The value from the project is quite evident. The project paid back within 18 months of operations in terms of capital expenditure. Generally, the operational expenditure is very high in polymer injection as a very high volume (running into hundreds of thousands of barrels) of polymer solution is injected every day to the reservoir. This year, we started testing another EOR technique called alkaline-surfactant-polymer (ASP). If successful, the technology will have a wider application in PDO, and it is expected to improve the recovery factor by another 10 per cent.

Junaid: Talking of investments and returns, we have to understand how we grow our business. We have a natural resource (oil and gas) base, sitting below the ground. And we are adding to that resource base through active exploration. The last few years have been very healthy for us in terms of exploration. These new discoveries fall more in the scope of our conventional recovery mechanisms to start with. Meanwhile, we have billions and billions of barrels of existing resources. We must continue to increase our recovery factor; there is no doubt about this. The discussion is always how do we prioritise? How do we make it efficient? Have we found better ways to increase our recovery factors cost effectively? The mandate is to deliver quicker and at a much lower cost.

Moving towards Qarn Alam, it is a unique and world-class steam injection project despite high complexities. What have been its salient features and how is it doing currently?

Nasser: Qarn Alam, with its fractured carbonate rock containing heavy oil, is ideal for the EOR steam injection technique. We did a pilot project during 2002-2005 and the field development started producing oil by 2012. We are using the thermally assisted gas-oil gravity drainage (TAGOGD) technique, which has never previously been deployed on this scale in a reservoir featuring fractured carbonate rock. TAGOGD is ideal for highly fractured reservoir rock like that found in Qarn Alam, because the steam can be injected directly into the fractures. There, it heats the surrounding rock and lowers the viscosity of the oil by a factor of up to 100 times.

However, there is no requirement for Qarn Alam’s steam – either in its vaporous form or condensed back into water – to actually drive the oil into producing wells as it does in conventional steam flood processes. Instead, the ‘gravity drainage’ element of the technique’s name comes into play. This makes a virtue of the fractures in the rock, through which the now freer-flowing oil drains down into horizontally-drilled producer wells that are situated towards the bottom of the reservoir.

How much it is producing currently?

Nasser: About 10,000 barrels a day. The field was discovered in the 1970s and we hardly produced 5 per cent from the field using conventional methods. We expect the thermal EOR to boost the recovery to 30 per cent of the estimated oil in place in the coming years.

The Harweel (2AB) project where you have implemented miscible gas injection won an Award at ADIPEC 2015. Tell us more about it and what makes the project an important element in PDO’s EOR plans?

Nasser: The term ‘miscible’ means the gas injected into the reservoir dissolves completely into the oil, creating a less viscous fluid which therefore flows more easily and more preferentially through the reservoir to the surface. However, miscible gas will only dissolve in oil typically under very high pressure: around 500 times that of our atmosphere is the norm at Harweel (2AB), where we are running our first full-scale miscible gas injection project.

Generating sufficient pressure is one of the biggest – and most costly – challenges faced when deploying the technique. There’s a huge additional challenge at Harweel, in that the hydrocarbons in the reservoir are ‘sour’ – which means they contain significant levels of dangerous hydrogen sulphide gas. As a result, the surface facilities must be built to the highest possible levels of integrity, as well as featuring multiple safety mechanisms, in order to minimise the risks of leaks that would harm the workforce and the neighbouring environment. The implementation of such measures necessitates a complex balance between achieving HSE (health, safety and environment) goals and meeting cost targets.

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