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Overall the fracture intensity in the drill core can be divided into; (i) an upper section of low frequency, (ii) the fault
zone of smectite rich fault rock (showing swelling) and surrounding damage zone of very high to high frequency, and
(iii) the section below the fault zone with moderate frequency. For the section of Dh4 that was imaged with teleview-
er, there seems to be a moderate fit with the fractures recorded in the cores. The overall analysis suggests that frac-
turing is controlled by lithology, with more fractures in shale compared to sandstone.
General water inflow and plug and miniperm analysis of drill core suggest that there are three aquifers in the study
area;
Upper aquifer: This unit is at 160 - 200 m depth (deeper to the west due to very gentle westerly dip of unit), consistent
with the sandy parts of the Helvetiafjellet Formation. Permeability data varies but are generally low for this unit, sug-
gesting that the rather high inflow of water in the wells is partly controlled by fractures. The aquifer seems regional,
and especially for Dh3 and Dh4 give artesian inflow of water (up to 60 l/min).
Middle aquifer: In Dh1 and Dh2 this aquifer makes up parts of the section from 350 to 400 m TD, i.e. within the Rurik-
fjellet Formation. This succession has some permeability. This unit represents a local debris flow deposit in the west,
which cannot be found in Dh4. There, in the east, the same interval consists of shale.
Lower aquifers/reservoirs: Both Dh2 and Dh4 drilled down into the targeted reservoir of the upper Triassic Kapp To-
scana Group (Wilhelmøya Subgroup and De Geerdalen Formation). In Dh2 this section starts at 732 m, in Dh4 at 667
m. Sedimentary facies correlations and encountered poro-perm data suggest that this unit has regional characteris-
tics and properties. However, in detail there are clearly large variations internally with variable degrees of digenesis
(Magnabusco et al. 2014).
During drilling, a water injection test was conducted on 770-870 m section. Subsequently, after completion of Dh4,
the lower 100 m (870-970 m) were left open for testing. Several water injection tests were conducted on the interval.
Evaluation of these datasets gives the following results:
There is -4 bar at the surface or 82 bar at 870 m depth.
• Fracture closure pressure is (at the surface) around 9 – 11 bars. This is equal to a pressure of 95-97 bars at 870 m
depth.
• The matrix injectivity is 0.6 -0.7 m3 / bar per day for the section 770 m - 870 m. In the deeper section (870-970 m),
a similar number is higher, but is dropping during testing, and could not conclusively be decided.
• Cement shoes of the NQ-rod at 770m (applied during test 1) and the BQ-rod at 870m (applied during test 2) are
sealing during all tests.
• The water level in the well drops after each test and each test period. This suggests either a low reservoir pres-
sure, and/or a reservoir that is isolated from its surroundings.
Except from technical drilling challenges, there were no HSE issues related to the project activity of Phase 1 (2007-
2009). It was therefore concluded that the planned high HSE standards had been kept. On the financial side, the pro-
ject during Phase 1 benefitted from increased funds from the partners as resources were running low due to drilling
challenges and, consequently, as new tasks were undertaken, for instance the well testing (not initially planned for
Phase 1). There was significant public outreach and exposure of the partners throughout these first three years.
The following key points can be extracted from the datasets of the Longyearbyen CO2 Lab now the Phase 2 project
has been finalized:
•
The identified stacked reservoirs at 670-970 m in the subsurface in Adventdalen, have been further tested.
•
Tests verify Injectivity.
•
LOT’s verifies a well-sealing caprock and further analyses of the data suggest burst pressure of around 120
bars at 655 m depth, some 15 m above the uppermost reservoir.
•
A basic reservoir model has been completed, and subsequently used as a basis for volumetric calculations
and some first, pilot-type simulations with a focus on history-match of well tests.
•
The first generation storage volume has been estimated, with uncertainties related to quality of the
stacked reservoirs, including sizes of each unit and location of lateral flow baffles/seals.
•
Flow of gas into wells from the upper part of the reservoir (less likely) or lower part of the caprock black pa
per shales (more likely).
In October 2013 the project made an application for permission to store a limited amount of CO2 (up to 100.000 tons)
in the subsurface near Longyearbyen, Svalbard. The application was submitted to the Governor and local authorities.
In parallel, application for future allocation of land (Delplan) for research purposes (incl. CO2 site and infrastructure)
in Adventdalen was submitted for evaluation by the local authorities. This was granted in May 2015,
The application around injection of CO2 is still under evaluation by Miljødirektoratet. The application had however
to be revised, as there was a request for more particular descriptions around the source for CO2 and the risk during
operation. To substantiate the application, the following assessments summarized in reports have been undertaken:
•
A HAZID report for storing CO2 in Svalbard has been prepared by DNV GL,
•
The application for further development / new project “Improved delineation of an unconventional reservoir
in Adventdalen for future CO2 injection tests. “De-risking and monitoring campaign 2014-2015” has been ap
proved by Climit/Gassnova with the project no. 238758.
As the exploration phase has come to an end, and especially as there is inflow of gas in several wells, plugging of wells
has become a major activity. The current (anno June 2015) status of the wells is:
•
Dh1, Dh2, Dh6 and Dh7 have been permanent plug according to standards of the P&A program.
•
DH4 was left open in 2014 for further injectivity tests, but it is temporary plugged. Permanent P&A is sched
uled for 2015.
•
DH5R was plugged but verification of the plug was insufficient. Accordingly, the well remains temporary
plugged for further evaluation in 2015
•
Dh3 (403 m deep) remains open as it hosts a geophone string. The well has the status of a shallow monitor
ing well, with a 120 m high ice plug towards the surface.
•
Dh8 (61 m deep) is plugged with ice, as this well cored the unconsolidated but frozen overburden and did not
enter solid bedrock.
Summary phase 1 continued
3. Status anno January 2015
Phase 2
The Phase 2 project was designed to further verify caprock integrity and injectivity versus available volume in the
stacked reservoir succession. In order to reach the goals, wells Dh 5, Dh6, Dh7 and Dh8 were drilled. In parallel, exten-
sive well testing added data.