Growing scrutiny on HPHT in North Sea well operations

Last year's leak at Total's Elgin platform has led to renewed scrutiny of high-pressure, high-temperature (HPHT) well operations, according to the UK's Health and Safety Executive.

Describing the evolving concern over HPHT well operations in recent years, the HSE's Donald Dobson, head of discipline, well engineering and operations, has told a conference that following the Elgin incident a new industry working group on HPHT operations has been established at the HSE's instigation.
And in well integrity overall, Mr Dobson said, the human factor needed more attention: “This is the area that we feel the industry has the poorest handle on,” he told delegates to DecomWorld's North Sea Well Integrity Conference, 27th February, in Aberdeen.

Mr Dobson said the HSE first commissioned a study of HPHT risks after a number of HPHT fields came onstream in the mid-1990s, leading to a noticeable increase in equipment failures. The study covered 130 HPHT-related well incidents.

Published in 2005, the study highlighted the major issues, including: liner damage due to compaction after reservoir depletion, the need to change well design to cope better with this compaction, and the effects of compaction on cap-rock and over-burden, which Mr Dobson said was not fully understood at that point.

The study also identified that geo-mechanical modelling was required to understand the issues better, and that more efficient sharing of information among operators was required.

New guidance from the HSE followed, but the Montara (2009) and Macondo (2010) incidents in Australia and the Gulf of Mexico prompted another examination.

HSE asked the industry to address issues identified in the Australian and US investigations. In response the industry set up the Well Life Cycle Practices Forum (WLCPF) to produce guidance on a range of issues.

 

Under the spotlight again

HPHT came under the spotlight again with the March 2012 gas and condensate release on Total's Elgin platform in the North Sea.

The HSE's investigation into that incident continues, Mr Dobson said, but meanwhile it has asked the WLCPF to look again at the HPHT issues raised in the 2005 report.

“We knew a lot of the issues had been addressed,” he said, “but some of the more complicated, difficult-to-do things like the geomechanical modelling – we weren't really sure what had been done and what hadn't been done.

“As a result, the Well Life Cycle Practices Forum HPHT forum has been set up particularly to answer these questions.”

Speaking of well integrity more generally, Mr Dobson said the industry needed to improve its approach to risk.

“People get complacent about risk,” he said. “Sometimes there is inadequate planning of complex activities... and there is sometimes a failure to plan for all possible contingencies.”

“The other issue is that well servicing is not always done to the same high standard as drilling, very often because it's done by a different department within an oil company.”

Summing up, he said “the essential elements of well integrity go beyond the actual hardware itself. It covers procedures, human factors, people's understanding, training, and it must involve everybody involved with the well and not just the drilling contractor or the well-servicing contractor and the operator.”

“Human factors are important,” he said, adding, “and it's all about making sure people are fully informed of the issues, that they are given clear instructions for what to do and what not to do, that they are properly trained and, if necessary, properly supervised.”