Prospect Analysis

5/27/2018 Prospect Analysis

1/36FWS 2005 L14Prospect AnalysisCourtesy of ExxonMobil

Lecture 14

Alpha Beta



Objectives & Relevance

Relevance:

Demonstrate some the tasks that go intodetermining the size of the prize and the

risk associated with a prospect

Objective:Introduce the types of considerations

necessary to get a prospect ready formanagement approval



Overview of Prospect Analysis

Given the geologic framework and the results of our data

analysis, our next task is to analyze and assess viableprospects:

Analyze prospect elements

Source, Migration, Reservoir, Trap, Seal

Consider the most-likely scenario Consider other cases - the range of possibilities

Assess the prospect

What volumes of HCs can we expect?

Will it be oil or gas?

Risk the Prospect

What is our level of confidence that all the prospect elements

work?



Outline

1. Define prospect elements

2. Estimating trap volume

3. HC Type4. Assessment

5. Risk

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Outline

1. Define prospect elements

2. Estimating trap volume

3. HC Type

4. Assessment5. Risk

A KitchenWhere Organic

Material IsCooked

A ContainerFrom Which

Oil & GasCan Be

Produced

PlumbingTo Connectthe Container to the Kitchen

CorrectlyPlacedWells



A Real HC System

Brent Sandstoneacts as a reservoir

Heather ShaleSognefjord Shale

both organic poor

FaciesChange

Draupne Shaleorganic rich

serves as a source rock

HC Generation & Expulsionoil & gas from the Draupne, gas from coals in the Brent

HC Migrationinto Brent carrier beds and up faults

HC Fill & Spill

Fault

Leak

Point

Oil

Spill

Point

late gas displaces early oil



Alpha Beta

Reservoir

Seal

Source

Basement

Overburden

18 Ma

Most-Likely Scenario

OilGeneration

OilMigration

OilFill & Spill

Sea Water



Alpha Beta

Reservoir

Seal

Source

Basement

Overburden

10 Ma


OilGeneration

OilMigration

Oil

Migration

Sea Water




Reservoir

Seal

Source

Basement

Overburden

Present

Alpha Beta

OilGeneration

Gas

Generation

Oil & GasMigration

Oil

Migration

Sea Water




Map of the Reservoir Unit

AlphaBeta

Oil

Oil

18 Ma





BetaAlpha

Oil

Oil

10 Ma




AlphaBeta

Oil Oil

Gas


Present



Explorations Task

To EMDC

or EMPCDrop

Area

Drill

Wildcats

Confirmation

Well

Identify

Opportunities

ProcessSeismic Data

Capture

Prime Areas

Interpret

Seismic Data

Acquire

Seismic Data

Assess

Prospects

Success

Success

Failure

Uneconomic1. Volume2. HC Type3. Assessment4. Risk



Outline

1. Define prospect elements2. Estimating trap volumes

3. HC Type

4. Assessment

5. Risk

Lets start an exercise



Exercise 12Parts 1 - 6

We will do some quick estimates using a

series of simplifying assumptions


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FWS 2005 L14Prospect AnalysisCourtesy of ExxonMobil

How can we get arough estimate ofthe cross-sectionalarea?

Base 1

Height 1

Consider This .

Lets say our trap incross-section viewlooks like this.

Base 2

Height 2


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From Area to Volume

Volume of a Cone = 1/3 r2* h

Consider the trap to beapproximately a cone

Alpha Beta

r

h

r r


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Outline


3. HC Type

4. Assessment

5. Risk

DHI AnalysisAVO Analysis

HC Systems Analysis


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Oil or Gas???

Should there be a difference in seismicresponse (AVO) between an oil-filledreservoir and a gas-filled reservoir? Model response with different rock & fluid

properties

If there should be a difference, which fluidtype does the seismic data support? Extract amplitudes from near- and far-angle

stacks

From our basin modeling & HC systemsanalysis, which fluid type should we expect What did the source generate

What did the trap leak or spill

Quantitative

Qualitative


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Model Seismic Responses - Input

10%

Porosi ty

Gas

Oil

Brine

20%

Porosi ty

30%

Porosi ty


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Model Seismic Responses - Output

10% Poros i ty

Offset OffsetOffset

30% Poros i ty20% Poros i ty


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Model Seismic Responses - Output

-0.4

-0.2

0.0

0.2

0.4

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3

Intercept

Slope

GasOil

Brine

Shale

10%

20%

30%

AVO Crossplot


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Questions???

How can we verify this scenario?

To what level are the traps filled with oil & gas?

What would be the value ($) if our scenario is correct?

How much more/less HC could there be?

How risky is this prospect (chance that we are totallywrong)?

Many times the seismic datawill give us clues!


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Seismic Line Across Alpha

Fluid Contact?Oil over Water?

Fluid Contact?Gas over Oil?

Alpha


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Outline


3. HC Type

4. Assessment

5. Risk


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Types of Assessments

Deterministic Assessment

One value for each parameter

One final number, e.g., 200 MBO Probabilistic Assessment

A range of values for each parameter

A range of outcomes, e.g. 200 50 MBO

Once a lead has been high-graded into a prospect,we have to assess its potential value


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Scenarios & Probabilities

Gas Cap & Oil Leg

Alpha

40% Chance of Occurrence

Scenario 3

Scenario 1 Scenario 2

Scenario 4Alpha

Alpha

Alpha

Gas Only

Oil Only Low Gas Saturat ion

30% Chance of Occurrence 10% Chance of Occurrence

20% Chance of Occurrence


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ESTIMATES Alpha Beta1. Gross Rock

Volume 2.91 km3 2.12 km3

2. Reservoir

Volume1.02 km3 0.66 km3

3. Pore Volume 0.25 km3 0.15 km34. In-Place

Volume 0.20 km3 0.12 km3

5. In-Place

Barrels1280 MBO 735 MBO

6. EURUnrisked 288 MBO 132 MBO

7. EURRisked MBO MBO

Deterministic Prospect Assessment

To Assess a Prospect, We Assign Numbers

to the Parameters related to HC Volumes

In our exercise,

we have assumedthe all oil case

(Scenario 3)

Unrisked means everything in the HC System has worked!


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Alpha Prospect Assessment Results

0 MOEB0 GCF0 MBOScenario 4Low Gas Saturation

288 MOEB0 GCF288 MBOScenario 3Oil Only

86 MOEB515 GCF0 MBOScenario 2Gas Only

178 MOEB97 GCF162 MBOScenario 1Oil & Gas

Oil Gas Oil-Equivalent

Assuming 100 MOEB is needed to make prospect economic

Uneconomic

Million Barrels Oil Billion Cubic Ft Gas Million Oil Equivalent Barrels

6 GCF = 1 MBO

Uneconomic


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Probabilistic Assessment

The Goal is to Get A Number and a Range ofPossible Outcomes

We Input a Range of Values for EachAssessment Parameter

usually minimum, most-likely, maximum

Area

2012 27

MLMin Max

HC Sat.

Thickness Net:Gross Porosity

FVF Recovery


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Unrisked Results

Million Barrels of Oil

Alpha ProspectUnrisked

0%

20%

40%60%

80%

100%

0 100 200 300 400

100

EconomicMinimum

50% Chance of finding 200 MBO or more

75% Chance of finding the economic minimum

Excedanc

e

Probability


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Outline


3. HC Type

4. Assessment

5. Risk

75% Chance of Success

25% Risk


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9 Key Elements of the HC System

Biodegra-

dation

Not Low Gas

Saturation

HC

Migration

Source

Maturation

Source

Quality

Trap

Quality

Seal

Adequacy

Reservoir

Quality

Reservoir

Presence

A team of experts consider these key elements for each prospect.

They rate the chance of success (COS) for each on a scale of 0 to 1


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COS for Alpha

Alphas biggest risk is that the fault does not seal.

There is also some risk that the trap holds low gassaturation and that reservoir quality is poor

Reservoir Presence

Reservoir Quality

Trap Quality

Seal Adequacy

Source Quality

Source Maturation

HC Migration

Not Low Gas Saturation

Biodegradation

- - - - 1.0

- - - - 0.85

- - - - 1.0

- - - - 0.8

- - - - 1.0

- - - - 1.0

- - - - 1.0

- 0.9

- - - - 1.0

0.61

chance of success

(COS)

Some Risk

Highest Risk

Some Risk


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Risked Probabilistic Assessment Results

0.0

0.2

0.40.6

0.8

1.0

0 100 200 300 400 500Million Oil Equivalent Barrels

Alpha ProspectMain Compartment - Risked

Gas Cap & Oil Leg

Gas Only61 % COS

51 % Chance of

Finding MoreThan theEconomicMinimum

72% Chance to find any hydrocarbons

58% Chance to find 100 MBOE

5% Chance to find 400 MBOE

100

Oil Only

EconomicMinimum


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Exercise 14Part 7

In the exercise we will useA COS of 61%

An economic minimum of 100 MBOE

Prospect Analysis

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