.

• Logistical capacity low.

Drilling Fluids Comparison

• Generally, the performance of oil based drillingfluids (OBM) is regarded as superior to their waterbased counterparts (WBM) due to:

Inhibition mechanisms

Lubricity, coefficient of friction

Temperature stabilityTemperature stability

Corrosion

Wellbore stability

• These are a few of the benefits derived from usingOBM’s versus WBM’s.

Laboratory Testing

The system has been tested extensively with regards to:

• Shale Inhibition

• Accretion Potential

• Recovery

• Cuttings hardness• Cuttings hardness

• Viscosity

• Reduce high-end viscosity w.r.t. hydraulics

• Effect of different contaminants

• Barite sag & Lubricity

Comparing WBM with WBM

Drilling Fluids Comparison

• As the industry strives to achieve improvedenvironmental solutions with regards to zerodischarge and re-use of drilling fluids, theintroduction of HPWBM creates the possibility ofusing HPWBM where OBM’s is typically used.

• As HPWBM contains environmentally acceptablechemicals with very good inhibition characteristics,

• As HPWBM contains environmentally acceptablechemicals with very good inhibition characteristics,the volume utilized on drilled cuttings compared tostandard WBM is reduced.

Benefits…

• Statement:As a result the drilling cost and impact to theenvironment is reduced.

• Furthermore, a reduction in contamination of thefluid allows for HPWBM to be re-used at a higherrate than conventional WBM’s. This is due to theimproved inhibition mechanisms.rate than conventional WBM’s. This is due to theimproved inhibition mechanisms.

HPWBM v.s. Conventional WBM

• The chemicals in the HPWBM system used for shaleinhibition are classified as YELLOW chemicalsaccording to the Norwegian Pollution ControlAuthority (SFT).

• What is the environmental benefit of this system incomparison to a conventional Potassium Chloridesystem with glycol – used widely on the Norwegiancomparison to a conventional Potassium Chloridesystem with glycol – used widely on the NorwegianContinental Shelf – which contains only oneYELLOW chemical

?

Comparison of Dilution Rates

• A standard KCl / Glycol system uses from 3 – 5 % byvolume of yellow components, whereas the HPWBMcontains 4.4 – 6 % by volume.

• Results from 17 ½” sections drilled gave thefollowing dilution rates of drilling fluid lost oncuttings – only:cuttings – only:

• KCl / Glycol: 2.76 m³ drilling fluid / m³ of cuttings

• HPWBM: 1.73 m³ drilling fluid / m³ of cuttings*

• Conv. OBM: 1.50 m³ drilling fluid / m³ of cuttings

* The results varied from 0.79 m³/m³ to 2.59 m³/m³

Environmental impact

YellowProductsHPWBM

Concentration %

by volume

Low

Conc.

kg / m³

High kg

Conc.

kg / m³

Shale Inhibitors 4.4 – 6 44.6 59.2

YellowProducts KCl /

Glycol

Concentration %

by volume

Low

Conc.

kg / m³

High kg

Conc.

kg / m³

Glycol 3 - 5 30.3 50.5

Environmental impact

DrillingFluid

System

Lowconc.

kg / m³

Highconc.

kg / m³

Dilutionfactor

m³ / m³

Actualdischarge

Low conc.

kg / m³

Actualdischarge

High conc.

kg / m³

HPWBM 44.6 59.2 1.73 77 102

KCl / Glycol 30.3 50.5 2.76 83 139

Result: From 7 % - 27% reduction in discharge ofyellow products when using HPWBMcompared to conventional KCl / Glycol.

Comparison of Re-use

TYPE % Re-use Year 1 % Re-use Year 2

OBM 70.8 82.8

HPWBM 57.8 66.6

KCl / Glycol 43.3 55.5

HPWBM Programmed Achieved

LGS (kg/m³) < 170 < 64

MBT (kg/m³) < 45 0 - 15

Summary

New water based technology versus HPWBM:

– Reduced viscosity without compromising sag.As a consequence; lower ECD values with thesame pump output, or equal ECD with morepump output.

– Very good shale inhibition results– Very good shale inhibition results

Hydraulic simulations between the new WBM andconventional OBM:

– Reduction in pump pressure

– Lower ECD’s

QUESTIONS???Thank you