Maui gasfield 'sidetracked' into lasting longer
New-age drilling techniques are extending the life of New Zealand’s veteran Maui gasfield.
Shell Todd Oil Services has invested more than $100 million to extend the life of the 33-year-old field and says it should last at least three more years, and possibly 10.
The potential is so good the company will use the same techniques at the even older Kapuni field, also just off the Taranaki coast.
STOS general manager Rob Jager says the challenge for oil and gas companies is to maximise the recovery from their fields, which can vary from 20% to 90%.
The company has modelled and tested the field, and believes much gas has been “bypassed” by existing extraction processes.
So it has set about drilling sideways from existing rigs to get the gas from pancake-like pockets, which may only be a few metres thick.
The technique, known as “sidetracking”, uses a drill pipe as small as 75-150mm in diameter, which can be “notoriously difficult to steer” as it extends out up to 4km from existing rigs.
Mr Jager says STOS uses a variety of modelling and testing techniques, which has helped increase the accuracy of the drilling and boosting the return on investment.
“We are continually looking at squeezing more from the reservoir. This has been the focus for the past five to 10 years. It’s morally inappropriate to leave it behind,” he told NBR ONLINE.
Mr Jager would not say how much the extra gas was worth, but the risk is paying off.
STOS is now drilling from the Maui B platform and next month it will drill from Maui A.
“We continue to look for these opportunities. If we are successful, it gives us more confidence about other opportunities,” he says.
Thus, the same recovery techniques will also be used at the nearby Kapuni field, which is more than 40 years old. Some $40 million will be spent there, with hydraulic fracking also being used in addition to horizontal drilling.
Elsewhere, STOS is drilling at the nearby Pohukura gasfield, also off the Taranaki coast – a new field at the start of its life.
The company is also spending “closer to $200 million” on developing the Great South Basin, a 5000sq km field to the south and east of Southland.
A 3D siesmic survey is being interpreted to determine whether or not the company should drill there. The waters are much deeper than off Taranaki, meaning different types of drilling rigs will be needed.
“It’s early days but from that we will make assessments of risks, volumes and costs and determine whether it is worth spending any more money. Before we start producing we need to spend quite a lot of money,” he says.
The project to extend the life of the Maui field won STOS the Energy Project of the Year Award at the Deloitte Energy Excellence Awards in Auckland this week.
A full list of winners can be seen here: