1

Primary funding is provided by

The SPE Foundation through member donations

and a contribution from Offshore Europe

The Society is grateful to those companies that allow their

professionals to serve as lecturers

Additional support provided by AIME

Society of Petroleum Engineers

Distinguished Lecturer Programwww.spe.org/dl

James Hemingway

Petrophysics Advisor

Schlumberger

Society of Petroleum Engineers

Distinguished Lecturer Programwww.spe.org/dl

2

Formation Evaluation Using

Measurements made

Through Casing

Reservoir description using information

from cased hole logs rather than openhole

logs is a little like comparing Fred Astaire to Ginger Rogers.

“She did everything he did, except she did it backwards

and in high heels”

In nearly every situation the quality of data

acquired in openhole will be better than that

acquired behind casing. This is simply due

to the fact that a measurement made behind

steel pipe and a cement sheath of unknown

quality and thickness will be more effected

by it’s environment than a similar

measurement done without the presence

of casing or cement."Sure he was great, but don't forget that

Ginger Rogers did everything he did,

backwards…and in high heels."

Robert Thaves 1982

3

4

Easy Way or the Hard Way?

Openhole Vs Cased Hole Logging

Openhole

Better Data Quality

Fewer environmental effects

More measurement choices

Completion decision prior

to setting casing

Cased Hole

Not using valuable rig time

Much lower risk of tool loss

including radioactive sources

Ease of deployment

Use of tractors in high angle

and horizontal wellbores

Evolution of Cased Hole Formation Evaluation

FE began with (of course) only open hole logs in 1927.

Cased hole designs: S (1960’s) and Carbon/Oxygen (70’s)

Migration of OH measurements to CH environment

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density ?

5

Approximately 95% of horizontal wells are not logged.

Completions are often designed before the well is drilled.

Comments from a SIG meeting on unconventional

reservoirs:

1 “ Once the well is drilled what would you do

with the information”

2 “Before the well is drilled the completion has already

been designed by the engineers”

3 “When drilling a Hz well you should know where you are.”

Geology is usually very flat.

When production results are available they show 30% to

40% of perforation stages are not producing6

0% 10% 20% 30% 40% 50%

1

5

9

13

17

21

25

29

33

% from Perf Cluster

Perf

Clu

ste

r

Well No 1

0% 5% 10% 15% 20%

1

4

7

10

13

16

19

22

25

% from Perf Cluster

Perf

Clu

ste

r

Well No 2

0% 5% 10% 15% 20% 25% 30%

1

4

7

10

13

16

19

22

25

28

% from Perf Cluster

Perf

Clu

ste

r

Well No 3

0% 2% 4% 6% 8% 10% 12% 14%

1

4

7

10

13

16

19

22

25

28

% from Perf Cluster

Perf

Clu

ste

r

Well No 4

Figure A

Snapshot of Production Log Results (4 of 109 wells) SPE 144326

Miller et al

7

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density ?

8

Measurement and Fluid SensitivitySigma

0 100

CO2 OIL Salty Water

Hydrogen Index

0 1

CO2 Oil, Water

WaterCarbon Yield

CO2 OIL

Carbon to Oxygen RatioWater

CO2OIL

Gas

Gas

Gas

Gas

Burst On Inelastic RatioWaterCO2 OILGas

Fresh Water

Monitoring Saturation Change using

Sigma

10

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density ?

11

Acoustic Measurements using

Coherence ProcessingSlotted

Time

Wavefo

rm n

um

ber

Time

Wavefo

rm n

um

ber

Solid Mandrel

Time

Wavefo

rm n

um

ber

Time

Wavefo

rm n

um

ber

Open

hole

Cased

hole

12

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density ?

13

Other Gamma Spectroscopy Applications

Courtesy of NASA/JPL/Caltech14

Gamma Spectroscopy measurements from

Martian surface prove existence of water

on the surface of Mars

Press release February, 2002

Courtesy of NASA/JPL/Caltech

15

Pulsed Neutron Spectroscopy measures the rock matrix

Quartz, feldspar

Calcite, dolomite

Clay

Muscovite

Elemental abundance

in earth’s crust

O 46.7

Si 27.6

Al 8.1

Fe 5.1

Ca 3.7

Na 2.8

K 2.6

Mg 2.1

S, Ti, Gd, Mn

> 99 %

Carbon16

17

Yields and Mineralogy

ELAN Lithology Al Si Ca Fe S Ti Gd H

17

TOC from Inelastic Spectroscopy

MeasurementTOC = Total Carbon – Inorganic Carbon

(TC) (TIC)

Integration of Inelastic and

Capture gamma ray spectra

allows to determine TOC

18

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density ?

19

Water

entries, low

resistivity

Oil entries,

high

resistivity

CHFR / PLT Data

(SPE 71715 AGIP North Sea)

3 300

CHFR ILD

1 0

CHFRGR

0 3000

OIL

FLOW

0 5000

WATER

FLOW

20

1600BWPD to 300BOPD after

Cased Hole Resistivity

SPE 76730

21

– Neutron porosity

– Sigma

– Sonics

– Spectroscopy & carbon/oxygen

– Resistivity

– Wireline formation testing

- - density

22

Extend Spine & Ribs Methodology for CH

Open Hole

• Only one environmental

effect: mudcake

• rLS, rSS: response with

no mudcake

• One spine (density

response)

• Rib compensates for

mudcake

Cased Hole

• Two environmental effects:

cement and casing

• rLS, rSS : response with no

cement (but through-casing)

• A different spine (density

response) for every casing

thickness

• Rib compensates for cement

Start with

OH. Eqn. Modify for

casing

23SPWLA Paper KK 2010

SPWLA Paper KK 2010

SPWLA Paper KK 2010

A Log

SuiteIs this good

repeatability?

26

An OH/CH

Triple-Combo

Log Suite

One dataset acquired in

Openhole.

The other data acquired

In cased hole

GR CH

GR OH

AHT90 OH

RT CH

HALC CH

TNPH OH

RHOZ CH

RHOZ OH

27

Lithology from Neutron

Induced Inelastic and

Capture Spectroscopy

Can be done in either

Open or cased wellbores

Openhole Cased Hole

Cased Hole Results

29

Trip

le

Co

mb

o

EL

AN

Ima

ge

Fra

ctu

re

Cla

ss

De

nsi

ty

Str

ess

YM

E, P

R

A B C D E F G H

Full Evaluation Suite (Sonic Derived Stress vs.

Geochemical analysis Vs. Image)

30

Marcellus Example:Production increase of 80% over nearby wells using

an engineered design based on a better

reservoir description

31

Production improvement was directly attributed to the

identification and selection of low-stress intervals. Production

logging measurements confirmed the improved production rates.

Conclusions

• Formation evaluation in cased wells is

another option

• Many OH measurements can be made

in cased hole.

• Many applications require that data be

acquired in cased hole.32

Society of Petroleum Engineers

Distinguished Lecturer Programwww.spe.org/dl 33

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