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    rpsgroup.com.au

    Volumetric Assessment of the Sea Lion Discovery

    Offshore Falkland IslandsPrepared forRockhopper Exploration Plc

    Date: 2nd June 2010

    RPS Energy

    38 Station Street, SubiacoWA 6008, Australia

    T +61 (8) 9211 1111 F +61 (8) 9211 1122

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    i

    RPS Energy Pty Ltd

    38 Station Street, SubiacoWA 6008, AustraliaT +61 (8) 9211 1111

    F +61 (8) 9211 1122

    The DirectorsRockhopper Exploration PlcHilltop ParkDevizes RoadSalisburyUnited KingdomSP3 4UF 2ndJune 2010

    Dear Sirs,

    Re: Volumetric Assessment of the Sea Lion Discovery, offshore Falkland Islands forRockhopper Exploration Plc (Rockhopper or the Company)

    Rockhopper Exploration Plc (Rockhopper) have requested a preliminary volumetricassessment of Oil Initially In Place and estimates of recoverable resources from RPS EnergyPty Ltd (RPS) on the oil discovery made on the Sea Lion prospect in Block PL032 offshoreFalkland Islands. This preliminary assessment of the Sea Lion discovery was performed in avery limited time span. Further detailed work has been commissioned by Rockhopper tocalibrate the seismic with well data and characterise the hydrocarbon sands. As a result

    these preliminary volume estimates may be subject to change following the more detailedtechnical review.

    We confirm that we:

    1. are professionally qualified and a member in good standing of a self-regulatoryorganisation of engineers and/or geoscientists;

    2. have at least five years relevant experience in the estimation, assessment andevaluation of the oil and gas assets;

    3. are independent of the Company, its directors, senior management and advisers;

    4. will be remunerated by way of a time-based fee and not by way of a fee that is linked tothe value of the Company; and

    5. are not a sole practitioner:

    Standard applied

    In compiling this report we have used the definitions and guidelines set out by the 2007Petroleum Resource Management System (PRMS), as the Standard required by the AIM

    Guidance note.

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islandsiv

    Table of Contents

    1. EXECUTIVE SUMMARY ...................................................................................................... 12. INTRODUCTION .................................................................................................................. 43. DATA BASE .......................................................................................................................... 5

    3.1 Wells ............................................................................................................................................. 53.2 Seismic ......................................................................................................................................... 5

    4. REGIONAL GEOLOGICAL SETTING AND EXPLORATION HISTORY .............................. 75. DESCRIPTION OF THE ROCKHOPPER ASSETS ............................................................. 9

    5.1 Production Licenses PL32 and PL33 (Rockhopper 100%) .......................................................... 96. SEA LION DISCOVERY ..................................................................................................... 107. VOLUMETRIC ANALYSIS .................................................................................................. 21

    7.1 Sea Lion Main Fan ..................................................................................................................... 217.2 Sea Lion Lower Fan ................................................................................................................... 23

    8. DECLARATIONS ................................................................................................................ 268.1 Independence and Qualifications ............................................................................................... 268.2 Basis of Opinion ......................................................................................................................... 268.3 Sources of Information ............................................................................................................... 26

    9. REFERENCES ................................................................................................................... 2710. APPENDIX A: GLOSSARY OF TERMS AND ABBREVIATIONS ................................... 28

    List of Figures

    Figure 1 ........................................................................................................................................................ 3Figure 2 - Location map of the Rockhopper Licenses, North Falkland Basin .............................................. 4Figure 3 - North Falkland Database Map ..................................................................................................... 6Figure 4 - Major Structural Elements and Positions of Existing Wells in the North Falklands Basin (Source

    Rockhopper) ......................................................................................................................................... 7Figure 5 - Representative Stratigraphic Column for the North Falklands Basin. ......................................... 8Figure 6 - Prospects and Leads Within Blocks PL32 and PL33 (Source Rockhopper) ............................... 9Figure 7 - Petrophysical Analysis of the 14/10-2 Well data (Source Rockhopper) .................................... 11Figure 8 - Seismic to well tie ...................................................................................................................... 15Figure 9 - East-West Seismic Line showing the Fan Geometries ............................................................ 16Figure 10 - RFT Pressure data through the Sea Lion Fan Sequence ....................................................... 14Figure 11 - Top Sea Lion Depth Contour Map with Full Stack Seismic Amplitudes .................................. 17Figure 12 - Extent of the Sea Lion Lower Fan, .......................................................................................... 18Figure 13 - Seismic Inline 1950 Through Sea Lion .................................................................................... 19Figure 14 - Seismic Crossline 1750 Through Sea Lion ............................................................................. 20

    Figure 15 - Arbitrary Seismic Section Through the Western Sea Lion Sequences ................................... 20

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islandsv

    Figure 16 - P90 and P10 Sea Lion Main Fan Areas .................................................................................. 22Figure 17 - Sea Lion Lower fan extent and Volumetric Polygons .............................................................. 24

    List of Tables

    Table 1 - Estimated STOIIP and Recoverable Resource for the Sea Lion Fan sequence .......................... 2Table 2 - List of Wells in the North Falklands Basin .................................................................................... 5Table 3 - Pay Analysis of Well 14/10-2 Oil bearing Section ...................................................................... 12Table 4 - Sea Lion Main Fan Volumetric Inputs ......................................................................................... 23Table 5 - Sea Lion Lower Fan Volumetric Inputs ....................................................................................... 24Table 6 - Volumetric Results for the Sea Lion Main Fan and the Sea Lion Lower Fan ............................. 25

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands1

    1. EXECUTIVE SUMMARY

    Rockhopper Exploration Plc (Rockhopper) have requested a preliminary volumetric assessmentof Oil Initially In Place and estimates of recoverable resources from RPS Energy Pty Ltd (RPS)

    on the oil discovery made on the Sea Lion prospect in Block PL032 offshore Falkland Islands.This assessment of the Sea Lion discovery was performed within a limited time span and maybe subject to change following a more detailed technical review. Further detailed work has beencommissioned by Rockhopper to calibrate the seismic with well data, and characterise thehydrocarbon sands. The assessment is based on the standards outlined in the 2007SPE/WPC/AAPG/SPEE Petroleum Resource Management System (SPE-PRMS).

    Rockhopper Exploration Plc has a 100% interest in Licenses PL023, PL024, PL032, and PL033all are located to the north of the Falkland Islands (see Figure 3). Blocks PL032 and PL033cover an area of 1,680 km2 and were awarded to Rockhopper in June 2005.

    Exploration well 14/10-2 was spudded on the 16th April 2010 to target the Sea Lion Prospect.

    This prospect, consisted of a fan/channel system characterized by high seismic amplitudes islocated on the eastern edge of the North Falkland Basin. The prospect is mostly within the areaof 3D seismic coverage. The prospect outline and the seismic basemap are shown in Figure 2.Post drilling, the well and other data interpretation has shown that two oil bearing sandstonereservoir zones were discovered within well 14/10-2. The upper zone was largely as per thepre-drill prognosis (Competent Person Report on the North Falklands Assets of RockhopperExploration Plc, March 2009) and located within the identified Sea Lion fan.

    A further oil zone was found to be within an additional lower fan that was recognised during theinitial interpretation, but was not categorised as a primary prospect. Pending any appraisaldrilling an initial probabilistic approach was used to estimate the resource volumes in placewithin the two oil bearing fan systems. Although the well is yet to be tested, Contingent

    recoverable resources were estimated using a likely range of recovery factors of 15% (P90) -30% (P50) -40% (P10) based on reservoir characterisation and the uncertainty in the drivemechanism. The estimated OIIP (Oil Initially-In-Place) and Contingent Resources are shown inTable 1.

    The Sea Lion discovery is categorized as Contingent Resources and falls within thedevelopment unclarified sub-class based on project maturity as outlined in PRMS 2007 (Figure1). In view of the immaturity of the discovery the chance of development has not beenquantified: commercial flow rates have yet to be established and there is no informationavailable on the quality of the oil. Further appraisal, a commercial flow on test, an economicallyviable development plan and evidence of a firm intention to proceed with the developmentwould be required before the resources could be classified as Reserves.

    .

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands2

    Figure 1 - Sub-Classes Based on Project Maturity

    Field Oil Initially-In-Place (MMbbls) #Contingent Resources (MMbbls)

    Operator

    PL032Low

    EstimateBest

    EstimateHigh

    Estimate

    Mean

    Estimate

    1C 2C 3C

    Mean

    Estimate

    Sea LionFan 232 717 1493 764 35 215 597 229 Rockhopper

    LowerFan

    53 146 370 185 8 44 148 63 Rockhopper

    *Totals 382 806 1673 943 57 242 669 291 Rockhopper

    Source: RPS*Consolidated probabilistic volume totals (and are not a summation of the individual accumulations)# Contingent on the determination of commerciality, based on well-flow rates and a economic development plan

    Table 1 - Estimated OIIP and Contingent Resource for the Sea Lion Fan sequence.

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands3

    Figure 2 - Seismic Basemap

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands4

    2. INTRODUCTION

    Rockhopper has a 100% interest in licenses PL023, PL024, PL032, and PL033 located to thenorth of the Falkland Islands.

    All of the subject licenses are located within the North Falklands Basin and lie in relativelyshallow water depths ranging between 140 and 500m. The climate is also relatively benignbeing similar to the UK Central North Sea. Six wells were drilled in the winter of 1998 in theNorth Falkland Basin and, although oil and oil and gas shows were encountered in five of thesewells, they were all plugged and abandoned. All of these wells targeted the same play type,namely mid-Cretaceous sands, and subsequent analyses of these wells have shown that thisplay type may be invalid over the greater part of the basin extent. These wells did howeverprove the presence of a very thick sequence of high quality source rock of predominantly lowerCretaceous age. Geochemical studies indicate that only the lower more deeply buried portionsof this source rock have entered the hydrocarbon generation window. This indicates that theupper immature portion of the source rock interval probably acts as an effective seal between

    the deeper mature portion and the reservoirs targeted by the wells. Hence it appears that apossible explanation for the failure of the previous wells is the lack of charge due to the absenceof suitable migration pathways between source and reservoir. Well 14/10-2 addressed thisquestion and drilled within the Barremian section where easy migration was possible.

    Figure 3 - Location map of the Rockhopper Licenses, North Falkland Basin

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands5

    3. DATA BASE

    3.1 Wells

    Six exploration wells were drilled between April and November 1998. In February 2010 DesirePetroleum Plc drilled the 14/.19-1 well to target the fan prospect Liz in block PL03, some oilshows were found in generally tight sandstones within the prospective fan and overpressuredgas zones were seen in the deeper targets.

    Well 14/10-2 on the Sea Lion prospect was drilled in April 2010 and was categorised as an oildiscovery after very strong oil shows while drilling and oil staining in side wall cores, loginterpretation indicated 53 metres of net pay of oil within the sandstone reservoirs intersected.Details of these wells are given in the following table.

    Well Operator TD (m) Shows/Oil/Gas14/10-2 Rockhopper 2744 Oil Discovery14/19-1 Desire 3667 Oil Shows +Gas14/5-1A Shell 4525 Oil shows + Gas14/10-1 Shell 3005 Live oil 27o API14/9-1 Amerada 2590 Oil stains14/9-2 Amerada 2345 Oil stains14/13-1 Lasmo 1475 Dry Hole14/24-1 Lundin 2914 Oil stains

    Table 2 - List of Wells in the North Falklands Basin

    3.2 Seismic

    Blocks PL023 and PL024

    Rockhopper have acquired 1500 km of 2D data to add to the pre-existing 1832km of 2D seismicwithin the blocks and four CSEM lines have also been acquired over the main prospects.

    Blocks PL032 and PL033

    Rockhopper have acquired 850 km2 of 3D data to add to the 300km2 of 3D seismic acquired by

    Shell and 1546km of pre-existing 2D seismic data. The new 3D data has been integrated intothe database and has been interpreted by Rockhopper.

    Blocks PL03 and PL04

    The blocks are partly covered by 3D seismic (804km2) with the remainder of the area coveredby 2122km of 2D seismic.

    The data base map is shown in Figure 4.

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands6

    Figure 4 - North Falkland Database Map

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands7

    4. REGIONAL GEOLOGICAL SETTING AND EXPLORATION HISTORY

    The North Falklands Basin is a north-south trending rift graben approximately 50km wide and

    230km long containing in excess of 5km of sedimentary infill. The basin comprises a number ofindividual depocentres offset by two dominant structural trends (NW-SE and N-S) as is shownin Figure 5. The two main depocentres (termed the western and eastern respectively) areseparated by a fault bounded ridge called the intra-graben high. Within the western depocentrethere is another fault bounded high known as the Minke High. The intra-graben high appears tohave a positive feature for much of the basins history and has had a significant effect onsedimentation. The Minke high appears to have been emergent throughout the syn-rift and theearly part of the post-rift. The basin margins are composed of a structural plateau composed ofprobably Devonian age sediments. The infill ranges from late Jurassic to late Tertiary in ageand a representative stratigraphic column is given in Figure 6.

    Figure 5 - Major Structural Elements and Positions of Existing Wells in the NorthFalklands Basin (Source Rockhopper)

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    Sea Lion FanWithin the BarremianOil Prone SourceRock

    EarlyCretaceous gas

    source Rock

    Figure 6 - Representative Stratigraphic Column for the North Falklands Basin.

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands9

    5. DESCRIPTION OF THE ROCKHOPPER ASSETS

    5.1 Production Licenses PL32 and PL33 (Rockhopper 100%)

    Blocks PL032 and PL033 cover an area of 1680km2 and were awarded to Rockhopper in June2005. Earlier wells were drilled in the licenses both by Shell in 1998. These wells targetedshallow structural closures related to the mid-graben inversion. Rockhopper have acquired 850km2 of 3D data to add to the 300km2 of 3D seismic acquired by Shell and 1546km of pre-existing 2D seismic data. The new 3D data has been integrated into the database and hasbeen interpreted by Rockhopper. The commitment exploration well was satisfied by the drillingof the 14/10-2 well in April 2010. A large number of prospects based on five different play typeshave been identified within these blocks. The different plays are basin margin pinch-outprospects, downthrown closures and rollovers, basin floor channel/fan systems, and invertedstructural closures. The basin floor channel/fan systems play type has been validated by the

    Sea Lion discovery and should lead to further delineation of similar prospects. The outlines ofthe currently identified prospects are shown in Figure 7.

    Figure 7 - Prospects and Leads Within Blocks PL32 and PL33 (Source Rockhopper)

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    6. SEA LION DISCOVERY

    The Sea Lion discovery consists of a fan/channel system characterized by high seismicamplitudes and is located on the eastern edge of the North Falkland Basin. The high amplitude

    feature is mostly within the area of 3D seismic coverage. Well 14/10-2 spudded in April 2010and targeted the southern lobe of the prospect. Very good oil shows were recorded duringdrilling and side wall cores showed oil staining and strong fluorescence within the main fansequences. No water bearing reservoir zones were seen.

    Petrophysical analysis of wire line logs including CMR was supplied by Rockhopper and theanalysis has been reviewed and endorsed by RPS. The results show two main oil bearingsequences between 2400 metres and 2466 metres (MD) with 34.5 metres of net pay andbetween 2488 and 2567 metres (MD) with 16.4 metres of net pay. Further thin layers of pay of2m was seen deeper down to 2617, Figure 8. No Oil-Water Contact (OWC) was encounted inthe well.

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    Net Pay Cut-offs Vshale 40%, SW 60%, Porosity 10%

    Figure 8 - Petrophysical Analysis of the 14/10-2 Well data (Source Rockhopper)

    Pay analysis based on the petrophysics on each of the individual reservoir sections within boththe Sea Lion Fan and the Sea Lion lower fan are shown in Table 3. The mean porosity and

    water saturation are also calculated from this data.

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    SeaLionMainFanPayAnalysisMDMetres NetPay

    Metres

    WaterSaturation

    (Fraction)Porosity(Fraction)

    2400.7 0.30 0.54 0.1252405.02 1.63 0.42 0.1912409.29 1.12 0.34 0.2202410.81 1.83 0.50 0.1542413.71 0.81 0.38 0.1682414.67 2.74 0.34 0.1912417.92 9.91 0.23 0.2372428.13 3.20 0.27 0.2042431.54 0.51 0.24 0.1252432.71 2.13 0.22 0.1352436.31 0.05 0.53 0.1012436.67 1.17 0.40 0.1862440.07 0.81 0.33 0.1772455.57 8.33 0.42 0.171Total 34.54 Mean

    Values 0.33 0.193SeaLionLowerFanPayAnalysis

    2488.64 1.83 0.49 0.2022507.18 0.20 0.39 0.1192509.21 0.76 0.50 0.1392523.03 8.59 0.29 0.2072548.38 0.71 0.49 0.1302550.36 0.71 0.42 0.1632557.67 0.61 0.37 0.1962561.99 2.95 0.28 0.218Total 16.36 Mean

    Values0.33 0.192

    Table 3 - Pay Analysis of Well 14/10-2 Oil bearing Section

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    A good analogue fan system that gives insight into the depositional environment of the Sea LionFan is the Liangjialou-fan in Eastern China, Figure 9, which is a typical deepwater fan in a earlytertiary basin that has extensive 3D, core and well coverage. This should give a good guide tothe geometry, porosity, and permeability of the type of facies within the Sea Lion fan system.The log analysis of the Sea Lion fans does give good agreement to the predicted facies andreservoir properties.

    Figure 9 - Analogue submarine fan, Eastern China. (Source: Reservoir Associates)

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    Seismic to well ties show that the Seal Lion Fan that was identified pre-drill corresponds to theupper pay zone as interpreted in the 14/10-2 well. The lower pay corresponds to a deeperseparate fan, (Figure 11 and Figure 12). Pressure data indicates that the Sea Lion fan and theSea Lion lower fan are on different pressure gradients and are not in communication andhence, they are likely to form separate accumulations, No water was seen in the Sea Lionreservoir sections of the well, therefore no gradient interception can be used to indicate whatlevel, if any, the OWC is located at, (Figure 10). Further detailed work has been commissionedby Rockhopper to calibrate the seismic with well data, and characterise the hydrocarbon sands.

    Figure 10 - RFT Pressure data through the Sea Lion Fan Sequence

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands15

    Figure 11 - Inline 4560 Seismic to well tie

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands16

    Figure 12 - East-West Seismic Line showing the Fan Geometries

    Mapping of the Sea Lion main fan is essentially the same as the pre-drill mapping with bothlithology and depth results in line with prognosis. Figure 13 shows the possible fan extent basedon the amplitude anomaly. This anomaly appears to be a reliable predictor of lithology andpossible hydrocarbon content. The figure displays the full stack amplitudes of the Sea Lion mainnegative reflector (trough) overlayed with the well tied depth contours. Mapping of the Sea LionLower fan is more subtle than the main fan. Bifurcation of the seismic trough directly below thebase of the Sea Lion Main fan corresponds closely to this section and has been interpreted as alower fan unit with an almost identical entry point as the Sea Lion Main fan. A high amplitudereflector of equivalent age merges with the lower fan sourced from the north and may represent

    further potential updip at this level. Figure 14 shows the extent of the lower fan unit and the

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    location of the equivalent aged high amplitude to the north. Figure 15, Figure 16, and Figure 17are seismic examples through the sea lion area.

    Figure 13 - Top Sea Lion Depth Contour Map with Full Stack Seismic Amplitudes

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    Figure 14 - Extent of the Sea Lion Lower Fan,Possible Equivalent Aged Fan Merges from the North

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    Figure 15 - Seismic Inline 1950 Through Sea Lion

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    Figure 16 - Seismic Crossline 1750 Through Sea Lion

    Figure 17 - Arbitrary Seismic Section Through the Western Sea Lion Sequences

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    7. VOLUMETRIC ANALYSIS

    7.1 Sea Lion Main Fan

    The volumetric estimates used an area and net pay methodology with reservoir inputs from thepetrophysical analysis. The extent of the P90 and P10 areas are shown in Figure 18 and thedetailed volumetric inputs are shown in Table 4.

    Area - The P90 area (13 km2) was derived from the lateral extent of the high amplitude mappingand was restricted to the southern lobe, The P90 area also extended down dip to match thelowest known oil (2440 mTVDSS) in the upper Seal Lion fan as seen in the well. The P10 area(55 km2) is the entire high amplitude event as mapped pre-drill on the 3D data. The highamplitudes would seem likely to extend further south than the 3D coverage and form a largerarea. This possibility is represented by the P1 area of 100 square km.

    Net Pay - A total thickness range of 2m to 65m), and using 34.5m (P50) as seen in the well forthe Sea Lion main fan. The total range is to accommodate both the possible downside of a

    restricted fan system, and also the real possibility of the reservoir thickening down dip in thedepot centre of the basin.

    Porosity and SW ranges were derived from the petrophysical analysis of the net pay sectionTable 3.

    The OIIP and Contingent resources are shown in Table 6.

    FVF - A range of 1.05 to 1.3 was used for volumetric purposes, little at present is known aboutthe GOR, the sealed MDT sample containers are currently being tested. Initial API gravity of theoil from a sample opened on the rig is 26.3. This and the filling characteristics of the MDTs bothsuggest it is likely to be movable oil.

    The reservoir permeability estimates based on results from traditional petrophysical log analysisand supported by CMR interpretation indicate that the reservoir has good permeability of 200-900 mD.

    Recovery factors were applied deterministically to the Probabilistic in place volumes estimated,Recovery factor ranges are 15% (P90), 30% (P50), and 40% (P10).

    The 15% (P90) is representative of likely recovery factor given a poor drive mechanism withinthe basin, It is possible that no aquifer support is available and little is known of any solution gasdrive. The (30%) P50 is likely if some aquifer or solution gas drive is present and / or frompossible pressure support from injector wells. (40%) P10 is possible with good drive mechanismand / or effective pressure support.

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    Figure 18 - P90 and P10 Sea Lion Main Fan Areas

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    Table 4 - Sea Lion Main Fan Volumetric Inputs

    7.2 Sea Lion Lower Fan

    The volumetric estimates used an area and net pay approach with reservoir inputs from the

    petrophysical analysis. The extent of the P90 and P10 areas are shown in Figure 19 and thedetailed volumetric inputs are shown in Table 5.

    Area - The P90 area (6 km2) was derived from the lateral extent of the mapped fan sequenceand was restricted to the mapped fan sequence and was extended down dip to the lowest depthpoint. The P10 (30 km2) area was the entire mapped fan sequence. The equivalent aged highamplitude feature to the north has not been included.

    Net Pay - A total thickness range of 2m to 35m, and using 16.5m (P50) as seen in the well forthe lower Sea Lion fan. This total range is to accommodate both the possible downside of amore restricted fan system, and also the possibility of reservoir thickening down dip in the depotcentre of the basin.

    Porosity and Sw ranges were derived from the petrophysical analysis of the net pay section.Recovery factors were applied deterministically to the Probabilistic in place volumes estimated.

    FVF - A range of 1.05 to 1.3 was used for volumetric purposes, little at present is known aboutthe GOR, the sealed MDT sample containers are currently being tested. Initial API gravity of theoil from a sample opened on the rig is 26.3. This and the filling characteristics of the MDTs bothsuggest it is likely to be movable oil.

    The reservoir permeability estimates based on results from traditional petrophysical log analysisand supported by CMR interpretation indicate that the reservoir has good permeability of 200-900 mD.

    Recovery factors were applied deterministically to the Probabilistic in place volumes estimated,

    Recovery factor ranges are 15% (P90), 30% (P50), and 40% (P10).

    The 15% (P90) is representative of likely recovery factor given a poor drive mechanism withinthe basin, It is possible that no aquifer support is available and little is known of any solution gasdrive, also the possibility of the lack of continuity between the reservoir levels seen at this levelmay make recovery difficult. The (30%) P50 is representative if some aquifer or solution gasdrive is present and / or from possible pressure support from injector wells. (40%) P10 ispossible with good drive mechanism and / or effective pressure support.

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    Figure 19 - Sea Lion Lower fan extent and Volumetric Polygons

    Table 5 - Sea Lion Lower Fan Volumetric Inputs

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    Volumetric Assessment of the Sea Lion Discovery, Offshore Falkland Islands25

    Field Oil Initially In Place (MMbbls) #Contingent Resources (MMbbls)

    Operator

    PL032Low

    EstimateBest

    EstimateHigh

    Estimate

    Mean

    Estimate

    1C 2C 3C

    Mean

    Estimate

    Sea LionFan

    232 717 1493 764 35 215 597 229 Rockhopper

    LowerFan

    53 146 370 185 8 44 148 63 Rockhopper

    *Totals 382 806 1673 943 57 242 669 291 Rockhopper

    Source: RPS*Consolidated probabilistic volume totals (are not a summation of the individual accumulations)

    Table 6 - Volumetric Results for the Sea Lion Main Fan and the Sea Lion Lower Fan

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    8. DECLARATIONS

    8.1 Independence and Qualifications

    RPS is an independent consultancy providing a comprehensive range of technical servicesand economical analysis to the petroleum industry. Except for the provision of professionalservices on a fee basis, RPS does not have a commercial arrangement with any otherperson or company involved in the interests that are the subject of this report. Mr DavidGuise (Managing Director-Consulting, Australia Asia Pacific) has supervised the evaluation.

    David Guise is a registered Professional Engineer with over 30 years of domestic andinternational petroleum engineering and operating experience in both onshore and offshoreenvironments. He has substantial experience and knowledge of field development planning,production optimisation and reserve estimation, as well as new venture identification and

    evaluation. David holds a Diploma of Technology (Petroleum Technology) from the SouthernAlberta Institute of Technology and a B.Sc. in Petroleum Engineering from the University ofWyoming.

    8.2 Basis of Opinion

    The evaluation presented in this report reflects our informed judgement based on acceptedstandards of professional investigation, but is subject to generally recognised uncertaintiesassociated with the interpretation of geological, geophysical and engineering data. Theevaluation has been conducted within our understanding of petroleum legislation, taxationand other regulations that currently apply to these interests. However, RPS is not in aposition to attest to the property title, financial interest relationships or encumbrances related

    to the property.In estimating oil and gas in place (OIIP/ GIIP), and Resources we have used the standardpetroleum engineering techniques. We have estimated the degree of uncertainty inherent inthe measurement and interpretation of the basic data and have calculated a range ofpetroleum initially in place and recoverable.

    It should be understood that any evaluation, particularly one involving exploration and futurepetroleum developments may be subject to significant variations over short periods of timeas new information becomes available.

    8.3 Sources of Information

    This report is based upon information which was provided by the licence operator(Rockhopper), from public domain information and proprietary data from within RPS databases.

    RPS is not in a position to guarantee the accuracy of data supplied by the operator orindependent open file sources.

    New mapping has been carried out in order to address the validity of the operatorsinterpretation and to address additional potential within the block. All data supplied werereviewed and audited with due diligence to provide appropriate confidence in their validity.

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    9. REFERENCES

    Competent Person Report on the North Falklands Assets of Rockhopper Exploration PlcMarch 2009

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    10. APPENDIX A: GLOSSARY OF TERMS AND ABBREVIATIONS

    AAPG American Association of Petroleum Geologists

    API American Petroleum Institute

    asl above sea level

    B billion

    bbl(s) barrels

    bbls/d barrels per day

    Bcm billion cubic metres

    Bg gas formation volume factor

    Bgi gas formation volume factor (initial)

    Bo oil formation volume factor

    Boi oil formation volume factor (initial)

    Bw water volume factor

    bopd barrels of oil per day

    BTU British Thermal Unit

    Bscf billions of standard cubic feet

    bwpd barrels of water per day

    CMR Combinable Magnetic Resonance

    CO2 Carbon dioxide

    condensate liquid hydrocarbons which are sometimes produced with naturalgas and liquids derived from natural gas

    cP centipoise

    CROCK rock compressibility

    Cw water compressibility

    DBA decibels

    Ea areal sweep efficiency

    EMV Expected Monetary Value

    EPSA Exploration and Production Sharing Agreement

    ESD emergency shut down

    Evert vertical sweep efficiency

    FBHP flowing bottom hole pressure

    FTHP flowing tubing head pressure

    ft feet

    ftSS depth in feet below sea level

    GDT Gas Down To

    GIP Gas in Place

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    GIIP Gas Initially in Place

    GOR gas/oil ratio

    GRV gross rock volume

    GWC gas water contact

    H2S Hydrogen sulphide

    HIC hydrogen induced cracking

    IRR internal rate of return

    KB Kelly Bushing

    ka absolute permeability

    kh horizontal permeability

    km kilometres

    km2 square kilometres

    kPa kilopascals

    kr relative permeability

    krg relative permeability of gas

    krgcl relative permeability of gas @ connate liquid saturation

    krog relative permeability of oil-gas

    kroso relative permeability at residual oil saturation

    kroswi relative permeability to oil @ connate water saturation

    kv vertical permeability

    LNG Liquefied Natural Gases

    LPG Liquefied Petroleum Gases

    M thousand

    MM million

    M$ thousand US dollars

    MM$ million US dollars

    MD measured depth

    mD permeability in millidarcies

    m3 cubic metres

    m3 /d cubic metres per day

    MMscf/d millions of standard cubic feet per day

    m/s metres per second

    msec milliseconds

    mV millivolts

    Mt thousands of tonnes

    MMt millions of tonnes

    MPa mega pascals

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    NTG net to gross ratio

    NGL Natural Gas Liquids

    NPV Net Present Value

    OWC oil water contact

    Pb bubble point pressure

    Pc capillary pressure

    petroleum deposits of oil and/or gas

    phi porosity fraction

    pi initial reservoir pressure

    PI productivity index

    ppm parts per million

    psi pounds per square inch

    psia pounds per square inch absolute

    psig pounds per square inch gauge

    pwf flowing bottom hole pressure

    PVT pressure volume temperature

    rb barrel(s) of oil at reservoir conditions

    rcf reservoir cubic feet

    RFT repeat formation tester

    RKB relative to kelly bushing

    rm3 reservoir cubic metres

    SCADA supervisory control and data acquisition

    SCAL Special Core Analysis

    scf standard cubic feet measured at 14.7 pounds per square inchand 60 F

    scf/d standard cubic feet per day

    scf/stb standard cubic feet per stock tank barrel

    SGS Sequential Gaussion Simulation

    SIS Sequential Indicator Simulation

    SPE Society of Petroleum Engineers

    SPEE Society of Petroleum Evaluation Engineers

    sm3 standard cubic metres

    So oil saturation

    Sor residual oil saturation

    Sorw residual oil saturation (waterflood)

    Swc connate water saturation

    Soi irreducible oil saturation

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    SSCC sulphur stress corrosion cracking

    stb stock tank barrels measured at 14.7 pounds per square inchand 60 F

    stb/d stock tank barrels per day

    STOIIP stock tank oil initially in place

    Sw water saturation

    $ United States Dollars

    t tonnes

    THP tubing head pressure

    Tscf trillion standard cubic feet

    TVDSS true vertical depth (sub-sea)

    TVT true vertical thickness

    TWT two-way time

    US$ United States Dollar

    Vsh shale volume

    W/m/K watts/metre/ K

    WC water cut

    WPC World Petroleum Council

    WUT Water Up To

    porosity

    viscosity

    gb viscosity of gas

    ob viscosity of oil

    w viscosity of water