The oil exploration site in Surrey, nicknamed the “Gatwick Gusher”, breached health and safety laws last year, DrillOrDrop has learned.
The site was issued with a formal notification and ordered to pay a fee by the Health and Safety Executive (HSE).
An inspector had found problems with the set-up of a critical safety device designed to prevent the uncontrolled escape of well fluids or gases from deep underground to the surface.
The inspector recorded material breaches of the law against the site operator, a subsidiary of UK Oil & Gas (UKOG), and ordered the company to make changes.
UKOG told DrillOrDrop “all matters were quickly and satisfactorily closed out with HSE”.
But Brockham Oil Watch, the campaign group which uncovered the breaches, said they showed the importance of active monitoring by regulators.
The HSE reported the breaches after a site visit to Horse Hill in August 2018, during extended well tests.
Five months earlier, the Oil & Gas Authority had asked UKOG for evidence of the technical capability of the site operator, HHDL, to carry out the tests.
UKOG is currently applying for planning permission to drill four more oil wells at Horse Hill and carry out long-term production. The latest public consultation on the application ends on Monday 24 June 2018 and a decision is due in September.
The Horse Hill notification of contravention was included in correspondence between the HSE and UKOG. This was released in response to a freedom of information request by Brockham Oil Watch. The HSE does not routinely publish these notifications.
“Inadequate means to handle well control problems”
One of the breaches concerned the blowout preventer on the single existing well at Horse Hill.
Blowout preventers are pressure control systems that usually comprise a large valve at the top of the well. This can be closed immediately if a drilling crew mis-manages the density of drilling fluids in a borehole, and loses control of formation fluids.
The Deepwater Horizon oil disaster was caused by a wellhead blowout, and took several months to bring back into control. DrillOrDrop understands that the size of a blowout could be small in the Weald. But a so-called “Gusher” is a well where oil and gas come to the surface without being pumped, driven by pressure of gas separating out from the oil.
In a letter dated 6 September, the inspector wrote to HHDL:
“The configuration of the blowout preventers (BOP) does not provide adequate means to handle potential well control events as required by the current API standards 53.
“While it has means for closing and sealing the wellbore on the work string and on open hole, it does not have means for stripping in the work string.
“The arrangements you have in place for kick [well pressure control problems] detection during tripping and circulation operations cannot provide sufficient assurance for an effective detection of anomalies of well parameters.”
Well integrity test concerns
The inspector also raised concerns about a well integrity test, the checks designed to ensure a well is not leaking or that there are no uncontrolled releases.
The notification of contravention said:
“With reference to the well integrity test report …. there is no evidence to suggest that there have been checks on the pressure and the integrity of the wellhead voids.”
The notice also recorded that the well handover form/certificate did not “contain all the necessary information as recommended by the UK Oil and Gas Guidelines”. It continued:
“It does not contain the number of turns required to close and to open the manual gate valve, the status of the annulus gate valves and well head voids.”
Instructions and advice
The failures represented a material breach of the Offshore Installations and Wells (Design and Construction etc) Regulations 1996, the inspector wrote.
The site operator, Horse Hill Developments Ltd, was instructed to carry out a risk assessment of the configuration of the BOP and act on the results.
It was also ordered to ensure:
- Sufficient and effective arrangements to detect kicks
- Well handover certificate had all necessary information
- Integrity of wellhead voids were checked regularly as part of well integrity tests
The company was ordered to display the breach notification to staff and to pay a fee to cover the cost of the HSE visit.
It was also advised to revise:
- well planning design and operations standards to incorporate current industry standards and best practice
- a safety document to reflect rig-less well testing operations
- risk assessment and well shut in procedures to make them more specific to reflect arrangements and equipment
The inspector also noted there was a risk of corrosion from topping up the annuli (void spaces between the tubes running up or down the well) with fresh water. During production, injection and suspension the annuli should be filled with inhibited fluids, the inspector recommended.
The FOI response included correspondence from HHDL to the HSE in October 2018. In it, HHDL said it had carried out the risk assessment and was reviewing operations and procedures.
A separate FOI request revealed that in March 2018 the Oil & Gas Authority asked UKOG to respond to a series of questions about HHDL’s ability to carry out the extended well test. They included HHDL’s in-house technical capability, its corporate and governance structure, arrangements to respond to unexpected events and financial capacity.
Company comment: “all matters quickly and satisfactorily closed”
A spokesperson for UKOG said:
“As requested, Horse Hill Developments Ltd responded to the letter from the Health and Safety Executive on 3rd October 2018. A risk assessment of the Blow Out Preventer was completed, and all matters were quickly and satisfactorily closed out with HSE. The wellhead voids had in fact already been inspected as part of our well integrity checks. There were records to this effect on the Horse Hill well site, which unfortunately were missed by HSE’s inspector on the day. This routine HSE visit to the Horse Hill site in August 2018 was considered by both parties to be successful. It should be noted that there was no comment on the Blow Out Preventer arrangement from HSE during their original regulatory review, prior to the commencement of operations.”
Reaction: “Highlights importance of active monitoring”
The campaign group, Brockham Oil Watch, which uncovered the breach, said:
“This breach demonstrates the importance of site visits and active monitoring by the regulators.
“Yet, according to responses to our FOI requests, which covered the period from 1 March 2018 to 15 April 2019, this was the only HSE visit the Horse Hill site. In February this year, the Environment Agency told us that their last visit to Horse Hill was in August 2018.
“These visits are too few and far between; all too often this inherently dangerous industry is left to self-monitor and self-report. In particular, the so-called “conventional” sites, where operations don’t qualify as “associated hydraulic fracturing”, normally receive less scrutiny and are subject to lower reporting/monitoring standards.
“We were told that the Notice of Contravention would not routinely have been shared with other regulators, or any third parties. The only reason it is now released is because someone asked the question. This lack of transparency on a serious issue doesn’t seem to serve the public interest.”
The application for long-term production and additional wells at Horse Hill is expected to be discussed by the Surrey County Council planning committee on 11 September 2019. Link
This is the latest postponement of the decision, which had previously been scheduled for March, April and most recently July 2019. Surrey County Council has reported there have been at least 1,000 objections to the proposal.
Updated 21/6/2019 to change “broke” to breached” in the headline