challenges for bentonite industry-drilling fluids

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Sustainable drilling for oil and gas:challenging drilling environments demandnew formulations of bentonite based

drilling fluids

V. C. KelessidisTechnical University of Crete

http://[email protected] International Conference on Sustainable

Development Indicators in the Mineral Industry

17-20 June, 2007, Milos

http://drillinglab.mred.tuc.gr/

http://drillinglab.mred.tuc.gr/



2

Summary of the presentation

• Introduction

• Energy Demand & Drilling environment

• Drilling fluids

• Demands for drilling techniques & drilling fluids

• Challenges for bentonite industry

• Summary / Conclusions



3

Energy demand will continuously increase



Where will thisenergy come from ?



5

Mainly Oil – Gas - Coal



6



Where the new

oil & gaswill come from ?



8

Deep & Ultra-deep water !

‘hydrocarbon potential is not

considered adequate to give

any optimism for the deeper

waters providing substantial

additions to the reserves of exploitable hydrocarbons’

Wharman, 1978.

Transactions of the RoyalSociety of London.

How things change !



9

Strong potential of subsurface oceanwaters ! (deep > 300 m)

>550%

~80%



10

R.M. Slatt, Un. Oklahoma, 2001-02 AAPG DistinguishedLecture Series



11

Fleet from one operator



12

But all come at a price !

• US $ 10 – 50 million , single well– for 300 – 1500 m water depth

• US $ 3 – 9 million,

– for onshore (TD ~5000 m)– or offshore shallow water (TD ~ 6000 m)

• 50% costs for Drilling / tripping• 9.5% for Drilling Fluids (3rd largest)



13

Cost distribution for deep drilling

drilling fluids

but many problems are drilling fluid related



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Drilling fluids

• the ‘blood’ of the well• cool & lubricate the bit

• transfer cuttings to surface

• apply hydrostatic pressure (safety)

• maintain stability of wellbore

INGREDIENTSwater oil (diesel or synthetic)bentonitepolymersmany – many additives



15

Bentonite use in USA (USGS, 2005)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1996 1997 1998 1999 2000 2001 2002 2003 2004

M e t r i c t o n

s * 1 0 5

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

drilling fluids total bentonite % of total

Greece ~ 5%South Africa ~ 5%



16

Drilling fluid costs

• 1990, total ~ 4.0 billion US $ (1996)

• per well, deep wells, 2006, 500.000$

• very difficult wells, reported savingsof up to 1.0 million US $



17

Drilling fluids base, pros & cons

• Synthetic based muds, ~ 825 $ / ton– C14-C24, esters, ethers, poly-α-olefins

– beneficial but costly

– deep water, pressure margin very narrow– great chances for fracturing formations losses of very expensive fluids !

• Oil based muds, less expensive butenvironmental problems

• Water based muds, even lessexpensive



19

Brownlee, J.K., et al., 2005. SPE 97590

HPHT Wells



20

Challenges for drilling fluid industry

• Difficult well environment Hollisticapproach• flexible drilling fluids

• different formulations at differentdepth intervals• adjustable parameters• new additives

challenges for bentonite industry

find additives to expand operating range

of water based fluids



22

Additives for bentonite fluids

• polymers• lignite

• expand operating range• in search for mechanism of operation

Representation of

adsorption of cationicsurfactants on bentoniteparticles (from Alemdaret al., 2000)



23

Our recent work – Greek lignites

• methodology for lignite ‘activation’• techniques for measuring

performance

• excellent performance of most Greeklignites as HT additives

• stable slurries for– rheology and filtration control

– maintaining original core permeability



24

Permeability of filter cake (1770C)

0.0

2.0

4.0

6.0

8.0

10.0

Β1 Β1 Β1-HYD Β1+Γ Β1+TH7 Β1+ΜΤ3 Β1+ΤΗ4 Β1+ΚΠ5

Permeability*103

(mD)

0.0

2.0

4.0

6.0

8.0

10.0

Β2 Β2+Γ Β2+TH7 Β2+MT3 Β2+ΤΗ4 Β2+ΤΗ4 Β2+ΜΤ6 Β2+ΚΠ5

Permeability *103

(mD)

aged

hydrated

+commerciallignite Greek lignites



25

Rheological control with lignites

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 200.0 400.0 600.0 800.0 1000.0 1200.0

Shear rate (1/s)

S h e a r s t r e s s ( P a

)

H A A+G A+MT6 A+TH4 A+KP5 A+I1 A+PP2



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Retention of core permeability

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 0.1 0.2 0.3 0.4 0.5 0.6

Flow rate (ml/sec)

P e r m e a b i l i t y r e c o v e r y ( % )

A A+G A+MT6 A+TH4 A+KP5 A+I1 A+PP2

~ 100% recovery

~ 50% recovery

minimal damage

No 19, Aged+KP5

10

100

1000

100 1000 10000 100000

Time (sec)

P e r m e a b i l i t y ( m

D )

4=>8



27

Summary

• Demand for hydrocarbons will be on the rise• > 1500 m water depth, > 6000 m wells• high and low temperatures• need for excellent performing fluids

• in search for flexible drilling fluids• WB fluids less expensive & environmentally

friendly

• bentonite additives can expand operatingranges

THE CHALLENGE ? focused

research and product development



28

the challenge

is there !

challenges for bentonite industry-drilling fluids

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