PALADIN GEOLOGICAL SERVICES

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Advanced Techniques to Increase

Returns for Horizontal Wells and

Reservoirs

Tom Arnold, Director of Training @ Paladin Geological Service

GEOGAP Training Service Co-Founder & Director

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MUDLOGGING

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What is NOT new!

Logging 1985

Photographing Samples

Infrared Total Gas

Infrared Chromatograph

Full Sensor EDR & Logging System

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Typical Horizontal MudLog

Equipment used in mud logging today..NOTHING NEW HERE!

• Desktop PC

• Bloodhound IR Gas Analyzer

• Agitator

• WITS• Pason EDR• Totco RigSense• Rig Watch

• Microscope and sample trays

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MUDLOGGING ADVANCES

Gas Detection Has Changed…

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FTIR GAS DETECTIONFourier Transform Infrared

C1-C5 under a second because …no column

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True Spectroscopic Analysis

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2.5-13 micron range

System Hardware

Mounted at the shaker w/wireless

data transfer

Optical Bench and

onboard computer

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FTIR Data Results

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Increased Accuracy

Assures better ‘SweetSpot’ placement and Formation Evaluation

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What can be learned from

this new DATA?

…increased analysis of formation evaluation?

Average Specific Gravity ofTypical Hydrocarbons

Gas .56 - .66Condensate Gas .6 - .8Volatile Oil .77+Heavy Oil 1Air=1

What is the importance of Specific Gravity?

Specific gravity is unit-less and is the density of the gas divided by the density of air at 68 deg F. @ 1 atmosphere.

Gas Specific Gravity

Knowing the Specific Gravity of a gas sample

can tell you what type of hydrocarbon created it!

Gas Specific Gravity

It provides a possible indicator of the type of hydrocarbon in the reservoir!

Constants: Gas SGC1 = .55C2 = .75C3 = 1.53C4+= 2

SG = ([ C1/TG ] *.55 ) + ([ C2/TG ] * .75) + ([ C3/TG ] * 1.53) + ([ C4/TG ] * 2)

NomenclatureSG = Specific GravityTG = Total GasC1-4 = Component Gas Value

Gas Specific Gravity ExamplesExample 1

TG = 68

C1 = (60 units / 68) * .55 = .642

C2 = (8 units / 68) * .75 = .086

SG = .728 Dry Gas

•Example 2

TG = 680

C1 = (500 units / 680) * .55 = .404

C2 = (150 units / 680) * .75 = .165

C3 = (25 units / 680 ) * 1.53 = .056

C4 = (5 units / 680 ) * 2 = .015

SG = .640 Gas Condensate

Example 3

TG = 1200

C1 = (650 units / 1200) * .55 = .298

C2 = (200 units / 1200) * .75 = .125

C3 = (175 units / 1200) * 1.53 = .223

C4 = (100 units / 1200 ) * 2 = .167

C5 = (75 units / 1200 ) * 2 = .125

SG = .938 Oil

Based on the specific gravity of each of the component gases in the total gas

sample, the gas specific gravity gives a direct indicator of the type of

hydrocarbon that produced it.

Specific Gravity in Cross-Section

Well A

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SG Cross-Section Cont.

Well B

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Molecular Ratios

Data from Molecular RatiosGWR – Gas Wetness Ratio

LHR – Light to Heavy Ratio

OCR - Oil Character Ratio

Benefit in Horizontal Drilling

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Ultraviolet Fluorescence

Spectrometry

Evaluation of Hydrocarbon

Fluorescence for Fluid Type

A simple visual examination

of the fluorescence of

hydrocarbon can yield a

general idea as to the

nature of the oil.

Evaluation of Hydrocarbon

Fluorescence for Fluid Type

By measuring the frequency at

which a hydrocarbon sample

produces light under fluorescence,

the type of oil can be readily

determined. Thus quantifying the

visual inspection discussed

previously.

Quantitative Fluorescence Testing (QFT)

At the rig UV-fluorescence

technique for detecting and

analyzing extractable whole oil

from drill cuttings.

Users can obtain both oil

quantity and API gravity from

emission measurements at

two wavelengths.

HC Fluorescence – Oil / Gas Shows

Advantages• Provides repeatable results with

greatly improved sensitivity over

visual methods, especially for

light oils and condensates.

•Provides immediately useful

weight percent oil (Wt % Oil)

instead of relative (subjective)

visual or descriptive values of

fluorescence.

• Provides API gravity estimates

that help characterize in-situ

hydrocarbons.

• Provides a direct estimate of oil

in the formation.

HC Fluorescence – Oil / Gas Shows

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Geochemistry at the Well Site

Advanced Geochemistry in Surface Logging

• Prediction Of Producible Oil Via Real-time Onsite Rock Eval

• Hollow Fiber Micro-extraction To Measure Oil Content (C5+)

• Stage-wise Degassing For Rock Porosity And Permeability

• Real-time Onsite Isotope Analysis (GC-IR2)

Field Requirement in Shale Oil/Gas Systems

GLWD with in-situ, on-site advanced geochemistry!

• There is a significant amount of samples available from the drillingwells. Normally, these samples will be shipped to laboratory foradvanced chemical and isotopic analysis.

• However, by the time of analysis, a prominent amount of light HCsare gone forever.

• In addition, drilling cannot wait for laboratory analysis, whichusually requires turning-around time up to months.

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How to identify “Sweet Spot” and Keep In It?

Conventional Surface Logging??

• Field S1/TOC—oil show

• S1 from cuttings (“remaining” oil)

• Direct idea of liquid HCs (Closer to “produced” liquid HCs)

• Isojar Headspace Gas (“produced” gases)

To Identify and stay in the “Sweet spot”

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Deliverables: Extractable oil on Log

DescriptionsLithology

high liquid HCs;

Extractable OilMud Log

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Real Time, High Density Data

DescriptionsLithology

High Perm by Mud vs. headspace gas

Permeability indicatorMud Log

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Deliverables: Gas quality on log

DescriptionsLithology

Gas QualityMud Log

Wetter Gas

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(1) Oilshow

(2) OilExtractable

(3) Gaswetness

(4) Isotopes ofC1,C2 and C3

(5)Permeability

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(1) Sources of gases

• Biogenic vs. Thermogenic (biological or heat created)

• Shale vs. Coalbed

• Primary vs. Secondary

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Specific Advantages of Geochemistry

(2) Thermal Maturity

• In general, gas Isotopes increase with maturation.

• As thermal indicator, gas isotopes can tell if the reservoir is at the right window for oil, condensate and gas generation.

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“Sweet Spot” can be predicted by:

• Secondary Cracking Source (oil-related)

• High Nano porosity and permeability

• Isotope Reversal

(3) “Sweet Spot” prediction

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(4) Primary vs. Secondary

• Gas isotopes help differentiate the sources of gases (primary vs. secondary).

• Oil-related gas wells are usually of high production rates.-50

-40

-30

-20

-10

-55 -45 -35 -25

de

lta

13C

3(p

er

mil)

delta 13C2 (per mil)

Red: High Production Well

Blue: Low Production Well

Gas from secondary cracking of oil

or condensate

Gas from Kerogen

(adapted from JIP Report , 2013)37

(5) Production Decline Prediction

Two inputs:

Gas production rates

Real time C1 isotopes for minimum of 6 months

(Gao et al., in prep, GCA)

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Geosteering

…keeping the wellbore within the target bed.

When Everything Works Right….

When the gamma

data is good and

matches the offset,

life is good. The bad

news is that it is often

not the case.

Lay-over correlation

The wellbore

remains near

the center-

line of the

target zone.

When Faulting Occurs… It Gets

Interesting!start

end

major change

resultWithout the aid of software, determining

the throw of the fault would require

careful analysis of the drill cuttings. Even

then, the exact displacement would be in

question. But with good software the

value is known to the foot.

Eroded Top: Mississippi FormationThe wellbore entered the top of

the Mississippi as it emerged

from the unconformity, showing

a normal transition between

shale and carbonate. Then after

drilling several hours, the

wellbore entered the eroded

surface indicating shale once

more.

Know your geologic setting and never loose

sight of the BIG PICTURE! Otherwise this could

have been miss-interpreted as a fault.

Mississippian Carbonate Signature

What appears to be

noisy gamma, may

indicate fractures and

micro-faults within the

formation.

..many are present but a few are pointed out.

Delaware Basin Turbidities

Gamma indicated significant shift in

lithology. Drill cutting confirmed the

same, showing extensive clastic

detritus.

The Smaller the Pay Zone, the more

Critical the Fault

fault

compression

fold

4’ fault begins

fault

ends

With small pay zones, a fault of only a few feet can make a big

difference. Couple that with increased dip angles and folding,

makes interpretation while drilling a nightmare. Without good

software to keep the wellbore in zone and either knowledge of

the area or experience to assist, the productivity of the well can

come into doubt.

Even without geologic changes, other factors effect the wellbore;

directional drillers, drill motors, anisotropy, other equipment, etc…

These situations lead to porpoising of the wellbore or drilling out the

pay zone . This can mean having difficulty during completion.

Other Factors

porpoising

Often times all we have

is the general shape

between the LWD and

offset gamma to work

with.

Since carbonates have such a low gamma signature, how is correlation possible?

Geosteering in a Carbonate

offset

LWD

Other times we have

nothing more than an

educated guess. The

‘educated ‘ part comes

from experience.

Bakken

The Final ProductAccurate Geosteering requires being able to

see the ‘Big Picture’. That means the ability to

look beyond the LWD data. When correlations

come into question, consider the lithology and

gas data from the logger. Account for other

information from LWD sensors like resistivity,

azimuthal gamma ray, neutron density and

others if available. When you add in

experience, this is the point where both

science and art merge.

The assimilation and analysis of ALL DATA available

provides the most accurate correlations and are

necessary to assure the successful completion of a

horizontal well.

Successful Horizontal!

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Thank You

Questions?