EXPLORATION/DRILLING/FIELD SERVICES 15
Better mapping and knowledge of minerals key to oil extraction
Scientists in the US and Denmark have made breakthroughs which will improve our ability to extract oil. The first involves more accurate mapping of reservoirs, while the second throws a light on how oil clings to its containing rocks. Sean Ottewell reports.
Científicos de EE.UU. y Dinamarca han logrado unos avances científicos que mejorarán nuestra capacidad para extraer petróleo. El primero consiste en una cartografía más precisa de los yacimientos y el segundo revela cómo se agarra el crudo a las rocas que lo contienen. Sean Ottewell informa.
Wissenschaftler in den USA und Dänemark haben mehrere Durchbrüche erzielt, die unsere Ölgewinnungschancen steigern. Beim ersten handelt es sich um eine exaktere Herstellung von Karten über Ölvorkommen und das zweite Verfahren gibt darüber Aufschluss, wie das Öl im jeweiligen Gestein lagert. Ein Bericht von Sean Ottewell.
funding from Shell International Petroleum, have developed technology that can generate an accurate underground map that has the potential to significantly increase the amount of oil extracted from reservoirs. The new technology uses the digital image compression technique of JPEG to create realistic-looking, comprehensive maps of underground oil reservoirs using measurements from scattered oil wells. These maps would be the first to provide enough detail about an oil reservoir to guide oil recovery in the field in real time. “Our simulation studies indicate that this innovative approach has the potential to improve current reservoir characterisation techniques and to provide better predictions of oil-reservoir production. The hope is that better predictions ultimately lead to more efficient operations and increased oil production,” said Behnam Jafarpour, a recent MIT graduate who is now an assistant professor in petroleum engineering at Texas A&M University.
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Jafarpour and Dennis McLaughlin, the HM King Bhumibol Professor of Water Resource Management at MIT, published a pair of papers describing the technique that will appear in an upcoming issue of the Society of Petroleum Engineering Journal, as well as a third paper that appeared in the June 2008 issue of Computational Geosciences. The spatial structure in geologic formations makes it possible to compress rock property
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esearchers at the Massachusetts Institute of Technology (MIT) Department of Civil and Environmental Engineering, with
Fig. 1. The image at left shows the oil saturation map in a benchmark reservoir model with known properties (referred to as the true model). The image at right shows a nearly identical reconstruction of that same reservoir map using the McLaughlin/ Jafarpour solution approach, which took isolated data from 23 wells and simulated a 36-month recovery effort. Black dots represent the wells, remaining oil is indicated in red, and blue shows the water that remains underground following water pumping.
maps. But JPEG compresses the many pixels in a detailed image down to a few essential pieces of information that require only a small amount of storage. In the oil reservoir characterisation application developed by MIT researchers, a similar mechanism is used to provide concise descriptions of reservoir rock properties. The new technique uses oil flow rates and pressure data from oilfield wells to create a realistic image of the subsurface reservoir. Petroleum extraction is expensive and
relatively inefficient – sometimes as little as one-third of the oil in a reservoir is actually recovered through pumping. So engineers rely on enhanced recovery techniques such as water flooding to mobilise the oil. To guide this work, they make real-time predictions of subsurface variables, including oil saturation and pressure, but they’re essentially working blindly. The rock properties needed to make these
predictions (for instance fluid conductivity of rock at a particular depth) can’t be seen or
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