Enhanced recovery methods for Kuwait’s reservoirs

Kuwait

Eissa Al Safran, professor of petroleum engineering at Kuwait University, talks to The Energy Year about advanced methods for recovering oil from ageing wells and the imperative of keeping production costs low in Kuwait’s oilfields. Kuwait University is a public research university that offers undergraduate and graduate programmes.

What are your views on the global demand for hydrocarbons and Kuwait’s position to satisfy it?
As highlighted by the International Energy Agency, the world still needs fossil fuels and there will be a long demand plateau until 2050, mainly due to an increasing population globally and energy poverty in specific regions such as India and Africa. Kuwait has plans to reach production of 4 million bopd, but it is an ambitious plan with several challenges. There are large onshore oil reserves and the offshore Durra field will be a major asset for non-associated gas production, requiring talent and experience in offshore drilling, production and transportation.
Once out of the ground, Kuwaiti crude is of superb quality, with a significant portion of our production being sweet crude. A lower-density oil with low sulphur content facilitates the refining process and offers the best conditions for producing diesel and other products to the highest standards.

What challenges might prevent Kuwait from reaching its production capacity target of 4 million bopd by 2035?
The key challenge is lowering the cost per barrel because it has to be economically viable to ramp up production. KOC’s production efficiency improvements are hindered by technical challenges such as the high amount of produced water. For example, the water cut in some fields such as Burgan is as high as 40-60%, which hampers flow assurance and limits productivity.
In addition, produced water is highly saline and can jeopardise the integrity of systems, causing corrosion, scale formation, hydrates and slugging in surface facilities. Lifting the oil-water mixture to the surface requires artificial lift methods, such as ESPs [electric submersible pumps]. They mix the fluids and create a tight emulsion, resulting in a high effective viscosity which undermines the flow rate, triggering further problems.
Kuwait is investing in technology to predict and prevent problems such as these and in designing operational systems that can bring steady production with acceptable costs. At the moment, production costs per barrel range between KWD 1 and KWD 10 [USD 3.25 and USD 32.5]. For example, in North Kuwait, it is very expensive to produce, but in West Kuwait and South and East Kuwait, it is relatively cheap.

What factors increase the cost per barrel and how can they be mitigated?
Costs depend on the characteristics of the reservoir and the properties of the crude oil. For example, in conventional greenfield reservoirs that have little or no produced water, the cost of drilling and completing wells and maintaining production is lower.
Digital solutions can play a big role in prolonging the life of reservoirs, even if they are already aged, and they can also significantly lower costs. Digitalisation is being introduced for remote monitoring in many industries. In oil and gas, they enable operators to check what is happening down the well and to react immediately, streamlining the process of locating malfunctions, conducting trial and error tests and repositioning rigs if necessary.
Technologies such as actuated valves, ICDs [inflow control devices], and ICVs [inflow control valves] help identify problems and partially or completely control the flow of water from water-producing zones.
KOC deployed the KwIDF [Kuwait Integrated Digital Field] system somewhere around 2007 and it has proven quite successful in several fields, such as those in South and East Kuwait. KOC also has very good simulation models for Burgan which allow them to predict potential challenges and understand the reservoir’s behaviour over time in a better way.

How important are EOR methods within KOC’s upstream strategy and what are the main techniques used in Kuwait?
Tertiary recovery is very important for KOC given the nature of their ageing reservoirs. There are multiple EOR techniques, and they are applied to different oil reservoirs according to, among other factors, the type of oil they hold and the depth of the reservoir.
For example, in the South Ratqa heavy oil field in North Kuwait, KOC is using steam flooding, which stimulates production by reducing oil viscosity through heat. Previously, they used cyclic steam stimulation, but that only works for around seven cycles of the well’s life and then you have to flood the reservoir with steam.
Steam flooding is one of the EOR techniques that KOC uses the most. South Ratqa is currently producing 80,000 bopd and the target is 280,000 bopd. In the Umm Niqa fields in North Kuwait, KOC is trying several chemical EOR techniques, including surfactant and polymer flooding. Some of the injections have shown promising results.
Currently, KOC and Kuwait University’s petroleum engineering department are collaborating on polymer flooding projects to develop polymers for optimal reservoir recovery factors. There is a broad spectrum of injection fluids, and you need to run simulations for each one to predict the recovery factor. You also have to keep in mind that whatever you inject into the reservoirs will return to the surface, and it should be properly disposed of or recirculated back into the reservoir.

Does KOC use CO2 for tertiary recovery? What are the risks associated with this technique?
KOC has not been keen to use CO2 injection because when they did simulations, the recovery factor was not promising. CO2 flooding is a type of miscible flooding where the CO2 is brought to a pressure where it dissolves in the crude oil, reducing its viscosity and improving its flow.
However, CO2 injection is a very delicate process. One of its main drawbacks is that there is a high risk of precipitating asphaltene within the reservoir, which is a solid fraction found in crude oil. It is soluble under certain pressure, temperature and composition conditions, but injecting CO2 can cause it to be unstable and precipitate. If it does, asphaltene solids may plug the reservoir’s pores, reducing the permeability of the reservoir and putting production at risk.
I am currently working on a project with KOC for the Marrat Jurassic formation, a very deep reservoir where we have been looking at the asphaltene issue, which is the main reason why KOC is holding back from CO2 injections. To help advance their decision-making, we are building an asphaltene deposition integrated model that couples the reservoir, well and surface facility to study asphaltene behaviour holistically and comprehensively.

How can the oil and gas sector, and petroleum engineering specifically, help drive energy transition efforts?
Our industry has been under pressure to decarbonise since the COP 21 Paris Agreement in 2015. The oil and gas sector generates substantial emissions, but it can also play a big part in their reduction and has already developed mitigation methods such as CCUS.
There are different ways to capture CO2, including direct air capture and pre- and post-combustion capture. While capturing CO2 is more in the realm of chemical engineering, transporting it to fields and injecting it into water aquifers or depleted gas reservoirs for storage requires petroleum engineers who understand well systems, reservoirs and subsurface engineering and have the skill set and technology to do it right.

What is Kuwait University’s impact on the domestic energy landscape?
Universities and research institutions are crucial because they provide talent and develop research and technologies to serve the energy industry. Regarding research, the College of Engineering and Petroleum at Kuwait University is currently collaborating with KOC on eight research projects. These projects aim to solve actual oilfield problems to improve oil recovery and maximise production. KOC is funding these projects and providing the necessary field data.
In terms of education, the petroleum engineering department graduates 50-60 students every year. 90-95% of our graduates go to work for KOC, and most of KOC’s current leadership are Kuwait University alumni. In addition, we are collaborating with KOC on professional training through short courses and workshops. Our petroleum engineering department is one of the largest programmes in the region, and it includes 20 full-time faculty members and around 300 enrolled undergraduate and graduate students.
Three years ago, following a request from KOC, we launched a PhD programme in petroleum engineering. It has already been approved and we are just waiting for KOC to provide us with students from among their employees. They have plans to establish the Kuwait International Petroleum Research Centre and they need Kuwaiti PhDs, so they asked us to deliver a PhD programme. I believe it’s a win-win, which highlights the synergy between Kuwait University and KOC, and between our departments and the national oil and gas sector.

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