Knowledge Centre
Drilling
Before drilling
When it has been established through seismic surveys that a part of the seabed is likely to contain oil and gas, the process of exploration and appraisal begins.
Each well proposed by a company must be submitted to DECC using a Petroleum Operating Notice (PON4) via the well operations and notification system (WONS). Applications to drill wells are considered with the licence obligations in mind, including any possible impacts on third parties (e.g. fishermen) and upon the environment under the Offshore Petroelum Production and Pipeline (Assessment of Environmental Effects) Regulations 1999.
A full environmental statement may be necessary depending on the location, size and estimated impact of the proposed well. To find out more about the well consents process, click here.
Drilling a well
Comprehensive information on the physical process of drilling is available here.
Suspending a well
In the same way as submitting an application for consent to drill a well, operators must also follow a procedure for suspending wells. The intention to suspend a well should be declared by fax to DECC soon after the result of drilling is known. A summary of the well information which states the rationale for suspension must be sent alongside the application via WONS.
Suspended wells must be listed by annual return to the well consents team, accompanied by the reason for continued suspension. If a licence expires or is divested, and the area contains a suspended well, then the licensee requires the agreement of the Secretary of State that the well is in ‘good order and fit for further working again with all casings and any well head fixtures whose removal would cause damage to the well’. This does not apply to wells for which consent has been obtained to plug and seal.
Abandoning a well
If an operator wishes to abandon a well, the same process as suspension should be followed. The well consents team do not require details of the plugging method or condition of the well but the licence operator must comply with sections 13 and 15 of the Offshore Installations and Wells (Design and Construction etc.) Regulations 1996.
Appraisal
When promising amounts of oil and gas are found in an exploratory well, a programme of detailed field appraisal may begin. Comprehensive information on the appraisal process is available here.
Data
DEAL, a web-based service, aims to provide a full national catalogue of UKCS geoscience data, pointing users to the source of data of interest.
Drilling data by quarter and basin of the UKCS is available here.
A list of significant discoveries can be found here.
