RESEARCHERS TO STUDY FRACTURED RESERVOIRS
HOUGHTON--Researchers at Michigan Tech have received a $700,000 contract from the Department of Energy to devise improved recovery methods for fractured oil and gas reservoirs in the Michigan Basin. The project will span three years and will involve a university-industry consortium whose aim is to develop a comprehensive model for fractured carbonate reservoirs based on the "data cube" concept.
"The 'data cube' is a 3D representation of data in spatial coordinates, such as latitude, longitude, and depth," explained Project Manager Dr. James Wood of MTU's Department of Geological Engineering and Sciences. "One way to look at this is that it is a 'cube' of numbers that represents surfaces in an oil field, such as the top of the Dundee Formation. You can think of it as a kind of Rubik's Cube, where each small cube is a number that represents some property of the subsurface, such as porosity or lithology."
Wood said the Michigan Tech research team will combine traditional historical data with data from modern methods in a novel way to produce a new methodology for characterizing fractured reservoirs. He said advanced visualization software will be used to fuse the data and to image it on a variety of scales, ranging from basin scale to well scales.
"Several new data logging tools will be used in this study," said Wood. "Formation scanner logs will be used to delineate and quantify the fracture systems, and hydrocarbon logs, which measure hydrocarbon content from fluid inclusions, well cuttings and core samples, will be used to identify and map diagenetic 'halos'." He said traditional geologic and engineering data will also be used to define and interpret the reservoirs.
A diagenetic halo is that area around a fracture where the original rock has been altered as a result of the fracture. "The common reaction in our Michigan fields is to replace original calcite with dolomite," said Wood.
The goal of Wood and his colleagues, which include Dr. William Harrison of the Geology Department at Western Michigan University, geoscientists from Western Atlas and Marathon Oil companies and consultant Eric Taylor of Traverse City, is to determine if fractures are present in a reservoir, then verify their orientation, density, whether they transmit or retard fluid flow, and most importantly, their scale.
"We need to know whether fractures are restricted to the local environment, or whether they are regional or basin wide," said Wood. "Once that is known, then recovery methods can be devised or implemented to take advantage of the fractures--for example, drilling a horizontal well so as to intersect the largest (or smallest) number of fractures."
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For more information, contact Jim Wood at 906-487-2894 or email: jrw@mtu.edu.
02/10/99-MTN021