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Understanding oil and gas wells notifications


OG status:
Fully open
Author unit / section:
Target audience:
OSD Wells Inspectors and well’s administrative support staff, other HID Inspectors dealing with notifications
Version No:


To brief wells inspectors and administrative support staff of the line to take on queries about well notifications and about common misunderstandings about notifications on the part of industry. In particular it addresses:

This SPC replaces SPC/Enforcement/164 which has been withdrawn.


It is becoming increasingly common for operators, having notified HSE of a well operation, to subsequently request when they can expect to receive approval for the notification. This stems from a failure to appreciate that well notifications are not part of a consent process.
Well operators are sometimes uncertain as to which well operations must be notified to HSE. This applies in particular to well servicing operations from fixed installation which, prior to the 2005 Safety Case Regulations, did not need to be notified.

Well operators are uncertain about which changes to a notified well activity should be covered by notifying HSE of a material change and which require an entirely new notification.

Differences between a notification and consent

Some operators seem not to appreciate that well notifications are not part of a consent process, such as is used by the majority of offshore regulators worldwide. Prior to the coming into force, in June 1996, of regulation 11 of the 1992 Safety Case Regulations, a wells consent regime was operated by HSE using the conditions under which petroleum licenses are issued. Up to 30th June 1996 the operators of petroleum licenses were required to seek consent in writing for any drilling, completion work or abandonment of a well. Applications for consent were required to be submitted 28 days in advance.
Since 1st July 1996, with some additions under the 2005 Safety Case Regulations, HSE has required notification of specified well operations, either 21 days or 10 days in advance, depending on the nature of the operation.
The purpose of the notification is to inform HSE of the forthcoming operation and demonstrate that the planned operation will be carried out safely. It should contain sufficient information for the inspector reviewing the notification to understand the nature of the operation and satisfy them that the risks to health and safety specific to the well have been identified and suitable precautions are being implemented.

HSE does not form part of the decision making process for the operation. That is the role of the well operator, the drilling and other contractors and the well examiner appointed by the well operator.

Key differences between a consent application and a notification

Consent Notification
Written consent was required before operations could commence. Absence of enforcement action against a notified operation is not implied consent to the operation. The well operator is responsible for the safety of the operations and ensuring that risks to the health and safety of persons are reduced to as reasonably practicable. Operations should not proceed unless it is safe to do so.
Operations could commence on receipt of written consent. No consent is issued. Operations may legally commence after the notification period, unless HSE has taken enforcement action to prevent them. However operations should not proceed unless it is safe to do so.
Operations could commence within the 28 day period provided operator was in receipt of written consent. Operations may not commence within the 10 or 21 day notification period unless HSE has formally agreed to a shortening of the notification period.

Line to take

Well operators will not receive consent from HSE to commence notified well operations. For a satisfactory submission well operators will receive only acknowledgement by HSE of receipt of the notification. They may commence operations after the notification period has passed, provided it is safe to do so. Well operators are responsible for the safety of the well.

Identifying which well operations must be notified

Requirements of regulations - Offshore

Offshore Installations (Safety Case) Regulations 2005 (SCR 05)
Regulation 17

Other than from production installations

(1) “Subject to paragraph (2) a well operator shall ensure that no well operation is commenced unless he has sent a notification containing the particulars specified in Schedule 6 to the Executive at least 21 days (or such shorter period as the Executive may specify) before commencing that operation.
HSE must be notified of all well operations, as defined in regulation 2 of SCR 05, carried out from a non-production installation. Notification is also required for any well operation carried out from a vessel not classified as an offshore installation. In all cases the notification must be sent to HSE at least 21 days before operations commence.

Some operations are conducted from a mobile installation in combination with a production platform. Where a jack-up rig is working through a wellhead jacket, and the well being worked on is in the control of the jack-up, then the operation is deemed to be from a non-production installation and all well operations must be notified. On the other hand, where operations are conducted from a production installation, with a mobile rig providing some of the drilling or well servicing facilities (i.e. tender-assist), then operations are deemed to be from the production installation and regulation 17(2) applies.

From production installations

(2) In the case of a production installation a well operator shall ensure that:

  1. no well operation which involves
    • insertion of a hollow pipe in the well; or
    • altering the construction of the well
  2. no well operation which involves drilling is commenced unless he has sent a notification containing the particulars specified in Schedule 6 to the Executive at least 21 days (or such shorter period as the Executive may specify) before commencing that operation.

All drilling operations conducted from a production installation must be notified in the same manner as all well operations from other installations or vessels, i.e. 21 days in advance. Drilling covers those well operations where hole is cut in subsurface formations.
Other well operations from a production installation, that do not include drilling, must be notified 10 days in advance. Operations for which HSE must be notified must include running or recovering drill-pipe, tubing, casing or coiled tubing through the wellhead or those operations involving alteration of the construction of the well.

Wire-line and other operations requiring notification are:

Notification is not required for some wire-line and other operations. Wire-line operations not deemed requiring include:

Requirement of regulations - Onshore

Borehole Sites and Operations Regulations 1995 (BSOR)
Regulation 6

(1)  In the case of petroleum, the operator of a borehole site shall ensure that no drilling operation, abandonment operation or other operation on a well which would make a significant alteration to it, or involve a risk of the accidental release of fluids from the well or reservoir, is commence at that site unless he has notified to the Executive the particulars specified in Part I of Schedule 1 at least 21 days in advance, or such shorter time in advance, as the Executive may agree.

This regulation applies to all wells drilled on land in Great Britain to prospect for or extract oil, gas or coal bed methane. Notification, 21 days in advance, is required:

The latter category should include running any tools into the well, including on wire-line, if the well is a naturally flowing gas well or has significant shut-in tubing head pressure.

For other wells the following operations are considered as not requiring notification

Line to take

In response to requests for advice on which well operations must be notified to HSE, refer to the above lists. If still in doubt, it should be assumed that notification is required.

Material change to notification of well operations

Requirements of regulations


SCR 17 (3)
“Where there is a material change in any of the particulars notified pursuant to paragraph (1) prior to completion of the relevant well operation, the well operator shall notify the Executive of that change as soon as practicable.”


BSOR 6 (5)
“The operator of a borehole site…..shall ensure that the Executive is notified as soon as is reasonably practicable of any material change of circumstances which would affect particulars previously notified under paragraph (1)……”

Change of rig

A change in the rig to be used will constitute a material change. If at the time of the notification it is uncertain which rig is to be used, it is recommended that details of all likely rigs, as listed in the appropriate schedule to the regulations, are included. If this is done, the notification of material change needs only to identify the rig.

Drilling to a new target location

Changes in target, including side-track, can be accepted as a material change, rather than a new notification, where the change is due to unexpected geological conditions or mechanical difficulties in the well, but the geological objective of the well remains the same.
Sidetracks to a new target with a different geological objective will require a new notification unless sufficient details of the proposed sidetrack have been included in the original notification.

Where the operator plans to sidetrack for a new geological objective from a current well and the sidetrack has not been included in the original notification, it may be appropriate for HSE to agree to a shortening of the notification period. SCR 17 (1) and BSOR 6 (1) specifically allow for this. HSE internal procedures must be followed before any shortening of the notification period is agreed.

Major changes

Where changes to a notified operation are of such a magnitude, or alter the risk profile to such an extent, that they require what is effectively a re-write of the drilling or work-over programme, then a new notification is required. An example of this is where a decision is made to change from conventional drilling to managed pressure or under-balanced drilling

Validity of old notifications

There is no time limit on notifications and they do not lapse after a preset time. It is recognised, however, that for many old notifications where the operations have not commenced they may have been dropped from well operators’ work programmes or the information in the notifications may have changed significantly.

For notifications of more than twelve months old, the well operator should be asked if the work is still planned and, if so, should be requested to inform HSE, in writing, before the work commences, advising of the planned start date and confirming that there are no material changes to the original notification. If there are material changes to the original notification HSE must be notified as required by regulation 17(3) of SCR 2005 or regulation 6(5) of BSOR.

Further information

For further information, please contact the Head of Discipline – Well Engineering & Operations OSD 2.4 (01224 252581)

Updated 2010-06-21