Baltic Basin

The Baltic Basin, located in Northern Poland - see Fig 1, has been identified as one of the prime areas of interest for shale gas exploration in Europe. The Basin contains significant unconventional gas and oil accumulations within Palaeozoic targets including the Lower Silurian, Ordovician, and Upper Cambrian. The targeted intervals contain thick, laterally extensive, organic rich source rocks deposited in a relatively quiet tectonic setting and now lying at a present day depth of between 2 and 5km. Table 1 shows how the Baltic basin in Poland compares to other world class, unconventional analogues.

Figure 1

Fig 1: Location of Lower Palaeozoic sedimentary basins and lateral extent of the Upper Ordovician and/or Lower Silurian shale formations (after Poprawa, 2010) 

. Barnett Montney Haynesville Marcellus Baltic Basin
Depth (ft) 6,500 - 8,500 6,500 - 11,000 11,000 - 13,000 4,000 - 8,000 7,000 -14,500
Gross Thickness (ft) 150 -700 1,000 - 1,400 1200 - 1300 50 - 300 500 - 2,500
Net Thickness (ft) 100 - 600 450 - 525 200 - 350 50 - 250 50 - 200
Thermal Maturity Ro% 0.8 - 1.3% 2.2 - 3.8% 1.8 - 2.5% 0.7 - 2.15% 1.0 - 2.6
TOC, % 4.50% 1.0 - 5.0% 0.5 - 4% 1.0 - 5.0% 1.0 - 6.0%
Silica Content, % 35 - 50% 45 - 60% 34% 20 - 60% 25 - 63%
Clay Content, % <35% - 33% 20 - 35% 30 - 48%
Total Porosity, % 4.0 - 5.0% 2.0 - 4.5% 8 - 15% 1.6 - 7.0% 4 - 8%
Permeability (nD) - 250 - 450 - - >300 nD
Gas-In-Place,  BCF/Section 50 to 150 130 - 320 200 to 250 40 - 130 40 - 200
Pressure Gradient (psi/ft) 0.46 - 0.50 0.65 Over pressured 0.45 - 0.60 0.44 - 0.60
EUR per well 2.65 BCF - 6.5 BCF - 2.25 - 4.0

San Leon’s acreage position is optimised for maximum potential future value and is based on the learnings made during our historic work programmes in the Basin combined with the additional benefit of analysing other acreage holders’ activities in the region.

Szczawno
Szczawno is located in the southern, deeper part of the Baltic Basin. Reinterpretation and integration of legacy 2D seismic data resulted in more detailed mapping of the fault zones and better definition on the depth of the main shale intervals. Geochemical analysis of the area, tied to historic well results, suggests this licence lies within the high grade 'dry gas' window. Core data and wireline log analyses from the Szymkowo-1 well (suspended for future frac) suggest very good parameters for the Silurian Caradocian shale. A multi-frac stimulation of the Lower Silurian and Upper Ordovician shale intervals is planned for the future.

Gdansk W.
Gdansk W. is located in the central, 'wet gas' prone part of the Baltic Basin. The Lewino 1G2 well located in the western Baltic basin has been successfully stimulated and tested. Vertical hydraulic fracture stimulations were performed in two planned intervals: one stage in the Lower Silurian shale (upper target – UT) and two stages in the Upper Ordovician shale (lower target – LT). The latest slickwater frack in the UT achieved all of the technical goals of the frac design (mainly increase in proppant concentration). The flow test showed a sustainable gas production rate of 45,000–60,000 standard cubic feet per day (scf/d) after 6 weeks of well clean-up, despite the well not yet being fully cleaned of frac fluid. Data acquired by SIGMA3 Engineering (previously known as Apex) estimates a potential rate of 200,000–400,000 scf/d, based upon full clean-up of frac fluid, with a condensate yield of around 20 barrels per mmscf.

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