IOR Centre Theme 2 – Task 5: Tracers for SOR measurements in

IW and SW application -Some recent results and future

plans

Tor BjørnstadMario Silva

Thomas BrichartAlexander Krivokapic

Sissel O. Viig

ENI, Milano 2016 Tor Bjørnstad

PITT and SWCTT• Interwell tracer injection probes the water-

contactable volume between wells. PITT measures SOR in this volume (SPE 164059)

• Single well push-and-pull (SWTT) tracer application measures SOR in a volume around a well 5-10 m from wellbore.

SWTT PITT

ENI, Milano 2016 Tor Bjørnstad

Injectionwell

Productionwell

Statified reservoir

• Preferential flow directions• Horizontal and vertical

communication between wells• Permeability strata• Sweep volumes• Large-scale heterogeneities

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• A passive water tracer moves only with the water water

• Phase-partitioning tracer distributes betweeen water and oil

• At residual oil saturation water moves, oil is (close to) stagnant

Passive and partitioning tracers…

K = (CTr)o/(CTr)w

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Passive and partitioning tracer –relative speed

Time

Conc

.

Inj.∝ SOR

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Volume (or time)

Rela

tive

conc

entr

atio

n

So = (Tp – Tnp)/[Tp + Tnp(K – 1)]

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Thermal degradation and sorption to substrates

Sealed glass ampoule

Rock substrate(sandstones, carbonates, clays etc.)

Heating bath,-thermallycontrolled

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2,3-Dimethylpyrazine (12 weeks)

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4-Methoxybenzyl alcohol (12 weeks)

ENI, Milano 2016 Tor Bjørnstad

Co-operation with Cornell Univ. - C-dots

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C-dots and fluorescenseDue to oxygen and nitrogen functional groups on their surfaces, these carbon nanoparticles shine brightly from blue to deep red when they absorb certain wavelengths of light

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SWCTT principle

Chemical reaction

Hydrolysis reaction

+ +

Ester Water Alcohol Acid

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Can a passive and a partitioning tracer be used in a SWCTT test?

See next picture frame:

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On backproduction……

The answer is NO!

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Therefore, injection of a reacting tracer is necessary

The well is shut-in for conversion of ca. 50 % of thereacting tracer into a passive water tracer

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Therefore, injection of a reacting tracer is necessary

On back-production, the produced water tracer starts on the same starting line as the remaining partitioning

tracer and they separate on their way back.

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Fluorescence of Rare Earth Compounds

Fluorescence spectra of selectedrare earths

Fluorescence colors ofselected rare earths

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Ester-based SWCTT = Single-WellChemical Tracer Techn.

Goal:* 3 – 5 new reacting tracers for H&P measurement of SOR

DTPA

* We synthesize new esters, for example starting with the poly-carboxylic acid DTPA etc.

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Promising reaction

+ Tb3+O O

O

O

O

OHOH

OHOH

OH

N N

NN

O O

O

O

O

OH

OH

OH

OHN

N

NN

OH

O

O

O

O

OOOH

OHOH

OH

N

NN

N

R

+ R-OH H2O +

Temporarilycencored

Temporarilycencored

Temporarilycencored

ENI, Milano 2016 Tor Bjørnstad

Post.docs and PhD-stud.

Thomas Brichart, post.doc.

Mahmoud Ould Metidji, post.doc.

Mario Silva, PhD-stud.

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New SWTT – reduction in volume and time

Present timeline – after a long production period

New timeline – after a long production period

Future timeline – beforeproduction start

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