Oils of the North Atlantic: Long lost families or just a similitude of strangers? James Armstrong 1 , Jean-Marie Laigle 2 , Samuel Piriou 2 , Alain-Yves Huc 2 , Ian Atkinson 3 , Michael Hanrahan 4 Kara English 4 (1). Petroleum Systems Limited, Prestatyn, Wales, UK., (2). Beicip-Franlab, Rueil-Malmaison, France., (3). Nalcor Energy - Oil and Gas, St. John's, Newfoundland-Labrador , Canada., (4). Petroleum Affairs Division, Department of Communications, Climate Action and Environment, Dublin, Ireland.
Contents Presentation Contents 1. Source Rocks – general comments 2. Oil Families of the west of Ireland basins • Slyne-Erris • Rockall • Porcupine 3. Oil Families of the south of Ireland basins 4. Oil Families of the Jeanne D’Arc Basin Studied basins 5. Oils of the Flemish Pass Basin 6. Cross-Atlantic relationships 7. Concluding remarks 8. Acknowledgements After Ternan 2007
Source Rocks Fifteen (15) potential source rock horizons are noted across the study area from within Mesozoic and Early Tertiary sediments. This widespread distribution of sources related to the episodic rifting phases across the North Atlantic realm. It is also recognised that older sources may locally be significant (e.g. Corrib Field, Ireland – Carboniferous source rock) Also see Gehlen et al, Poster on display for Episodic, extensional regime that, through successive rifting stages more detail of sources shaped basin development in the North Atlantic
Source Rocks Classic OM Purbeck Formation Types 50/11-3 Toarcian 27/13-1 Egret Member Egret K-36 Westphalian 27/5-1 Considerable variation in source facies has been recognised from the available geochemical datasets. Thirteen differing potential facies are proposed. Subsequent analyses to determine kerogen kinetics show that there are source facies present within the study area that can readily be related to classic organic matter types.
Irish Oils 14°0'0"O 12°0'0"O 10°0'0"O 8°0'0"O 6°0'0"O 4°0'0"O The Irish database includes 27 wells with oil samples plus numerous A A A A extracted oil shows. The oil samples are as follows: A A 54°0'0"N Celtic Sea and Rockall Basin 56°0'0"N Fastnet/Goban Spur 12/2-1 A 48/18-1 A A 48/19-2 A A Slyne - Erris Basin A A A A A ! ! ! ! A A ! ! 48/23-3 A 19/11-1a 48/24-1 A 27/4-1(1z) 48/24-2 A 52°0'0"N A In total there are 38 Irish 48/24-3 Porcupine Basin 54°0'0"N A A A 48/24-10 A A A A 26/28-1 (a1/a1z/a2) A A A A A A A A ! oils in the database A A A A A A A A A A A A A A A A A A 48/28-1 A A A A A ! A A ! ! ! A A A 26/28-2 A A A A A A A A A A A A 49/9-2 A A A A A 34/15-1 A A A ! A A A A A A A A A A A A 49/9-4 A A A A 35/6-1 A A A ! A A A A A A A A 49/13-2 A A 35/8-1 A A A A A ! A A 49/19-1 35/8-2 A 50°0'0"N A A A A 52°0'0"N A 50/6-1 35/15-1 A A 50/11-3 A A A A A A 56/14-1 A A A Oil Samples A A 57/9-1 A 63/10-1 0 15 30 60 90 120 Kilometers 16°0'0"O 14°0'0"O 12°0'0"O 10°0'0"O 8°0'0"O
Oils of the west of Ireland basins – Slyne/Erris Oil Samples Carbon isotope analyses indicates a close relationship between the oils that have been encountered within the Slyne Basin. There is also a close isotopic relationship between these oils and Early Jurassic source rocks.
Oils of the west of Ireland basins – Slyne/Erris Slyne oil-source correlation Slyne oil-source correlation Pr/Ph 1.0 Pr/Ph H35/H34 0.9 %C27 aaaR (217) 1.0 H35/H34 %C27 aaaR (217) 0.8 0.9 0.7 0.8 0.6 0.7 G/H30 %C28 aaaR (217) 0.6 0.5 G/H30 %C28 aaaR (217) 0.5 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 H29/H30 %C29 aaaR (217) 0.0 H29/H30 %C29 aaaR (217) 0.0 H28/H30 C27/C29 (abbS) (218) H28/H30 C27/C29 (abbS) (218) C24T/C26t C28/C29 (abbS) (218) C24T/C26t C28/C29 (abbS) (218) C26t/C25t C26t/C25t 19/11-1 Oil 27/13-1 2107m Toarcian 19/8-1 1750m Toarcian 18/20-1 Oil The 18/20-1 oil has an offset trend to its biomarker ratios Biomarker ratios obtained from gas chromatography relative to the 19/11-1 oil and associated source rocks. This may and GC-MS analyses also indicate a close indicate a modification in source facies with perhaps the parent relationship between the 19/11-1 oil and Early source of the 18/20-1 oil having a more marine signature. Jurassic source facies within the basin
Oils of the west of Ireland basins Well 19/11-1A – Middle Jurassic Rockall oils and oil shows often Rockall Basin – Dooish (although not always) have Well 12/02-1 Jurassic East Shetland Bisnorhopane present. This Cormorant Field biomarker is also present in both Upper Jurassic West and East Shetland basins. Peters et al 2005 Rockall Basin - Surface Geochem Well 18/20-1 - 1967m – Middle Jurassic Licence 4/97 Upper Jurassic Slyne, Erris and Porcupine oils Rockall Bisnorhopane and oil shows Bisnorhopane Present are lacking in Present Bisnorhopane Slyne Connemara – 26/28-2 DST#2 – Mid ? Jurassic 4/97 BNH ? Bisnorhopane 83/20-Sb01 Bisnorhopane Absent Rockall Basin - Surface Geochem Absent Porcupine 83/20-Sb01 BNH?
Oils of the west of Ireland basins – Rockall Basin Dooish Oil 12/2-1 R145 R119 4/97-03 To further expand on the distribution of Bisnorhopane, R109 having a cohesive dataset allows 8/97-03 more detailed analysis of the 83/20 distribution of this biomarker in sb001 the Rockall Basin to be made. ? Furthermore, other independent geoscientific data can be integrated to try to explain this occurrence and its potential significance
Oils of the west of Ireland basins – Rockall Basin Following images are taken from interpretation of sand provenance studies pertaining to the Rockall, Erris, Slyne and Porcupine basins. Early Jurassic setting suggests that all the above basins were linked to marine areas to the north. This would further suggest that any source facies developing at this time in these basins may display common characteristics. Early Jurassic sources in the Erris, Slyne and Porcupine basins are associated with some of the oils and oil shows discovered in these basins. Reconstruction courtesy of Shane Tyrrell
Oils of the west of Ireland basins – Rockall Basin Middle Jurassic sees the emergence of the Erris and Porcupine highs that effectively cut off the supply of sand to the eastern basins (Erris, Slyne and Porcupine) from the west. Sands into the Slyne and Porcupine come from more local sources. The Rockall Basin still retains links to the West Shetland Basin and ultimately to the basins of the North Sea. Reconstruction courtesy of Shane Tyrrell
Text Oils of the west of Ireland basins – Rockall Basin Porcupine High well established and influential over provenience of sediments within the Porcupine Basin Rockall Basin still retains links with West Shetland Basins to the north. Extent of links to the south and into the basins of the conjugate margin are more problematical. Reconstruction courtesy of Shane Tyrrell
Oils of the west of Ireland - Porcupine Basin Isotope determinations – North Porcupine Basin North Porcupine oils and oil shows Oils – North Porcupine Basin 26/28-1 DST#3 26/28-1 DST#2 26/28-1 DST#1 26/28-2 DST#2 35/6-1 RFT 35/8-1 35/8-2 Pr/Ph (0-2) Steranes/Hopanes 1 Pr/nC17 (0-1.25) 0.9 0.8 H35/H34 Ph/nC18 0.7 0.6 0.5 G/H30 %C27 aaaR (217) 0.4 0.3 0.2 H29/H30 0.1 %C28 aaaR (217) 0 H28/H30 %C29 aaaR (217) C27/C29 (abbS) C24T/C26t (0-5) (218) C28/C29 (abbS) C26t/C25t (0-1.25) (218) C23t/C24t (0-2) C19t/C23t Carbon isotope determinations, gas chromatography and GC-MS biomarker analyses of the oils are indicative of more than one source facies for these oils and oil shows. Three principal oil families are recognised.
Oils of the west of Ireland basins – Porcupine Basin Family Porcupine C Family Porcupine B: Correlation Family Porcupine A using GC-MS biomarker ratios 35/2-1 3265-3270m K/O 26/28-1 DST#3 35/8-2 34/15-1 (3745m) Bath./Bajc. 35/6-1 RFT %C27 %C27 aaaR between 35/8-1 oil and aaaR 1.0 (217) St/Hop %C28 aaaR 0.9 Kimmeridgian source rocks of 1.0 %C28 0.8 0.9 Ster/Hop aaaR 35/8-2 0.7 0.8 (217) 0.6 H35/H34 %C29 aaaR 0.7 Family Porcupine B 0.5 0.6 0.4 0.5 %C29 0.3 0.4 35/8-1 Oil 35/8-2 14500-14560ft 35/8-2 14550-14600ft H35/H34 aaaR 0.2 0.3 %C27 aaaR G/H30 C27/C29 (abbS) (217) 0.1 0.2 1 0.0 0.1 St/Hop %C28 aaaR 0.9 0.0 0.8 0.7 C27/C29 0.6 H29/H30 C28/C29 (abbS) H35/H34 %C29 aaaR G/H30 (abbS) 0.5 (218) 0.4 0.3 0.2 H28/H30 C19t/C23t C28/C29 G/H30 C27/C29 (abbS) 0.1 H29/H30 (abbS) 0 C24T/C26t C26t/C25t (218) H28/H30 Family Porcupine C: Correlation H29/H30 C28/C29 (abbS) Family Porcupine A: Correlation using GC-MS biomarker ratios using GC-MS biomarker ratios between 26/28-1 and 35/8-2 oils between 35/6-1 oil and H28/H30 C19t/C23t and Kimmeridgian source rock of Bathonian / Bajocian source rock C24T/C26t C26t/C25t 35/2-1 of 34/15-1
Oils of the west of Ireland - Porcupine Basin, 43/13-1 43/13-1 1 Source Rock 3400m Source Rock Ave TOC 1.4% Ave HI 528 2 Show Ave TOC 1.6% 1 3530m Ave HI 189 2 Geochemical characteristics of oil shows and source rock samples from the 43/13-1 well – Porcupine Basin
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