69- www. energy- future. com Profile - Todd Wise Name: Todd Wise Company: Chevron Present job: Petroleum engineer Age: 25 Nationality: American Degree: Petroleum and natural gas engineering, Penn State University In college, I did three internships in the oil industry - two of them at Chevron. I liked the way the company did business; its val-ues were aligned with mine - its focus on safety, the environment, ethics and the way people are treated. Those things develop trust and a sense of partnership. I started full- time in 2007, working on heavy- oil projects, using steam floods to en-hance recovery. Heavy oil's viscous, so it doesn't flow well. Think of pancake syrup: it sticks to itself and anything it comes into contact with, but if you heat it in the micro-wave, it pours easily. Steam's the most eco-nomic and operationally reliable way of do-ing the same thing to heavy oil. I'm based in California's San Joaquin Valley, managing a heavy- oil steam- flood pi-lot venture. It's a test- bed for new technolo-gies and hypotheses - a real project, with all the appropriate wells and data surveil-lance and all the hardware and the water supply you need for a steam flood, but eve-rything's scaled down. Steam floods are typically performed in sandstone reservoirs and we're looking at ways of using them in other types of reser-voirs. Most of the world's easy oil has been produced, so finding new ways of produc-ing heavy oil and other unconventional hy-drocarbon resources is an important part of maintaining energy supply. The challenges in my present job are dif-ferent from those I faced in my first assign-ment with Chevron. I spent my first two years as a reservoir engineer; that involves understanding what's going on in the sub-surface and devising ways of optimising pro-duction - getting the most you can out of the ground. It's a strategic- thinking role; you're focused on the long term. The demands of the production side of the business are more immediate. For example, I have to coordinate multifunctional groups - welders, drillers and so on - and ensure that everything we do complies with environ-mental and safety standards. You have to think on your feet, but I relish the organisa-tional challenges the job involves. Professional variety is one of the great things Chevron has to offer. In your first five years, you complete three different - and diverse - assignments, which gives you a wide base of experience on which to build your career. My next assignment might be business planning or facilities management, either of which would be a big departure from what I'm doing now. You get a lot of help from the many expe-rienced people in the company. But lots of young people are coming into the business too, seeing things with a fresh set of eyes. I'm part of a group of young people working together on innovative ways of doing busi-ness - coming up with ideas for how we can cut our carbon footprint, for instance. Some jobs, you're in the office all day and others you're always outside. In energy, it's both. You work in an office - crunching numbers, assessing the economics, speak-ing with management. But you also have to be out where the rubber meets the road: seeing wells being drilled, cables being laid, trenches being dug and meeting the people doing that work gives you a vitally important perspective on the operation. It's a mix of strategy and practice. ??

70- www. world- petroleum. org 5.4- Technology: pushing boundaries Chevron. " And the beauty is there is no ex-ploration cost." So how's it done? Underground reservoirs of oil, gas and water are naturally under con-siderable pressure; when they're perforated with a well, their contents spurt to the surface - like a can of carbonated drink that has been shaken up and opened. This phase of production is called primary recovery and might push out 10- 15% of the oil in place. But once that natural fizz has dissi-pated, the oil needs help to reach the sur-face. Pressure can be maintained by vari-ous means. That might involve mechani-cal devices such as giant electrical pumps. Alternatively, injecting steam into the reser-voir can lower the viscosity of sticky oil, ena-bling it to flow more freely to the surface. But the most common method of enhanc-ing oil recovery involves injecting water or gas into the reservoir to flush additional oil out through the production wells ( see box). These floods - or reservoir sweeps - might bring recovery factors up to some-thing around the 35% level. But the trouble with injecting water into an oil well is that it's naturally mobile, pushing quickly through the reservoir without neces-sarily displacing much oil. At first, only some of the reinjected water will burst back out of the production wells, mixed in with whatever oil it has succeeded in driving to the surface. But the longer the flood goes on, the higher the water cut - the proportion of water in the mix; eventually the water- handling costs outweigh the financial returns of the dimin-ishing volume of oil being produced and the operator will have to admit defeat. Good chemistry Or maybe not, if the company is prepared to invest in the next stage of EOR, in which chemicals can be used to squeeze out even more oil - perhaps another 20%. Chemical EOR might involve mixing a surface- acting agent - a surfactant - In the past, natural gas was often reinjected into oil fields to enhance recovery, but that's no longer desirable because hydrocarbon gases are too valuable as energy sources in their own right. The big hope is that CO2 captured from industrial processes and power plants will be widely used to enhance oil production, becoming permanently iso-lated from the atmosphere in the process. Operators in the US have been inject-ing CO2 into oil reservoirs to boost oil recov-ery for decades - experience there sug-gests CO2 injection can boost recovery rates by 5- 15%. In the US, natural sources of CO2 have generally been used for EOR. But man-made CO2 is widely available and the need to deal with it to mitigate the effects of climate change should provide oil companies with a steady supply of the gas in the future. In fact, the supply of manmade CO2 that the world will have to prevent from reaching the atmosphere in order to keep global tem-peratures at acceptable levels is far greater than could be used for EOR purposes. Nonetheless, it's in the industry's obvious economic interest to use as much CO2 as possible for EOR because, at the same time CO2 is being stored, a valuable commodity is being produced. CO2 EOR can be made more effective with the use of chemicals by, for example, mixing a surfactant into the gas that pro-duces a foam when it comes into contact with water. The idea is that the foam is gen-erated when the CO2 comes into contact with an area that has already been swept with a water flood. The foam blocks the path of the CO2, diverting it into oil- bearing ar-eas of the reservoir that haven't yet been flushed out with water. Given growing determination around the world to deal with climate change and other environmental issues, expertise in this kind of technology will be at a premium." ?? CO2 injection: two birds with one stone