Intermittent flaring from the Ocean Bounty semi-submersible rig started at the weekend and then progressed to a full 36-hour program, which is scheduled to finish either late tonight or early Wednesday.
Operations during the past week have included reaching the 3760m target depth along hole in the Mangahewa reservoir, which is part of the Eocene-aged Kapuni group of sands prevalent through much of the Taranaki Basin. Wireline logs were completed and the well perforated for production testing.
STOS expects to complete the well, which is designed to test the northern extent of the possible 1tcf gas field, later this week.
Pohokura project manager Phil Moore has so far declined to detail intervals or flow rates, though STOS may release further information late this week or early next week.
Gas flows of up to 30.7 million cubic feet a day were achieved during testing two years ago of the last offshore well, Pohokura-2, though those rates were limited by the capacity of the test equipment aboard the Ensco 50 jack-up rig. Then-operator Fletcher Challenge Energy believed the absolute open flow potential of that well to be 5-10 times greater.
Meanwhile, the Parker Drilling 188 rig is making slower progress from its onshore Motunui well site in drilling the deviated Pohokura South-1B well. The well still has about 800m to go before reaching its along-hole target depth of 5447m. Scheduled activities include taking a 30m-long core in the Turi sands, before drilling to a second coring point and taking another sample. Pohokura South-1B is to help define the southern extent of the field and will extend about 2.6 km off the coast in a northwesterly direction.
Pohokura will still be New Zealand's second largest gas resource after the faltering Maui field, even if recent rumours of a significant reserves downgrading - from 1tcf-plus to only 600 bcf or so - prove true. The field is expected to last 10-20 years, with production coming onstream from 2005, at production rates varying from 60bcf-120bcf per annum from up to three mini-platforms in each of the near-shore, middle and northern limits of the field.