Rhyl field, a new discovery by combining basic geological principles with advanced seismic imaging in the Irish Sea

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1 Rhyl field, a new discovery by combining basic geological principles with advanced seismic imaging in the Irish Sea Presented by: Gavin Ward, RISC UK Data provided courtesy of Serica Energy

2 Disclaimer The statements and opinions attributable to the presenter and RISC (UK) Ltd (RISC UK) in this presentation are given in good faith and in the belief that such statements are neither false nor misleading. In preparing this presentation RISC UK has considered and relied solely upon information in the public domain. This information has been considered in the light of RISC UK s knowledge and experience of the upstream oil and gas industry and, in some instances, our perspectives differ from many of our highly valued clients. RISC UK has no pecuniary interest or professional fees receivable for the preparation of this presentation, or any other interest that could reasonably be regarded as affecting our ability to give an unbiased view. This presentation is the copyright of RISC UK and may not be reproduced, electronically or in hard copy, without the written permission of RISC UK. This presentation examines what a top depth structure map should look like. The structural image is confused by the seismic response and the velocities in the overburden. 1

3 Content 1. New Field context Location Creaming curve and size Time line Where s the field? 2. Critical Success Factors 3. Evolution of mapping Volcanics Overburden Structural styles Seismic velocity fields Trust geology over algorithms Source: Ant Track Extraction derived from PSDM reprocessed seismic Reference = Devex 2014 ( Reservoir = Lower Triassic (Ormskirk Sst) 2

4 Content 1. New Field context Location Creaming curve and size Time line Where s the field? 2. Critical Success Factors 3. Evolution of mapping Volcanics Overburden Structural styles Seismic velocity fields Trust geology over algorithms Source: Ant Track Extraction derived from PSDM reprocessed seismic Reference = Devex 2014 ( Reservoir = Lower Triassic (Ormskirk Sst) 3

5 Triassic - Creaming Curve Irish Sea Triassic Creaming Curve Tertiary Cretaceous Jurassic U.Triassic L.Triassic Permian Carboniferous 4

6 Triassic - Creaming Curve Rhyl is a P40 discovery Over 100 Bcfe of Reserves Irish Sea Triassic Creaming Curve Tertiary Cretaceous Jurassic U.Triassic L.Triassic Permian Carboniferous Basin has undergone inversion and removed Tertiary & Cretaceous 5

Mature and Busy Offshore Area Rhyl Field Time Line 2006 24 th Round application 2007 Licence start 1 st April 2008 First Seismic reprocessing 2009 Discovery 113/27b-6 2010 Geo model and Wind licence

7 Mature and Busy Offshore Area Rhyl Field Time Line th Round application 2007 Licence start 1 st April 2008 First Seismic reprocessing 2009 Discovery 113/27b Geo model and Wind licence 2011 Shallow seismic 2012 Appraisal and Dev drilling 2013 First Gas 31 st March Stakeholders: DECC The Crown Estate Renewables operators : Dong, Vattenfall Ferries & Port Authorities Ministry of Defence Hoegh LNG Terminal Gateway Gas Storage Power Stations Refineries BHP, Centrica, ConocoPhillips, Eni, EOG, First Oil, MPX, Nautical, Serica 6

8 Mature and Busy Offshore Area Rhyl Field Time Line th Round application 2007 Licence start 1 st April 2008 First Seismic reprocessing 2009 Discovery 113/27b Geo model and Wind licence 2011 Shallow seismic 2012 Appraisal and Dev drilling 2013 First Gas 31 st March 201X Wind Farm and Drilling? Stakeholders: DECC The Crown Estate Renewables operators : Dong, Vattenfall Ferries & Port Authorities Ministry of Defence Hoegh LNG Terminal Gateway Gas Storage Power Stations Refineries BHP, Centrica, ConocoPhillips, Eni, EOG, First Oil, MPX, Nautical, Serica 7

9 Pre Rhyl Field Drilling 113/27-1 (Ramsey) 1986 Esso Dry with residual gas shows Magnetic Anomalies Millom Field Spill to south into Morecambe North Morecambe North Field 1 Tcf Reference = Devex 2014 ( 8

10 Pre Rhyl Field Drilling 113/27-1 (Ramsey) 1986 Esso Dry with residual gas shows 113/27-2 Esso 1988 Dry Missing Triassic section 113/27b-6 Centrica Dec 2009 Rhyl Field Discovery Magnetic Anomalies Millom Field Spill to south into Morecambe North 113/27-3 Esso 1988 Extension to Millom Morecambe North Field 1 Tcf Reference = Devex 2014 ( 9

11 Rhyl Pre-Discovery Seismic TWT 2008 PSDM stretched back to TWT South Coarse depth increment in shallow = unpopulated. bins Millom Recent Glacial 113/27-1 (Ramsey) 1986 North Morecambe N Morecambe North Field Upper Triassic Shale & halite sequences Rhyl Prospect Faults and/or Dykes Amplitude from Stanah Dolomite Lower Triassic Sandstones Lower Triassic/ Permian Halite Permian Carboniferous Aeolian and Fluvial sandstones & shales 10

12 Rhyl Geoseismic and Drilling N Geophysical borehole S Seismic Distortion Area U.Triassic Mercia Mudstone Seal L.Triassic Sherwood Sandstone Reservoir Reference = Devex 2014 ( 113/27b-8 113/27b-7 113/27b-6 113/27b-9 11

13 Rhyl Geoseismic and Drilling Exxon - Ramsey 1986 Sept 2012 Nov 2009 Dec 2012 N Rig NBW Ensco 92 NBW S Geophysical borehole Seismic Distortion Area U.Triassic Mercia Mudstone Seal Where is top reservoir? L.Triassic Sherwood Sandstone Reservoir Reference = Devex 2014 ( 113/27b-8 113/27b-7 113/27b-6 113/27b-9 12

Successful Oil and Gas Finders Use Geological Principles Priority #1 Understand the structure first and before you start seismic processing 1. Seismic velocities not the same as rock velocities 2.

14 Successful Oil and Gas Finders Use Geological Principles Priority #1 Understand the structure first and before you start seismic processing 1. Seismic velocities not the same as rock velocities 2. Compression can create lineaments 3. Understand relay-ramp fault structures 4. Deep structure can/will control shallow structure 5. Igneous dykes follow paths of weakness (i.e. faults) 6. Understand formation of L.Triassic pull-apart structures Risk Analysis does not replace good G&G it presupposes it... Dr. Peter R Rose, AAPG Short Course Successful oil and gas finders ensure that their interpretations are geologically and geometrically valid in three dimensions e.g. M.C. Escher Dan Tearpock, AAPG Ten Habits of Successful Oil Finders 13

15 Evolution of Rhyl Maps Pre-Reprocessing (2012) TWT : Licence Application Jun 2006 Av Well Vels Licence Application Jun 2006 Seis Vels Licence Application Jun 2006 Seis Vels Peer review Jul 2009 Reference = Devex 2014 ( Peer review Mar 2009 Technical Assurance June 2010 FDP Apr

North Basic Geology = Lineaments are Stress Fields Magnetic values (nt) Calculated magnetic response

16 Igneous Magnetic Response South Extended D2 sill to left (south) to fit magnetic data BUT no intrusives encountered in well 113/27b-6. North Basic Geology = Lineaments are Stress Fields Magnetic values (nt) Calculated magnetic response Observed magnetic response 113/27b-6 113/27-1 Sherwood SST Group D2 Reference = Devex 2014 ( 15

Shallow Velocity Field Basic Geology = Shallow Channels Excellent imaging of the base

underlying tectonics Good imaging of Dykes over northern extension achieved on the PSTM

Rhyl field Base Quaternary depth PSTM 2013.

17 Shallow Velocity Field Basic Geology = Shallow Channels Excellent imaging of the base quaternary channel systems in Rhyl area Good correlation between channel orientation and underlying tectonics Good imaging of Dykes over northern extension achieved on the PSTM Interpret and include in PSDM velocity model (RTM) Impact the GRV on western side of Rhyl field Base Quaternary depth PSTM Time slice through velocity model Reference = Devex 2014 ( 16

18 Triassic Pull-Aparts : SNS v EIS Basic Geology = Extension followed by compression Therefore expect to see Compressional AND Extensional faulting 17

19 SNS Lower Triassic Pull-Apart Tertiary muds Cretaceous chalk Jurassic & U.Triassic mudstones & halite L.Triassic sandstones U.Permian halite L.Permian sandstones Jurassic & U.Triassic Permian Southern Gas Basin (Quadrant 48) Tertiary U.Triassic Cretaceous L.Triassic U.Permian (Salt) L.Permian Basic Geology = Analogues (Bunter in SNS is Sherwood in EIS) Carboniferous sandstones & mudstones 18

20 SNS Lower Triassic Pull-Apart Tertiary muds Cretaceous chalk Jurassic & U.Triassic mudstones & halite L.Triassic sandstones U.Permian halite L.Permian sandstones Jurassic & U.Triassic Permian Tertiary East Irish Sea Basin has undergone inversion and removed Tertiary & Cretaceous U.Triassic Cretaceous L.Triassic U.Permian (Salt) L.Permian Basic Geology = Analogues (Bunter in SNS is Sherwood in EIS) Carboniferous sandstones & mudstones Quadrant 49 Triassic Pull Apart 19

21 Geology First 48/10b-6 48/10-1 Southern Gas Basin (Quadrant 48) Basic Geology = Conservation of Mass Cretaceous Rim Synclines 20

22 Geology First 48/10b-6 Southern Gas Basin (Quadrant 48) Basic Geology = Conservation of Mass Cretaceous Rim Synclines 21

23 Smooth Migration Velocities Basic Geology = Seismic Velocities are not same as Rock Velocities 22

24 Recognition of Structural Style Brittle and lithified strata Basic Geology = Compression can create Thrust Faults Halites U.Triassic Shale and Salt beds L.Triassic Sandstones Some interpreters incorrectly interpret doming/pillowing as salt movement 2008 reprocessing of Rhyl field area did not recognise thrust and inversion in basin. Thrust decouples on halite members 23

Triassic Sandstones Structures actually result of reverse faulting due to compression 2008

25 Recognition of Structural Style Brittle and lithified strata Basic Geology = Compression can create Thrust Faults Halites U.Triassic Shale and Salt beds L.Triassic Sandstones Structures actually result of reverse faulting due to compression 2008 reprocessing of Rhyl field area did not recognise thrust and inversion in basin. Thrust decouples on halite members 24

26 Combining Theory and Data Shear fault or dyke? Shear fault or dyke? Shear fault or dyke? Triassic Pull-Apart Zone 1. East-west seismic discontinuities have negligible throw and are shear faults, not dykes as previously interpreted. (Dykes at Ramsey well exploited previously existing crustal weakness/shear) Possible Shear fault? Negligible Throw across lineaments as mapped Change in direction of throw across fault/ lineament 2. Shears set up by offset in Tynwald graben fault 3. Shears created as a response to compression following extension of the Tynwald graben Triassic Pull-Apart Reference = Devex 2014 ( 25

$Water Bottom Velocity inversion Point diffractions and migration smiles$ (velocity problems) at compressional shears and dykes Improved image with

(velocity problems) at compressional shears and dykes Improved image with

Dykes however still problematic PreSDM Final Stack Full Time Reference =

27 Geology v Processing Original seismic did not reflect geology MM3D PSDM Water Bottom Velocity inversion Point diffractions and migration smiles (velocity problems) at compressional shears and dykes Improved image with velocity inversions and shorter period changes to velocity field. Dykes however still problematic PreSDM Final Stack Full Time Reference = Devex 2014 ( 26

Post Drill Mapping Basic Geology Fault terraces stepping back

Approx 96 ft Net Pay Same GWC as Rhyl Flowed @ 30 mmcf/d

113/27-1 well Depth mapping improved by better understanding

apertures 113/27b-8 113/27b-6 & 113/27b-7 113/27b-9 SOUTH

67 feet net pay Same GWC as Rhyl Flowed @ 31 mmcf/d GWC

28 Post Drill Mapping Basic Geology Fault terraces stepping back from Triassic Pull-Apart Graben NORTH Approx 230 ft (70 m) col Approx 96 ft Net Pay Same GWC as Rhyl 30 mmcf/d 113/27-1 Production data AND more mapping required at Ramsey 113/27-1 well Depth mapping improved by better understanding of: Volcanic Dykes Shallow channels Thrust faulting Migration apertures 113/27b-8 113/27b-6 & 113/27b-7 113/27b-9 SOUTH Approx 190 ft (58 m) column Approx. 67 feet net pay Same GWC as Rhyl 31 mmcf/d GWC 4680ftTVSS Reference = Devex 2014 ( 27

Thank you My thanks to the following people and organisations for their contributions and support Serica Energy Swift Exploration Ltd Subsurface Consultants & Associates LLC Clara Altobell and Graham

29 Thank you My thanks to the following people and organisations for their contributions and support Serica Energy Swift Exploration Ltd Subsurface Consultants & Associates LLC Clara Altobell and Graham Pritchard Linda Stasiuk Dan Tearpock and Rob Bisckhe Tsunami Bill Kamps CGGVeritas Fugro UK WesternGeo...and finally, friends & colleagues : Arnaud, Ayo, Blae, David, Dean, Ed, Iain, Jalal, Jeremy, Mick, Montse, Nick, Stela, Stephen, Tom, Vishal, Viv 28

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Serica Energy (UK) Limited. P.1568 Relinquishment Report. Block 110/2d. UK East Irish Sea

Serica Energy (UK) Limited. P.1568 Relinquishment Report. Block 110/2d. UK East Irish Sea Serica Energy (UK) Limited P.1568 Relinquishment Report Block 110/2d UK East Irish Sea August 2012 1 Header Licence: P.1568 Round: 25th UK Licensing Round Block: 110/2d Licence Type: Traditional Equity: