Hague and London Oil Plc Exploiting Shallow Gas Offshore Netherlands De-Gassing Shallow Hazards or De-Risking Shallow Gas November 2016
The Shallow Gas Play can be Summarized as Schematic evolution of the deposition of reservoir sands/seals. Sands are shown as yellow, clays as green or blue. Note the back ground subsidence, which ultimate controls the creation of accommodation space on the shelf. Deltaic sands, ranging from deeper water delta-toe sands to shallow water delta top-sets 2
The Shallow Gas Play can be Summarized as deeper marine sands sealed by continuous shale deposition off the shelf, sourced by delta clays 3
The Shallow Gas Play can be Summarized as structure developed by the rising of salt diapirs causing deformation of the overburden. The diapirism of the Permian salt may be caused by the rapid infill of the basin, and W Block F4 E structuration is post deposition and contemporaneous if not earlier than the gas generation. Shallow anomaly Deeper anomaly 4
Shallow Gas Opportunity Likely Biogenic Gas High Calorific Value (99% Methane) Tertiary Reservoirs (Pliocene or Miocene) High Porosity (20-35%) Good Permeability Low Pressure (30-60 bar) History Occurence of Shallow Gas Leads have been Known since 1970 s Production of these had been proven by wells in the 1980 s Water and Sand Control caused them not to be developed A12-FA developed in 2007 F02a-B-Pliocene developed in 2009 B13-FA developed in 2011 A-18 developed in 2015 1-4 TCF GIIP 0.5-2 TCF EUR 5
Challenges Thinly Stacked Reservoirs Poorly Consolidated Sands Shallow Low Relief Low Pressure Solutions Horizontal Wells Expandable Screens Hi-Res Seismic Compression Expandable Screen in Horizontal Well A12 Central Processing Platform with Compression Facilities 6
N Legacy 2D Seismic Data Indicates Strong Amplitudes which Conform to Structure Block F5 S Chaotic seismic character and chimneys may indicate higher Sg Prospect C Prospect A Lead F Logs from drilling within the area would indicate that the bright amplitudes, conforming to structure, are within the Late Miocene- Early Pleistocene gas sands 7
Tertiary Sand Well Correlations in Quad F F04-03 F04-01 F04-02 F05-02 F05-05 F05-01 F05-03 F05-04 0 500 TPS H1 1000 Mid Miocene Unconfrmity 1500 Base Tertiary The correlation is largely based on the correlation of the strong Top Pleistocene gas sands (TPS) and the Horizon 1, representing the base of a regionally correlatable sand while the bars highlight the section logged through casing, with a reduced GR response. 8
Legacy 2D Seismic Data Indicates Bright Amplitudes Conforming to Structure 9
Structural Prospects May Have Added Stratigraphic Potential The GWC, as well as saturation (Sg) and reservoir quality (Φ), remains the biggest variables and risks within the Shallow Gas Prospect for both volumes and deliverability. There is some seismic indication, in bright amplitudes & phase change outside of closure, that there is a possible down-dip, on-lap stratigraphic component to some Prospects Phase Change Flat Spot Sg & Φ can only be quantified in drilling but, there is a strong possibility that the GWC could be de-risked seismically & that this could indicate volumes in excess of the current maximum in the structural spill-point. 10
Time & Depth Correlations Multiple Shallow Gas prospects and leads have been identified within the Late Miocene and/or Early Pleistocene in Quad F Time/Depth correlation is very linear within the zones of interest above the Mid-Miocene Unconformity (MMU) The target zone is generally restricted to1500m depth which is equivalent to 1500ms (TWT); mostly within the Deltaic Front 11
However, these data. Have irregular near offset distribution (min 500m) and low fold for the Shallow Objectives; Had a source designed for deeper objectives; May be too coarse in Temporal sampling of 4ms; and Have spatial sampling of 12.5x25m bin spacing which is likely too large for target spectrum. Therefore, the. Legacy 2D seismic may be superior for current use; and New seismic parameters need to be designed for new 3D data. Extensive 3D Seismic Coverage 12
Site survey vessel; <1x1km grid; <1000in3 air-gun source; 6.25m CMP interval; 2000m cable; and Processed at 2ms. Future Seismic Survey Design Considerations Possible to use dense 2D grid: If 3D is required, then: Dual flip/flop are-gun sources; Single cable; 2 bin lines per sail line; 12.5x6.25m bins; 2000ms recorded; 2000m cable; and Processed at 2ms. 13
Multi-Client 3D vs. Shallow Gas 3D Acquisition Parameters Shallow Gas 3D Parameters <1000in3 5m 12.5m 2s 1,200-2,000m 5-7m 1-2 25m 14
Possible Seismic Solution: Perpendicular Acquisition 15
Indicative Project 50m water depth 700-1000m target depth Amplitude Anomaly 4-way Dip Closure Pleistocene Deltaic Sand Natural Gas (likely hi-cal) Anomaly and Phase conform to Structure 120Bcf Recoverable 16
Shallow Gas 120Bcf Development Economic Summary Summary Company Oil reserves (mbbls) - 0 Gas reserves (Bcf) 120 120 Total reserves (mboe) 20 20 Capex 247 247 Capex/boe 12,3 12,3 Opex/boe 12,4 12,4 NPV 10% 79 79 NPV/boe 3,9 3,9 IRR 25% 25% Breakeven, $/bbl Govt take (%) 41% 41% 17
Shallow Gas Summary Proven Hydrocarbon Resource Proven Development Technology (Expandable Screens) Availability of Acreage Extensive Existing Seismic Coverage Amplitudes Lead and Sesimic Character Lead Exploration Key Risks: Gas Saturation Reservoir Quality New Seismic Data Would be Cost-Effective Improved Reservoir Characterizaton through New Tuned Seismic Stratigraphic Component Could lead to much larger Structural Leads Favorable Economics (i.e. Small Fields Policy) Access to Infrastructure (i.e. NOGAT, etc) Hub and Spoke Development Concept: CPP & Satellites Delays Abandonment by Years for Ageing Infratstructure 18
Thank You to: EBN TNO Petrogas WGP Spectrum PGK 19