Ultimate Recovery: EOR in the Middle East

Injecting reservoir gas and water cooks up secondary production, and then anything more advanced, such as heating the reservoir or adding something new to the injectant is the realm of enhanced oil recovery, or EOR.

“EOR aims to improve sweep efficiency and/or lower residual oil saturation. This is achieved by using a range of methods, including gas injection (CO2, natural gas, nitrogen), chemical injection, microbial injection, or thermal recovery (which includes cyclic steam, steam flooding, and fire flooding),” explains Stuart Walley, region manager, Middle East & India at Senergy.

The global market for EOR is thought to be in the region upwards of $62.5 billion (for barrels of crude oil), having grown rapidly from $3.1 billion in 2005, largely thanks to sustained higher-than-average oil prices.

Although technical challenges and costs have often precluded many oil companies from adopting EOR methods, it has quickly become more feasible and is expected to continue to grow rapidly with ongoing government investment.

However, for the most part in the Middle East, it is the abundance of light, sweet, cheap to produce oil which has kept the wider roll-out of EOR projects at bay.

“If we look at the Middle East then there is so much easy oil, that people don’t really think about deploying large scale EOR in Abu Dhabi, Saudi Arabia, or even Qatar – these are really big fields, and they are able to get oil out quite easily, for a lift cost of a couple of dollars per barrel. This reduces enthusiasm for EOR projects of course,” explains regional resource volumes manager for Shell, Christiaan van der Harst.

However, experts agree that may be about to change, as governments and national oil companies bring into sharper focus the lifetime value of their fields and increase production goals.

“Abu Dhabi has always been very keen to investigate what could be done in terms of EOR. The governments in this region are interested in getting a higher recovery factor, because ultimately they want to achieve the maximum use of their oil fields. They have encouraged the international oil companies, like Shell, to help them with plans to come up with EOR schemes,” explains van der Harst.

In fact, back in 2001 Shell was invited to participate in a carbon dioxide injection pilot.

“We had a group of Shell and ADNOC people looking into CO2 injection into the Bab reservoir to see if we could raise the ultimate recovery for that field. North East Bab now has an operational gas injection scheme, which is demonstrating the benfits that option can provide,” he says.

The national oil companies across the region are acutely aware they will one day require EOR technology to exploit some of their resources, and they are keen to develop the knowledge and the know-how ahead of that time.

“With an abundance of conventional reservoirs, the region is not normally regarded as an area known for EOR or heavy oil extraction; however with an estimated 970 billion bbl of discovered heavy and extra-heavy oil resources in the region, much of which is undeveloped, an oil price exceeding $100 per barrel is making the economics progressively more attractive,” adds Walley.

There is a consensus that EOR is becoming more important due to the fact that the region’s giant, and super-giant fields have been under primary, and secondary production for decades. As these fields age further, EOR will be needed to sweep the field and boost the ultimate recoverable quantity of hydrocarbons.

Dr. Angelo Farcasanu, local head of reservoir engineering, Middle East and India for Senergy adds that whilst right now EOR is regarded as a bit of luxury by some in the Middle East, the projects are being talked about at the highest levels.

“When NOCs are screening their projects they, of course, look at the economics of cheaper options as more appealing right now. However, the earlier companies start looking at EOR in this region the more value they can add to their fields.

This is because the research and experiments, even in their early stages often unearth the unknown, which means when the time comes the project can be kickstarted immediately,” he says.

Farcasanu adds that early work and laboratory testing in this part of the world will have a big knock-on effect later. “As more and more companies in the Middle East invest in research and publish their information it will act as an accelerator to wider and more comprehensive adoption.”

Carbon Conundrum

Around the world, EOR is at its most advanced, and indeed, most widespread adoption in the mature fields of the US. This is partly historical – they have been producing for almost a century.

And partly due to the lack of giant, easy fields being discovered onshore. In that environment there is a huge concentration of expertise, but due to the geology, not a great deal of that knowledge can be transferred to the Middle East.

“The fields may be similar in the regard that they are mature provinces, but the problem is that many of the fields are made up of clastic reservoirs. This present a problem in terms of knowledge sharing because in terms of accessing analogues to compare and contrast with local formations, they simply don’t match the local geology, which is primarily made up of carbonates,” explains Walley.

However, one area where valuable lessons have been learnt is in the field of carbon dioxide injection and sequestration. “CO2 dominates the North American EOR scene, whereas in the rest of the world it is probably steam injection which is used most often and most widely,” he adds.

The CO2 conundrum in this region arises because, whilst there is a will from large NOCs, including ADNOC, to implement these projects, the availability of commercial quantities of CO2 simply isn’t here – yet.

“The fiscal terms for carbon capture and sequestration (CCS) have to be right. In Europe and the US there is an economic imperative driven by government policy to eliminate, or reduce carbon emissions. That has been key to the availability of CO2 for EOR projects,” explains van der Harst.

Separating CO2 from raw emissions at industrial complexes such as aluminium smelter, or power plants is a complex and costly process.

That said, there is clearly the will in some parts of the Middle East to improve the availability of CO2, and combat emissions. Masdar, ADNOC and ADCO’s initiative to use emissions for reinjection to boost oil production will be a regional first.

“The government in the UAE has set a target to cut CO2 emissions by 14-15%, and part of that solution will be using CO2 EOR techniques in the North East Bab field,” outlines Walley.

Oman Apart

Aside from pilot stage projects one country stands out in the Midde East as an EOR haven. In Oman, several cutting edge, world class EOR projects are underway. Due to a geological quirk, Oman naturally has more heavy oil in shallow reservoirs, ranging from 300 to 800 metres deep.

“Oman is an interesting exception to the rule in the Middle East. The fields there aren’t on the same scale as Abu Dhabi and Saudi Arabia, and some years ago some of the important fields were reaching the end of the production plateau and begain to decline,” explains van der Harst.

“Moreover, some of those reservoirs had only achieved around 20% recovery. By deploying enhanced oil recovery you can easily get another ten percent out. With some thermal projects we’ve even seen that figure reach as high as 50%,” he adds.

Anything between ten and fifty per cent is hugely significant, but that incremental increase comes with the cost of setting up the project, investing a lot of money, and burning a lot of gas to run steam boilers, explains van der Harst.

“You have to heat the whole reservoir, so it is not just an intense challenge generating and getting the steam into the oil, you also need a deep understanding of the geology of the reservoir to work out how to drill the wells and what configuration will work best, in some cases that may be deviated wells, in others a network of horizontal wells, or any other combination you can think of really.”

At Harwheel, where Shell is engaged through PDO, the field is being developed using CO2 and miscible gas injection. “The idea there is that the oil is displaced by the gas and we aim to achieve high recovery factors, around 50 – 70%. Harweel is a great example of starting a field development project using EOR right from day one,” says van der Harst.

Also in Oman, Shell is engaged in a polymer flood project at Marmul. The Marmul Field, in the South of Oman, was discovered in 1956. Like many fields in the southern part of the country, Marmul is characterised by heavy, viscous crude oil that is difficult to extract from the ground using traditional methods such as pumping or water flood.

“Initial estimates were that PDO might only recover about 10-20% of the oil in the reservoir through traditional recovery methods. So right from the outset the field was earmarked as a test bed for polymer flooding,” says van der Harst.

The first small-scale polymer flood pilot took place between 1986 and 1988, with one injector well and four producing wells. A second pilot a few years later sought to confirm these estimates.

PDO estimated that by using polymer flooding it could raise the total percentage of oil recovered from the reservoir to the high 20s or even low 30s.

Because of discoveries in Oman that promised cheaper extraction costs than the tough Marmul field, the Marmul polymer project was shelved.

However, today’s economic conditions make the increased unit cost of EOR more feasible. PDO’s need to maintain production levels as its fields mature has also brought the need to innovate into sharp focus.

“That project is now running and we are already seeing even better benefits than we expected. The polymer flood seems to be working there very well,” says van der Harst.

Future Focus

The fact that there may be little need to implement EOR on the giant fields of the region does not mean willing investment is not forthcoming. When the ultimate recovery issue is understood, it is clear there is an imperative now, when revenues are high, to inject some of the capital flowing in to tackling tomorrow’s problems.

“I’d say that’s certainly the case,” says Walley. “In Saudi Arabia they may not actually need to implement an EOR strategy for twenty or so years, but they are investing in research and technology now. Their driver is obviously boosting ultimate recovery, and the investment being made today will pay off in the future when it comes to selecting the right EOR solution.”

Adopting the correct methodology and approach is critical to a successful EOR project.
“In this region we are seeing a very phased approach. There is a lot of work which happens up front in terms of screening methods, and that’s the investment which is starting to be made in this part of the world.

This is typically followed by a small pilot, because moving to full implementation could affect the ultimate recovery from a reservoir, so decisions have to be taken at the very highest level,” explains Walley.

One of the problems with a large scale implementation is that it would be difficult to monitor the effects of chemicals injected. That very sensitive and careful monitoring has to be carried out on a small part of a field.

“Also, practically speaking, by keeping the pilot quite small, the owner mitigates the risk and cost if the EOR is not as successful as they would have hoped,” adds Farcasanu.

Senergy is currently conducting a number of studies in the Middle East. “We have also been providing support to companies in Sudan looking into feasibility for EOR projects on fields there, and they are looking to take those to pilot stage. We are currently undertaking the analytical modeling ahead of going to the screening stage for the right methodologies. It’s quite an exciting project,” says Walley.

“One of the key areas we provide advice on is not just the mechanics and methodologies which would work best, but also the economics of embarking on the projects. Senergy is not tied to a technology, or a solution provider when it comes to engaging the project. We are totally impartial, which means we have flexibility, and also means we can provide truly independent advice regarding the overall economics of a project,” he adds.

What’s next?

Shell’s van der Harst says there are exciting developments afoot, which could lead to a much cheaper method of enhancing relatively simple water injections – with a twist.

“We are working with something right now we have dubbed “designer water”. We design the injection water in such a way that it releases the residual oil bubbles which are still left behind after the normal water injection. This is done by tweaking the salinity levels of the water injected,” he reveals.

“In reservoirs oil gets stuck in pores or in rock crevices, and by reducing, or in some cases increasing, the salinity to match the oil properties and the rock properties. Sometimes the oil is glued to the rock. There can be all sorts of molecular processes going on there, so understanding that chemistry is the key to boosting production.”

Shell currently has a “designer water” pilot project in the field in Syria right now. “The laboratory work has been done and now we are deploying it, and in Russia there is also one, at a slightly more advanced stage,” he adds.

Van der Harst says that a polymer injection is a rather bulky operation, and where the polymer itself is expensive, then the economics could be less attractive. “Playing with the water quality is a lot more sensible. That said, we look at a unique solution for each field and from the wide range of technology we can deploy, we will select the optimum combination and thus maximise the return for Shell and its partner’s,” he concludes.

Siemens Solution

Siemens Energy has developed a solution for the treatment of water before it is pumped back into an oil reservoir for EOR. The company claims its modular solution cleans the water after gas/oil/water separation more efficiently and cost-effectively than traditional systems.

A solution tailored to specific process requirements can be delivered within 18 months. The system covers process steps such as hydro-cyclones, flotation and filtration as well as electrification, instrumentation and automation based on Siemens standard components.

This can be tailored to the requirements of the water to be injected and is modularized in intervals of 20,000 barrels per day which enables incremental extension – and stepwise decommissioning – over the entire lifecycle of an oil field, thereby permitting optimization of CAPEX and OPEX.

“Against the backdrop of increasing global demand for oil and depletion in many existing fields the enhanced oil recovery market will continue to grow in the future,” said Tom Blades, CEO of the Siemens Oil and Gas Division.

“The new Siemens solution uses components with a proven track record in the oil and gas industry. Our customers get an efficient, cost-effective and eco-friendly all-round package from a single source, in which all components are optimally matched.”