N orwegian Continental Shelf and ED50

Norwegian Continental Shelf and ED50Use of ED50

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Subjects

• Why this presentaton

• Many ways to display your position

• What is a datum

• Navigational charts

• Jens Evensen and continental borders

• Why do we use ED50 on Norwegian Continental Shelf

• Seismic interpretation and well trajectory (D&W)

• Projection of ED50

• Datum transformation (dimensions and errors)

• Examples

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Why this presentation?

• What is ED50?

• Why is ED50 used, why not GPS?

• Is latitude and longitude ED50?

• What is this UTM?

• Is it a big difference between thoose two?

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Many ways to display your position

Geocentric coordinates• X, Y, Z

• Origo in earth center

• No ellipsoid used

Geographic coordinates• Latitude Φ, Longitude λ

• Origo in earth center

• No ellipsoide used

UTM coordinates• North/South, East/West

• Origo at equator and given central meridian

• Need ellipsiod

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Many ways to display your position

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What is a datum

Norwegian datum• NGO1948

• ED50

• WGS84

• EUREF89

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Origo

Perpendicular axes

Navigational charts

• Up to 1957

− NGO1948

• 1957 – 1992

− ED50

• From 1992

− WGS84

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Jens Evensen and continental borders

• Norway <-> UK• March 10th 1965

− Navigational chart no. 301

− 1 : 1 000 000

− 8 points defining border

• Norway <-> Denmark• December 8th 1965

− Navigational chart no. 301

− 1 : 1 000 000

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Carl Erik Fleicher, Erik Løddesøl

Why do we use ED50 on Norwegian Continental Shelf

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Aktivitetsforskriften

• § 82

− Brønnens lokasjon og bane skal være kjent til enhver tid og velges på grunnlag av brønnparametere som har betydning for en sikker bore- og brønnaktivitet.

Veiledning

• § 82

• For å oppfylle kravet til brønnens lokasjon og bane som nevnt i første ledd, bør standarden NORSOK D-010 kapittel 4.3 og 5.7.4 brukes, med følgende tillegg:

• brønnens lokasjon og bane bør angis i Universal Transverse of Mercator (UTM)-koordinater.

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http://www.standard.no/en/sectors/Petroleum/NORSOK-Standard-Categories/D-Drilling/D-0102/


• 5.7.4.2 Well trajectory measurements• The following apply:

• a) The surface location coordinates of the well bore center shall be determined with use of differential global positioning system. Well slot co-ordinates can be established by measurements from a known reference point (fixed point on a platform, sub sea template, etc.).

• b) During drilling of new formation, measurement of well bore inclination and direction shall be obtained at least every 100 m MD. All survey plots should be referenced to grid north.

• c) The position of the well bore being drilled (reference well) and the distance to adjacent wells (object well) shall be known at all times. The minimum curvature method or other equivalent models should be used.

• d) A model for quantifying the uncertainty shall be established. The probability for the well bore to be within the calculated uncertainty ellipses should exceed 95 %.

• e) Minimum acceptable separation distance between well bores and risk reducing actions shall be defined.

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• Norwegian Petroleum Directorate (OD)

− Registration of wells

• Datum to be used is ED50, geographical coordinates

− (no accuracies required)

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Seismic interpretation and well trajectory (D&W)

Large fields

• 1021km2

High accuracy

• Shallow gas pockets

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http://tle.geoscienceworld.org/cgi/content/full/30/9/1026/F6

Projection of ED50

ED50 (International 1924)

• Semi-major axis a = 6 378 388m

• Semi-minor axis b = 6 356 911.946m

• Flattening = 1/297.0

WGS84

• Semi-major axis a = 6 378 137m

• Semi-minor axis b = 6 356 752.314m

• Flattening = 1/298.257223563

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Projection of ED50

Transformation

• Translation

• Rotation

• Scale factor

Parameters

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Datum Transformation

• We start with following position

61°04'54.5"N 2°29'49.9"E

• Dose this position tell you where you are?

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• NO

• If we add following information

DATUM ED50

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• YES

• What with theese coordinates?

Northing 6477873.916 m

Easting 437502.434 m

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• NO




DATUM ED50

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• NO




DATUM ED50 UTM Zone 31N

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• YES




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Best practise to display a position

Geographical Coordinates

DATUM ED50

UTM Coordinates




CM003E

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− GPS receivers will normally output WGS84 datum

− GPS raw data are processed by a navigation SW. This SW will be set up to convert WGS 84 into the requiered datum.

− For Datum transformation Statoil use mainly two different programs to convert between different datums

• Geomatrix Inca

• Blue Marble Desktop

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Examples

Lets look at som error figures between WGS84 and ED50

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ExamplesED50 UTM Zone 34N CM21E ESPG 1612 (N62)

Lat :71°35'30.975"

Long :21°16'33.860"

Northing :7943655.0 m

Easting :509730.7 m

WGS84 UTM Zone 34N CM21E ESPG 1612 (N62)

Lat :71°35'31.507"

Long :21°16'28.367"

Northing :7943456.0 m

Easting :509676.3m

Distance between theese two positions

56.3m

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ExamplesED 50 UTM Zone 31N CM03E ESPG 1613 (S62)

Lat : 58° 26' 08.80"N

Long : 01° 55' 46.80"E

Northing : 6 477 873.9 m

Easting : 437 502.4 m

WGS84 UTM Zone 31N CM03E ESPG 1613 (S62)

Lat : 58°26'06.59"N

Long : 1°55'41.11"E

Northing : 6477658.8 m

Easting : 437412.2 m

Distance between theese two positions

114,8m

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Examles

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Expamles

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Expamles

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Expamles

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Examples

Difference between WGS84 and ED 50 in the Norwegian continental shelf are between 50 and 300 meters.

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Norwegian Continental Shelf and ED50

Bength EriksenSenior SurveyorE-mail: [email protected]: +47 936 92 070

www.statoil.com

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N orwegian Continental Shelf and ED50

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