Indicator approach

Integrated Operations (IO) provides the opportunity to monitor and control processes offshore from remote locations onshore. This has mainly been utilized to provide information about process parameters to monitor, control and optimize production. In a similar manner, risk significant information can be captured from systems offshore and transferred to locations onshore. The principle difference is that the information being captured and transferred is utilized for risk control, not production control.

A weakness related to the present methods for risk monitoring is their lack of ability to continuously measure the changes to the risk picture, thereby limiting their suitability to provide decision support during daily operations. Challenges for the industry include:

1. What kind of barrier information is required to take "safe" decisions?
2. How can this information be visualized and how can IO support and strengthen the presentation of such essential information?
3. Can the status of selected barriers indicators be combined into one "common risk measure"?
4. Can this risk measure be continuously updated to reflect the instantaneous change in risk level and thereby provide day-to-day decision support?

As part of the IO3 project, we have performed a case study to address these questions.  Our main objective has been to develop a method that better utilizes "on-line" data to assess the impact on the risk level, and to use this information to provide daily HSE management decision support. The case study has focused on process related risk and a set of barrier indicators have been suggested as a means of monitoring the risk continuously.

In order to identify the most important safety barriers for which to develop indicators, we applied information from quantitative risk analysis (QRA), qualitative barrier-analyses as well as discussions with operational personnel. The figure below illustrates three important barrier functions to prevent, control and mitigate process leaks ("prevent release", "prevent ignition" and "limit the feed of hydrocarbons") and the selected barrier systems for these functions (in green).

Some examples of selected indicators for these systems include:

• Number of open barrier breach notifications for barrier system "containment";
• Number of inspection findings during the three last months that has resulted in a notification, maintenance request or a project;
• The number of open work permits that have extended beyond one shift;
• Number of bypasses and overrides/inhibitions of the gas detection system;
• The fraction of failed valve tests, including all ESD valves and valves defined as safety critical.

A total of 20 such indicators were developed, all of which were possible to measure more or less continuously based on information obtained from existing systems. The information or status of the indicators was then combined into one common risk measure. For this purpose we developed a simple and pragmatic algorithm that combines the value (or status) of each indicator in terms of their risk importance (or weight).

Risk barometer

To visualise the risk, a "risk barometer" was proposed as shown in the figure below.

This barometer can be used as a qualitative aid to say something about the estimated risk level at a given point in time (instantaneous risk), and whether it is above or below the average risk over the last period. Beyond this it can also be applied to support certain decision criteria or rules. Examples of such rules or criteria may be as follows:

• When the total risk indicator is exceeding a certain value, no more work permits related to work on HC-systems is allowed in that area.
• When the indicator is exceeding another values all work on HC-systems in that area is stopped.