Regional Subsurface Seismic Analysis

3rd October 2018

© OGA 2017 This presentation is for illustrative purposes only. The OGA makes no representations or warranties, express or implied, regarding the quality, completeness or accuracy of the information contained herein. All and any such responsibility and liability is expressly disclaimed. The OGA does not provide endorsements or investment recommendations. Oil and Gas Authority is a limited company registered in England and Wales with registered number 09666504 and VAT registered number 249433979. Our registered office is at 21 Bloomsbury Street, London, United Kingdom, WC1B 3HF History of regional seismicity

Date ML locality 15/08/1996 1.4 E GRINSTEAD

18/06/2005 1.4 BILLINGSHURST

19/06/2005 1.5 BILLINGSHURST

16/07/2005 2.1 BILLINGSHURST

01/04/2018 2.6 NEWDIGATE

01/04/2018 1.8 NEWDIGATE

01/04/2018 1.7 NEWDIGATE Newdigate “Swarm” Scaynes Hill (2018) (2018) 08/04/2018 1.6 SCAYNES HILL 28/04/2018 1.5 NEWDIGATE

27/06/2018 2.6 NEWDIGATE

29/06/2018 2.4 NEWDIGATE

05/07/2018 3 NEWDIGATE

Billingshurst 10/07/2018 1.9 NEWDIGATE “Swarm” (2005) East Grinstead (1996) 18/07/2018 1.9 NEWDIGATE 18/07/2018 0.4 NEWDIGATE

18/07/2018 2.4 NEWDIGATE

18/07/2018 0.9 NEWDIGATE

Source: BGS Historical UK seismicity Regional Faulting

• OGA structural interpretation of regional scale Brockham Oil field faulting across the Weald Basin, with BGS Horse Hill Site historical Newdigate “Swarm” Scaynes Hill (2018) seismicity (2018) overlain OGA (2018), Modified from Magellan (2012), Area of Investigation UKOG (2013), Pullan & Butler (2018) Billingshurst • Note the “Swarm” (2005) relationship East Grinstead (1996) between E-W trending faults and historical seismicity Fault related to seismicity?

• Zoomed map of Regional Weald Brockham Oil field structure OGA (2018), Modified from Magellan (2012), UKOG (2013), Pullan & Butler (2018) • Previous regional work has mapped surface-faulting, Horse Hill Site but only limited seismic used • Detailed 2D seismic mapping now identifies a East-West, “normal” fault previously un- dipping to the south mapped E-W normal fault, close to the Newdigate Events Seismic Line TWLD-90-15

Plotted events from the Newdigate “Swarm”

• A Fault can be mapped in the 2D seismic that aligns closely with the recent cluster of events (all lie within ~1000 m of fault) • The fault is a Normal fault, and trends East-West for approx. 10 km in length Seismic Database

• Licences grant the OGA powers to request well and other subsurface data • OGA holds access to 2D Seismic database across the Weald Basin • Further OGA work has now reinterpreted 2D seismic across the Weald Basin to map faulting in detail

Location map with Seismic Database (UKOGL, 2018) Project Interpretation • 2D seismic lines (dashed grey) were Brockham Oil field interpreted across the region • Faults were mapped by building a regional Newdigate Horse Hill Site volume of fault sticks “Swarm” (2018) (dark red) where all offsets were identified in seismic Billingshurst “Swarm” • Fault model (orange) (2005) was generated using faults which could be mapped with a high certainty Portland Fm view looking west

• 3D view looking westwards along the regional E-W fault trend • Top Portland Fm Brockham Oil surface interpreted Mapped field across area “Newdigate” • Seismic events plotted Fault in 3D space, to show relative position to Oil developments and faults • Brockham Field is Newdigate separated from the “Swarm” Newdigate seismic Horse Hill events by a series of site significant E-W faults Brockham to Newdigate geology

N Brockham Newdigate S

500 Lower Cretaceous

Portland Fm 1000 Kimmeridge Clay Fm

Depth (m) Depth 1500 Middle Jurassic

2000 Lower Jurassic

2500

Triassic 3000 0 1 2 3 4 5

Distance (km)

Geological cross section from Brockham through to the Newdigate Fault. Seismic event locations plotted from Hicks (2018).