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Below: A diagram of wells DH4 through to DH7a - this diagram shows the depth of the well and the research oper-
ation preformed at a given date.

Well operation description

6)  Well operations 2010-2014

As mentioned and summarized in the table above, two boreholes (Dh1 and Dh2) are located to the west of Longyear-
byen, while the remaining wells (Dh3-Dh8) are clustered around the well park in Adventdalen to the east of Longyear-
byen. Four of the boreholes (Dh2, Dh4, Dh5 and Dh7) penetrated the top of the reservoir at c. 670-730 m, and fully 
cored the entire Knorringfjellet Formation, the most promising reservoir interval. The deepest borehole, Dh4, was 
drilled to 972 m and cored the majority of the entire target interval comprising also the De Geerdalen Formation. 
Wireline logging (e.g. Gamma Ray, Resistivity, Sonic, Temperature; Elvebakk, 2010) has been conducted at selected 
intervals in some boreholes. The televiewer log, collected across the upper part of the reservoir, was particularly 
important for mapping borehole fractures (Ogata et al., 2012, 2014). Due to the relative proximity of the boreholes 
within the ‘UNIS CO2 well park’ there is potential for splicing and combining many of the wireline logs between the 

individual wells.

When it comes to water injection tests in the wells, a comprehensive program has been undertaken, as shown in the 
table opposite. Both leak-off tests and step-rate tests have been undertaken. A typical LOT targets tight rocks like 
caprock shales. This test records injection pressure vs. time, with key observations being the drop in pressure seen 
by breakdown/fracturing of the tested formation, allowing calculation of the rock strength.  A step-rate injection 
test pump constant amounts of water for given time intervals, with a step-wise increase in flow rate. In the end, the 
pump is stopped and the well shut in to record a fall-off curve back to reservoir pressure. This curve can be used to 
predict the formation permeability. This test is normally used to estimate the transition from matrix (or radial) flow 
to fracture-dominated, more linear flow in rocks of some permeability such as reservoirs. 

These tests are summarized and concluded in Bahman et al. (2014) and in UNIS CO2 Lab reports of Larsen (2010 to 

2014).

Well operations

     

2009 - 2014