ECA business development vice president Denny McGowan told PetroleumNews.net that Waitahora-1 was drilled to a depth of 1352m and the well encountered very high reservoir pressure in reservoir-quality rocks over a 70m interval from 1180-1250m measured depth.
“The unusually high reservoir pressure encountered, about 3500psi, in this well allows for potentially significant gas reserves at very shallow depths,” McGowan said.
Numerous conventional cores were taken from the prospective intervals and these were being integrated with downhole electric logs and pressure data to develop a testing plan.
Waitahora-1 is a direct offset to the Kauhauroa-1 wildcat well that in the late 1990s, on an extended production flow test, gauged over 11 million standard cubic feet per day (MMscfd) of gas and over 70MMscfd during open-flow testing.
Denver-based ECA, which operates as Westech Energy in New Zealand, used the Ensign International Energy Services Rig 19 to drill the shallow well near the town of Wairoa in licence PEP 38346, which it acquired last July.
McGowan said working in highly pressured operational environments was nothing new for ECA, which had recently announced the results of the deepest and highest temperature Lower Wilcox Meek horizontal well drilled in onshore Texas.
The Foster Farms Deep-1 horizontal well was completed at a total measured depth of 5630m (total vertical depth 4815m) and, after fraccing, initial production was about 7.5MMscfd of gas and 200 barrels per day of condensate, with a flowing tubing pressure of over 8500psi.
McGowan said this Texas project, using leading edge technology to drill deep wells, also had relevance to Westech’s New Zealand operations.
The company drilled six exploration wells and five appraisal wells in the onshore East Coast Basin in the late 1990s.
All wells encountered significant gas shows, with two, Kauhauroa-1 and Tuhara-1, discovering hydrocarbons in potentially commercial volumes. Kauhauroa-1 flowed from the Kauhauroa limestones, an early Miocene-aged reservoir.
Westech has said it believed there were several significant East Coast accumulations, totalling several billion cubic feet or larger, that could be developed economically.
