It has been said that the Welltec® Annular Barrier (WAB®) can revolutionize the industry. How is that?
The WAB can simply eliminate the need for cement. Likely, this is the most revolutionary thing you can do in today’s oil and gas industry. Cement has been around from day one. But today the operators are basically saying that a least 40% – 50% percent of the wells that uses cement as the primary barrier have challenges with sustained annular pressure (SAP).
Typically, this is due to the pressure / temp cycle of cement. Over time it becomes brittle. Channels are then created in the cement, which the pressures and the accompanying HC’s (gas) can migrate between zones or come back up to surface.
Well integrity: A cementless barrier
The WAB can be applied as a cementless primary barrier. Will the industry embrace this new piece of technology?
Yes, I believe so. It has been run as such already, following the ISO14310 V0 leak criteria qualification. While developing the product we saw that the WAB could also support well integrity applications. As I see it, it is a really disruptive change in the industry. It’s simply a fundamental change.
We take a reliable, mechanical solution, that is engineered for the specific well application and verify it as a barrier. It will likely change the industry’s thinking about using a complex fluid/cement solution to run the barrier envelope in the well, in the construction phase.
You can now construct and complete your wells for a barrier that is designed for your well in the construction phase, which can function effectively throughout the operational phase . And it can also be an enabler for an easier or a planned P&A operation.
Can you clarify?
By positioning the WABs in the correct place in the open hole, you will have a pressure barrier for your P&A operations. You do not to have to challenge yourself anymore to guess reservoir pressures from surface, faced with the uncertainty of whether or not your downhole barriers are ‘leaky’.
Avoid expensive surface control equipment
In what ways do you think the industry can improve its procedures?
Today, I think a big challenge is the enormous complexity of the wells. Also, the kind of information that the operators think they need for the production phase of the life.
Let me clarify. Today operators complete these wells with all kinds of surface control equipment on the well. As soon as any of this surface control equipment fails, you either have to live without the information or you have to recomplete the wells, because it’s part of the completion.
Another tendency is that a lot of engineers within the industry think they are really dependent on this information at surface – in order to be able to act on the production profiles of the wells. However, in real life, a lot of the time, many are so afraid of actually operating these solutions that they basically end up just monitoring them.
But why are they so careful?
Because the equipment keeps failing after a time. Also, by including all these components in the well you also complicate the plug and abandonment side of the well. You have all the control ends. You have all the components that you put down the well, and you have to capture coming back out, to try and plug and abandon the well.
Optimize with low-risk interventions
What would be a better and more cost-efficient approach?
Go back to the beginning where you construct and complete the wells. A completion concept, in which you have a reliable, mechanical barrier as the main component, is much simpler but yet with the capability of zonal isolation and inflow control (edt. Read about zonal isolation and inflow control in the second part of the interview). This can be accomplished by the use of intervention methods instead of working with control line. This is an efficient way to significantly reduce the initial cost of the well. At the same time it enables the well to be maintained by interventions, and with intervention equipment that doesn’t have to be reconstructed to fit these over-complex wells.
In the end, if you want to optimize the well through the life, you have to do some intervention. So why don’t you construct the wells with a much more robust and easy solution to actually run and to maintain the well? And you now have a solution you can actually compare to time for running it, setting it up, and getting it down there.
What I mean is, that if you’re running a full-bore solution, you have access with all your intervention tools. You can optimize, you can do clean-outs, you can maintain the production flow clean, and you’re actually able to do the work that is needed. You don’t have to design specific intervention tools to go through a valve or a pick-up scenario, which is not in the design in the first place. Now you have a well that is designed for maintaining and being optimized for intervention in the future.
Full-bore, optimized for maintaining the well
So it’s basically a matter of increasing recovery?
Exactly. And maintaining a life-of-well concept on the wells. Compared to the smart well solutions and intelligent well solutions, which are typically very costly with surface control, this Flex-Well® concept offers a much simpler solution with greater potential.
My point is, if you have to do anything intervention-wise, for example, if this well starts to produce sand or scale it’s a challenging intervention job to perform. So instead, why don’t you go back and put the finger in the ground and say: okay, we will have sand, we will have scale; we need to optimize this well; we need to intervene this well at some point!
With the Flex-Well® solution we will have a well flow valves solution that is full-bore, optimized for maintaining the well of life and potentially also to go down there, clean out the well or position plugs, or isolate the valves by closing the sleeves etc. You will maintain an optimized well for the life of the well and you won’t have to do all the particularly challenging intervention work. Instead, you will reduce the risk of intervention work significantly because you have optimized the well for that, already in the construction phase.
Data: Back up your decision-making base
How can you monitor the well?
The data monitoring is basically a solution that you can download with the intervention tools. When operators know their reservoirs and production profiles, they will see if anything changes at surface. Based on that you can order an intervention job to do some sort of investigation. During the investigation you can download the pressure and temperature profile of the well external to the completion and then act on it. If you compare this to the intelligent wells today, with this information potentially available at surface, you won’t be able to operate, for example, the downhole valves, because they are scaled up or you have lost communication to the valves, etc. You would still have to mobilize intervention, but then it is a challenging intervention job, because you have all the restrictions and problems in the well.
Instead, by looking at the life-of-well concept again, i.e. the Flex-Well® concept, you’ll have full bore, you’ll have set up the well for future potential intervention and optimizing the well. Also, you’ll have zonal isolation, you’ll have inflow control, and you have the data to back up your decision making base for how you’ll act on the challenges in the well. Finally, you can intervene and fix without having to recomplete the well. And again, you are also prepared for the permanent P&A of the reservoir. You don’t have to be facing bad cement jobs that need to be fixed up. You can basically just go ahead, plug back, isolate, go back to the next part you have to isolate and then go from there.
So all in all, you are set for life. You just need to take a decision to reconfigure, to rethink a little bit, and see the benefits of constructing your wells in a way that enable interventions to optimize the well if needed.