A look at how Petroleum Development Oman is contributing to environment preservation
For large corporate incumbents in the oil and gas industry such as Petroleum Development Oman (PDO), making a positive contribution to the environment does not always come naturally. "A major change in the company's DNA is required not to mention a commitment by management and shareholders alike to put the planet before financial performance," explains PDO's Head of Environment Khalifa al Harthy. "But changing its corporate DNA is precisely what PDO has done."
One of the results of this change has been a radical re-think of the way it consumes energy and how it can mitigate the effect of its operations. PDO has been producing oil and gas for over 40 years and operates over 120 oilfields throughout Oman. In order to maintain oil production and secure Oman's income for future generations - PDO consumes a massive amount of electric power. To put this into perspective, PDO's operations use as much electricity as the whole of greater Muscat (population one million). Much of this power is used to pump water into oilfields to maintain reservoir pressure and will soon be used in enhanced oil recovery projects using schemes to inject steam into oilfield.
Cogeneration
To meet its rapidly growing power requirements, PDO planned to construct several new power stations. As a direct result of its new planet-friendly mindset, PDO scrapped plans to site plants where the power was required. Instead, at a considerable extra cost, it chose to locate the plants at oilfields where waste heat could be used to generate steam for oilfield injection. From these power stations, PDO will generate steam using exhaust heat that previously would have been wasted by direct venting to the atmosphere. The temperature of these exhaust gases is over 500 degrees C and can be used to make steam - a process referred to as cogeneration. This cogeneration takes place in a "Heat Recovery Steam Generation" unit that is built adjacent to the power station. By utilising the power station waste heat cogeneration, the energy for the steam is provided without additional firing of fuel and there are no additional emissions that go on to contribute to green house effect.
Three power plants linked to cogeneration units currently under construction will save nearly one million tonnes of CO2/yr compared to the traditional direct-firing approaches. A further network of linked thermal EOR projects and power stations will be constructed over the coming years. These projects will help PDO realise a total emissions savings of over four million tonnes of CO2/yr within five years. Further power station and EOR expansions will yield savings totalling well over six million tonnes CO2/yr within the decade. This re-think has not come cheaply. The heat recovery units typically add about 30 per cent to the cost of the power stations. As well, the power must be transported to the demand centres via an overhead power line network that has required expansion and reinforcement. PDO has shown it is committed to finding environmentally-friendly solutions to its strategic investments. It has realised that in addition to protecting the planet, there is an eventual payback in terms of the reduced fuel requirement. PDO recognises that what makes good environmental sense also makes good business sense.
Greening the desert
In the barren desert of Nimr in South Oman, dust and sand will soon give way to a green oasis. Taking its cue from the ancient Egyptians who used natural reed beds to clean up dirty water, PDO is using the age-old principle to remove oil from water produced alongside oil productionSuch water is currently re-injected into deep reservoirs where it can be safely stored without affecting groundwater, a process known as deep water disposal. After a successful eight-year experiment, the Nimr reed bed project is set to treat 45,000 cubic metres per day of water from local oilfields. PDO will create a giant farm with 240 hectares (2.4 million square metres) of reed beds which will become operational in early 2011. "Our trials demonstrated that reed beds are a technically viable alternative to deep water disposal," explains Khalifa al Harthy "Reed beds reduce energy consumption due to the elimination of the need to pump the water underground and will therefore lead to a reduction in PDO's carbon generation as well as introducing a carbon sink by the reed uptake of CO2"
Using solar power to generate steam
South Oman is the site of another technological step forward aimed at limiting the carbon footprint of PDO's operations. At Thayfut, PDO is embarking on its first solar energy project. Approval was recently obtained for a pilot project known as "Thayfut solar steam generation pilot". If successful, the project could lead to step change in way PDO generates energy for its thermal enhanced oil recovery (EOR) projects. "This is an important strategic project in which we will test a promising new technology," says Head of New Technology Implementation, Shaikhan Khaduri. "This is the first time parabolic trough technology has been used to generate steam directly." Under the project, PDO will install parabolic troughs which will be used to generate steam for injection into underground reservoirs. Parabolic troughs work by concentrating the sun's rays onto receiver tubes carrying water which under the intense heat then turns into steam. The Thayfut location was chosen for the trials because the field is subject to a planned steam injection project which will include the building of a reverse osmosis water treatment plant. This will provide water for the solar project and allow the steam to be injected into a parallel project. PDO's corporate technology teams believe that the pilot system to be installed could produce as much as 100 tonnes of steam a day based on ten hours of sunshine. The Thayfut steam pilot is planning to generate 200 tonnes of steam using conventional gas-fired turbines. The objective of the pilot project is to understand the operability and the maintainability of the technology, Shaikhan Khaduri explains. The technology has been used in Spain and the United States but has never been tested in the tough conditions of the Omani desert. The other aim of the project is to demonstrate whether it can be seamlessly integrated into an existing steam injection project. If successful, solar-generated steam could be injected during the day and conventional steam at night. Longer term potentialities of the technology is to use the steam to generate electricity or to heat water before it goes to boilers in conventional gas-fired steam power plants.
Changing mindsets
PDO knows that its ability to continue improving its environmental performance depends on changing the mindsets of its own staff. In order to promote environmental and sustainable development (SD) awareness within PDO, the company regularly holds mini-workshops. The purpose of the workshops was to help project planners to incorporate SD principles into new projects. Leaving oilfields in a pristine condition once operations end is another ongoing area of focus for the company. PDO has an ambitious ongoing well-abandonment campaign aimed at returning oilfields to their original state.
Last years, 74 wells were closed down in a safe and environmentally friendly manner. In addition, a further 17 oil production sites in the Musallim area were subject to a full restoration programme, including the removal of contaminated soil. In recent years, PDO has continued to implement an aggressive flare-reduction programme. In 2008, 1.71 million cubic metres of gas per day were flared - 10 per cent less than in 2007. In addition, Global Warming Potential was well below target on account of the company's more efficient generation of its electric power. The company's actual atmospheric emissions were only 6.13 million tonnes of CO2 equivalent, against a target of 7.07 million tonnes CO2 equivalent.
© Oman Economic Review 2009
