A well control incident, often called a well kick, means inflow or loss of formation fluid in the well, accompanied by pressure build up with a closed BOP following a positive flow check. The kill method is determined and implemented.
While the results from the investigations generally point to technology as the triggering cause of well control incidents, the professionals generally focused more on the role of humans than technology when explaining main causes of well control incidents in interviews.
Should investigate more
“The fact that the gap between causes in the investigation reports and the informants’ viewpoints is so large is worrisome, and shows that there is good reason to investigate more incidents,” says Monica Ovesen, discipline leader in drilling and wells in the Petroleum Safety Authority Norway (PSA).
The background for the study was the negative development during the period from 2008 to 2011, when the number of well control incidents increased from 11 to 28 incidents annually.
From 2003 to 2010, only ten of a total of 146 well control incidents were investigated. Correspondingly, 130 hydrocarbon leaks were investigated during a similar period.
“Every well control incident is unique, which underlines the need for more investigation. Even though there are many similarities between incidents such as Deepwater Horizon, the Montara accident off Australia and the gas leak on Gullfaks C in 2010, there are also considerable differences. And the more we investigate, the more we learn about the causes surrounding the incidents and can thus implement the correct risk-reducing measures,” Ovesen says.
Stronger efforts in technical measures
Despite a large part of the triggering causes revealed in the investigation reports being related to technology, the study shows that the percentage of technical measures implemented in the industry is low. Several informants also emphasise the need for improved systems for presentation of safety-critical information for the driller and drilling fluid engineer, in addition to better alarms.
“There is a significant potential in achieving better technical systems relating to early detection of a well control incident and communication in the drilling operations. If safety-critical information regarding a well’s condition is spread to all involved parties in an operation, you have a better chance of ensuring that important information is not overlooked,” says Monica Ovesen.
Framework conditions and risk analyses
In addition to more investigation and increased efforts in technical measures, the study points out two other main challenges that should be addressed by the industry: Framework conditions for good collaboration and increased efforts in risk analyses.
Good framework conditions deals with ensuring that conditions are facilitated in the best possible manner for the involved parties in safety-critical tasks. Good framework conditions can also be seen in context with technical measures such as development of better systems for presenting the condition of wells.
Within risk analysis, the study particularly points to the importance of having a method for risk assessment of changes that arise during drilling operations.
Part of RNNP
The study, which was carried out by SINTEF on behalf of the PSA, addresses causes and measures related to well control incidents in Norwegian petroleum activities. The study is part of the main report in this year’s Risk level in Norwegian petroleum activities (RNNP).
The results from the study have already been utilised in the PSA’s audit work directed at well activities.