Every year the drilling operators experience large periods of downtime in their drilling activities due to time spent on unforeseen, but necessary BOP (Blow Out Preventer) inspections. This is very costly – we are talking about hundreds of millions US dollars every year for the industry in total. There is no doubt the BOPs are important, and we should never come to a situation where we delay responding to indications of related safety-critical failures. But today it seems like the pendulum has swung too far, and many companies are pulling their BOPs to the surface too often. It is becoming apparent that determining to “pull” or “not pull” a BOP is lacking the structure of a transparent risk model, resulting in an increased possibility of a BOP not being pulled when necessary.
There are two well-known facts within the industry regarding BOPs, which the regulators also recognise:
- They are a critical operational item in any drilling operation, being, the final line of defence for protecting life and the environment.
- The operational cost of drilling a deepwater well typically ranges from US$750,000 to over US$1m per day. Retrieving a BOP in a deepwater or an ultra deepwater environment may take multiple days; the subsequent repair, testing and running of the device will require additional non-productive time (NPT).
Deepwater and ultra deepwater drilling operations typically involve a BOP latched onto a wellhead situated on the seabed. When a failure is detected in a system or component on the submerged BOP, the industry’s typical response is to analyse the possible consequences and perform a risk assessment to define risk levels. These risk assessments typically help stakeholders, including regulators, decide: whether the fault of the component is an unacceptable increase in risk levels which requires immediate repair – resulting in the BOP being pulled to the surface; or whether the faulty component does not present an unacceptable risk to continuing operations, meaning the BOP remains on the wellhead.
These inherent facts illustrate the demand for a detailed, transparent and well-structured approach to risk assessment with well-defined parameters. Although, the deepwater drilling industry is facing the following complex challenges:
- Risk assessments currently in use are not uniform in process, detail and nature. As a result, (“pull” or “no pull”) decisions are not being made based on consistent risk models. This can create a subjective, non-transparent and difficult to understand decision processes which are unacceptable to senior management or regulatory bodies.
- BOPs and their control systems are very complex units. So a detailed analysis of what failed and why — along with the possible consequences of any shift in risk levels after a faulty component is identified — can take anywhere from a few days to several weeks to achieve the required level of detail.
- Parties performing the risk assessment tend to be direct stakeholders such as oil companies and rig owners. This may affect the decision-making process and interpretations and consequently decrease the level of comfort for regulatory bodies.
Consider the limited resources and knowledge on-hand to carry out these ad-hoc risk assessments and take into account the added complexity of carrying out the assessment in the field in a stressful situation. Now add the fact that these assessments are rarely based on a transparent, well-established and reviewed methodology and it’s easy to see why someone would doubt a risk assessment in these conditions would, in any way, be beneficial in determining whether or not to pull a BOP.
The industry needs a BOP failure-decision model which defines any change in operational risks within hours, not days. This model must be fully transparent, with all subjectivity removed, and verifiable. When the operating circumstances change, and/or the operating criteria of the BOP are altered, the model must instantly illustrate the change in operating risk.
My colleagues in Scandpower and ModuSpec, (both members of the Lloyd’s Register Group) have acknowledged this challenge, and are currently working on a new type of BOP-monitoring software which will solve many of these challenges. In the case of an event, a faulty component is identified and entered into the BOP risk and reliability model, which will directly demonstrate the new operational risk levels in which the BOP is operating. This will in turn facilitate and often dictate whether the BOP will need to be pulled to the surface for repair, or left connected to the wellhead to continue operating.
The Scandpower proprietary software, RiskSpectrum (c), will be used as basis in the modelling, and the BOP Monitor will be validated by a joint-industry review panel to strengthen and improve the models capabilities on a continual basis.
You can read more about this process of development through my updates in future blogs.