Safety is always the number one priority in drilling operations, but this can often impact an operator’s ability to reach their targets and optimize future production. However, there are ways engineers can increase the efficiency of field development and maximize production flow, without compromising safety (preventing blowout).

Morten Haug Emilsen is the Manager of Well Control at AGR, and his team specializes in blowout contingency, well kill support, and reservoir and flow simulations. In this blog post, Morten shares his insights around preventing blowouts, what is involved in blowout kill simulation studies, and effective ways to ensure single relief well contingency while maximizing production and saving costs.

Why are blowout and well kill simulations so important?

“In general, blowout and kill simulations contribute to risk awareness among engineers and other stakeholders typically lacking the experience from real blowouts.  Drilling for hydrocarbons always involves risk of uncontrolled releases of oil and gas, and our simulations contribute to reducing the probability by incorporating this awareness in the planning phase.

“Before you’re allowed to drill, you need to apply for consent to drill and provide the regulator with documentation for the upcoming operation. This application should include a contingency plan for regaining control of the well if the worst was to happen.

“Many countries now have regulations that require companies to demonstrate single relief well contingency, and some of the major operators have similar internal guidelines and policies that dictate this. In Norway, for example, there is legislation that forces operators to show and demonstrate that they can stop a blowout by drilling only one relief well.

“Relatively speaking, it can be straightforward to control a blowout. But often, it can be very challenging. We look at the reservoir properties, reservoir fluid, drilling program, well completion, wellbore survey, etc. and develop possible scenarios of why things might not go according to plan. And once established, we calculate the potential blowout rate, simulate it and calculate what is required in terms of gaining control of that blowout scenario. We then pass our findings to our client, along with our recommendations for contingency planning and whether a single relief well is viable or not.”

What factors do you take into consideration when conducting a blowout kill simulation study?

“In our studies, we look at a range of factors and parameters including:

• The design of the well, including casing strings, drill pipe and bottomhole assembly configuration
• The well trajectory – the direction of where the well will be drilled
• Reservoir properties – typical pressure, temperature, thickness, extension and permeabilities, which will tell us how much the reservoir is capable of flowing
• Fluid properties.”

What happens if the kill requirement exceeds the capacity of one relief well?

“The new regulations in place have introduced limitations to what operators can do in their planning phase. If calculations show that the kill requirement exceeds the capacity of one relief well, the operator would usually have to redesign the well.

“This could introduce added costs to the project, and also, in some cases, add or increase the risk of running into a problem. It can also impact the ability to meet production targets of that well, as smaller completions might be required.

“In this scenario, we often recommend the Relief Well Injection Spool (RWIS), as this piece of equipment enables operators to stop a blowout from prolific reservoirs safely and efficiently via a single relief well – without having to redesign the well.

“The RWIS does this by increasing the pump rate of kill mud into the blowing well by removing the bottleneck caused by restrictive choke and kill lines from the surface vessel to the seabed – and it can pump in excess of 200 barrels of kill mud per minute, which is roughly four times as much kill fluid as typically achievable. With the RWIS, we have seen projects go ahead that wouldn’t normally be sanctioned, as operators are able to comply with legislation.”

How can I maximize production without exceeding the capacity of a single relief well?

“Again, we often recommend the RWIS as it very much has a dual benefit. It ultimately has the safety benefit of being able to achieve single relief well contingency, without having to redesign your well, but it can also unlock the potential for planning bigger bore wells and therefore enable more efficient field development.

“Even if you can achieve a single relief well without requiring the RWIS, it can still unlock economic benefits for you by allowing you to maximize flow rates through increasing the size of the wellbore, while still maintaining a single relief well.

“The knock on effect is also hugely beneficial to operators. As production targets can now be met with fewer wells by having access to the RWIS, the CAPEX cost savings achieved can be incredible. You can learn more about this in a previous blog post we have written – Optimize your well economic: how to exceed production targets with less wells.”

If you would like to learn more about the RWIS, click here to visit our product page. Or alternatively, if you’d like to speak with us directly, you can get in touch with our specialist team.