Tehnologija kaptiranja i skladištenja Cτ2 prepoznata je kao jedna od uspješnih za
ublažavanje klimatskih promjena, a iscrpljena polja ugljikovodika predstavljaju realnu
mogućnost za njenu primjenu. Predmet istraživanja su neogenska (gornjomiocenska)
pješčenjačka ležišta ugljikovodika Savske depresije, a kao tipsko, odabrano je polje Ivanić.
S ciljem izračuna kapaciteta naftnih ležišta, Gama 3 i Gama 4, dostupnog za
skladištenje Cτ2, geostatističkim metodama (obično i indikatorsko krigiranje te sekvencijske
Gaussove simulacije) procijenjena je distribucija petrofizikalnih parametara. Simulacijom
utiskivanja CO2, koja se zasniva na materijalnom uravnoteženju svih pridobivenih i utisnutih
fluida, dobivena je razina praktičnog kapaciteta uskladištenja. Vrijednost početnog ležišnog
tlaka korištena je kao konačna vrijednosti do koje se provodi utiskivanje Cτ2.
Potencijalni putovi migracije CO2 iz podzemnog skladišta uključuju rasjede, pukotine,
bušotine, ali i izolatorske stijene. Rizik migracije kroz izolatorske stijene u dosadašnjim
istraživanjima je marginaliziran. Predlaže se izračun vjerojatnosti očuvanja ležišta zasićenog s
CO2 primjenom metodologije geološke vjerojatnosti pojave ležišta, ali i nužnost
laboratorijskog ispitivanja izolatorskih stijena na propusnosti za CO2. U tu svrhu je osmišljen
uređaj, koji je prijavljen u Registar prijava patenata Hrvatskog zavoda za intelektualno
vlasništvo. Mogućnost mineraloškog uzamčivanja za ležišta polja Ivanić izvedena je koristeći
analogiju s objavljenim podatcima o provedenim istraživanjima na drugim ležištima.
Sigurnost procesa transporta se povećava ukoliko se Cτ2 transportira u superkritičnom
stanju. Utiskivanjem CO2 u tekućem stanju povećava se učinkovitost i sigurnost skladištenja.
Model transporta i utiskivanja CO2 izrađen je primjenom softvera HYSYS, pažljivim odabirom
uvjeta, kako bi se postigla ravnoteža između sigurnosti i učinkovitosti transporta i
|Abstract (english)|| |
Carbon Capture and Storage Technology (abbr. CCS) is recognized as one of the most
successful method in climate changes mitigation. Depleted hydrocarbon reservoirs represent a
realistic option for its application. The subject of research are Neogene (Upper Miocene)
sandstone hydrocarbon reservoirs in the Sava Depression, represented by the Ivanić Field case
study. Teoretical storage capacity for some aquifers and hydrocarbon reservoirs in the
Republic of Croatia has been assesed on 188.83·106 t within the 6th Framework Programme
projects (FP6), CASTOR and GeoCapacity. Calculation was made by using a simplified
methodology based on data on ultimate recoverably reserves. The storage capacity for the
Ivanić Field is assessed on 5.4λ6·106 t. For more accurate assessment distribution of
petrophysical parameters must be done, which is possible by using different geostatistical,
deterministic and stochastic, assessment methods. Within the scope of dissertation, variogram
analysis and mapping of the Ivanić field's reservoir variables were done. Calculated volume of
CO2 which can be injected after the Enhanced Oil Recovery (EOR) project, up to conditions
of initial reservoir pressure, is on the level of 13.722·106 t. It was also simulated using
material balance equation for produced and injected fluid in the MBAL program module.
Obtained value (3.705·106 t) is of the practical capacity level.
CO2 geologic storage system must allow permanent and safe disposal of CO2 (of the
order of 104-105 years). Although migration of CO2 through active and abandoned wells,
fractures and faults is a real possibility, these issues are well investigated so far, such attention
has not been paid to reservoir seal rocks migration pathway. Probability of preserving
reservoirs saturated by CO2 is done by applying the probability of successful discovery
methodology (Probability of Success, abbr. POS). By testing seal rocks permeability the
hypothesis of the need for laboratory tests was justified and for that purpose, in the scope of
dissertation, an innovation „Chambers for testing of isolator rocks impermeability for carbondioxide
accumulated in reservoir below seal" was designed, which was awarded with a silver
medal at the International exhibition of innovation and modernization, INOVA 2013.
Temporary, the patent is under verification of the satate authority institution.
Mineral trapping mechanism is the safest mechanism for permanent CO2 retention, but
due to long process, this phenomenon is still quite unexplored. Possibility of mineral trapping
for the Sava Depression’s hydrocarbon reservoirs is done by analogy with published data of
other projects. Sandstones composed of quartz, dolomite and K-feldspar, as it is case in the
target sandstones may be considered favorable for mineralization, but there is no significant
CO2 binding capacity due to lack of alkaline earth metals (Ca and Mg) and/or mafic rocks
fragments. Given that some clay minerals, (such as anorthite, zeolite, smectite, etc) are
considered reactive, mineralisation may occur in transitional lithofacies. Accurate assessment
could be obtained after many years of research in controlled laboratory conditions. In CO2
geological storage the temperature represents an important factor because it significantly
affects fluid physical properties, interaction of the CO2-reservoir fluid-rock system, the
trapping mechanisms, and the storage safety. For the effective CO2 storage pressure and
temperature must be above supercritical. However, VILARRASA et al. (2013) analysed
changes in stress caused by injecting cold CO2, and concluded that injection of liquid CO2 is
more favorable regarding energy efficiency and seal rock mechanical stability. The changes in
fluid pressure and temperature can lead to gas phase appearance causing different problems.
Modelling of CO2 pipeline transportation was done in a specialized software (HYSYS) by
using a part of exsisting pipeline system. The transportation conditions were carefully selected
to achieve a balance between transport safety, storage efficiency and migration risk reduction.
The values of the inlet temperature (40 ° C, 65 ° C and 80 ° C) and inlet pressure (140 bar,
180 bar and 200 bar) were carefully chosen to meet criteria of pipeline transportation in
supercritical state and its injection into the reservoir in liquid state. Simulation results showed
that for the fluid phase preservation, a sufficient supply is needed because, due to the pipeline
lenght, the heat transfer coefficient significantly influences the change in phase equilibria.
Preservation of supercritical fluid flow requires huge energy demand for heating, putting into
question project's viability. In order to maintain fluid temperature through the selected
pipeline system, mass flow should be greater than 20 000 kg/ h. Regarding power
consumption, temperature of 40 ° C and pressure of 140 bar was selected as most suitable.
As depositional environment, structure and Neogene lithofacies in the Ivanić Field
completely fit into the geological history of Croatian Pannonian Basin System evolution or
into individual structures in that area, the model of CO2 injection and storage made in this
dissertation can be considered applicable throughout the whole area.