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The challenges and opportunities for Enhanced Oil Recovery (EOR)

24/03/2011

Stuart Walley, Region Manager, Middle East & India explores the challenges and opportunities for Enhanced Oil Recovery (EOR), and explains the increasingly  important role EOR is playing in meeting the world’s growing demands for energy.

 

With the oil price gains achieved since the lows of the financial crisis in mid 2009, many economies in the Middle East and India have seen a dramatic boost in hydrocarbon-related revenues. As the Middle East is a relatively mature exploration province, there is renewed focus on improving recovery from many of the large and well established fields. With an abundance of conventional reservoirs, the region is not normally regarded as an area known for Enhanced Oil Recovery (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 US$100 barrel makes the economics progressively more attractive.


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). At the end of 2009 the global market for EOR was estimated as $62.5 billion (for barrels of crude oil), having grown rapidly from $3.1 billion in 2005. 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.


Extracting heavy oil from many of the Middle East reservoirs is fraught with unique challenges. Unlike the heavy oil sands of California or Canada, heavy oil resources in the Middle East are generally contained in carbonate reservoirs which are highly heterogeneous, presenting additional challenges when designing and implementing EOR methods. Many carbonate formations are fractured, greatly complicating flow in the reservoirs. Adopting heavy oil production strategies in carbonates often requires a good understanding of the fracture network, which itself is a major technical challenge. The fracture network can sometimes enhance the efficiency of steam injection by aiding the heating of the oil; it can also detract from the EOR process by allowing steam to bypass much of the oil. A further complication is that the fracture network can change as a result of production, such as the closing of fractures. Geomechanical studies can offer a key insight to predicting some of these changes, enabling mitigation strategies to be implemented.


An interesting development is in the use of solar power to drive Enhanced Oil Recovery. The world’s first solar EOR project recently came on stream in California, using solar-generated steam as an alternative to steam injection derived from natural gas. Solar EOR may be a real alternative to conventional thermal EOR in regions with abundant sunshine as the economics start to become viable with higher oil prices.


Senergy expertise
Senergy has become increasingly active in EOR within the region and is currently working on three EOR studies, in addition to providing advisory support to a number of other companies who are undertaking EOR pilot studies utilising gas injection, chemical injection and thermal recovery techniques.


We believe that National and International Oil Companies utilise our broad EOR expertise in Reservoir Engineering, Production Technology, Geomechanics, Well Engineering and Economics because:

  • Senergy promotes an integrated approach to implementing robust EOR screening processes. This helps determine which EOR method is most likely to deliver the best results for improving the production and ultimate recovery.
  • Senergy provides clients with objective independent recommendations on the best technology to use on a case by case basis. Since Senergy does not sell services used at the well site, the client knows that our advice is unbiased and impartial.

The development of new recovery technologies, along with the increasing scarcity of conventional hydrocarbon resources, is creating a rapidly growing market for efficient EOR methods, particularly related to heavy oil. Senergy sees this as a great opportunity for the industry as a whole and is investing in developing the expertise that will enable us to support our clients in meeting the EOR challenges which lie ahead.


Snapshot of EOR projects in Middle East & India
Oman in particular has seen considerable investment in a range of EOR technologies to produce heavy oil and now a host of other countries in the Middle East and India have been encouraged by Oman’s success. Between 2001 and 2007 Oman’s oil production fell by 27%, but by 2009, due mostly to EOR projects, oil production had increased by 17%.  


In total, four major projects are planned to start by 2012, with at least another two expected soon after.  Implementation of EOR technologies have contributed to the reversal of Oman’s production decline. Occidental, operator of the Mukhaizna field in south-central Oman, implemented a major steam flood project that utilises a modified Steam Assisted Gravity Drainage (SAGD) approach with vertical steam injectors around horizontal producers. Between mid 2005 until early 2010, gross daily production increased by more than 10 times with total production recently exceeding 100,000 bopd for the first time. Similarly, Petroleum Development Oman (PDO) is implementing a number of EOR projects in the Marmul field - in the South of Oman (polymer flood to revitalise a mature field); in the Harweel field (injecting miscible sour gas to enhance recovery from some of the oldest carbonate reservoirs in the world; and in Qarn Alam (the world’s first commercial application of steam-assisted gas-oil gravity drainage in a fractured carbonate reservoir). By 2012, Oman is expected to be producing between 250,000 and 300,000 bopd using EOR methods.


In Kuwait the Kuwait Oil Company (KOC) and its Research & Technology Group are focused on developing its extensive heavy oil resources in sandstones at Ratqa, in the north of the country. KOC will soon begin its first pilot steam soak wells, and plans to inject into its first nine spot patterns by 2012. KOC plans to be producing heavy oil at 50,000 bopd by 2015 and more than 250,000 bopd by 2030.


In the UAE, the Abu Dhabi Company for Onshore Oil Operations (ADCO) initiated an EOR project in November 2009 to test the injection of CO2 into the North-East Bab Field, a complex carbonate reservoir.  Masdar, a subsidiary of Mubadala is supplying up to 60 tonnes of CO2 per day which is injected into a series of pilot wells. ADCO’s main objectives for utilising CO2 EOR are to significantly increase reserves, sustain long term production, and maximise ultimate recovery. The UAE is a signatory to the Kyoto Protocol and is therefore committed to reducing greenhouse gas emissions. Masdar has earmarked a series of Carbon Capture projects from Abu Dhabi power plants and is building the surface infrastructure required to supply more fields with CO2 for EOR.


Egypt has large resources of heavy oil. Issaran is one of the first heavy oil carbonate fields in which steam EOR has been successfully implemented. Its fractured reservoirs contain oil with 10-12 API gravity. Although they have good porosity and are highly saturated with heavy oil, the producing zones contain impermeable stringers that create breaks in vertical permeability. Favorable results have been obtained with Cyclic Steam Soaking (CSS) where sufficient fracturing exists to distribute the steam. To further optimise production, wells have been acid-fractured, some with proppant to keep the fractures open.


Sudan has many fields containing heavy oil; those with lighter oils, which have to date been developed using cold production, are now in decline. Numerous resources of more viscous oil are still awaiting development. It is expected that heavy oil will represent about 50% of the country’s production by 2020. An operator in the country is performing reservoir studies and investigating techniques - including SAGD and in-situ combustion - focused on resources in excess of 1 billion barrels. A pilot project is currently being designed, scheduled to start operation in 2011. A Chinese-led group tested a steam-assisted recovery project in 2009, but with limited success, due partly to the failure of elastomers in progressive cavity pumps. The Sudanese Oil Exploration and Production Authority (OEPA) is currently actively encouraging more operators to consider EOR projects in the country.


Syria has considerable resources of heavy oil. Technical information required by Syrian Petroleum Company for companies who want to qualify for its recent onshore bid round includes full details of their experience in a broad range of EOR techniques.


In Bahrain Occidental has partnered with Bapco and Mubadala to form Tatweer, who are currently conducting pilot studies on the heavy oil reservoirs in the Awali field. The reservoirs have low permeability (2mD) unfractured carbonates with large volumes of heavy oil, and a trial of steam injection above the fracture gradient is being considered for 2011/2012.


In Saudi Arabia, Aramco is currently evaluating the use of CO2 injection and plans a series of pilot programs in mature fields like Ghawar by 2012. Although full-scale EOR implementation is still 20 to 30 years away, the feasibility studies form part of Aramco’s carbon management road map, in which they wish to be engaged in developing EOR technology for global carbon management. However, Aramco believe that careful reservoir management, new drilling technology and state of the art information-gathering can significantly extend conventional production plateau of many of its fields.


In-situ combustion has been used in Indian heavy oil fields for many years, particularly on the onshore assets operated by ONGC. In Ahmedabad, ONGC have carried out polymer flooding pilot studies on the Khalol field with some success and are conducting pilot studies in Ankleshwar using miscible gas flooding and CO2 injection. As production from many onshore fields is in decline, companies are now looking to implement EOR technologies to boost and maximise domestic production. For instance, Cairn India is finalising polymer flood pilot on the Mangala field and with encouraging results is now considering a field wide application of the technique.