Safety is the first priority of any responsible oil and gas operator, and Shell is striving to reach ‘Goal Zero’ – operating without any fatalities or significant incidents. In exploration and production, ensuring safety through well integrity has taken on renewed importance – and one event in particular is responsible for that.
"Macondo definitely raised awareness of well integrity, but prior to that, we already had business requirements in place that go as far back as Piper Alpha and other events even outside our industry, like Chernobyl," says Marco op de Weegh, well engineering team lead for Shell P&T Wells, Unconventionals. "Incidents like those really highlight the need to make sure that lessons learnt are implemented."
Identifying areas of major risk during well operations and learning from high-potential-for-fatality near misses has been a key focus for the company. For example, it has significantly reduced the frequency of dropped objects over the past five years.
"We have personal safety efforts and process safety efforts," says op de Weegh. "With those come KPIs. We monitor and analyse those KPIs, and investigate any events, low risk or high risk."
In well integrity, events that breach or could potentially breach the well barriers have the highest potential for fatalities. These are recorded and investigated for their root cause, and that learning is then applied to adjust the process safety practices the company employs.
"We call that ‘learning from incidents’, or LFI," op de Weegh says. "LFIs are communicated back to the field and back to the organisation."
Tools for the job
The technology and procedures needed to safely manage a well – particularly a deepwater, high-pressure one – are complex in the extreme. Staff must employ intricate equipment and follow detailed best practices to ensure process safety.
"We had ten general Process Safety Basic Requirements [PSBRs] prior to Macondo," explains op de Weegh. "We added an extra
These PSBRs cover everything from permit-to-work systems to change management and H2S. However, it’s one thing to have rules, but how do you ensure that staff comply with them during challenging, fast-moving operations?
Full visibility of every critical process, backed up by staff and system monitoring, is the answer. In 2008, the company introduced its electronic well integrity management system (eWIMS) to track every live well throughout its life. With two-hourly status updates, eWIMS reports test data, whether corrective or preventative maintenance is up to date, and displays real-time sensor information on metrics like casing corrosion or annular pressure.
By constantly comparing this data against design specifications, the system can automatically alert managers to problems like leaks between casing strings or unwanted communication between different formations. But to be sure of well integrity during the critical construction phase, Shell needed a further way to make standards visible, trackable and measurable.
Macondo definitely made us verify that we had the right procedures for well integrity," says op de Weegh. "We found that we had very good coverage in our equipment, personnel training and process safety, but we did not have a simple central system to assess the status."
The solution was to build its electronic well control assurance tool (eWCAT). First implemented on deepwater wells in 2011-12 and then rolled out globally, eWCAT monitors and makes visible key metrics for well integrity compliance.
"It’s a spotlight focused on the construction phase to make sure that execution is going exactly as planned," states op de Weegh. "It verifies that we have the right equipment in place to safeguard the primary and secondary barriers, that we have competent personnel with the right well-control training, that we have a suitable plan for the particular design being executed and that the right tests are being conducted in the field to go on to the next construction phase."
Staff plan each well in line with Shell’s own and all relevant industry-wide standards for design and operations – as well as all the other best practices contained in the company’s manuals for design engineering, well standards, casing tubing design and pressure control. Rigorous testing and verification that blowout-preventer (BOP) shear rams will indeed cut all the tools that will run through that BOP during a project is one example of Shell’s own criteria.
Based on Shell’s well-delivery process guidelines and a series of risk assessment techniques like the Bowtie principle, managers then generate a customised plan for the whole well life cycle showing what to do at each stage, the equipment to use, and who must approve each new step to ensure well control and integrity.
"We need to simplify the plan to make it usable at a practical level," says op de Weegh. "There is no use having an excellent manual without good implementation in the field."
Making all the right moves
Encoded into eWCAT as a step-by-step workflow, that easily visualised plan is nonetheless built on a staggering amount of rigorously researched detail. For example, it will set out the casing and tubulars to be used, their design, maximum operational loadings like casing running tension and a clear schematic of all principle components.
As part of the barrier verification plan, eWCAT lists the minimum specifications for the critical primary and secondary pressure-containing barriers, making visible at all stages of construction that equipment meets Shell’s own requirements and regulatory standards. Detailed piping and instrumentation diagrams show how to construct the barrier equipment – chokes, BOPs, rams, manifolds, control units – with eWCAT configured to match the rig’s own equipment for that project, from BOPs and top drives to mud gas separators.
The system monitors all barrier equipment certification and maintenance in line with each manufacturer’s quality-control systems, alerting if equipment changes or certificates for compatibility, conformance, compliance or service go out of date. At each new stage – for example, drilling and cementing an 11.75in section – eWCAT lists critical design parameters such as the expected maximum wellhead pressure and temperatures, or hydrogen sulphide levels.
As construction proceeds, it sets out required checks like casing pressure, shoe and inflow tests, or cement bond logs. As staff add the relevant results, management again has full visibility.
The system also makes a note of who should manage each task, specifies the expertise required by engineers and service crews for each role, and again monitors for compliance.
At each stage, eWCAT employs a traffic light system to demonstrate approval is in place and explicitly states who must sign off for the next step. There might be multiple approvals needed: supervisors in the field, the business manager in the office or separate technical authorities.
"You have that interaction between the superintendent, the personnel on site and the engineer so that they are ready for the next phase," says op de Weegh. "The highest level would be ‘technical authority zero’, which is actually a Shell vice-president.
"That would be a case where you need to make a judgement about a change in the design – for example, if an industry standard has been updated."
Without a green light, work must pause, and management can see exactly where they need to focus their attention. The system automatically notifies managers if the correct steps are not reported, or when staff training or equipment certification is out of date.
By making the rules explicit, and then monitoring and measuring compliance, eWCAT effectively encodes a safe culture for well integrity. In fact, it embodies two of Shell’s three golden rules of safety: comply with the law, standards and procedures; and intervene in unsafe or non-compliant situations.
"If the right safety culture is there, then personnel will properly use the tools provided," notes op de Weegh.
By providing the framework to highlight any exceptions, eWCAT makes proper use – and Goal Zero compliance – in well integrity more likely than ever.
