Polish Geological InstituteNational Research Institute
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l CO2 storage in gas-bearing shales of the Baltic basin
Marek JAROSIŃSKI, Adam WÓJCICKIPGI-NRI
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EERA Birmingham, 24-25.11.2016
Polish Geological InstituteNational Research Institute
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SHALESEQ project and its goals
PHYSICO-CHEMICAL EFFECTS OF CO2 SEQUESTRATION IN THE POMERANIAN GAS-BEARING SHALES (2014-2017)
Developing a multi-scale model of CO2 sequestration in shale formations combined with simultaneous stimulation of natural gas production.
...understanding the underlying mechano-chemical processes governing CO2 behavior in shale formations... contribute to characterize the mechanisms of permanent storage of CO2 in shales.
CO2 has a substantially higher sorption capacity than methane to the organic matter contained in shales. CO2 may therefore be used to enhance shale gas production, as the secondary method, while at the same time remaining trapped in the shale matrix.
The assessment of the CO2 storage capacity is not directly mentioned in the Project scope, however it can make a good platform of the ShaleSeq results integration
Polish Geological InstituteNational Research Institute
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Shale gas and oil resources world-wide
after eia.gov, 2015
The development of unconventional hydrocarbon resources has changed the energy-political landscape of the world (actually North America, recently China) and could provide economic and safe solutions for the future energy supply in Europe (?).
Polish Geological InstituteNational Research Institute
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Shale gas and oil exploration in Poland
Till now 74 exploratory wells for unconventional hydrocarbon reservoirs (some of them also for conventionals), including 18 directional/horizontal wells. Hydraulic fracturing has been performed in 28 vertical and directional/horizontal wells. Test results from a few wells suggest a possible gas production of about 10% to 30% of the commercially sustainablelevel.The most prospective area is the Baltic basin (northern Poland/Pomerania.
http://baza.pgi.gov.pl/
Polish Geological InstituteNational Research Institute
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SeqWell – new POGC(PGNiG) B-1 well
The study is mostly (not exclusively) based on data from that well.
Polish Geological InstituteNational Research Institute
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Location (maturity map – PGI-NRI, 2012 report)
The old maturity map is incorrect - new data changed the picture dramatically -wet gas zone shifts towards W/SW, covering the well in question.
Dry Gas Wet Gas + Oil
SeqWellP O M E R A N I A
depth (Silurian/Ordovician) ~3,5 km;reservoir pressure ~36 MPareservoir temperature >85 °C
Polish Geological InstituteNational Research Institute
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Accumulation spaces for natural gas in shales
after Dyrka, in: Sidorczuk et al., 2013
Gas adsorbed and diffused in nanopores in organic matter
Polish Geological InstituteNational Research Institute
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Shale gas production
after Godec, 2013
after 10 years of productiondominance of sorbed gas
In course of production a change of the ratio: (interpore+fracture gas)/(desorbed gas) can be observed. After 10 years the share of free gas decreases significantly and dominance of desorbed gas can be observed. Then CO2 injection could be used as a secondary method to gas recovery, similarly to CO2-ECBMR (CO2-CH4 replacement).
Shi et al., 2005
Polish Geological InstituteNational Research Institute
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The dynamic CO2 storage model has to cover:Flows and diffusion matching the dynamic reservoir model (i.e. production history);A good deal & quality of (trustworthy) data to calibrate the porosity structure and permeability models in reservoir-scale (???);One is not able to make a robust dynamic assessment without CH4 production data.
If you are not able to construct a dynamic reservoir model ...Construct the static CO2 storage model only
- In the static model flowrates, processes and transport routes are neglected
- It is assumed that CO2 reaches „somehow” a permanent storage space
Static vs dynamic CO2 storage capacity
Polish Geological InstituteNational Research Institute
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CO2 injection scenario for dynamic assessment
Preferential scenario of CO2 injection into shale reservoir (an example after Kalantari-Dahaghi et al., 2010). Assuming 1 km2 assessment unit area we need a few wells.
Polish Geological InstituteNational Research Institute
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Components of the static CO2 storage capacityassessment
Adsorption capacity (mostly on dry organic nanopores, inorganic –adsorption on illite grains partly blocked by presence of capillary and ireducible water; CO2-CH4 replacement ratio 2-6 x - Kang et al., 2011; Heller & Zoback, 2014; good, positive correlation with TOC)
Pore space in shale matrix (macropores > 20 nm – predominantly freegas, mezopores 5-20 nm, micropores 2-5 nm – predominantly adsorbedgas; Kang et al., 2011)
Fracture space (natural & technological)
Threshold values of input parameters (TOC, thickness, brittleness…) for storage complex are necessary.
Polish Geological InstituteNational Research Institute
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Sorption capacity and storage potential of shales
CO2 storage capacity of the entire Marcellus shale play (~144 000 km2; 20 years of storage), after Godec et al. 2013. The effective storage capacity (storage efficiency coefficient -10%) corresponds to storage potential in saline aquifers of Poland.
Volume[Bcm]
Mass[Mt]
Adsorbed CO2 52 880 104 545Free CO2 29 033 57 399Total CO2 81 914 161 944As above – 10% storage efficiency 8 191 16 194Total CO2 /1km2 0,56 1,1210% storage efficiency 0,05 0,112
Sorption characteristics of CH4 and CO2 compiled from a variety of published sources
Tao i Clarens, 2013
Polish Geological InstituteNational Research Institute
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Sorption capacity (a function of Langmuir volume & pressure and reservoir
pressure) of shale rock [m3/t].
Bulk density of shale rock.
Net thickness of shale reservoir (based on TOC, porosity filled with
hydrocarbons, gas content, quartz+carbonate and clay content)*.
Total values and distribution of effective porosity (classes of
pores/fractures: 3-10 nm (predominantly adsorbed gas), 10-100 nm, 100-
1000 nm, >1000 nm).
Gas expansion ratio (free gas).
*based on both laboratory analyses and well logging data interpretation
Input data (POGC wells, mainly SeqWell)
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Input data
Example of well logging interpretation (porosity) used to determine net thickness of shale reservoirs (ShaleSeq: M. Roman, 2016).
Sasino formation, Jantar member of Pasłęk formation and, to a lesser extent, lower part of (Wenlockian) Pelplin formation are prospective shale reservoirs there.
Polish Geological InstituteNational Research Institute
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Synthetic static model of the unit area (1 km2) based (mostly) on data from POGC/PGNiG SeqWell, and other wells in the vicinity. The complexes of TOC>1.5%, gas filled porosity >2%, gas content >0.5 m3/t, quartz&carbonate content > 40% were considered A simple formula for adsorbed gas GIPa: GIPa=V×ρ×G (Ladage & Berner, 2012) was used and the (theoretical) CO2 storage
capacity in shales is: GIPa x CO2/CH4 ratiowhere V is reservoir rock volume, ρ – bulk density and G – sorption capacity.
The assessment (adsorbed gas)
Formation /member Stratigraphy
thickness [m]
average TOC
[%wt]
net reservoir thickness
[m]
Sorption capacity G
[m3/t]bulk density
CO2/CH4 ratio***
Pelplin1 lower Wenlock 67 0,8 20±2 0,80±0,16 2,60±0,02 2,53±0,51
Pasłęk(Jantar)(upper & middle) Llandowery 44 1 0
Jantar (basal) Llandowery 13 3,2 13,0±1,3 1,40±0,28 2,45±0,02 3,76±0,75Prabuty Ashgill 7 0,5 0Sasino Caradoc (+Llanwirn) 15 2,5 10±1 1,60±0,32 2,48±0,02 2,60±0,5
***CO2/CH4 ratio - ShaleSeq: Lutyński & Gonzalez, 2015
Polish Geological InstituteNational Research Institute
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Monte Carlo method was applied assuming tentative uncertainity ranges: ±10% in case of net reservoir thickness, ± 20% - sorption capacity & CO2/CH4 ratio, and a fixed value of ± 0.02 g/ccm was assumed in case of bulk density.The following estimations of the (theoretical) CO2 storage capacity in 1 km2 unit area of Polish Baltic basin were obtained:
The assessment (adsorbed gas)
The median of total (theoretical) CO2 storage capacity of Llandovery-Ordovician complex is 0.121 Bcm/km2 or 0.24 Mt/km2. Assuming 10% storage efficiency we got effective storage capacity 0.024 Mt/km2 (a pilot project). CO2 sorption capacity per tonne of shale varies from 0.5 kg CO2/t (lower Wenlock) to 2.4 kg CO2/t (basal Llandowery).
Formation /memberStratigraphy minimum
(P10) [Bcm]median
(P50)[Bcm]average[Bcm]
maximum(P90)[Bcm]
Pelplin1 lower Wenlock 0,004 0,041 0,042 0,096
Jantar (basal) Llandowery 0,001 0,041 0,042 0,093
Sasino Caradoc (+Llanwirn) 0,003 0,039 0,04 0,089TOTAL - 0,121
Polish Geological InstituteNational Research Institute
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Shales in Polish Baltic basin do not have such good parameters as Marcellus shale – that is reason not only basal Llandowery and Caradoc shales of relatively high TOC (but of small net thickness) but also mediocre shales of lower Wenlock have been considered in the study. As a result, the assumed total thickness is similar as Marcellus productive shales (about 40 m) but only the CO2 sorption capacity of the Jantar/basal Llandowery matches the corresponding parameter of Marcellus (in our case the storage capacity is likely 3 times lower than in the US).
Till now no commercial production in the area in question was achieved –most likely because of low frackability (relatively high content of clay minerals), the lack of overpressure and, last but not the least, the fact Polish shales are located considerably deeper than their US counterparts.
The study is devoted to some aspects of enhanced recovery of shale gas AFTER meaningful gas production from shale reservoirs. At this moment that is a purely theoretical exercise.
Conclusions
Polish Geological InstituteNational Research Institute
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Thank you for your attention:www.pgi.gov.pl
