Seismic inversion studies uncover North Sea Forties satellite

Apache Corp. (NYSE:APA) has started producing the Tonto oil field in the UK central North Sea.

Seismic inversion processing
Seismic inversion processing

Offshore staff

HOUSTON – Apache Corp. (NYSE:APA) has started producing the Tonto oil field in the UK central North Sea.

Tonto-1 was drilled as a deviated well from theForties Bravo production platform. The appraisal wellbore encountered 62 ft (18.9 m) of net oil pay in an Eocene sandstone reservoir at a depth of 6,325 ft (1,928 m). This was followed by a horizontal completion lateral that logged 243 ft (74 m) of net oil pay. Currently, the well is flowing 10,346 b/d of oil.

“Seismic inversion processing unlocked pay in the Tonto field, which lies above the main Forties Paleocene reservoir,” said James L. House, Apache’s regional vice president for the North Sea.

“We penetrated Tonto several times in wells targeting Forties. New seismic techniques enabled Apache’s North Sea geoscience team to gain a better understanding of Tonto and establish a development plan.”

House added that a new 3D seismic survey will be acquired over Forties in July. Oil from Tonto produced ahead of the survey should allow the company’s geoscientists to image production patterns within the Eocene reservoir to optimize placement of future Tonto producers.

Apache plans to drill an additional development well by year-end following analysis of the 4D time lapse seismic data.
This is the third new oil field brought online by the company in the Forties area in the past three years, the others being Maule and Bacchus. All three developments qualified under the UK government’s small field allowance system.


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