50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
50thKaikoura05 -1- Kaikoura 2005 CHARACTERISATION OF NEW ...
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and on the following morning the miners arrived at<br />
work to find the debris moving. Just after they<br />
retreated down the road, the debris dam failed and<br />
the resulting debris flow destroyed the road end and<br />
access to the mine.<br />
What went wrong? The Strongman #2mineisin<br />
rugged terrain with coal outcropping against an<br />
escarpment. The licence conditions required a<br />
reasonable range of environmental protections.<br />
Mining best practice and the mine plan and called<br />
for an outcrop barrier, however, the mine plan also<br />
called for high extraction under shallow cover.<br />
Problems soon occurred with surface subsidence<br />
developing from early 1996. Extensive extraction<br />
of the outcrop barrier was also initiated in 1996.<br />
This lead to the collapse of the escarpment and the<br />
generation of debris flows in Doherty Creek. These<br />
debris flows ultimately destroyed access to mines<br />
operating in the area. The ongoing instability<br />
precluded restoration of access as the safety of<br />
workers could not be guaranteed nor was it possible<br />
to design a new cost effective means of access that<br />
would survive any future debris flows from the<br />
degraded catchment.<br />
The court cases that arose out of the debris flow<br />
damage have now all been settled but the<br />
subsidence, escarpment damage and associated<br />
mine fires at Strongman Mine is having an ongoing<br />
environmental impact. Just as important is the<br />
damage done to the reputation of coal mining on<br />
the Coast, and of the mining industry as a whole as<br />
a socially and environmentally aware industry.<br />
The consequence has been for a far greater level of<br />
scrutiny of other mining projects such as Pike<br />
River. To some extent this degree of scrutiny is<br />
beneficial because it can be too easy for mine<br />
developers to “accentuate the positive” and<br />
minimise the potential downsides. Industry<br />
acceptance of the rigorous examination of the<br />
issues by independent analysts may help to offset<br />
the concerns of those currently concerned at the<br />
impact of mining in NZ.<br />
POSTER<br />
A LONG TIME COMING: WILL NIAGARA 1<br />
BE THE SOUTH ISLAND’S FIRST<br />
COMMERCIAL OIL WELL?<br />
Murry Cave 1 & Selwyn Love 2<br />
1 Resource Solutions<br />
Western Exploration Ltd & Resource Solutions, PO<br />
Box 3523, Wellington<br />
2 Ocean Harvest<br />
(cavem*paradise.net.nz)<br />
Niagara 1 is located in the Aratika Forest, between<br />
Lake Brunner and Greymouth on the West Coast of<br />
the South Island. The well was drilled by New<br />
Zealand Oil and Gas in 1985 as a test production<br />
well using the Rockdrill 20 rig. The well was a<br />
limited success in that hydrocarbons were<br />
discovered and some oil was recovered to surface<br />
during testing. The well was subsequently<br />
suspended pending a re-entry and a new well was<br />
drilled to test the projected up-dip extension to the<br />
play. The updip well, Niagara 2 was poorly located<br />
and thus not a success and NZOG subsequently<br />
surrendered the permit.<br />
Ocean Harvest obtained the permit in late 2000 and<br />
undertook a review of the potential for Niagara 1.<br />
The existing data was reviewed by Western<br />
Exploration who concluded that the poor<br />
production performance of the well was most likely<br />
due to formation damage resulting from drilling<br />
with an excessively overbalanced mud over the<br />
production zones. M Pearson (Pers comm) of<br />
Kappa SEA reviewed and re-interpreted and<br />
available test production data in 2002 and<br />
confirmed the formation damage assessment. The<br />
kappa assessment also considered 40 bbl/day to be<br />
a realistic production target.<br />
Since 2002, Western Exploration and Ocean<br />
Harvest have been exploring cost effective<br />
solutions for undertaking a re-entry of the well.<br />
Because of uncertainty over the potential of the<br />
well, mobilisation of a full-scale oil rig could not be<br />
justified because of the impact this would have on<br />
project economics. Alternatives such as the Failing<br />
DMX used to undertake the P&A of Blenheim 1<br />
were explored but lack of trained crew precluded<br />
that option. Eventually a suitable rig was obtained<br />
and crew trained to undertake the re-entry in <strong>2005</strong>.<br />
The re-entry was more successful than anticipated<br />
with oil and gas flows to the surface immediately<br />
after the bridge plug had been drilled through and<br />
additional flows once the main production zone was<br />
reached. A post re-entry review suggested that the<br />
40 bbl/day production target is a minima and<br />
production of up to 80 bbl/day plus enough gas for<br />
small scale on site power generation is possible.<br />
The design of the Niagara 1 well impacts on the<br />
development programme. In particular the 5”<br />
production casing and the barefoot completion<br />
below the casing shoe constrains our ability to<br />
install suitable artificial lift equipment. A<br />
production design has been formulated and is<br />
presently being tested. In addition, existing seismic<br />
will be reprocessed and additional seismic<br />
acquisition is planned. Depending on the results a<br />
new well may be drilled to intersect the producing<br />
formation within the fault bound Niagara structure.<br />
ORAL<br />
50 th <strong>Kaikoura</strong>05 -15- <strong>Kaikoura</strong> <strong>2005</strong>