By Jan Willem Flamma - Training Director
As well engineers, we operate in a world of inherent uncertainty. Every well we design, every drilling operation we oversee, and every completion we execute carries a degree of risk. From the unpredictable nature of subsurface formations to the complexities of downhole equipment and the ever-present potential for HSE incidents, managing these risks isn't just a good practice – it's fundamental to our success and, more importantly, to the safety of our people and the environment.
Unlike some fields where risk might be viewed as an abstract concept, in well engineering, the consequences of unmanaged risks can be immediate, significant, and even catastrophic. A stuck pipe event can lead to millions in lost time and resources. A well control incident can have devastating human and environmental repercussions. Therefore, a robust and proactive approach to risk management isn't a bureaucratic exercise – it's the bedrock of responsible and efficient well operations.
So, how do we, as well engineers, navigate this landscape of potential hazards? We rely on a systematic process, a framework that allows us to identify, analyse, and ultimately manage the risks that could impact our projects. This process typically involves the following four key steps:
Step 1 Risk identification: Unearthing potential threats
This initial stage is about casting a wide net and identifying anything that could potentially go wrong. Brainstorming sessions with the drilling team, members of the subsurface team, and other stakeholders are crucial. We delve into historical data, review offset well performance, analyse geological surveys, and consider the specifics of the planned operation. What are the potential hazards associated with the drilling program? Could we encounter unexpected pressure regimes? Is the well trajectory particularly complex? Are there any novel technologies being deployed that introduce new uncertainties? No stone should be left unturned in this phase.
Step 2 Risk analysis: Understanding the likelihood and consequence
Once we have a list of potential risks, the next step is to analyse them in terms of their likelihood of occurrence and the severity of their potential consequences. This often involves assigning qualitative or quantitative values. For example, the likelihood of a stuck pipe in a shale formation might be rated as “likely” while the consequence could range from “minor delay” to “significant sidetrack”. For more critical risks, we might employ quantitative risk assessment techniques, using historical data and statistical models to estimate probabilities and potential financial or operational impacts. Tools like risk matrices, which plot likelihood against consequence, help visualise the relative significance of different risks.
Step 3 Risk evaluation: Prioritising and deciding
With a clear understanding of the likelihood and consequence of each identified risk, we can then evaluate their overall significance. This involves establishing a risk tolerance level – what level of risk are we willing to accept? High-impact, high-probability risks will naturally demand immediate attention and robust mitigation strategies. Lower-impact, low-probability risks might be accepted with monitoring. This evaluation phase allows us to prioritise our efforts and resources, focusing on the risks that pose the greatest threat to our objectives.
Step 4 Risk treatment: Developing mitigation and contingency plans
This is where we develop strategies to either reduce the likelihood of a risk occurring (mitigation) or minimise its impact if it does occur (contingency). For a high risk of lost circulation, mitigation measures might include careful mud weight management and the use of lost circulation materials proactively. Contingency plans could involve having specialised equipment and personnel on standby. For every significant risk, we need a well-defined plan of action.
Risk monitoring and review: Ensuring ongoing effectiveness
Risk management isn't a one-time activity – it's an ongoing process. Throughout the well's lifecycle, we continuously monitor identified risks and look for new emerging threats. Regular risk review meetings ensure that our mitigation and contingency plans remain relevant and effective. Lessons learned from previous operations are invaluable in refining our risk management strategies for future wells.
The indispensable role of acceptance criteria
Within this risk management framework, the establishment of clear and measurable acceptance criteria is paramount. Acceptance criteria define the boundaries of what is considered an acceptable outcome or level of performance for a given risk. Without them, risk evaluation becomes subjective and decision-making can be inconsistent.
For instance, let's consider the risk of loss of wellbore integrity due to poor casing centralisation or inadequate cement bond. This is a critical risk that can lead to inter-zonal communication, well control issues, or environmental contamination. Our acceptance criteria for this risk would be very specific:
- Casing centralisation: We might specify a minimum of two centralisers per joint within the open hole section, with a standoff percentage of no less than 70% in critical zones (e.g., pay zones, water-bearing formations).
- Cement top: The cement top must be within ±50 ft of the planned depth, verified by temperature log or cement bond log (CBL/VDL).
These precise criteria provide objective benchmarks against which we can measure our performance and determine if our risk mitigation efforts are successful. If any of these criteria are not met, it signals an unacceptable deviation and triggers pre-defined contingency actions to rectify the issue.
Clear acceptance criteria ensure that everyone on the team understands what constitutes an unacceptable deviation and what actions need to be taken.
In conclusion, for well engineers, risk management is not just a theoretical exercise – it's an integral part of our daily work. By systematically identifying, analysing, evaluating, treating, and monitoring risks, and by establishing clear acceptance criteria, we can navigate the inherent uncertainties of the subsurface and ensure safe, efficient, and successful well operations. It's about drilling down deep into potential problems before they surface and ensuring we have a solid plan to manage whatever the earth throws our way.
