Photo: Maersk Resilient rig; Source: Maersk Drilling

Serica upbeat over Columbus well results ahead of tie-in

Oil and gas company Serica Energy has achieved successful flow test results from the Columbus development well, located in the North Sea, and will now be working to tie it to the Arran field export system with a start-up expected in 4Q 2021.

Serica started drilling the Columbus well, using the Maersk Resilient jack-up rig, in mid-March 2021. The Columbus 23/16f-CDev1 development well is located 35km southwest of the Shearwater platform in the UK sector of the North Sea.

The drilling was supposed to last about 70 days. However, Serica encountered difficulties during drilling operations in late May. A 5,900ft horizontal section was drilled through the reservoir formations of the upper Forties and encountered a sequence of sands and shales.

The well required sand screens to be installed to prevent fine particles being produced, but difficulties were encountered while running the screens and it was ultimately not possible to install them.

As a result, the reservoir section of the well was side-tracked and re-drilled, using data collected during initial drilling to optimise its trajectory and avoid the difficulties encountered running the screens in the original well.

Due to these additional operations, the Columbus well took longer and cost more than expected, but it did not affect the timing of the first production.

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In an update on Tuesday, Serica said that the well was drilled to a measured depth of 17,600ft with a horizontal section of over a mile in length in the Forties Sandstone formation. The completion equipment has been successfully installed into the well and a flow test has now been performed.

A stabilised flow rate of 38.0mmscf/d of gas and 1,560bbls/d of condensate has been achieved through a 56/64ths inch choke. This rate was at the upper end of the pre-drill range of expected outcomes and was constrained by the surface well test equipment onboard the Maersk Resilient jack-up drilling rig.

Maersk Resilient jack-up rig; Source: Serica Energy
Maersk Resilient jack-up rig; Source: Serica Energy

A diving support vessel (DSV) will tie the subsea wellhead into the Arran field export system directly after the rig leaves the location. It is anticipated that Columbus start-up will occur in 4Q 2021 once the initial flow from the Arran field has reached stable conditions. Once it has been brought on stream it is anticipated that the Columbus well will produce at around 7,000boe/d (gross) of which at least 75 per cent is expected to be gas.

Columbus was discovered by Serica in 2006. Serica has a 50 per cent interest and has been the operator throughout the exploration, appraisal and field development stages and has developed the field with its partners Waldorf Production UK and Tailwind Energy.

Minimal subsea equipment has been installed to enable the tie-in of the Columbus well to adjacent infrastructure.

Mitch Flegg, Chief Executive of Serica Energy, commented: “We are delighted to have achieved the objectives of this challenging but ultimately very successful campaign”.

Flegg added: “Columbus is part of Serica’s ongoing capital investment programme which is aimed at boosting production in the second half of this year and beyond”.