MÆRSK OLIE OG GAS MÆRSK OLIE OG GAS ASAS – – GYMNASIE OPGAVE GYMNASIE OPGAVE - 2008- 2008

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Velkommen til olie industrien – MAERSK OLIE OG GAS AS

Oooooohh…! Jeg kan se, at du har en vigtig

rolle, at spille i olie industrien!

Se den positive side! I 2008 vil din rådne krop

koste 11 kr. literen på tanken!

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The Geology Case – now it is your turn!

MY OWN LITTLE OILFIELD

THE MOLO FIELD

OPGAVE

OPGAVE – beregn olie mængden i et reservoir

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Gross Rock Volume is:

Volume of rock containing our reservoir

STOIIP (Stock Tank Oil Initially In Place) or

GIIP (Gas Initially In Place) is:

Amount of hydrocarbons present in our reservoir

RESERVES are:

Hydrocarbons we can produce (given present conditions)

OPGAVE – Baggrundsinformation 1

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Recovery Factor is depending on:

• Reservoir Quality & Conditions

• Oil and Gas Type

• Number of Production Wells and Type (Cost)

• Production Method (Enhanced Recovery)

RESERVES = [STOIIP] · [Recovery Factor]

OPGAVE – Baggrundsinformation 2

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YOUR FACTS:

1) We have 2 seismic profiles across the reservoir

2) The MOLO-1 well penetrated the top of the reservoir at a depth of XXXX feet

3) An oil-water contact was found in MOLO-1 at a depth of XXXX feet

4) The average porosity (Φ) was found to be 0.XXX (XX.X vol.%)

5) The penetrated reservoir is reduced by interspaced non-reservoir rock → N/G ratio of 0.90 (90 vol.%)

6) The average water saturation (Sw) is 0.XX (XX vol.%)

7) The Formation Volume Factor (FVF) is 1.2 (the reduction in oil volume due to loss of gas content when moving from reservoir pressure and temperature to surface conditions)

8) The Recovery Factor (RF) is estimated to be 0.25 (i.e. 25 % of the STOIIP will be produced to surface).

OPGAVE – Baggrundsinformation 3

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YOUR TASK:

1) Calculate the Gross Rock Volume (GRV)

2) Calculate Stock Tank Oil Initially In Place (STOIIP)

3) Calculate the Reserves

OPGAVE: My Own Little Oilfield 1

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OPGAVE: My Own Little Oilfield 2

EAST

SOUTH

NORTHMOLO-1 well

Seismic ProfilesSeismic Profiles

WEST

Top of Reservoir

1000

feet

5700

6000

6300

6600

6900

7200

7500

7800

NOTE – feet!

MOLO-1 well

Oil-Water Contact / Transition Zone

OPGAVE: My Own Little Oilfield 3

NOTE – meter!

MOLO-1

A wireline log showing the porosity and hydrocarbon saturation profile from the well

Approximately 180 ft of chalk oil-reservoir

h 60 meters

GRapi0 150

TVDSSFT7700 6700

LLDOHMM0.2 200

LLSOHMM0.2 200

MSFLOHMM0.2 200

TNPHCFCF0.6 0

DRHOG/C30.75 -0.25

RHOBG/C31.7 2.7

DTCO1US/F140 40

DEPTHFT

PHI-CFCF0.5 0

BVW 0.5 0

VGAS-CFCF0.5 0

VOIL-CFCF0.5 0

SW-CFCF1 0

VSHCFCF0 1

PHI-CFCF1 0

0 VSH

VSH PHI-

TVDSSFT

Lista Fm

North Sea MarlTop D1

GOC

Top D2A

Top D2B

MhM1A

M1b1M1b2M1b3

M1b4M1b5

M1b7

M1b8

M2

M3

OWC

M4

6950

7000

7050

7100

7150

7200

7250

7300

7350

6800

6900

7000

7100

7200

GRapi0 150

TVDSSFT7700 6700

LLDOHMM0.2 200

LLSOHMM0.2 200

MSFLOHMM0.2 200

TNPHCFCF0.6 0

DRHOG/C30.75 -0.25

RHOBG/C31.7 2.7

DTCO1US/F140 40

DEPTHFT

PHI-CFCF0.5 0

BVW 0.5 0

VGAS-CFCF0.5 0

VOIL-CFCF0.5 0

SW-CFCF1 0

VSHCFCF0 1

PHI-CFCF1 0

0 VSH

VSH PHI-

TVDSSFT

Lista Fm

North Sea MarlTop D1

GOC

Top D2A

Top D2B

MhM1A

M1b1M1b2M1b3

M1b4M1b5

M1b7

M1b8

M2

M3

OWC

M4

6950

7000

7050

7100

7150

7200

7250

7300

7350

6800

6900

7000

7100

7200

OPGAVE: My Own Little Oilfield 4

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OPGAVE: My Own Little Oilfield 5

Apply a known geometrical shape to the reservoir shape: The Spherical Cap

αh

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OPGAVE: My Own Little Oilfield 6

Gross Rock Volume is then the volume of a spherical cap with a height of h and a radius of α

h is estimated using the log from the well –

You then find α from the seismic profiles

Calculate GRV from this expression (expect a large number!):

GRV = 1/6·π·h·(3·α²+h²)

αh

0

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OPGAVE: My Own Little Oilfield 7

• Gross Rock Volume (GRV)

• Net to Gross (N/G)

• Porosity (Φ)

• Oil Saturation (Soil equal to 1 minus Water Saturation Sw)

• Oil Formation Volume Factor (FVF given as a value of 2)

STOIIP = GRV ∙ N/G ∙ Φ ∙ Soil / FVF

Calculate STOIIP using this expression(the unit at this stage is m3):

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OPGAVE: My Own Little Oilfield 8

Reserves = STOIIPmillion bbls ∙ RF

STOIIPmillion bbls= STOIIPm3 ∙ 6.29 / 1,000,000

We now re-calculate STOIIP in m3 to STOIIP in million bbls using this expression:

Finally the reserves are calculated given a recovery factor of 0.25 (25%):

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OPGAVE: My Own Little Oilfield 9 – Excel regneark til beregning

How can I learn more?How can I learn more?

http://www.maerskoil.comhttp://www.maerskoil.com

MÆRSK OLIE OG GAS AS

The End