P1906 Relinquishment Report

Transcription

1 Relinquishment Report Date of Document: Approval list Date Centrica North Sea Gas Ltd Carla Riddell 16/12/15 Serica Energy (UK) Ltd Clara Altobell 11/12/15 Atlantic Petroleum North Sea Ltd Alyson Harding 09/12/15 Disclaimer No liability whatsoever is accepted and no representation, warranty or undertaking, express or implied, is or will be made by Centrica plc or any of Centrica plc's subsidiaries, or any of their respective agents, being their directors, officers, employees, advisers, representatives or other agents, for any information, projections or any of the opinions contained in this report or for any errors, omissions or misstatements in this report. Neither Centrica plc nor any of Centrica plc's subsidiaries, nor any of their respective agents makes or has authorised to be made any representations or warranties (express or implied) in relation to any of the matters described herein or as to the truth, accuracy or completeness of this report, or any other written or oral statement provided. This report shall not be deemed to be an offer to sell or invitation to invest in Centrica plc or any of its assets and no information set out in this report is intended to form the basis of any contract, investment decision or any decision to purchase or invest in any such assets. Neither Centrica plc nor any of Centrica plc's subsidiaries nor any of their respective agents undertakes any obligation to provide any recipient with access to any additional information or to update or correct any inaccuracies in or omissions from this report. This report should not be considered as a recommendation by Centrica plc or any of Centrica plc's subsidiaries or any of their respective agents to invest in any securities (including, without limitation, those issued by Centrica plc) or any other assets. Recipients should rely solely on their own judgement, review and analysis in evaluating the information set out herein.

2 PAGE: I OF 13 CONTENTS CONTENTS... I LIST OF FIGURES... II LIST OF TABLES... II 1 LICENCE INFORMATION LICENCE SYNOPSIS Licence Status Summary Prospectivity WORK PROGRAMME SUMMARY DATABASE PROSPECT UPDATE FURTHER TECHNICAL WORK UNDERTAKEN RESOURCE AND RISK SUMMARY CONCLUSIONS CLEARANCE i

3 PAGE: II OF 13 LIST OF FIGURES Figure 1.1 Location out lined in blue... 1 Figure 2.1 Prospects identified at bid application... 3 Figure 3.1 Seismic Database... 4 Figure 3.2 Comparison of Seismic Data (Old vs. New)... 5 Figure 4.1 Well Location Map... 6 Figure 5.1 Waterloo SW-NE Depth Section... 8 Figure 5.2 Westminster SW-NE Depth Section... 8 Figure 5.3 Apollo North: W-E Depth Section... 9 LIST OF TABLES Table 1.1 Licence Information... 1 Table th Round Bid Application Volumes... 7 Table 7.1 Prospect Resource Summary ii

4 PAGE: 1 OF 13 1 LICENCE INFORMATION Licence Number Licence Round 26 th Licence Type Traditional Seaward Multiple block Licence awarded on 1 st February 2012 Block Number(s) 47/02b, 47/03g, 47/07a & 47/08d Licensees Centrica North Sea Gas Ltd 52.5% (Operator) Serica Energy (UK) Ltd 37.5% Atlantic Petroleum North Sea Ltd 10% Table 1.1 Licence Information Figure 1.1 Location out lined in blue 1

5 PAGE: 2 OF 13 2 LICENCE SYNOPSIS 2.1 Licence Status is at the end of the initial licence term. All firm work commitments have been fulfilled. The relinquishment decision is aligned with the timing of a drill or drop decision required at the end of the initial term. 2.2 Summary The licence was awarded as part of the 26 th Licensing Round to operator Centrica North Sea Gas Ltd (52.5%) and partners Serica Energy (37.5%) and Atlantic Petroleum (10%). Start date: 01/02/2012 (executed 31/07/2012) Initial Term Expiry: 31/01/2016 Firm Work Commitments: o o Shoot 160 km 2 of 3D seismic data Reprocess 180km 2 of 3D seismic data No licence extensions have occurred during the initial term of this licence. 2.3 Prospectivity In the 26 th bid application, one lead (Westminster), eight modest-sized prospects and one small discovery (Vaduz) were identified in the Greater York Area (as shown in Figure 2.1). All leads identified in Figure 2.1 have been analysed with the exception of Lead D which was not awarded as part of the licence area. All permissions to publish have been obtained from the Partnership of Centrica Energy, Serica Energy and Atlantic Petroleum. 2

6 PAGE: 3 OF 13 Figure 2.1 Prospects identified at bid application Top Rotliegend Depth (m) Map 3 WORK PROGRAMME SUMMARY is in the Initial Term which has the following Firm Work Commitments: Firm Commitment a) Shoot 160 km 2 of 3D seismic data b) Reprocess 180km 2 of 3D seismic data Both firm work commitments have been fulfilled. The new 3D seismic data was acquired as part of a larger survey (Figure 3.1) over the York area which was successfully completed by Dolphin Geophysical in In total 459km 2 of 3D seismic was shot, of which 171km 2 covered the licence. The reprocessing was subsequently carried out by GXT and the final product in the depth domain was delivered in December 2014, covering 740km 2. 3

7 PAGE: 4 OF 13 Figure 3.1 Seismic Database A comparison from old to new seismic data has been made in Figure 3.2. It can be seen clearly that the overburden is more coherent with better multiple attenuation. Within the Zechstein, there is an improvement on the imaging of steep dips and at reservoir level (Top Rotliegend) an improved reflector continuity is observed. It also appears that there is improved imaging and better multiple attenuation in the Pre-Permian, however it is still difficult to map Top Carboniferous or any structures within. 4

8 2011 Western Geco PSDM 2014 GXT PSTM Final 2014 GXT PSDM Final PAGE: 5 OF 13 Figure 3.2 Comparison of Seismic Data (Old vs. New) 5

9 PAGE: 6 OF 13 4 DATABASE The seismic database for the Greater York Area is shown in Figure 3.1. There are many wells in the area which were used for failure analysis and for petrophysical analysis. Due to lack of well control to the west of the licence area, York and Rough gas fields were used as an analogue for predicted reservoir properties (Group A & B wells, Figure 4.1). 42/27a- 3 42/28d- 1342/28d- 12 Tolmount 42/26 42/27 42/28d 42/28e 47/2c 47/3i 47/03c /03c- 3 47/03e /3c 47/4c Apollo N 47/03c-M247/03c-M3 MINERVA 47/ /03b- 6 47/3g 47/3k 47/04a- 2 47/03b- 6A 47/03b /1 47/04a- 7Z47/04a- 7 47/2b ARTEMIS Westminster 47/ /03a- 7 47/03b- 5 47/03e- 8 47/03b-A147/03b-A2 47/4a 47/3a 47/03b-A1Y 47/03a-Y3 47/3e 47/03a-Y2 YORK 47/ /3b APOLLO 47/03b- 4 47/2a 47/04a- 3 47/03a- 11Z 47/6 LANGELED PIPELINE CLEETON CP TO DIMLINGTON YORK METHANOL PIPELINE EASINGTON TO ROUGH 47/3B 47/7a ROUGH 47/3B IMPORT/EXPORT 47/03a /3j 47/03-C11 47/3f 47/3d 47/4f 47/03-C147/03-C8 47/3h Waterloo 47/03d-B9 ROUGH 47/08-A6 ERIS 47/08-A5 47/08-A4 47/8b 47/08c- 4 47/8c 47/ /8d 47/ /09b- 5A 47/08a- 3 47/09b- 1047/09b- 9 MERCURY 47/9b 47/7b 47/8e WEST SOLE TO EASINGTON 24IN GAS LINE MERCURY TO NEPTUNE 42/29d MINERVA TO CLEETON PIGGY 42/29-9 Legend 42/29-C642/29-C7 42/29-C4CLEETON Group B Wells 42/29a 42/29-4 Group A Wells Pipelines. 47/04b- 547/04b- 4 NEPTUNE 47/04b-N2 47/04b- 6 47/4b 47/4e 47/ /4d 47/5e 47/5d 47/9e 47/09b- 4 47/9c 47/10c CERES 47/ / /09b- 6 HELVELLYN 47/ /9d NEPTUNE TO MERCURY Apollo North Waterloo Upside Westminster DECC_OFF_Wells DECC_OFF_Hydrocarbon_Fields Centrica Equity (Feb 15) Centrica - Operated Centrica - Non Operated DECC_28th_Rnd_Provisional_Awards DECC_OFF_Sub_Areas DECC_OFF_Licensed_Blocks AMETHYST A2D TO EASINGTON 47/8a 47/9a 47/10d 47/11 47/ Km AMETHYST WEST 47/09a- 8Z47/09a- 8 Figure 4.1 Well Location Map Within the licence area only three wells have been drilled to date. Well 47/03e-8 drilled the noncommercial Vaduz discovery, 47/03e-10 did not penetrate the Rotliegend and 47/08a-3 targeted a small 4-way dip closure however drilled too far down-dip. 6

10 PAGE: 7 OF 13 5 PROSPECT UPDATE Bid Application Prospect Summary Estimated volumes of leads presented at the 26 th round bid application are shown in Table 5.1. The smallest of these identified leads (for example Leads F & G) did not have volumes estimated. Vaduz is an undeveloped accumulation discovered by well 47/03e-8 in It tested 14 MMscfd in the Rotliegend however the accumulation was deemed too small to further pursue. Westminster had the largest volumes attributed to it however due to the highly compartmentalised nature of the Rotliegend, the lead was subdivided into multiple fault compartments. GIIP (Bcf) Resources (Bcf) Lead Min ML Max Min ML Max GCoS A B C E >0.50 F not fully evaluated Vaduz Westminster Table th Round Bid Application Volumes Prospectivity Summary Update Of the many leads identified in, three were progressed to economic evaluation, the location of which can be viewed in Figure 4.1. Waterloo Westminster Apollo North The primary target of each is the Permian Rotliegend Leman Sandstone Formation, capped by Permian Kupferschiefer and Zechstein evaporates and are sourced from early to peak mature Carboniferous formations (Westphalian coal measures or Namurian shales). The Rotliegend comprises aeolian, fluvial and clastic sabkha facies which thickens dramatically to the east of the Dowsing Fault Zone. Carboniferous potential has not been identified in this area due to poor reservoir quality. Each prospect is structurally trapped, with the traps requiring multiple fault seals and an element of dip closure. Westminster and Waterloo prospects are fully covered by the GXT data and have been mapped on the PSTM volume. Apollo North is on the edge of this survey where the data quality is better on the WesternGeco survey and so was mapped on this older dataset. The volumetrics and risk for each are shown in Table

11 PAGE: 8 OF 13 Waterloo Waterloo is a NW-SE elongate structural trap in the south of. The prospect is 14.5km long and measures 3km at its widest point. The two potential spill points at 2950m and 2965m are depicted in Figure 5.1 by the green and blue outlines respectively.. The prospect requires hanging wall fault seal to the south and abuts the seismic anomaly to the west. The fault along the southern edge of the prospect is critical to trapping any sizeable volume. Figure 5.1 Waterloo SW-NE Depth Section Westminster Westminster is a complex structural trap consisting of narrow ridges and multiple highs. The prospect is 2.6km from SW to NE and 5.4km from NW to the SE edge of. The prospect extends out with by 3.5 km into the York block 47/02a with this ridge measuring between 200 and 400m wide. Westminster has a shallow potential spill point at 3045m, as designated by the darker orange outline and arrow in Figure 5.2, but can be extended to 3075m, labelled upside and outlined in yellow. The trap comprises a fairly flat structure surrounded by ridges to the southwest and northeast. Along the western edge the trap is defined by a NNE-SSW fault that has very little vertical throw. Figure 5.2 Westminster SW-NE Depth Section 8

12 PAGE: 9 OF 13 Apollo North Apollo North is a polygonal structural trap in the northeast of that requires four sealing faults. The prospect measure 2km from east to west and 3.7km from north to south with a single crest at 3140m and a mapped spill point at 3245m (Figure 5.3). The fault orientation around Apollo North is different to that in the west, such that the bounding faults trend more north-south and west-east. Figure 5.3 Apollo North: W-E Depth Section 6 FURTHER TECHNICAL WORK UNDERTAKEN A feasibility study was conducted using RokDoc to determine if reservoir or fluid properties could be determined from the new GXT PSTM data. The rock physics relationships indicated a reliable correlation of rock properties with seismic acoustic parameters for the Rotliegend interval. Therefore an inversion study was conducted in Q Q by Qeye Labs with the aim to create acoustic impedance volumes. The AI volumes enabled an improved delineation of the prospective Rotliegend and Carboniferous sandstones of the licence area. In addition, modelling demonstrated that the Rotliegend interval amplitudes were affected by tuning when the Leman thickness decreased to around 40m. This is critical for the licence where the Leman thickness is expected be in the 25-45m range. Therefore a detuning project was undertaken with Earthworks Environment & Resources Ltd on the relative Impedance volume created by Qeye. 9

13 PAGE: 10 OF 13 7 RESOURCE AND RISK SUMMARY A summary of the three high graded prospects in is shown in Table 7.1 Gas Resources (Bcf) Prospect Low Mid High GCoS Waterloo Westminster Apollo North Table 7.1 Prospect Resource Summary 8 CONCLUSIONS has been fully evaluated from a subsurface perspective. Prospects located in the western part of are exposed to uncertainty in reservoir quality and source due to lack of well control. Apollo North to the east of is surrounded by existing producing fields however the structure is restricted in terms of size. Due to the highly compartmentalised nature of this area, each prospect relies on fault seal which is the largest risk component in each of these prospects. This is of significant importance in larger volumetric scenarios as upside potential requires additional faults to seal. The low recoverable volumes combined with the heavy reliance on a fault seal required to achieve larger accumulations meant that each of the prospects was not economically viable. With all work commitments on the licence having been met, the decision was taken, with approval by partners, not to proceed past the initial term and thus relinquish the licence. 9 CLEARANCE All permissions to publish have been obtained from the Partnership of Centrica Energy, Serica Energy and Atlantic Petroleum. Operator Centrica North Sea Gas Ltd confirms that DECC and OGA are free to publish this relinquishment report. 10