50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...

and on the following morning the miners arrived at
work to find the debris moving. Just after they
retreated down the road, the debris dam failed and
the resulting debris flow destroyed the road end and
access to the mine.
What went wrong? The Strongman #2mineisin
rugged terrain with coal outcropping against an
escarpment. The licence conditions required a
reasonable range of environmental protections.
Mining best practice and the mine plan and called
for an outcrop barrier, however, the mine plan also
called for high extraction under shallow cover.
Problems soon occurred with surface subsidence
developing from early 1996. Extensive extraction
of the outcrop barrier was also initiated in 1996.
This lead to the collapse of the escarpment and the
generation of debris flows in Doherty Creek. These
debris flows ultimately destroyed access to mines
operating in the area. The ongoing instability
precluded restoration of access as the safety of
workers could not be guaranteed nor was it possible
to design a new cost effective means of access that
would survive any future debris flows from the
degraded catchment.
The court cases that arose out of the debris flow
damage have now all been settled but the
subsidence, escarpment damage and associated
mine fires at Strongman Mine is having an ongoing
environmental impact. Just as important is the
damage done to the reputation of coal mining on
the Coast, and of the mining industry as a whole as
a socially and environmentally aware industry.
The consequence has been for a far greater level of
scrutiny of other mining projects such as Pike
River. To some extent this degree of scrutiny is
beneficial because it can be too easy for mine
developers to “accentuate the positive” and
minimise the potential downsides. Industry
acceptance of the rigorous examination of the
issues by independent analysts may help to offset
the concerns of those currently concerned at the
impact of mining in NZ.
POSTER
A LONG TIME COMING: WILL NIAGARA 1
BE THE SOUTH ISLAND’S FIRST
COMMERCIAL OIL WELL?
Murry Cave 1 & Selwyn Love 2
1 Resource Solutions
Western Exploration Ltd & Resource Solutions, PO
Box 3523, Wellington
2 Ocean Harvest
(cavem*paradise.net.nz)
Niagara 1 is located in the Aratika Forest, between
Lake Brunner and Greymouth on the West Coast of
the South Island. The well was drilled by New
Zealand Oil and Gas in 1985 as a test production
well using the Rockdrill 20 rig. The well was a
limited success in that hydrocarbons were
discovered and some oil was recovered to surface
during testing. The well was subsequently
suspended pending a re-entry and a new well was
drilled to test the projected up-dip extension to the
play. The updip well, Niagara 2 was poorly located
and thus not a success and NZOG subsequently
surrendered the permit.
Ocean Harvest obtained the permit in late 2000 and
undertook a review of the potential for Niagara 1.
The existing data was reviewed by Western
Exploration who concluded that the poor
production performance of the well was most likely
due to formation damage resulting from drilling
with an excessively overbalanced mud over the
production zones. M Pearson (Pers comm) of
Kappa SEA reviewed and re-interpreted and
available test production data in 2002 and
confirmed the formation damage assessment. The
kappa assessment also considered 40 bbl/day to be
a realistic production target.
Since 2002, Western Exploration and Ocean
Harvest have been exploring cost effective
solutions for undertaking a re-entry of the well.
Because of uncertainty over the potential of the
well, mobilisation of a full-scale oil rig could not be
justified because of the impact this would have on
project economics. Alternatives such as the Failing
DMX used to undertake the P&A of Blenheim 1
were explored but lack of trained crew precluded
that option. Eventually a suitable rig was obtained
and crew trained to undertake the re-entry in 2005.
The re-entry was more successful than anticipated
with oil and gas flows to the surface immediately
after the bridge plug had been drilled through and
additional flows once the main production zone was
reached. A post re-entry review suggested that the
40 bbl/day production target is a minima and
production of up to 80 bbl/day plus enough gas for
small scale on site power generation is possible.
The design of the Niagara 1 well impacts on the
development programme. In particular the 5”
production casing and the barefoot completion
below the casing shoe constrains our ability to
install suitable artificial lift equipment. A
production design has been formulated and is
presently being tested. In addition, existing seismic
will be reprocessed and additional seismic
acquisition is planned. Depending on the results a
new well may be drilled to intersect the producing
formation within the fault bound Niagara structure.
ORAL
50 th Kaikoura05 -15- Kaikoura 2005