UK-based oil and gas exploration company Deltic Energy, together with Shell UK, has announced a significant gas and oil discovery on Licence P2252 in the Southern North Sea.

The discovery was made with well 41/05a-2 in the Pensacola prospect, northwest of Breagh gas field in the Zechstein Reef play fairway, which is operated by Shell UK.

The well reached a total depth of 1,965m true vertical depth subsea (TVDSS).

Wireline logs confirmed the presence of mobile gas and oil in the primary Zechstein Hauptdolomite carbonate target interval.

The well encountered the top Hauptdolomite reservoir at 1,745m TVDSS and a confirmed reservoir thickness of 18.8m with superior porosity averaging 16%.

It penetrated the edge of the Pensacola structure in a down dip location as planned, and has proven a substantial hydrocarbon column, said Deltic.

Deltic Energy chief executive Graham Swindells said: “Deltic’s first exploration well at Pensacola has resulted in a highly positive outcome and, at approximately 300 BCF, would represent one of the largest natural gas discoveries in the Southern North Sea in over a decade.

“This discovery is a major milestone in the development of our Company as we continue to execute our exploration led strategy and progress our portfolio of high-quality drilling opportunities as we seek to create value for our shareholders.

“We believe that the Pensacola discovery will open a new Zechstein play in this mature basin and highlights the remaining potential of the North Sea as a source of further discoveries which can provide domestically produced natural gas.”

After acidisation, the new discovery produced at a rate of nearly 4.75mmscf/day of gas at peak, declining to 1.75mmscf/day after the 12 hours of the test.

It also produced light oil with a preliminary gravity of 34-36° API, at a rate of nearly 18bbls/day during the well test.

Deltic said that the results are in-line with pre-test expectations based on the reservoir parameters derived from the well.

The flow rates observed during the well test are not expected to be representative of flow rates of potential future production wells, as they are located down dip.

The future production wells would target the central part of the Pensacola structure and are expected to generate higher rates of gas flow, according to the company.

Building on the drilling and testing data, Deltic has updated its volumetric models and estimates the Pensacola discovery to contain P50 EUR of 302 BCF.

Upon completion of the well test programme, the well is planned to be plugged and abandoned, and the Noble Resilient will be de-mobilised from site, said Deltic.