Elaine Maslin reports on Saudi Aramco’s work to improve recovery through “smart” completions, thereby simultaneously reducing intervention.
Dr Mohamed Nabil Noui-Mehidi speaking at the Society of Petroleum Engineer’s 2nd Inwell Flow Surveillance and Control Seminar.
For some years, Saudi Arabian oil giant Saudi Aramco has been on a mission to improve recovery from its wells, simultaneously reducing intervention, using smart completions.
Core to its mission has been increasing reservoir contact, first through drilling horizontal wells and then through multilaterals.
But, it wants to take matters further. While extended well drilling increases the amount of the reservoir the well bore is exposed to, managing the flow into the well can increase gains even further. It’s not a concept lost on Saudi Aramco. The firm has been installing interval control valves, or ICVs, into its wells, creating so-called intelligent completions.
But, that’s still not enough, says Dr Mohamed Nabil Noui-Mehidi, petroleum engineer consultant for Saudi Aramco’s production technology team. Saudi Aramco wants to take this idea and technology a step further, by gathering live downhole data, which is then transmitted real-time to surface and used to control down hole control valves – also in real time – Initially through wired valves and sensors, but eventually using wireless technologies down hole.
Speaking at the Society of Petroleum Engineer’s 2nd Inwell Flow Surveillance and Control Seminar, held in Aberdeen late 2015, Noui-Mehidi said: “We [the industry] call them intelligent wells, or smart wells, etc., but all of them are valves getting information from the wells. They are not [currently] smart, but the way we are driving them has to be smart.”
A smart evolution
Saudi Aramco started drilling horizontal wells in the 1990s. By 2000, it was drilling multilaterals and by 2004, it was looking at intelligent completions, following the launch of a well architecture program called Maximum Reservoir Contact (MRC) wells, Noui-Mehidi says.
The need to develop smart completions was driven by both the complex environments and the up to 37,000ft-long extended reach horizontal wells Saudi Aramco has drilled. This meant using downhole ICVs with downhole temperature and pressure monitoring on individual laterals. This enabled the operator to see what was coming out of each lateral and therefore optimize each lateral’s contribution to overall production and mitigate water breakthrough, faster than it would if it had to rely on well intervention operations for logging.
“We can increase recovery and have better sweep of the well by controlling these valves,” Noui-Mehidi says. “But, the important thing is that we have gathered all the data from the last 10 years to help us to the next generation of completions.”
The next generation is where all laterals, not just the mother bore, are divided into segments, each with a control device and a monitoring device. “To push the control into the laterals and into compartments will hopefully give us better operability and increasing predictability,” Noui-Mehidi says. “And we have started seeing this in new completions we have implemented.”
The first project which deployed this type of completion was a wired, full control monitoring project started 5-6 years ago, he says. “We went from classic MRC wells with hydraulic valves and hydraulic lines and gauges and replaced this with a single wire, which controls the valves and gauges,” he says. Each section of each lateral has a control unit with a Venturi meter to measure roughly the flow rate, a capacitance water cut meter, to measure the water cut and total production, and an ICV. All are connected to the wire, which transmits the data to surface and controls the valves.
“But, we are not stopping here,” Noui-Mehidi says. “We are going from maximizing reservoir contact to extreme MRC… to a non-wired solution in which you have a completion in which you would have a well that has multilaterals and the mother bore completed with segments, each with a control valve and a couple of gauges. They would communicate wirelessly with the heel of the well and then up to the operator.”
In a vision presented separately by Saudi Aramco, live data analytics could then help automate the wells using the data gathered down hole.
There are a number of technology hurdles to get over to achieve this aim, Noui-Mehidi says.
1. Power is needed to power the sensors, but, while there is potential to generate power in the well, there is a big gap when it comes to storage at temperatures in downhole temperature conditions. “There are no reliable solutions right now, but people have ideas and maybe in 5-10 years we will see solutions,” Noui-Mehidi says.
2. Everything also relies on this wireless communication. “We are talking about a very salty environment. Brines are 150-200,000 ppm of salt, which is a very high-loss environment for any communication. Waves die very quickly in this,” he says.
3. One of major challenges is to deliver this system through tiny diameters into bigger diameters – 4½in to 6 1/8in. “To do this we need to think about a new generation of packer that can expand from 4½in to 6 1/8in for example.” Noui-Mehidi says. “Also, the sensors and gauges we are putting in there need to be reliable.”
There will also need to be work done around sensor technologies, which will need to be able to work in complex, multiphase flow regimes, he says. “Understanding the physical properties of the field we deal with is very important and crucial in the development of the sensors. We have to decide what we are trying to measure before we decide what type of physics we use to get that data to the surface,” Noui-Mehidi says.
But, Saudi Aramco thinks the effort will be worth it. “We are doing this because we want to cut down intervention costs,” he says. “We want interventionless wells. With the wired solution there is no redundancy, which means if something fails, that’s it, you can’t do anything about it, except if you want to recover everything. That’s why we are going to this wireless solution where we can deploy freely through the 4½in tubing into the laterals or mother bore so if a valve fails we can go and retrieve them and put in another one. This is the dream we have.”