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Offshore petroleum exploration is busier than it has been for years, with projects planned from near the tip of the North Island down to the bottom of the South Island. By Neil Ritchie.
The giant vessel has been here for two of the most extensive oil and gas exploration programmes yet seen in this country – scheduled to drill at least four wells in the geological Taranaki Basin, followed by another two off Northland. However, things got off to an inauspicious start when, shortly after starting the Hoki-1 well for permit operator AWE and its partners, rig operator Maersk Drilling halted drilling to carry out repairs to the rig’s derrick. And what initially was a week-long repair job ended up taking three weeks. Minority permit partner New Zealand Oil & Gas says it was very disappointed repairs were not completed before the rig arrived in our waters, with Maersk, which carried out the repairs, retorting that it had intended doing the remedial work while the rig was in transit between the two countries but that weather conditions had prevented this. There were also rumours of the rig having passed several inspections and gaining several acceptance documents before leaving Australian waters, despite there being some sub-standard welding, missing welds and some rusty and cracked steel beams on the derrick needing attention. Maersk flew in a team of specialist technicians, essentially offshore abseilers, to ensure the necessary remedial work was completed as quickly and efficiently as possible. The Kan Tan IV – built in 1983 and currently owned by Chinese company Sinopec – has now earned the nickname “Tin Can IV” among some Australian and New Zealand offshore workers. The ageing rig has a history of past problems that have included difficulties while working for Canadian Superior Energy in the waters off Trinidad – the most recent job before it arrived in Australia late last year. There were also several tens of millions of dollars spent at Port Geelong where the rig’s aft crane and crane boom were damaged while preparing for its Bass Strait programme. Drilling of Hoki-1 – the country’s most isolated well yet drilled, about 135 kilometres west of New Plymouth on the continental shelf – restarted just after Easter, but the well was plugged and abandoned two weeks later, after failing to find any hydrocarbons. Well operator AWE believed the Hoki prospect – the first well in its current New Zealand campaign – had the potential to contain up to 250 million barrels of oil. The Kan Tan’s next wells are scheduled to be two near field appraisal wells close to the commercial Tui Area oil fields – Tui South West-1 then Kahu-1 – that have the potential to replicate the original Tui, Amokura and Pateke wells, which discovered just over 50 million barrels of recoverable oil. The last scheduled well of the AWE-coordinated campaign, Tuatara-1 near D’Urville Island in the Marlborough Sounds, is targeting up to 100 million barrels of oil from the Moki formation, the same sandstones from which the more northern Maari oil field flows. However, there are rumours the Tuatara well will not be drilled if AWE, which presently holds 100 percent equity in the permit, cannot find partners to take some stakes and share some of the risk of drilling in that sparsely explored region. After its Taranaki campaign, the rig is scheduled to head north to drill two wells, Korimako-1 and Tarapunga-1, in another sparsely explored region, the offshore Northland Basin for Australian company Origin Energy, which operates the Kupe field and numerous small onshore Taranaki fields. These Kan Tan IV campaigns have the potential to discover hundreds of millions of barrels of the so-called black gold or trillions of cubic feet of less valuable, but still nationally important, natural gas that would lift New Zealand to a new level of energy self-sufficiency and propel petroleum exports back to being one of the country’s top three foreign exchange earners. There is also the recently approved “repeat” of last year’s successful $60 million Maui B workover programme aimed at boosting recoverable reserves by “re-completing” existing wells and drilling sidetrack wells to access previously bypassed pockets of oil or gas. The same sort of programme is now being done at the more northern Maui A platform, with United States group Cudd Energy Services carrying out hydraulic workovers using a specially modified rig to enhance production and/or restore the mechanical integrity of wells. As well, the seismic vessel Reflect Resolution, owned by Singapore-headquartered company Reflect Geophysical, recently finished an extensive seismic acquisition programme over several frontier geological basins for the Government’s Crown Minerals Group. The vessel acquired several thousands of kilometres of two-dimensional (2D) data over the Pegasus Basin, to the southeast of Wellington, the Great South Basin and nearby Bounty Trough, to the southeast of the South Island. It also acquired some “reconnaissance”, less detailed, data over parts of the Challenger Plateau and Bellona Trough areas, east of the South Island, the Outer Taranaki Basin and Northland East Slope Basin. Some private explorers are also using the seismic vessel Reflect Resolution, including Todd Energy and its Australian partners Horizon Oil and Cue Energy Resources to acquire about 200 square kilometres of 3D data over the Matariki prospect to the south and west of the Maari oil field. There are also rumours United States company Global Resource Holdings and its partners may use the vessel to shoot some more seismic over their deepwater Taranaki licence before the ship leaves New Zealand waters. A final indicator of the good state of the offshore exploration sector is the entry into New Zealand of United States major Anadarko, which has taken two 50 percent stakes in two large licences off Canterbury and Otago from Origin Energy. Last February the US company, with proven deepwater exploration experience, bought a 50 percent stake in a licence containing the Carrack-Caravel structure, the most promising prospects yet identified by Origin in the area. Anadarko is funding the first US$30 million of the cost of drilling an exploration well that is likely to be drilled in the licence during 2011. Then, in early April, it also took a 50 percent stake in an adjacent deeper water licence immediately to the east for US$100,000. Investment banker and broker McDouall Stuart Securities believes the arrival of Anadarko signals significant optimism for the petroleum potential of the country’s frontier basins. Anadarko, one of the largest independent oil companies in the world, “clearly likes what it sees,” says McDouall Stuart in a recent report. And it adds that the pro-resource development stance of the National-led government is contributing to the upswing in exploration effort. “The Government’s laying out of the welcome mat since coming into office will certainly not have hurt Anadarko’s deliberations, and could actually have been the deciding factor to a ‘yes’ rather than ‘no’ decision.”
Energy NZ Vol.4 No.3 May-June 2010 |
Offshore Taranaki is busy over the autumn and winter of 2010, with the multi-well campaign of the semi-submersible rig Kan Tan IV, which arrived from Bass Strait, Australia, in early March, attracting most attention.